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Multi-Hazard Mitigation Plan: 10. Floods
CIVIL DEFENSE AGENCY COUNTY OF HAWAII 920 ULULANI STREET HILO,HAWAII 96720 r f 10. Floods Chapter 10:Hazard Analysis—Floods CHAPTER 10 - FLOODS 10.1 Description of Hazard Floods are temporary inundation of land from excessive rainfall or wave action. Because flooding causes millions of dollars of damage each year, the federal government created the National Flood Insurance Program (NFIP) to assist those who suffer from flood disasters. Under the NFIP, each county has mapped flood hazard areas and established a permit system to regulate development within these flood hazard areas. The Flood Insurance Rate Maps (FIRMs) include areas prone to rainfall flooding(A zones) and high waves (V zones). In this County, the permit system is set forth in Hawaii County Code Chapter 27. The NFTP man- dates federal insured banks to require purchasing of flood insurance as a condition for financ- ing the construction of buildings in flood plain areas, thereby shifting the primary burden for flood disaster relief to those who choose to live or conduct business in flood hazard areas.48 Although the NFIP has significantly mitigated flood damages, major flood problems exist in older areas developed prior to flood control regulations and building standards, in areas that are subject to flooding but not identified on the FIRMs, and areas with flood control improvements that are inadequate to contain or control larger floods by present standards. Direct economic losses from flooding result from soaking, dislocation and destruction of property as well as erosion and scouring from the velocity of the flow, and deposition of sediment and debris transported by the water. Dams can exacerbate flooding should they fail; hence, a dam safety program is also an integral part of flood control. In the past, flood control meant engineered structural solutions such as dams, levees, stream channelization, diversion channels, and other costly improvements. In spite of these improvements, flood damage continued to escalate. A broader approach to flood management that attempts to work with nature instead of trying to control the awesome forces of nature has evolved. The federal government's flood management program embraces these non-structural measures by encouraging regulatory measures that direct development away from flood prone areas (e.g., zoning and subdivision codes), requiring flood-proofing building standards where structures are located in flood prone areas (e.g., flood control and building codes), allowing federal disaster assistance funds to be used to buyout and restrict future development in flood-prone areas where such acquisition is more cost-effective than heightened structural flood control improvements, and allowing upgrades to damaged structural flood control improvements (e.g., bridges) to resize inadequate structures rather than strict"in kind"replacements. 10.1.1 Rainfall Flooding Four types of storms produce heavy rainfall: e Frontal storms. Frontal storms usually occur during the period from December through 48 For an overview of the National Flood Insurance Program in Hawaii,see State of Hawaii Department of Land and Natural Resources,National Flood Insurance Program in Hawaii,Circular C90, 1994. 10-1 Hawaii County Multi-Hazard Mitigation Plan Chapter 10:Hazard Analysis—Floods March. They originate over the Pacific Ocean as a result of the intersection between polar and tropical Pacific air masses and move eastward over the islands. These storms reflect orographic influences and are accompanied by widespread precipitation(see Figure 10-1). Subtropical Cyclonic Storm Mid-latitude Cyclonic Storm 1075 L lots f\ 707o L roz5 99',0 1020 107 995 .'.5 1011.5 1015 X7005 H rOO5 1010 1000 ` H 1075 KONA STORM Hawafi� c 7011.5 1011.5 Heweri 7015 1010 7070 COLD FRONT 1071.5 780° 150` _ 170' `�•1�' 180° 150' 120' Kona storms are low-pressure areas(cyclones)of subrrop- between CMtober and April,mark the leading edges of ical origin that usually develop northwest of Hawaii in cold air masses associated with low-pressure systems winter and move slowly eastward,accompanied by south- moving north of the Islands in the prevailing westerlies. erly winds,from whose direction the storm derives its They bring widespread clouds,heavy rain,and occasional name,and by the clouds and rain that have made these thunderstorms.Vigorous fronts may be preceded by strong storms synonymous with bad weather in Hawaii.Kona southwest winds and followed by gusty northerly winds. storms vary in number from year to year.Some winters Kauai experiences as many as 20 cold fronts per year,but have had none,others five or more.Cold fronts,common generally only about half of them reach Hawaii Island. Figure 10-1. Kona Storms and Cold Fronts • Upper troughs. Upper troughs are low pressure storms over wide areas that cause heavy rain and strong winds. • Convective-type storms. Convective-type thunderstorms can occur at any time of the year. They are most common during periods of relatively high humidity and unstable air conditions. These storms cover comparatively small areas and result in high-intensity rainfall of short duration. • Hurricanes or tropical storms. Hurricanes and tropical storms cause heavy rains, strong winds, and high surf. Heavy rainfall creates three types of flooding: 1) channel overflow, 2) overland sheet flow, and 3)ponding of standing water in poorly drained low-lying areas. Channel overflow occurs when the carrying capacity of the channel is exceeded,which can be exacerbated by develop- ment changes within the drainage basin or clogging by debris or overgrown streambed vegetation. Overland sheet flow occurs primarily in areas with undefined drainage ways, such as Puna and the leeward side of the island (e.g., Kona, Waikoloa, and Kawaihae). Poorly drained low-lying areas are a problem when flooding occurs even when rainfall is not heavy. Intense rainfall may trigger "flash-floods"which provide little warning (less than six hours)before the affected area experiences flood conditions. Prolonged rainfall may result in an accumulation of water creating flooding conditions that last several days, or even weeks. Factors influencing flooding conditions include rainfall intensity and duration, topography, soil type, antecedent soil moisture, and ground cover. 10-2 Hawaii County Multi-Hazard Mitigation Plan Chapter 10:Hazard Analysis—Floods Flash floods are characterized by rapid rise in water level,high velocity, large amounts of de- bris, and concentration in stream beds that are often normally small or even dry. The major factors are the intensity and duration of rainfall, rain shed area, and steepness of the streambed. They can also be caused by a dam break. Flash floods typically carry large amounts of debris which increase the damage they do, and are very capable of undermining bridges and carrying away vehicles. There is a major public safety hazard from these events, as the National Weather Service (NWS) estimates that over 50% of the flash flood deaths in Hawaii involve vehicles. The records provided by Mr. Tom Heffner of NWS show that since 1959, when their records began, 30 deaths from flashfloods have occurred. They do not have the data by county, but assuming that this County had one fourth of the deaths, that averages one every six years. 10.1.2 Dams A dam is a barrier constructed across a watercourse for the purpose of detention (control), storage, or diversion of water. Detention dams retard and minimize the effects of flood runoff by storing the flood flow and releasing it at a rate that does not exceed the carrying capacity of the downstream channel. Storage dams impound water during periods of surplus supply for use during drought periods. Diversion dams provide hydraulic head for diverting water into ditches, canals, or other means of conveyance. These various types of dams are constructed for one or a combination of the following reasons: flood control;water source for domestic or irrigation use; recreation; and/or hydroelectric energy production. The volume of water impounded is measured in acre-feet referring to the number of acres of land that would be covered to a depth of one foot. A list of all dams on Hawaii County is provided below and mapped in Figure 10-2: 1. HA00026 Lalakea Reservoir 2. HA00051 Hawi No. 5 Reservoir 3. HA00027 E-13 Reservoir 4. HA00052 Kehena Reservoir 5. HA00040 Waikoloa 50 MG Reservoir 6. HAO0122 Waikoloa 50 MG Reservoir 2 7. HA00042 Puukapu Reservoir S. HA00123 Pint Pulehu Reset voir 9. HA00043 Puukapu Watershed Retarding Dam R-1 10. HA00131 Paauilo Reservoir 11. HA00049 Keaiwa Reservoir 12. HA00136 Waikoloa 50 MG Reservoir 3 13. HA00050 Hawi No. 3 Reservoir 10-3 Hawaii County Multi-Hazard Mitigation Plan Chapter 10:Hazard Analysis—Floods HAW I NO.5 RESERVOIR AIAWI 40.3 RESERVOIR M .. KEMENARESERVOIR n I "KEA RESERVOIR E13 RESERV WAIMER O R I RESERVOIR PUUKAPU RESERVOIR W4iKOLOA SD MG RESERVOIR pMAI�C'SO MG RESERVOIR 3 WAIKOLOA 50 MG RESERVOIR I Qp IN dol Dam Locations Legend ■ Dams KEAIWA Major Road O 3.757.5 15 2U 30 ®MIMB Figure 10-2.Map of dams on Hawaii Island See Chapter 1 1 for dam break inundation hazards. 10.2 Significant Historical Events The Historical Stream Flooding Map shown in Figure 10-3 provides a list of flooding events on the Big Island,by location and dates, since 1890. 10-4 Hawaii County Multi-Hazard Mitigation Plan Chapter 10:Hazard Analysis—Floods HumRYi Da r !IM 41x9 eTYI MOSS Oulm .l Wrcra .w* 'a ■ ■a a i i 6[@ 6yrd sl,M l�io6s•Nrrrdrn i5F6 LW9i 9latt Mows 566 Jv 16-11 uYY•POO�p\'Nnl Wn IbB2 JYq r ID G%,a'leM lbrtllq 18LY JYSFFIO T'a J0.'n 1°R rb6drq!NFroirn Stream flooding 41pWYd�ew� F ��� Pa1M ut�e FY ItAerp ices xel n aM+rotlre ,aY 1y-8-9y1F1.n lbedry 5g{r,1Rr'.h FiM boEn3 in 0.e6 Ftaani 1998 rQra FleNlboarq "tau" i"Wv tltivtllrlA cm fe,a-,a BwxelLd6y BR4 brd Fbotlnp 14btlYBl pt iteeN¢1Fi11B �[CdWP am fa"+-a Fcodryy IM M, FbeRloo�.alp ltln ,a JW-rFlo nL.h roust§ ]I iw;:-1 FLyd.y 1981[,�I P-0 Fk°len lbe'FaW6�rIC'nlr• .4!d JR°5 i non lioy�rr rl•M 1n�1rR n � .1' IBR4[ia'Fbr6tp.IF-16'rsn ,9ro - 4•6 Meatp K ,4ri 0.e t6 FtnrYy Inc iBdA M i�r96 1po FrR'mn ,OhO liFrfiffi Ep.[unM NWrq 14q R-Ie I'MN14xdry 19p9 FboWq\47ft 196,IX1aJ�Q8 s1 taR Maar9 190 PK as-A 1°o�.g I9W pag4P?I W[r p9n tggat ,9aE.J 9,]E�Jxrs�.mmaraa.9 11Raa F�l.lae,tru lensy K'*R'v1°° - 5G— _. 9F0 dc19-za Fnae,9 ,9EO A e8 F l3u mm.5eaa9 11e�fvR fm}p\WRWn,66owr 4 1 1681 lag6-T F„rd.ry 1949 JyrB FYa6r9 Fax Ra t1.�11twanR NaLwR 2tii . --� IM f°r•1-t2 FWtlg Rna doe lop FW,29 FboDry 11aF fvaFaa+IrrRm 106"M. ,i1 FFbIl 119x1 F.q s,ryn.maq ��v, ,96T Ore.i.ra FNS1Yep 119'6]]qq ti8 fSrM1rma '� - ,099 1968 1 R•8.0 NF[rtr, HF gerly J" 'e w]YlalJea a aaa aeaa•w} '1Pa,�wr]WgrnnWlltiar ,066 Fa&d.-1 won' VYlau„teo� i96P Val 1'c.yY.a _ Hilo fRg1P oea.els..o�sol°.nlbnere Kagtoq � Nlla n,11YCl.nadw.m�- 1980 u11{iE FWt4rp Rw!�A fwrw ltxi 189"8ap'1 TMo= I N Hvin[ _ - usr rwy Z-,1 1rw#ud.r r.n 19 Nee]0 nTa u_b W 1 n tFrT Fryrn rm�p46 rNM 1068.J 814ETS Oxo P1a8N - urn h.n le-v rt�en.g allp.w.., 11918 par ld�Inlwo 6 Fn911MI n1. 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'1940:s&4wle+eem+n Md IbeAtpptlp { `� 'i1R YrrS�l�r�ootlrq IM ran 19M I,L1M 1n11a+tls9EO.n Fam ' � •�i41s1r YsimM r.N.�R ''6[A MEfi�,M1:W&:1Cerrw,i f :L F4nnlNOtlrg yR'oh n.ury 1&F SOp 9F GW1:wk V Wet. 1+P�+nr rFra.w.p 10W dol a-0 F�5ro6, CwtblkYwn u bmmq ra-nin 1&•T Oc11c 5Tfentl r0.pupglpvy taF.a Sp ad'Y IYa� 194'+CC18e Y1{me � axe'ti'aFW imh 19ra..i 1 r,ucal ltw Rrony v waakerta � Fa+4 9..x+few ro.rl.°.o-1p'w.� r7 xmml 1960 X16 uVM lbaah4KRma R 1m.0 h1xn M1mary lo-�an re,u 1971 N,.5 vaeew<Wx„eaHWW�n.,.c r,lma __ �P°I1�q,rti1F'vv � ME4.zuM1lbearq Wneuvll oL J..R.-n erati,n,rr.y ml[N 19M sw MCWI C .n uyM1af•n 9 24Lr. 1 986 Sep 19 Fi•eh'+,otln9CW1 Coot b4rYkpwa sbro RW,a�.a•1vwa,g yr nn 1966 tyr 18 x1 aq}+I,.al pox lr'a.�l 1966 F.p 1fi l.o°Replyo,Yq\IF Ka+e M\'V rw B+F la-K Ci°�a•.�n�rend L.°kC allB ICYCJ,UIIt 119p s�8-d 1fM Rr5pn9 P5 Vin r4'r Y WA" 1�i �1-rlboepr b�tan 0-2008 kb[ 1194@ Sap rr T11%mwwt In " r6s6 br FN1]ootl aG - iR4RMP28.1'ma1r.ndr bR,otlr14 •618 Yn 1816 VPo p 2040-'1000 h,Ct 1944 x°16 4MWt91oM ryaW F n9 Wk ' 'Bd0 uar 19 F,rotleV {ppp-rs000�B! 'M JO 1i T8 E1trN BR2 Mp 15a h AOL70 belt[ TA 'BR6 Xw Ifi VT°rVM1RwUe9'n 10'n011 x, 6000-10.090[xl 'BB4 lew 8 F!#4nA IV m9 rR6 111 TS Oahe 1—T T6.000-12,4p9 Jgg[ r89p Jxl 1a�2 r?man0.unr 90'1W preT 12,404 6?9e •Rae srp 1d ror.vr rRd]Xw 1f�]�°nealp a V ten tkpan dfBd9 I1' Mao ranbd Inun xkxrn{irc M1raj E11111�1 �F }1i�wy� 1elro�h Mm�k diRl:Jyrge,Sk'F��1 Bro rw lgac NraVh'a�PoRab.28d'�pan'1 Almm,tc S H W nrzgM M ft—ding{WIJ 1m.,1,annual—W firrIl—? Figure 10-3. Historical Stream Flooding Events for Hawaii Island. Sotu'ce: Fletcher,C,B.Richmond,E.Grossman,A.Gibbs,Atlas of Natural Hazards in the Hawaiian Coastal Zone,Pre- pared in cooperation with University of Hawaii,State of Hawaii Office of Planning,and National Oceanic and Atmospheric Administration,U.S.Geological Service Geologic Investigations Series I-2761,2002. FEMA DR-1398-HI November 2000 A severe flooding event occurred in November 1-2, 2000 from prolonged intense rainfall concentrated in two distinct areas, Waiakea and Kapapala (over 30 inches), with lesser rainfall in most of East Hawaii (5 to 25 inches). The resulting flood damage to homes,roads, bridges, businesses, and farms totaled in excess of $70 million, among the highest totals associated with flooding in the State's history. Four meteorological and topographic conditions simultaneously converged to cause the extreme nature of the storm: 1) the upslope topography of eastern Hawaii, 2) the location of a large upper level trough, 3) the pattern of southeasterly trade winds, and 4) the location of the remnants from tropical storm Paul. Although maximum 1-hour rainfall totals were not extreme (recurrence interval of 1 to 2 years, except for Kapapala Ranch and Hilo Airport gages at 5 to 10 years recurrence interval), the severity was in the prolonged nature of the storm with a recurrence interval for a 24-hour period equal to or in excess of 100 years at several rain gages. The recurrence interval for peak stream discharges determined from stream gage data ranged from 50 to 100 years for streams south of Wailuku River in the Waiakea area; the majority of remaining 10-5 Hawaii County Multi-Hazard Mitigation Plan Chapter 10:Hazard Analysis—Floods streams in East Hawaii had recurrence intervals between 5 and 30 years.49 Governor Cayetano declared the island of Hawaii a disaster area and President Clinton declared Hawaii County a federal disaster area, which authorized federal assistance (FEMA DR-1398-HI). More than 1,131 Big Island flood victims registered for assistance through FEMA's toll-free tele-registration number.50 FEMA DR-1743-HI December 2007 A complex storm system developed in the northwest Pacific Ocean and moved southeast toward Hawaii on December 3, 2007. As the system moved southeast, the associated cold front intensified and approached the island chain from the west. Strong southwest winds ahead of the cold front were reported across Kauai and Oahu on the fourth and fifth. Lingering atmospheric instability behind a previous frontal system combined with warm, moist conditions ahead of the cold front lead to extremely heavy rains across the state with Maui and the Big Island receiving the heaviest rains between the sixth and the eighth of December. The storm weakened and drifted northeast toward the end of the period, but a surface trough remained across the state keeping conditions unsettled until roughly December 11. Widespread property damage was reported all across the state during this weather event. The approach of the front and the strong southwest flow prompted forecasters to issue high wind warnings for parts of Kauai and Oahu. As the front moved down the island chain, additional warnings were issued. Although winds were generally strong across the state, downslope zones of northeast Kauai, central Oahu, windward Oahu, and Molokai saw the highest gusts, in the 60-70 mph range. Very strong winds were also reported at the summits of Haleakala on Maui and the summits of Mauna Kea and Mauna Loa on the Big Island of approximately 70-80 mph. Maui and the Big Island experienced the heaviest rainfall during the event. Widespread flooding was common across portions of central and upcountry Maui. Flash flooding in the Waiohuli area of Maui swept a house from its foundation. Two day totals for the period ending at 8:00 am HST Thursday, December 6, 2007 were between ten and twelve inches at the Kapapala Ranch and Hawaii Volcanoes National Park Headquarters gauges. Up to two feet of water covered portions of Highway 1 1 in the Kau district of the Big Island. State wide totals for the same period ranged from one to six inches. Conditions on the summits of Mauna Kea and Mauna Loa deteriorated rapidly during the approach of the front on the fifth of December. High winds and snow showers created white- out conditions on the summits. Snow levels dropped down to around eleven thousand feet. Seven foot snow drifts and icing forced park rangers to shut down the Mauna Kea access road on the fifth. Conditions did not allow for the road to be reopened until the end of the storm period. 49 Data on the November 2000 flood cited in this paragraph are from Fontaine,R.and B.Hill,Streamflow and Erosion Response to Prolonged Intense Rainfall of November 1-2,2000,Island of Hawaii,Hawaii,U.S. Geological Survey,Water-Resources Investigations Report 02-4117,2002. 50 Hawaii Hazard Mitigation Forum website,http://www.mothemature-hawaii.com. 10-6 Hawaii County Multi-Hazard Mitigation Plan Chapter 10:Hazard Analysis—Floods Extensive property damage resulted from the event. Roofs were blown off of houses in downslope areas and downed power lines created widespread power outages. Estimates compiled from local authorities placed the damage cost for the event in the area of $3.4 million. 10.3 Probability of Occurrence The recurrence interval of a flood, or flood frequency, is the average time interval within which a flood of a given magnitude will be equaled or exceeded. Flood frequencies can be determined by plotting a graph of the size of all known floods for an area and determining how often floods of a particular size may occur, or gathering hydrologic and hydraulic data from streams and calculating probabilities through models. The FIRM maps identify a flood hazard area as the area that would be inundated by a 100-year flood, or a flood with a 1% chance of occurring annually. The 100-year flood, also referred to as the base flood, is a national standard adopted by the NFIP that represents a compromise between minor floods and the greatest flood likely to occur in a given area (see Figure 10-4). The FIRM maps delineate the 100-year flood zones for rainfall flooding, coastal flooding, shallow flooding, and distinguish areas where detailed studies have been conducted to determine base flood elevations. Special Flood Hazard Area, ti - —- --(1oo-Year Floodplain) Flood Fringe Floodway Flood Fringe Base Flood Elevation Not rnal Water Level --Sttpm Channel Special Flood Hazard Area is the area that has a 1%chance of being flooded in any given year(100-year floodplain). The 100-year flood is also referred to as the base flood. Floodway is the stream channel and that portion of the adjacent flood plain that must remain open to permit passage of the base flood with- out raising the water surface elevation by more than one foot. Flood Fringe is the area within the 100-year floodplain other than the floodway. Base Flood Elevation(BFE)is the elevation of the water surface resulting from a 100-year flood in reference to a defined datum. Figure 10-4. Flood Insurance Rate Map Terminology Data compiled over the last 50 years indicate that, on average, a damaging flood event occurs on the Big Island with a annual probability of 0.5%. 10-7 Hawaii County Multi-Hazard Mitigation Plan Chapter 10:Hazard Analysis—Floods 10.3.1 Regional Hazards Annual rainfall on the island of Hawaii ranges between 300 inches on the slopes of Mauna Kea above Hilo, to below 10 and 20 inches in the and regions around Kawaihae and South Point. As expected, flooding is rather common on the wet, windward side of the island where high annual rainfall is the norm. Most of the flooding that has caused damage has been flash flooding during extreme rainfall events that bring about sheet flow between stream channels. In addition, the soils along the Hamakua Coast readily absorb precipitation - thereby facilitating mudslides and landslides. The Hilo and Puna areas are probably the most frequently flooded and hardest hit by flash floods on the Big island and perhaps in the State.51 Perhaps more surprising is the degree of flooding experienced by the more and regions of the Big Island. The Kohala and Kona districts have a long and active history of flooding largely due to flash flooding and intense storms. More recently, the South Kohala and Waikoloa areas have experienced intense flash flooding that has caused considerable damage.'` 51 Fletcher,C,B.Richmond,E.Grossman,A.Gibbs,Atlas of Natural Hazards in the Hawaiian Coastal Zone, Prepared in cooperation with University of Hawaii,State of Hawaii Office of Planning,and National Oceanic and Atmospheric Administration,U.S.Geological Service Geologic Investigations Series 1-2761, 2002. 52 Ibid. 10-8 Hawaii County Multi-Hazard Mitigation Plan Chapter 10:Hazard Analysis—Floods z-- �4 HAWAII 3_ •5 k - _ f' f{ t 5 . ll � }I ?III N .1.11-1.2G�2,C•1-2273.01-3.7a■�51-5,06�SA1-6.59 .1�1-1.d6�2.21-2L'�3.51-SA6■6.01-fi.50 0 1A1-1.60EI 2.11-20=I]1.01-1.50 6.51-7.00 ■1-fi1 AM[]2.61-2a9 1.51-SAD 7.01-7.50 0 1-81-20002.E1-&CO S01-5.967.51-8.00 Figure 10-5. 100-year return period 1 hour rainfall for Hawaii Island No district on the island is immune from rainfall flooding hazards. In some of the districts flood hazard areas are difficult to delineate due to the lack of defined drainage ways. The fol- lowing provides a summary profile for each district:53 • Puna. The climate of the Puna District varies considerably from the rocky shoreline to the rain forest areas in the upper elevation. Rainfall amounts are generally heavy and most of the district receives over 100 inches per year. The district is subject to heavy rainfall and there is record of severe flooding. Historically, flooding along the Belt Highway and the highway from Keaau to Pahoa had been the most prominent problems of the district. However, highway improvements have done much to alleviate the flooding on the roadways. Currently, the lack of development and the extremely permeable soils have helped to minimize major flooding and damage to life and property. However, as the amount of development increases within the district, flood problems will also increase. Furthermore, the conversion of land historically planted in 53 Hawaii County General Plan,2005. 10-9 Hawaii County Multi-Hazard Mitigation Plan Chapter 10:Hazard Analysis—Floods sugar to other crops may increase runoff. In this regard, Soil and Water Conservation District conservation programs can help lessen the potential problem. Some of the flood hazard areas for the Puna district are difficult to delineate due to the lack of defined drainage ways. Recorded flood damage has mainly been caused by surface sheet flows that are likely to occur anywhere when heavy storms strike. Examples of this are found in Fern Forest, Eden Rock, Fern Acres, Orchidland, and Hawaiian Paradise Park. In addition to these subdivisions, flooding occurs in certain areas of Pahoa. Other areas, such as Hawaiian Acres, may be more defined. The flooding below Mt. View may be the result of diversion of the Mt. View watershed into some of the substandard subdivisions. Systems that incorporate diversion channels to intercept sheet flows and main channels to transport the flows away or through the area have been proposed for the communities of Kcaau and Pahoa. Along the Kcaau-Pahoa Road, the State Department of Transportation (DOT)has installed culverts to facilitate the movement of water and minimize overtopping of the road in certain sections. In addition, the DOT plans to replace those culverts that are ineffective or inadequate. Drainage systems incorporating the use of diversion channels to collect and transport surface flows safely through the area are also proposed for Mt. View. A portion of this system has been constructed. • South Hilo. The South Hilo District is divided into two watershed study areas divided by the Wailuku River. North of the river, the coastline has abrupt cliffs 30 to 80 feet high that are broken by deep stream channels. Flooding problems in this area are primarily caused by runoff from former sugar cane fields situated above the communities situated closer to the coast. South of the Wailuku River is a relatively flat plain that extends towards High- way 11 with slopes gradually increasing in southerly and westerly directions. Development in the upper section of the Waiakca Stream Watershed has been susceptible to flooding. Two recent studies by NRCS examine the problem areas of the Waiakea and Wailuku-Alenaio watersheds.54 With the Wailuku.River as a dividing line,the South Hilo district can be separated into two watershed study areas. To the north of the river, the coastline has abrupt cliffs 30 to 80 feet high that are broken by deep stream channels. Usable land areas have a ground slope of six to twelve per cent. Above the 4,000 foot elevation,the stream channels diminish in number and depth and have all but disappeared above the 7,000 foot elevation. Flooding problems in this area are primarily caused by local water runoff from former sugar cane fields situated above the communities. South of the Wailuku River is a relatively flat plain of less than one per cent slope that extends towards Highway 11. Above Highway 11, the slope steepens to approximately six to twelve per cent. Stream channels are poorly defined and disappear at elevations above 2,500 feet. 54 Natural Resources Conservation Service,The Waiakea Stream Preliminary Investigation report, November, 1999;NRCS,The Wailuku-Alenaio Watershed Reinvestigation report, December, 1999(identified a new flood diversion alternative that could provide 100-year flood protection to development on the south side of Kaumana Drive in the vicinity of Akolea Road and Chong Street). 10-10 Hawaii County Multi-Hazard Mitigation Plan Chapter 10:Hazard Analysis—Floods Waiakea Until recently, the existing drainage system was the result of uncoordinated development. Lacking a comprehensive plan, property owners have constructed and installed drainage facilities to protect their own interests. In many instances, these facilities have seriously concentrated flows and aggravated situations downstream. Many proposals of the "Hilo Drainage and Flood Control Report" have been completed in the Waiakea area reducing the flooding problems. Many culverts in upper Waiakea are inadequate. Roadside ditches, though small in cross- sectional area, are aided by the highly porous ground and are fairly effective even during heavy storms. One of the most serious problems faced by County maintenance crews is the frequent washout of cinder-gravel shoulders along road pavements. Another problem is the accumulation of vegetation growth and debris in waterways,which causes overflow. The Waiakea Stream Preliminary Investigation report prepared by Natural Resources Conservation Service in November, 1999 identified the channel constrictions at the Hoaka, Kupulau, and Kawailani bridges as a major factor in the flooding of the Waiakea Stream Watershed. Several recommendations in the report suggests an increase in the level of maintenance for the Waiakea stream channel, reconstruction of the three bridges to handle the 100-year flood, installation of a flood levee above the properties along Kupulau Road, and Stream channel improvements to manage the volume of a 100-year flood. In the lower Waiakea area, storm damage is minimal due to the effectiveness of the Wailoa and Waiakea-Uka Flood Control Projects. The Waiakea coastal area is subject to tsunami and hurricane storm surge inundation and has suffered considerable loss to life and property from tsunami activity. Kaumana-Ainako-Wailuku River Kaumana's drainage system consists of roadside ditches, culverts, and narrow channels. Except for the Ainako Avenue area, all of upper Kaumana's storm water runoff is discharged either through the Waipahoehoe or the Alenaio Streams. The Chong Street Diversion No. 3 and the Wailuku-Alenaio Diversion No. 4 along Akolea Road serves to reduce flooding in the lower areas and the Ainako Avenue sections. The Wailuku-Alenaio Watershed Reinvestigation report prepared by Natural Resources Conservation Service in December, 1999 identified a new flood diversion alternative for the watershed. The alternative will control stormwater in Waipahoehoe and Kaluiiki Streams and could provide 100-year flood protection to communities on the south side of Kaumana Drive in the vicinity of Akolea Road and Chong Street. The County has requested the Natural Resources Conservation Service's assistance to further plan and implement the new alternative. The drainage system in the Ainako-Wailuku River area is comprised of box culverts that pass the discharge of the Ainako River across Kokea, Koula, and Kapaa Streets. The residential areas bordering the Wailuku River have a system of collection ditches. Except during very intense storms,there are few problems in the area. Hilo Urban Area Between tsunamis and runoff from higher elevations, the commercial district has displayed amazing recuperative abilities. Prior to the completion of the Waiolama Canal in 1924 and 10-11 Hawaii County Multi-Hazard Mitigation Plan Chapter 10:Hazard Analysis—Floods the Ponahawai Storm Drain System in 1926, this area was a virtual "sea" during heavy rain. The construction of the canal and the storm drain system has since provided some degree of protection for the area. The Alenaio Stream Flood Control Project, completed in 1998, begins just below Kapiolani Street and ends below Kilauea Avenue with an earthen levee leading into the Waiolama Canal. The project consists of three flood walls, a 1,790-foot rectangular concrete-lined channel, a 200-foot concrete entrance transition, and an 830-foot earthen levee. The project also included the reconstruction of four bridges located at Kapiolani, Ululani,Kinoole Streets, and Kilauea Avenue. The Alenaio Flood Control project mitigated much of the flooding that occurred in the Alenaio flood plain. Except for the northern section of the business district, all of downtown Hilo falls within the Wailoa River basin and within the area tributary to the Alenaio Stream. The State Department of Transportation (DOT) has indicated that there are periodic shifts of beach material along the Hilo bay front shoreline. in addition, occasional storm events will close the roads at bay front due to storm surge. A study detailing the level of storm surge and the periodic shifts of beach material is needed before a solution can be developed. The shoreline areas south of the Wailuku River are subject to damage from tsunami and hurricane storm surge inundation. Paukaa, Papaikou, Pepeekeo, Honomu, Hakalau; these communities have no serious flood problems although Honomu and Papaikou have experienced minor flooding. These result from runoff from the areas above the communities. • North Hilo. The district is characterized by an average ground slope of approximately 10 per cent with scores of deep intermittent and perennial streams. Other than runoff from former cane lands, there is little record of flooding in urban areas. Each community is in close proximity to one or more gulches that carry flows from the upper watershed areas. The key to flood control within the district is to collect and divert surface runoff to the gulches. In addition, soil conservation practices are highly recommended. The flood hazard areas are extremely difficult to delineate. High intensity storms can produce localized flooding in almost any area. The only definite flood hazard area is Laupahoehoe School. The community of Ookala has not experienced heavy flooding although there are minor problems due to surface waters from the former cane fields above the town. There is no record of any flooding within the community of Ninole. The existing flood control system provided by the plantation is adequate. The community of Laupahoehoe has not experienced any extreme flood flows. However, there will be a need to supply flood protection for the community since Laupahoehoe School, which is located just to the south of the urban center, has experienced some flooding. Water flows from the former cane fields, when the natural vegetation does not form a complete cover. 10-12 Hawaii County Multi-Hazard Mitigation Plan Chapter 10:Hazard Analysis—Floods The community of Papaaloa has not experienced any serious flooding problems. With the projected expansion of the community, there will be a need to provide flood protection for the area. • Hamakua. The Hamakua District can be divided into two major watershed areas. The northern watershed, which affects the Waipio Valley area, extends upward into the Kohala Mountains. The second watershed extends to the peak of Mauna Kea and affects the communities of Kukuihaele,Honokaa,Paauhau,Paauilo, and Kukaiau. The majority of the flood damage in this area is felt by the State or the County through damage to improvements within former cane fields,roads, ditches, and bridges. Streams originating above and flowing through Honokaa have caused flooding in the town. The existing culverts within the town also do not have adequate capacity to handle volume flows. The communities of Paauhau and Kukaiau have not been subject to any high flood flows in the past and the only recommended flood prevention measures would be the construction of diversion channels above the communities to divert water from former sugar cane fields and into the surrounding gulches. Occasional flooding along the Hawaii Belt Road between Ahualoa and Waimea occurs when rainwater comes down from the pastures and overtops the road. Although there are no mitigation measures planned at this time, road improvements have alleviated some of the flooding and improved sheet flow. Localized drainage problems exist within the limits of Paauilo. These problems are caused by allowing surface waters to collect from large areas within the town and flow down narrow roadways. The problems could be eliminated if this water was intercepted and transported to the gulches for disposal. • North Kohala. The North Kohala district is subject to occasional heavy rainfall that creates heavy runoff. Streams collect water from the upper watershed and convey most flows safely through the urban centers. Although the gulches are generally smaller than those on the Hamakua coast, they have adequate capacity to handle storm flows. Other than damage to highway culverts, there is no record of any flood damage to structures. There are areas, however, which are subject to flooding problems. These include the town of Hawi which has experienced surface sheet flows concentrating along the highway within the town, the highway and road culverts at Lipoa Gulch, and Halelua and Pueka gulches. The community of Kapaau has problems similar to those of Hawi. The existing highway culverts are inadequate to handle peak flood flows and have caused minor flooding problems in the past. On each side of the highway, the Makapala area is relatively flat and is susceptible to flooding by the Niulii and Waikani Streams. The solution to the flood control and drainage problems of this district lies in the practice of proper soil conservation in agricultural lands and forest areas to help reduce and retard 10-13 Hawaii County Multi-Hazard Mitigation Plan Chapter 10:Hazard Analysis—Floods surface water and sediment runoff. In addition, there are the improvements to natural channels to increase their capacity. The North Kohala district has recorded runup from tsunami and hurricane storm surge activity. Areas subject to inundation include Pololu Valley, Upolu Point Airport, and the Mahukona Harbor areas. • South Kohala. The South Kohala district can be divided into two separate watershed areas. The Waimea Village watershed extends into the Kohala Mountains. Heavy rainfall occurs in these mountains and several intermittent streams flow through the Waimea area. Upon reaching the Waimea plains, these streams turn to the west and flow toward Kawaihae across the extremely permeable lava flows of Mauna Kea. The Waikoloa stream has caused flooding within the town of Waimea during high intensity storms when waters overflow due to sharp stream bends and generally inadequate flow-carrying capacities. In addition, there is some flooding concern around the area abutting the Kawaihae road. The second watershed area above the Kawaihae to Anaehoomalu shoreline extends from the coast to the peaks of Mauna Kea to Mauna Loa. The area is semi-arid with few well- defined channels and infrequent stream flows. High intensity storms have caused flooding along the Queen Kaahumanu Highway from Kawaihae to Puako, and at Puako. These storms are very infrequent and tend to create flash floods. High flows have been experienced in the Hapuna Beach and Spencer Beach Park areas due to the flash floods. The Puako Beach lots have also been subject to flooding. During the evening of September 8, 1996, heavy rains generated a flash flood along Auwaiakeakua Stream. The floodwaters overtopped the existing drainage ways causing damage to private properties, particularly the Fairway Terrace Condominium at Waikoloa Village, County roads and drainage facilities. In 1997, construction was completed on the Parker Ranch drainage improvements. The improvements diverted the Kamuela and Lanimaumau Streams toward open pasture lands. Flooding has done substantial damage to the residential subdivision at the Mauna Kea Beach Resort. To mitigate the flooding, the developer has constructed flood control measures off site and the State Department of Transportation intends to install three sets of new culverts on site. The State Department of Transportation also intends to realign and replace Waiaka Road. An added threat to the coastal areas results from fire that leaves the upper slope areas with limited ground cover and thus more susceptible to flooding. • North Kona. The North Kona district can be divided into two watershed areas. The area north of Keahole Point and the summit of Hualalai have very low rainfall and runoff. Rainfall for this area reaches a maximum average of 40 inches per year, but most of the area receives less than 20 inches per year. The soils in the area are extremely permeable and there is no record of hazardous flooding in this area. The southern area, extending southward from Keahole Point, contains most of the urban development and is subject to increasing hazards from floodwater damages as land is more intensively utilized. The area is characterized by dry vegetative growth along the coastal 10-14 Hawaii County Multi-Hazard Mitigation Plan Chapter 10:Hazard Analysis—Floods areas and thick tropical vegetation in the upper forest reserves. The ground slope is steep, averaging approximately 15 per cent. The steep slopes, shallow soils, frequent high intensity rains, and the lack of well-defined drainageways make many areas in the North Kona district susceptible to flooding and overland flows. Flash floods,primarily from overflows of the Keopu/Hienaloli, Waiaha, Kaumalumalu and the Holualoa/Horseshoe Bend drainage ways, have been identified by the Natural Resources Conservation Service's "North Kona Flood Plain Management Study." Flood water and sediment damage occurs along the entire coffee belt with the Kainaliu, Holualoa and Kailua village areas experiencing the heaviest damage. • South Kona. Being geographically young, there are few well-defined drainage ways in the district. Overland and stream flows are rare and can only be detected when the rainfall intensity exceeds the rate of infiltration. The district is subject to sudden high intensity rainstorms that can strike anywhere and cause localized flooding. Flood prone areas have been identified by the Natural Resources Conservation Service's "South Kona Flood Hazard Analyses." Coffee and other agricultural lands are subject to erosional damage and roads and culverts are sometimes damaged by high flows and sediment deposition. The Sunset Coffee Mill Flood Prevention Project has provided substantial relief in the Napoopoo area. There are also records of minor flooding from Kiilae, South Keokea, Honaunau and Wailapa Streams. In general, an area within 150 feet of the stream channels can be considered subject to flooding. Other areas with records of minor flooding include the areas along the Belt Highway in the area of the 1950 lava flows and at Hookena Road. • Ka'u. The Ka'u district can be divided into three separate regions. The northeastern region is dominated by the Ka'u desert. The average annual rainfall here is approximately 20 inches. There are few defined stream channels, none of which are perennial. The soils are very shallow, covering rough lava flows that are extremely permeable. The southwestern region that extends westerly from the South Point Road is characterized by moderate slopes, extremely permeable soils, and relatively young lava flows. The median annual rainfall varies from less than 20 inches at South Point to 75 inches at the 5,000-foot elevation. There is little evidence of stream flow within this region and no record of damage from flood flows other than the flooding of roads within the Hawaiian Ocean View Estates subdivision. The central region contains the communities of Pahala, Naalehu, and Waiohinu. There are several streams within the region, none of which are perennial. Flood flows occur when the soils are saturated and rainfall intensity exceeds the rate of infiltration. Storm runoff descends steep slopes behind the communities and causes flooding and deposition of sediment and debris in the communities. 10-15 Hawaii County Multi-Hazard Mitigation Plan Chapter 10:Hazard Analysis—Floods There are three existing flood control measures in this district. A flood water channel and debris basin in Naalehu was completed in 1965 with additional improvements and modifications completed in 1969 and 1982. The second project is within the town of Pahala and consists of diversion channels in the former sugar cane fields above the town and the improvement of Paauau Stream. The third project is within the town of Waiohinu. It is designed to collect flows from the watershed areas and transport them around Waiohinu for disposal in the rock land area. This project has been implemented, but needs additional improvements. Although major flooding within the communities has been addressed, flash flooding along the Hawaii Belt Road still occurs. The Piikea, Keaiwa, Paauau, Punaluu, Hilea, Kawaa, and Honuapo streams often exceed the capacity of the existing bridges and culverts and flood the roadway. This temporarily closes the road and effectively cuts off this district from the Puna, Hilo and Kona districts. However, in the Piikea ford area, the State DOT completed the construction of a new Piikea bridge in 1998. In addition to the bridge, improvements to the Piikea ford are proposed with the construction of three large box culverts. At the Paauau stream, there are plans for the construction of a new bridge. There are also plans for the replacement of the Ninole bridge located just past Pur luu. A new culvert is proposed in the Kawaa flats region. 10.3.1.1 NFIP Flood Insurance Profile for Hawaii County Insurance Overview As of D3/31/2 00 9 Community: HAWAII COUNTY' State: HAWAII County: HAWAII COUNTY CID: 155166 overview I occupancy I Zone I Preil FIRM Total by Community Group Flood Insurance Total Number of Policies: 4,277 Total Number of Policies: 0 Total Premiums: $2,64605 Total Premiums: $0 Insurance in Force: $820215,800 Insurance in Force: $0 Total Number of Closed Paid Losses: 407 Total Number of Closed Paid Losses: 0 $of Closed Paid Losses: $/,U33,H32 $of Closed Paid Losses: $0 Post Firm Minus Rated Policies Manufactured Homes Total Number of Minus Rated Policies: 9 Total Number of Policies: 0 A Zone Minus Rated Policies, 5 Total Number of Closed Paid Losses: 0 V Zone Minus Rated Policies: 4 $of Closed Paid Losses: $0 ICC 1316 Total Number of ICC Closed Paid Losses: 0 Number of Properties by Community: 0 $of ICC Cll Paid Losses SO Substantial Damage Losses Number of Substant al Damage Closed Paid Losses. 17 10-16 Hawaii County Multi-Hazard Mitigation Plan Chapter 10:Hazard Analysis—Floods Insurance Zone As of 03/3112009 Community: HAWAII COUNTY' State: HAWAII County: HAWAII COUNTY CID 155168 overview I occupancy I Zone I PrelPost FIRM Number of Policies in Insurance In Closed Paid S of Closed Adjustment Force Premium Force Losses Paid Losses Expense A01-30& AE Zones 1,243 $569,380 $196,299,300 59 S1.0-Q6,794 85 $37,30631 AZones 119 S176,265 $24,782,300. 37 S522,776.88527,855.42 AO Zones 14 $10,469 $3,408,600 7 $216,00157 $5,779.00_ AH Zones 14 $9,771 $3,250;400 3 $31,90126 _ S1,650_00 AR Zones 0 $0 $0 0 $0.00 $0.00 A99 Zones 0 $0 $0 0 $0.00 $000 V01-30& VE Zones 727 $969;880 $116,243,000 134 $2,335,640.21 S88,079-86 V Zones 0 $0 $0 0 $0.00 $0.00 D Zones 11 $14,533 $2,525,000 10 $23,46611, S2,00000 .8 CS XZone _ �_ Standard 15521 $677,783 $279,441,200 50 51,559,8493 _1 541,518.5'1 Preferred 628 S218,814 $194,266,000 17 $348,848.01 S20,42664 Total 4,277 $2,646,895. $820,21580n 317 56,135,275_00 $224,613,00 Insurance Occupancy As of 03131/2009 Community: HAWAII COUNTY' State: HAWAII County: HAWAII COUNTY CID: 15516E Overview I Occupancy I Zone Pre/Post FIRM Number of Policies in Insurance in Closed Paid S of Closed Adjustment Force Premium Force Losses Paid Losses Expense Single Family 122.`_ $1,053,784 $321,043,600 209 $4.021,381 69 $127,021 65 2-4 Family 250 $182,591 $56046,900 _ 40 $609,30634 $30,710.00 AII Other Residential 2.604 $857,178 $364,100,400 95 $1,202,837.97 541,328.36 Non Residential 198 $552,942 $79,024,900 63 $1_,200,30571 $54,325.731 Total 4,277 $2 646 895 5820,215 B00 4071 $7 033 829.00 i $253 384.00 Policies In Insurance in Number of Closed $of Closed Paid Adjustment Force Premium Force Paid Losses Losses Expense Condo 2,880 $1,054,102 $426,516,300 91 $1,45'1,045.21 5568'13.31 Non Condo 1,397 $1,592,793 $393,699,500 316 $5,582,786.50 $'196572:6 Total 41277 i$2,646,895 $820,215,800 407 $7,033,831001 _ S25338500 10-17 Hawaii County Multi-Hazard Mitigation Plan Chapter 10:Hazard Analysis—Floods Insurance Pre/Post FIRM As of 03/31/2009 Community: HAWAII COUNTY' State: HAWAII County: HAWAII COUNTY CID: 155166 overview I Occupancy I Zone I Pre/Post FIRM Pre-FIRM Number of Policies In Insurance in Closed Paid $of Closed Adjustment Force I Premium Force I Losses Paid Losses Expense A01-30& AE Zones _ 1,055 $506,882 $144,966,700 49 $933,960.50 $32,541.31 A Zones 82 $108,669 $16,124,000 33 $454,390.17 $15,780.42 AO Zones I 4 $5,692830,100 7 $216,001.57 $5,779.00 AH Zones _ 3 $4,479 $733,200 2 $16715.09 $1,050.00 AR Zones 0 $0 $0 0 $0.00 $0.00 A99 Zones 0 $0 $0 0 $000 $0.00 V01-30& VE Zones 698 $858,617 $107,986,200 128 $2,129,686.94 $84,504.86 V Zones 0 $0 $0 0 $0.00 $0.00 D Zones 4 $5,783 $1,011,000 9 $23,085.10 $1,910.00 B.C& X Zone 1,386 $488,204 $250,249,600 44 $1,179,005.64 $33,339.12 Standard 1,176 $416,230 $189,954,600 40 $1,094,521.57 $29,347.64 Preferred 210 $71974 $60,295,000 4 $84,484.07 $3991.48 Grand Total 1 3,2321 S11,978,32 - $521,900,800 272. $4,952,842.00 $174,903.00 Post-FIRM Number of Policies in Insurance in Closed Paid S of Closed Adjustment Force Premium Force Losses Paid Losses Expense A01-30& AE Zones 188 $62,498 $51,332,600 10 $162,834.35 $4,765.00 A Zones 37 $67,596 $8,658,3001 4 $68,386.71 $12,075.00 AO Zones 10 $4,777 $2,578,500 1 0 $0.00 $0.00 AH Zones 11 $5,292 $2,51 200 1 $15186.17 $600.00 AR Zones 0 $0 $0 0 $0.00 $0.00 A99 Zones 0 $0 $0 0 $0.00 $0.00 V01-30& VE Zones 29 $111,263 $8,256,800 6 $205,953.27 $3,575.00 V Zones 0 $0 $0 0 $0.00 $0.00 D Zones 7 $8,750 $1,514,000 0 $0.00 $0.00 B.C& X Zone 763 $408,393 $223,457,600 23 $729,691.68 $28,606.03 Standard 345 $261,553 $89,486,600 10 $465,327.74 $12170.87 Preferred 418 $146840 $133,971,000 13 $264363.94 $16435.16 Grand Total J 1,045 $668,569 J $298,315,000 44 $1,182,050.00 $49,621.00 10.3.1.2 Repetitive Loss Properties Per FEMA, counties are encouraged to develop plans that address the mitigation of target repetitive loss properties, as insured properties may be eligible for Flood Mitigation Assistance and Hazard Mitigation Grant Program (HGMP) Funds, in order to reduce the number of repetitive claims against the NFIP. Refer to Figures 10-6 through 10-8. 10-18 Hawaii County Multi-Hazard Mitigation Plan Chapter 10:Hazard Analysis—Floods First, a check was made of whether all structures on the NFIP Claims list would still be considered repetitive losses, i.e., having 2 or more losses of more than $1,000 within a ten- year period.All properties on the list met these criteria. Refer to Table 10-1. Second, a check was made of whether any of the properties would fall under the TCC (Increased Cost of Compliance) coverage funding criteria, i.e., two or more substantial damage losses in the past ten years, with each loss being 25% or more of the market value of the structure per occurrence. None of the losses would have qualified for this additional coverage. Third, FEMA's national Severe Repetitive Loss Strategy criteria was used to identify structures with higher priority for mitigation, i.e., insured structures with four or more losses, and structures with 2 or more losses where cumulative payments have exceeded the property value. Nineteen of the 50 properties met the criteria to be classified as target repetitive loss structures. It may be recommendable to determine whether there are any insured properties adjacent to these 19 target repetitive loss structures that should be considered in any specifically proposed mitigation action. The list includes the cumulative property values of these 19 structures (about$52AM). Then, the NFIP Claims list was sorted using the above criteria and whether they are currently insured and by descending total cumulative claim amount, and given a ranking ordinal from 1 to 50. Nearly all the repetitive loss structures are located at coastal sites. All but one of the target 19 properties is pre-FIRM. All repetitive loss properties have been mapped with specific identification of those residential properties falling within the FEMA target criteria. Eight properties (ordinals 12 to 19), have made claims in the past meeting the target criteria, but are not currently insured. Five properties (ordinals 7 to 11) are currently insured under Special Direct Facility(SDF). With regards to mitigation, then acting administrator Robert Shea of FEMA's Federal Insurance Mitigation Administration testified to Congress as follows in 2001: "A factor to be considered in offering assistance to the owners of these target properties — whether they choose to move out of the flood plain or to improve their properties—is how to treat those who refuse such an offer. Most people living in these high-risk areas are looking for help to alleviate their plight. However, there will be those who, for various reasons, are reluctant to move. This approach to addressing repetitive loss properties will receive public acceptance only if it is voluntary, and it will be important to provide an insurance consequence to the decision not to accept an offer of assistance. Alternatives proposed have included denying further insurance coverage, requiring that full actuarial rates be paid for future coverage, and substantially increasing deductibles to have those who refuse to move shoulder a greater portion of their cost of recovery. It is our belief that shifting more of the financial burden to the property owner is a more effective incentive than the denial of insurance." Accordingly, it appears that uninsured properties with higher losses (those in the gray portion of the list, ordinals 12 to 19) would not be targeted for mitigation, as there would be no insurance consequence to the decision not to accept an offer of insurance. There may be good reason to examine these cases to determine why they are not continuing under 10-19 Hawaii County Multi-Hazard Mitigation Plan Chapter 10:Hazard Analysis—Floods coverage, as part of an annual repetitive loss area outreach project. (Flood insurance could have lapsed after repayment of a disaster assistance loan.) In addition, examination of the NFIP repetitive loss data indicates that there are numerous typographical corrections, mostly relating to Hawaii location addressing, which should be reported to the Corrections Clearing House at ISO. Repetitive Loss Properties • CRS* Target for Mitigation Criteria* *Number indicates miti-ation rank,see table Other Roads Major Roads Total Losses Paid $3,860,982 Flood Zone 100 Year - 500 Year X OUTH KOHALA, HAMAK SOUTH HILO NORTH KONA NORTH HILO PUNA � OUTH KONA x Figure 10-6. Flooding Repetitive Losses Map,County View 10-20 Hawaii County Multi-Hazard Mitigation Plan Chapter 10:Hazard Analysis—Floods �r 1 1 31 49 10 • �I I :a _t 1 I scurH Hi_� 4 48 25 14 5 Repetitive Loss Properties 27 • CRS Target for Mitigation Criteria Other Roads Major Roads 24 Flood Zone 100 Year -500 Year X Figure 10-7. Flooding Repetitive Losses Map,Hilo zoom 10-21 Hawaii County Multi-Hazard Mitigation Plan Chapter 10:Hazard Analysis—Floods 17 r 409 /r 39 Repetitive Loss Properties NORTH KONA r • CRS 1S Target for Mitigation Criteria Other Roads $ Major Roads '22 Flood Zone "; 6 100 Year - 500 Year 1523 - X29 - i 194 1q 3 6 441 r Figure 10-5. Flooding Repetitive Losses Map,Kona zoom 10-22 Hawaii County Multi-Hazard Mitigation Plan Chapter 10:Hazard Analysis-Flonds Table 10-1. Repetitive loss property list and ranking ��„� All ok $311 ., ;=+?5.1 So ;=,?5.1 ;=+?5.1 131161 _ "LET 9 Y $19,,sa�$x3,6 3$vas6a$466,,61 $631nn $1.1.- x1115,1 $. rn 15+1 ;142..1 91. 41661.. 416.,4x4 n.aa.Yn1.ISI 4153,1. 41.5mn1'1 Y5?2.. $1.1,1.9 Y. 11.1,1.9$95,319 $196,61. $n1- 141,614 Yla S]]YS_'$1,.12166 43.11,.x41 7S-112 All DP c3 $5,031 151,984 Y. 156196,$1,-411 + $2,15 855=v g. gss o=r$1,114+35 Sv,,ov ale 7S-112 All DP A! _ $11.14 $44991 14918 Y,9,9o4$1,174,384 f1 4,'14,321 All $]SS So g3+sal$34541 fl toa yc 114494331 8153,151 813,638 816x3¢fx9.e]5$1,x38,644 E14787 871 KINa :� 14 8x19534 Y. $259,530 - -- SI 141314 $1465.3 $+1,515$13441= �_ 1153,¢85 $111,892$35,393$244,185 _ + $vas+ $I=3.535 863,1 as$146,7=3 + ie $35A $I x3.998$x],G9x$151,494 ANH .. .� ;531 $1..... $. $13.5.2 z3'1 239E ie Ea oo 84 123,114$x3]Ia - -- 82836 $11147 $1 415543 4 141 141 INIT 11171-6111 All 11 - 11 11711 NIRT1 11- 111_ ba eo IS 415,5+5 815.515 I. A E 11 $138,5,3[$7 11 IS8$155,411 + + $ 000 181 431 $11135 893,106 1117117 - $]x149 YI3,I�4$95,6]9 ;21„93 $IS 342 gu 814342 .+ 6 4 4 M 1I 7_'-"-", $186,333 - 115,311 446Sx 861.431 ye,4.q..4 $3x654 $835 3,1,425 I IA I ALINA IT HI 917. YEE I, 4464,436 414.554 4. E41114 $1111 $3x134 $1 $38134 +.111 11 1AILU1 KINA 11 11711 11161.5 INILE 111 13:833 ;4191 $33,115 NI - GIL7 s148s44 $15,6]1 $14142$3x,113 A 11711 .� $1.RS0 ;19,153 $. $IV,153 G- - 111p44 - IL III $. 44131 2 911 111 1 All HOTEL n. oar ;13,]59,9,2 $296x.3$1x99,$399,19] $195,44. S6x,341 55,341 161,152 GI $151392 $62454 1891 $63146 117 711111 All 11 IND 41 1AILIA 1 + $1+9,44. $61,194 S. $61711 41 N.IRD oR �e $171444 - $11LI44 115,535$43x35 All 11 117+ .� ;50.00 ;I-2,003 81]131$34135 i_ $344,44. 811164 $I U.3uu$x1..64 Il oa .. ;o ;o g2ILL$z�444 4x43,13 41x.6]] $12,6]] �. 5611.. $6,415 151x5 s12�44 + $1=5,444 $11,]15 $. $11]85 + �e Y35o,o0o Y9,IO3 Y7ns $915.1 "UTH 171 IAIYIN IR 11 1-1 A's 1 5441.. $8,5+1 $383 $1914 HIL, P'fe Hloee - $1,]35 $o $4]35 ' ;11�0o g�s25 g. g�s1v 34 S4 SI,111 811432 L15 A HAILTST IT IHILI HI 91721 ND 8219 Ysp24 g4 $sox, S4 40 $4 5+.655 84655 [$ pE�es3x ol9 uz p iez 4 E 14531,531 10-23 Hawaii County Multi-Hccard Mitigation Plan Chapter 10:Hazard Analysis—Floods 10.4 Mitigation Strategies 10.4.1 Previous/Current Efforts Description of adoption and enforcement of floodplain management requirements, including regulatory and inspection practices in Special Flood Hazard Areas: The County of Hawaii implements the FEMA/NFIP regulations through Hawaii County Code (HCC) Chapter 27 - Floodplain Management (attached). Chapter 27 was adopted on May 5, 1982 and was last updated on November 30, 2007. Implementation and enforcement of HCC Chapter 27 typically occurs during: review of subdivision proposals (HCC Chapter 23),building permits (HCC Chapter 8), grading/grubbing permits (HCC Chapter 10); and/or, public or private complaints. HCC Chapter 27 includes variance process from Chapter 27's requirements, which includes very specific criteria for reviewing, recording, reporting and appealing a variance. HCC Chapter 27's enforcement provisions include: right of entry; notice of violation and/or administrative order process; injunctive relief through the circuit court of the third district, State of Hawaii, or United States District Court, State of Hawaii; criminal enforcement, where violations constitute a misdemeanor and are subject to a fine of $1,000/day for each day of none compliance and/or one year imprisonment; and, removal of floodplain encroachment/obstruction notices, and/or removal of encroachment/obstruction by County at the violator's expense. See the appendix at the end of this chapter. Description of community assistance and monitoring activities: Assistance includes, in part, the following activities: participating in the NFIP so the community has access to flood insurance, and Federal disaster relief/low interest loans; maintaining and providing information/assistance on FEMA's Flood Insurance Rate Maps (FIRM), Flood Insurance Studies and letter of map changes; requiring, reviewing and maintaining FEMA's Elevation Certificates for structures built within FEMA's Special Flood Hazard Area (SFHA); providing review of subdivision proposals and related construction plans,building permits, grading/grubbing permits,which all relate to improvements proposed within FEMA's SFHA; providing FEMA flood zone determinations to the public, governmental agencies, lending institutions and realtors; Participating in FEMA's Community Rating System, which is a program to reduce flood insurance rates based on the County doing certain floodplain management activities; updating FEMA's FIRMS through detailed flood studies; receiving and as appropriate, responding to complaints related to activities with floodplains; providing review of variances and appeals, as provided in HCC Chapter 27; and, providing educational literature, presentations, website information and sponsoring training. Monitoring compliance with HCC Chapter 27 is accomplished, in part, by: requiring FEMA Elevation Certificates (pre and post construction submittals), which help assures buildings within SFHA are constructed in compliance with HCC Chapter 27; reviewing applications for subdivisions and related construction plans, building permits and grading/grubbing permits for compliance with HCC Chapter 27; responding to complaints and taking appropriate actions to correct noncompliance. Reviewing, approving, preparing, submitting to FEMA and maintaining Letter of Map Changes,which are used to update FEMA's FIRMS. 10-24 Hawaii County Multi-Hazard Mitigation Plan Chapter 10:Hazard Analysis—Floods 10.4.1.1 County of'Hawaii Flood Studies The County is currently doing flood studies (map updates) in the following areas: Puna, Hilo, North and South Kona. There are several privately funded flood studies ongoing in the Kona, Hilo and Waimea. See the County of Hawaii Flood Studies in Table 10-2. Table 10-2. County of Hawaii Flood Study list County of Hawaii Flood Studies Prepared on October 12,2009 Estimated FEMA Case FEMA Panel Completion Identifier TMK No. Flooding Source No. Engineer Start Date Status/Remarks Date DHHL Lalamllo Housing,Phase 5-5-001:077 09-09-2407R Keanuimano& 0164 D Anson Murayama, 7/17/00 91 Withdrew CLOMR Jan-10 2 Waikoloa Streams Community due to possible change in Q Planning&Engr value based on CLOMR Inc Case No.95-09-154R. Waiakea Trio Area 3A Various 09-09-2120P Waiakea Trio 3A 0870 C,0830 C Cary Korea,Belt 1/26/09 Formerly Case No,09-09- Dec-09 &0890 C Collins 0862P.9/11/09 FEMA requests information. Kailua Gardens Subdivision 7-5-010:088 and 09-09-1818R Hlenal i 0713 D Mr.Geoffery 5/19/09 6/19/09 FEMA requested Dec-09 089 Drainageway Casburn,with more Information. CMF Engineering, Inc. Waipahaehoe Trio 2-5-006:152 09-09-1789P Walpahaehoe Stream 0859D Paul Nash,Atlas 5/18/09 6/17/09 FEMA requested Feb-10 Trio En r more information. Greenwell Family Flood Study 8-1-004:001,045, 09-09-1820P South Kona 0939 C and Mr.Ty Dempsey, 5/19/09 7/6/09 FEMA requested Jan-10 052,053,054, Watercourse#1 and 0943 C with Lyon Assoc. information. 055,070,074, Watercourse#2 075 Kawailani Street Bridge 09-09-1608P Waiakea Stream and 0880 C,0890 C Wesley R. 12/20/07 LOMR Issued&Effective Done Replacement Waiakea Tributary Sag—&Assoc. 2/16/10 N..2 Hilo Medical Center Parking Lot 2-3-032001 09-09-1400P Unnamed Trib to 0880C Alex Kalawe, 4/2/09 Recently combined With Jan-1a Walluku River Engineering Case No.09-09-1398P Partners,Inc. Alnako Stream Flood Zone Various 09-09-1398P Alnako Stream 0880C Cary Kando,Belt 4/6/09 5/13/09 FEMA requested Jan-10 Drainage Basin Collins information. Kona Coffe and Tea Company 7-5-017:031 & 09-09-0036R Waiaha Drainageway 0713D Ty Dempsey, 7/08 CLOMR-3/24/09 letter Flood Channel 045 Lyon Assoc. from FEMA requesting data within 90-days. North Kona Flood Study 7-5,7-6&7-7 None Waiaha,Horseshoe 713D,7140, Berry Muranaka, 12/11/2008 Completing topographic May-10 Bend,Halualaa, 926 E&927D Metcalf& mapping within 30-days. Kaumalumalu Eddy/AECOM watercourses. South Kona Flood Study Phase 1 8-4 None Watercourses 13-20 1166C&1167C Michael Wang, 6/24/2008 Completed preliminary Flood Nav-09 Army Corps of study.Ready to submit to Engine— County. South Kona Flood Study Phase 11 8-1,8-2,8-3,8-4, None Watercourses 1-12 91 Michael Wang, 6/24/2003 Working an developing Jul-10 8-5,8-6 and 21-23 944C,1155C, Army Corps of topographic maps 11570,11580, Engineers 1159C,1169C& 1407C Puna Flood Study 1-6,1-7,1-8,1-9 None To be determined None printed Jay Stone, 12/19/2006 Completed hydrology and May-10 Oceanic H droullc analysis. Keopu-Hlenaloli Flood Study 7-5 None Keopu and Hienaloli 0712C,713D& Derrick Elfalan, 11/20/2007 Preliminary flood study May-10 Watercourses 714C Oceanic c ompleted.Continuing to refine flood boundaries (hydraulics study). County of Hawaii's flood control levees certification project: Levees that are not properly constructed and regularly maintained, inspected and certified have the potential to create significant community disruption and considerable cost in flood insurance,repairing and replacing flood damaged structures. Consequently, on November 2, 2007, the Federal Emergency Management Agency (FEMA) notified the County of Hawaii that the County's levees (refer to Table 2)require certification in accordance with Code of Federal Regulation Title 44 Section 65.10 (44 CFR 65.10). FEMA's April 2007 "Fact Sheet — Meeting the Criteria for Accrediting Levees on Flood Maps"is a good resource on FEMA's levee certification process. 10-25 Hawaii County Multi-Hazard Mitigation Plan Chapter 10:Hazard Analysis—Floods The County needs to certify the four levees listed in Table 10-3, which includes Waiakea Stream Levee 11 (refer to Figure 1), Alenaio Stream Levees 12 and 20 (refer to Figure 2) and Paauau Stream Levee(refer to Figure 3). Table 10-3. List and Status of Levees FEMA Levee USACE PAL Flood Source Levee Owner Object ID Levee? Status 1 No A Kamuela Stream Parker Ranch 2 No A Lanimaumau Stream Parker Ranch 9 Yes B Keopu Drainageway County of Hawaii I I Yes B Waiakea Stream County of Hawaii 12 Yes B Alenaio Stream County of Hawaii 20 Yes A Alenaio Stream County of Hawaii 21 Yes B Keao u Drainageway County of Hawaii (1) Yes B I Paauau Stream I County of Hawaii USACE—United State Arm Corps of Engineers PAL—Previously Accredited Levee B—Received a USACE acceptable maintenance level rating in a recent inspection review. A—Levees not in the USAGE program with no approved maintenance review for FEMA. 0 -Levees subject to this CDBG funding request (1)—Levee not originally listed in FEMA November 2,2007,letter. Given the time needed to comply with 44 CFR 65.10, FEMA issued its March 16, 2007, Procedure Memorandum No. 43 (PM No. 43), which establishes a process that gives communities additional time to acquire and assemble the necessary levee certification documentation. In accordance with PM No. 43, the County of Hawaii entered into a PAL Agreement with FEMA on January 29,2008. 10-26 Hawaii County Multi-Hazard Mitigation Plan Chapter•10:Hazard Analysis—Floods Site Location ti Levee No. 20 _ r //yy Jt �y l Levees not certified 100-Yr Flood(1%) Inundation Area �t 1 Levee No. 12 2009 Community Development Grant ti County of Hawaii Department of Public Works Engineering Division � Figure 1 -Alenaio Stream (Levees 12 & 20) Note:Inundation areas are estimates only. 10-27 Hawaii County Multi-Hazard Mitigation Plan Chapter 10:Hazard Analysis—Floods Levees not certified 1 o Flood Inundation j Area ' ^4 4o e y ow � R-__ __ _ __ ♦• Zone AE z Z cA Levee No. 11 1 Zane X � B 0 ,N00 X00 ,Sa sa C �{ ]11 Site Location 2009 Community Development Grant County of Hawaii Department of Public Works Engineering Division Figure 2 -Waiakea Stream(Levees 11) Note:Inundation areas are estimates only. 10-28 Hawaii County Multi-Hazard Mitigation Plan Chapter 10:Hazard Analysis—Floods ! f _ I,I Levees not certified 100-Yr(1%)Flood i' Inundation Area Levees � � s Site Location .w 2009 Community Development Grant County of Hawaii Department of Public Works Engineering Division 1 � ` • , Figure 3—Paauau Stream(Levee) Note:Inundation areas are estimates onlv. 10-29 Hawaii County,Multi-Hazard Mitigation Plan Chapter 10:Hazard Analysis—Floods Currently, the areas landward of County's levees are mapped as "X Zones" on FEMA's Flood Insurance Rate Maps (FIRM). Areas designated as "X Zones" are not considered by FEMA as being subject to 100-year (1%) flood inundation. Mortgaged structures located within "X Zones" are not required to have flood insurance under National Flood Insurance Program (NFTP), or the flood insurance premium is greatly reduced. If the levees are not certified in accordance with the PAL Agreement and 44 CFR 65.10, the area landward of the levees will be remapped on the FIRM as "A Zone" Special Flood Hazard Areas (SFHA). Areas designated as "A Zone" SFHA are considered by FEMA as being subject to 100-year(1%) flood inundation. Any mortgaged structure located within an "A Zone" SFHA is required to have NFIP flood insurance. The annual premium for NFIP flood insurance can be in the thousands of dollars. If the County's levees are not certified, Table 10-4 presents an estimate of the acres of inundation (64 aces) and number of parcels (175 parcels) potentially affected (Refer to Figures 1, 2 and 3 for: the location of the levees; flood sources; estimated 100-year (1%) flood inundation areas landward of the levees; and,potentially affected parcels). Table 10-4. Estimated Inundation Area and Number of Parcels Potentially Affected if Levees are not Certified FEMA Levee Tnundation Area, Object ID Flood Source acres(i) No.of Parcel'" 11 Waiakea Stream 12 10 12&20 Alenaio Stream 43 133 --- Paauau Stream 9 32 Total 64 acres 175 parcels (1) Based on the inundation areas shown on Figures 1,2 and 3. The USACE has the expertise to prepare the certification documentation requested by FEMA. As part of the USACE Interagency and International Support Authority, the County entered into a Memorandum of Agreement with the USACE, on October 1, 2008. Under the October 1 MOA, the USACE will assist the County in acquiring, assembling and submitting the necessary levee certification documentation to FEMA for Alenaio Stream (PAL Levee Nos. 12 & 20), Waiakea Stream (PAL Levee No. 11) and Paauau Stream (no PAL no. assigned). See Table 10-5. Table 10-5. USACE October 1 MOA Com ensation Allocation FEMA Levee Flood Source HUD Funds County Funds Total Funds Object ID (10%) (90%) 11 Waiakea Stream $ 27,500 $ 247,500 $ 275,000 12&20 Alenaio Stream 14,500 130,500 $ 145,000 --- Paauau Stream 14,500 130,500 $ 145,000 Total $ 56,500 $ 508,500 $ 565,000 10.4.1.2 Accuracy and Completeness ofFlood Zone Mapping Many known flood-prone areas have minimal FIRM coverage (e.g., upper Puna). Some FIRM maps do not completely include all flood areas, as evidenced by the November 2000 flooding (e.g., FIRM maps for Hilo). FEMA and the County are working to digitize the FTRMs, which should be completed by late 2010 or early 2011. Figure 10-9 shows those 10-30 Hawaii County Multi-Hazard Mitigation Plan Chapter 10:Hazard Analysis—Floods areas that have not been mapped, the mapped areas that have been digitized by FEMA, the mapped areas that FEMA did not digitize but which the County has recently digitized. Figure 10-10 compares the information on a digitized preliminary DFIRM to the paper FIRM maps, illustrating that alignment checking and correction are a part of that process. Legend FIRM not printed,minimal tsunami inundation zone(per FEMA) FIRM not printed,area all in Zone X FIRM Printed LOMR(Letter of Map Revision)pending on a portion of panel Figure 10-9. FIRM Coverage. 10-31 Hawaii County Multi-Hazard Mitigation Plan Chapter 10:Hazard Analysis-Floods Rioode Reel M2071 °� KSTDKTA o� Keakea Point o --A ZONE VE uRC Q . (mo(� o 0 0 IIHIKAI STREET AEHALA ST" Op e o b Puhi&Y + R oD9Fq KEOKEA AOs I bq Fy A.ARAHE RDA AE 022 SST RE F7A ZONE AE �5 19 CCE is i xm h a ZONE VE Kuhfo Boy 20 M206 ' 2 V i QLO�i ,g Zo 17 r ZONE AE- 1 ZONE VE ""i- aT ' i {.py��Iyyir��/ JE Ilfl nJE P � C aJE JE Paper Map FIRM showing base flood elevations R E E F K—kea PC �9 T` Slav :a Rnn Pt7f, Kignnka Raywry tCeaukaha '- . .,� •'..' 12D , tLa IY`j,Vt Liapit) t {r Digitized firm w/out BFE, but showing relationship to parcels and topographic features. Figure 10-10.Comparison of Paper vs.Preliminary Digitized FIRM Draft,showing alignment issue being resolved. 10.4.1.3 Hurricane Flood-Insurance Study for the Hawaiian Islands The Hurricane Flood Insurance Study for the Hawaiian islands was conducted under FEMA contract number EMW-2003-CO-0046, RMTC/URS Task Order 013. Under this contract, RMTC/URS, a joint venture consisting of R.M. Towill, URS, Dewberry, TerraPoint, Airborne 1, and Sea Engineering, was tasked to evaluate and map the magnitude and extent of coastal hazards due to hurricanes for six Hawaiian Islands, divided into four counties: Kauai (Kauai County), Oahu (City and County of Honolulu), Molokai, Maui, Lanai (Maui 10-32 Hawaii County Multi-Hazard Mitigation Plan Chapter 10:Hazard Analysis—Floods County), and Hawaii (Hawaii County). Although the effective (i.e., past) FIRMs for each county have accounted for tsunami hazards, the hurricane flood hazard had not been previously separately evaluated in a comprehensive study throughout the islands. Tn general, the hurricane coastal hazard analysis was limited to the southern coast of each island. This is due to several factors, including the predominance of tsunami hazards and limited low-lying areas susceptible to hurricane hazards along the north shore of the islands. Table 5-1 provides a summary of study limits. Table 10-6. Summary of Study Limits Island Western Limit Eastern Limit Reach Length (Miles) Hawaii Upolu Point Cape Kutnukahi 193 Kauai Nohili Point Kuaehu Point 56 Lanai Kaumalapau Manele 16 Maui Hon okahuaBay Koali 69 Molokai Ilio Point Cape Halaawa 54 Oahu Kaena Point Kawaihoa Point 60 Total: 448 r� Keus� J� LanaiMaui t Haw@ ii Figure 10-11. Extents of Hurricane storm surge inundation study Transacts were laid-out within the study limits and representative placement was evaluated during the field reconnaissance performed from July 24th through August 6th, 2007. The topographic base consisted of LiDAR collected under FEMA Task Orders 12 and 26. The LiDAR data were collected in the Fall of 2006, post-processed to bare earth and quality 10-33 Hawaii County Multi-Hazard Mitigation Plan Chapter 10:Hazard Analysis—Floods controlled to meet FEMA mapping standards. These data were assimilated together with the best available bathymetric datasets, including USACE hydrographic LiDAR, into high- resolution seamless digital elevation models. The hazard analysis considered the combination of storm surge and hurricane-induced wave hazards. This included independent analysis and/or modeling of storm surge, return frequency flood elevations, wave setup, overland wave hazards, and wave runup. The ADvanced CIRCulation model for coastal ocean hydrodynamics (ADCIRC) was selected to develop the stillwater elevations or storm surge for the study area. The Empirical Simulation Technique (EST), also developed by the USACE, was used to determine the stillwater frequency curves for the 10-, 2-, 1-, and 0.2-percent annual chance stillwater elevations. Deepwater wave conditions were determined using the Shore Protection Manual (SPM) prediction technique and limited fetch analyses were performed in harbor and sheltered areas. Wave setup was differentiated and evaluated for areas with and without fronting reefs. Areas of primary frontal dune were identified, delineated, and eroded. Overland wave propagation hazards were evaluated using the WHAFIS model. Wave obstructions were verified at representative transect locations by field reconnaissance. Wave run-up was evaluated using the RUNUP 2.0 and TAW methodologies, depending of the presence of reefs and local steepness of the bathymetry. Wave hazard analyses were conducted at FIS transect locations, in addition to more tightly- spaced"mapping transacts." These additional transacts were facilitated by the application of an integrated GIS toolset that automates repetitive modeling tasks, and enables a more detailed analysis than typical coastal FIS studies. Wave setup values were assigned to these transects according to analysis at adjacent FTS transects. Otherwise, the mapping transects were treated with the same overland wave propagation and wave runup assessments as the FIS transects. The coastal hazards determined from the above analyses were synthesized in the form of the standard FEMA special flood hazard boundaries for the Zone VE, Zone AE, Zone AO, and Zone X hazard areas. These are presented in the TSDN as workmaps produced at a scale of 1':500". The workmaps also include stillwater stations, topographic elevation contours, FIS and mapping transect locations, and the shoreline. Wave analysis for the 0.2%annual chance event was not included in the scope of the study. The 0.2% return frequency stillwater elevation was exceeded by cumulative flood elevation from the 1% stillwater elevation and wave setup, therefore, the boundary of the 0.2% annual chance event was not delineated. To steeper areas where mapping scale limits the gutter placement, the SFHAs are only identified by the position of the 100-yr flood boundary. Mapped Base Flood Elevations (BFEs) are considerably dependent to the topographic representation at each transect. As a result, localized variations in the topography at other locations may not be fully reflected in the mapped SFHAs and BFEs. A Technical Support Data Notebook (TSDN) was compiled for each county in the study area. Storm surge and return frequency elevation analyses were inclusive of all counties, and thus all materials pertaining to those analyses, including model input, output, and documentation are included in each county TSDN. The remainder of the data, including wave modeling, mapping, workmaps, topography, etc., are island and county specific. Therefore,these data are only presented in the appropriate countywide TSDN. 10-34 Hawaii County Multi-Hazard Mitigation Plan Chapter 10:Hazard Analysis—Floods Limitations of the study being addressed prior to FIRM adoption: • Modifications to the Flood Maps to include tsunami inundation as a factor in zoning and construction requirements. • Phase I: The first step presently underway is comparing the differences between the existing and new FIRM maps to determine where historic or the recently modeled tsunami hazard is greater. • Phase II: UHM SOEST mapping (by the Kwok Fai Cheung Group) could produce 100-year and 500-year probabilistic tsunami hazard maps to provide future local modifications to the DFIRMs. 10.4.1.4 Adequacy of Managing Existing Flood Problems and New Development with Watershed Planning and Drainage Standards The current comprehensive drainage plan for the County is the"Drainage Master Plan for the County of Hawaii" prepared over 30 years ago in 1971. This plan needs to be updated to incorporate new studies and to provide a watershed perspective in managing floods using both structural and non-structural methods. This plan would be the basis to prioritize CIP projects and to initiate regulatory changes. FEMA has funded an Area Development Plan for Existing and Future Development project to investigate: County regulations and policies for new development to provide community outreach in regards to protection/precaution measures. Floodplain management and land use regulatory integration scope of work includes examining regulatory integration of grading ordinance (HCC chapter 10), flood control code (chapter 27), subdivision code(chapter 23), and zoning code (chapter 25): Reduction of flood hazards through regulary measures(recommended revisions to hcc chapters 10,23,25& 27) DESCRIPTION: This project will recommend new regulatory measures to the Hawaii County Code that would reduce flood hazards, including hazards caused by dams and levees within the County of Hawaii. Proposed regulatory measures will focus on Chapter 10, Erosion & Sedimentation, Chapter 27, Flood Plain Management, Chapter 23. Subdivisions and Chapter 25, Zoning. Recommendations to other Chapters of the Hawaii County Code may be made as may be appropriate. We are focusing on the four chapters for the following: Chapter 10, Erosion & Sedimentation Control: Any land disturbance activity has the potential of causing flood hazards or aggravating existing flood hazards to surrounding properties and the environment. There is a need to improve enforcement as well as to increase the use of mitigating measures and/or best management practices that would minimize erosion, sedimentation impacts during land disturbance activities that would create flood hazards. Major recommendations are anticipated as this Chapter has not had any major changes since its adoption in November 1975. 10-35 Hawaii County Multi-Hazard Mitigation Plan Chapter 10:Hazard Analysis—Floods Chapter 27, Flood Plain Management: This Chapter focuses on establishing building code and infrastructure requirements that would minimize flood damages based on hazards identified by the FEMA Flood Insurance Rate Maps. Recommendations may also address uncertainties inherent with the FEMA maps and measures to reduce flood hazards for non- compliant structures in special flood hazard areas. Because substantial changes to this Chapter were made in November 2007, major revisions are not anticipated. Chapter 23, Subdivisions: This chapter needs to be revised to reflect current requirements for subdivisions that are within special flood hazard areas. Upgrading of current drainage improvement requirements will also be considered. Chapter 25, Zoning: Like Chapter 23, upgrading of drainage improvement requirements will be a consideration. However, its applicability to the various types of zoning within Hawaii County and/or development restrictions within special flood hazard areas, watersheds, forests and other similar areas will a major issue of consideration. Because it is the responsibility of the implementing agency to develop legislative proposals, identification of pros and cons of each recommendation including any economic impacts, implementation measures and/or any legal issues or constraints is an essential part of this project. 10.4.1.5 Flood Forecasting In recent years, the NWS has installed more telemetered rain gauges to aid in flood prediction. Two Doppler radars on this island provide rainfall intensity in quantitative graphic form. A corps of human observers is also maintained to report significant events. Warnings for specific areas are broadcast via normal and special radio/TV forecasts and by special County Civil Defense announcements as well as over the NOAA Weather Radio. Thus, short-term mitigation is being addressed. The problem of vehicles being driven across flooding streams must be met by road hazard signs and public education for hunters and others using remote roads. 10.4.1.6 Pacific Services Center Flood Response Tool The Hawai'i Flood Response Tool is an ongoing project to develop a geographic information system (GIS)-based application to provide enhanced flood response in Hawai'i. The application will centralize access to diverse weather and stream flow data from various locations and sources to allow for timely analysis and response. This software, which is being developed for local emergency managers, will provide an improved operational picture for flood response activities by automatically logging disparate real-time and near real-time observation data and text products via the Internet. The information will be displayed along with historical and baseline data in an-easy to-interpret format utilizing GIS. This rapid access to new data streams should provide a more realistic picture of on-the-ground conditions and reduce data compilation time. More information on the Hawai'i Flood Response Tool is available at nos.csc.psegnoaa. og_v. 10-36 Hawaii County Multi-Hazard Mitigation Plan Chapter 10:Hazard Analysis—Floods 10.4.2 Future Plans Project Description Status Modernize FIRM maps with local amendments See http://k�is.hawaiinfip.org,/that On Dec. 12,2008 and Feb.26,2009,FEMA FEMA has revised the DFIRM's and Flood Also included a re-evaluation of issued Preliminary Digital Flood Insurance Insurance Study based on hurricane flooding the Puukapu Watershed of the Rate Maps(91 panels)for Hawaii County hazard. Waimea area (Pre-DIRMs).On April 21,2009,FEMA These FIS maps do not include historic tsunami held its Pre-DIRMs flood hazard mapping inundation data. The next step is to compare the community coordination meeting with the differences between the existing and new FIRM County.On April 22,in Kona,and April 23, maps to determine where historic or the recently in Hilo,FEMA and the County held public modeled tsunami inundation hazard is greater. meetings on the Pre-DIRMs. On June 30,2009,the County sent a letter to FEMA indicating,until the Pre-DFTRMs are revised to acceptable standards,the County will continue using the County's current floodplain management records to make land use and building permit issuance decisions. On July 7,2009,FEMA acknowledge the County's June 30 letter and accepted the County's support in preparing improved digital presentations of the riverine flood zones.On Sept.28,2009,FEMA approved a $71,300 Cooperative Technical Partners grant to assist in improving the riverine flood zones on the DFIRMs.FEMA will continue to improve the DFIRMs coastal high hazard areas by combining the more protective inundation areas from either FEMA's 2008 hurricane flood study for the County of Hawaii(refer to Section 10.4.1.3)and the current effective FIRMS'coastal high hazard areas. Participate in the Community Rating System Results in reduction in flood Project requires documentation effort and insurance premiums analysis of repetitive loss properties Precipitation-Frequency Atlas of the US Hawaiian http://hdsc.new.noas.gov/hdsc/pfds NOAA release May 2009 Islands Includes:precipitation frequency estimates for durations from 5-minutes through 60 days,for return periods of 1-year through 1000 years. Develop policies for repetitive loss structures Policy may or may not make This depends on an analysis of repetitive loss economic sense from a Benefit properties Cost Analysis Area Development Plan for Existing and Future Floodplain management and land Ongoing project scope: Recommend Development use regulatory integration scope of revisions to the Department of Public Works This project proposes to refine regulations and work includes examining for Chapters 10 and 27;and recommend policies for new development and provide regulatory integration of grading revisions to the Planning Department for community outreach in regards to ordinance(HCC chap 10),flood Chapters 23 and 25 and develop new protection/precaution measures. Context Sensitive control code(chap 27), regulatory measures to reduce flood hazards Solutions methodology will be used to identify a subdivision code(chap 23),and within the County of Hawaii and to earn comprehensive programmatic approach to mitigate zoning code(chap 25) FEMA Community Rating System(CRS) the risks to existing and future developments. The points for the County of Hawai'i. study also proposes to identify and prioritize floodplain mapping,develop policies for unprotected subdivisions,and coordinate disaster preparedness planning for floods. Develop rainfall and streamflow gauging system Internet accessible tool to view NOAA PSC developing prototype suitable to flood monitoring real-time rainfall and streamflow application for emergency managers data 10-37 Hawaii County Multi-Hazard Mitigation Plan Chapter 10:Hazard Analysis—Floods 10.4.2.1 Community Rating System The National Flood Insurance Program's (NFIP) Community Rating System (CRS) is a voluntary incentive program that recognizes and encourages community floodplain management activities that exceed the minimum NFTP requirements. As a result, flood insurance premium rates are discounted to reflect the reduced flood risk resulting from the community actions meeting the three goals of the CRS: 1. Reduce flood losses; 2. Facilitate accurate insurance rating; and 3. Promote the awareness of flood insurance. For CRS participating communities, flood insurance premium rates are discounted in increments of 5%; i.e., a Class 1 community would receive a 45%premium discount,while a Class 9 community would receive a 5% discount (a Class 10 is not participating in the CRS and receives no discount). The CRS classes for local communities are based on 18 creditable activities, organized under four categories: 1. Public Information, 2. Mapping and Regulations, 3. Flood Damage Reduction, and 4. Flood Preparedness. The table below shows the credit points earned, classification awarded, and premium reductions given for communities in the NFTP CRS. Credit Points Class Premium Reduction Premium Reduction SFHA* Non-SFHA** 4,500+ 0 45% 10% 4,000-4, 40% 10% 3,500-3, 0 35% 10% 3,000-3, ® 30% 10% 2,500-2, � 25% 10% 2,000-2, © 20% 10% 1,500-1, 0 15% 5% 1,000— 1,499 ® 10% 5% 500-99 5% 5% 0—499 10 0 0 *Special Flood Hazard Area **Preferred Risk Policies are available only in B,C,and X Zones for properties that are shown to have a minimal risk of flood damage.The Preferred Risk Policy does not receive premium rate credits under the CRS because it already has a lower premium than other policies.The CRS credit for AR and A99 Zones are based on non-Special Flood Hazard Areas(non-SFHAs)(B,C,and X Zones).Credits are:classes 1-6, 10%and classes 7-9,5%.Premium reductions are subject to change. 10-38 Hawaii County Multi-Hazard Mitigation Plan Chapter 10 Appendix Chapter 27 FLOODPL.AIN MANAGEMENT Article 1.Authorization. Section 27-1. Statutory authority. Section 27-2. Findings of fact. Section 27-3. Purpose. Section 27-4. Scope and methods. Article 2.General Provisions. Section 27-5. Applicabilily. Section 27-6. Basis. Section 27-7. Compliance. Section 27-8. Other laws and regulations. Section 27-9. Interirretation. Section 27-10_ Warning and disclaimer of liability. Section 27-11. Severability• Section 27-12. Definitions. Section 27-13_ Nonconfotming structures. Article 3.Administration. Section 27-14. Director of public works approval. Section 27-15. Designation of the floodplain administrator. Section 27-16. Duties and responsibilities of the floodplain administrator. Article J.Standards. Section 27-17. Certification standards. Section 27-18. Standards i'or construction. Section 27-19. Standards for utililies. Section 27-20. Standards for subdivisions and outer development-,. Section 27-21. Standards for manufactured(tomes. Section 27-22. Standards for lloodways. Section 27-23, Standards for coastal high hazard areas. Section 27-24. Standards for general floodplain. Section 27-25. Standards for improvements adjacent to drainage facilities. Section 27-26. Slorm drainagc standards. Article 5.Variances and Appeals. Section 27-27. Criteria for variances. Section 27-2X. Application for variance. Section 27-29. Review of variance applications. Section 27-30. Recording and reporting of variances. Section 27-31. Appeals. j SUPP 5 (1-2008) 10A-1 Hawaii County Multi-Hazard Mitigation Plan Chapter 10 Appendix Article 6.Enforcement. Section 27-32. Right to enter. Section 27-33. Notico of violation. Section 27-34. Administrative order. Section 27-35. Injunctive relief. Section 27-36. Criminal enforecment. Section 27-37. Removal of encroachment andior obstruction notices. Section 27-38. Removal by County.costs. I� 10A-2 Hawaii County Multi-Hazard Mitigation Plan Chapter 10 Appendix FLOODPLAIN MANAGEMENT 27-1 Chapter 27 FLOODPi.AIN MANAGEgfEN r Article 1.Authorization, Section 27-1. Statutory authority_ This chapter is enacted pursuant to the U.S.National Flood Insurance.pct of 1968(Public Laws 90-416 and 91-152), as amended, and the U-S. Flood Disaslcr Protection Act of 1973 (Public Law 93-234), as amended. in addition. the Legislature of the State of llawai'i has in Ilawai'i Revised Statutes 46-1.5(5). 46-1.5(14),46-11,46-11.5,and 46-12 conferred upon the various counties the authority to adopt regulations designed to promote the public health,safety,and general welfare of its citizenry (1993,Ord.No,93-78,see.3;Am.2007,Ord,No,07-169,sec.3.) Section 27-2. Findings of fuel. (a) The flood hazard areas of the County of Hawaii are subject to periodic inundation which results in loss of life and property, health and safety hazards, disruption of commerce and governmental services, extraordinary public expenditures for flood protection and relief and impairment of the tax base,all of which adversely affect the public health,safety and general welfare. (b) These flood losses me caused by the cumulative effect of obstructions in areas of special flood hazards which increase flood heights and velocities and,when inadequately anchored,cause damage to uses in other areas.Lases that are inadaqualcly floodproofcd,clovated.or otherwise protected Vrom flood damage also contribute to the flood loss. (1993.Ord_No.93-76,sec.3.) Section 27-3. Purpose. I[is[lie purpose of iltis chapter to promote the public healft safety,and general welfare,and it)minimize public and private losses due to flood conditions in specific areas by provisions designed: (a) To protect human life and health: (b) To minimize expenditure of public money for costly flood control prgiccts; (c) To minimize the need for rescue and relief efforts associated with flooding and generally undertaken at the expense of the general public; (d) To minimize prolonged business interruptions; (c) To minimize damage to public facilities and utilities such as water and gas mains.electric,telephone and sewer lines,streets and bridges located in areas of special flood hazard: (f) To help maintain a stable tax base by providing for the sound use and development of areas of special flood hazard so as to minimize future flood blight areas; (g) To assist in notifying potential buyers that properly is in an area ofspecial flood hazard;and (h) To ensure that those who occupy areas of special flood hazard assume responsibility for their actions. (1993,Ord.No.93-76,sce.3.) Section 27-4. Scope and methods. In order to accompll4h its purposes,this chapter Includes methods and provlslom;for: (a) Restricting or prohibiting uses which are dangerous to health..safety.and property due to water or erosion hazards,or which result in damaging increases in erosion or flood heights or velocities: (b) Requiring that uses vulnerable to fluods,including lacilitics which serve such uses,be protected against Rood damage at the time of-initial construction; 27-1 SUPP 5 (1-2008) 1 0A-3 Hawaii County Multi-Hazard Mitigation Plan Chapter 10 Appendix §27-4 IIAWAI'I COUNTY CODE (e) Controlling the alteration of natural floodplains,stream channels,and natural protective hanier:s,which help accommodate or channel llexrd walers; (d) Controlling fill.grading,dredging,and other dcvclopment which may increase flood damage;and (e) Preventing or regulating the construction of flood barriers which will unnaturally divert flood waters or which may increase flood hazards in other areas. (1993,Ord.No.93-78,sec.3.) Article 2.General Provisions. Section 27-5. Applicability. (a) Ills chapter shall apply to all areas of special flood hazards identified by the Federal Emergency Management Agony in a scientific and engineering report entitled "Flood insurance Study," dalcd April 2,2004, with accompanying Flood Insurance Rate Maps and all future changes, revisions and amendments to these documents, and shall apply to all areas bordering identified special flood hazard areas,and all other areas outside the idcntificd special flood hazard areas encompassing and adjacent to a river,stream, stormwater channel,outtall area, or other inland water or drainage facility determined by the director of public works to be subject to flood hazards.'Thc special flood hazard areas are as follows: (1) Hoodway fringe-Zones AL.All,and AO. (2) Floodway. (3) Coastal high hazard(tsunami)-Zones V and VF._ (4) General floodplain-Zone A. (5) Land adjacent to drainage facilities,and Zone A99. (b) This chapter shall not apply lo: (l) Any building permit lawfully issued prior to May 5,1982 or building permit application property filed and accepted for review prior to May 5, 1982 provided that approval was obtained without any significant changes in plaits or specifications made after May 5,1952. (2) Roadway and site improvements for subdivisions for which tentative approval had been granted prior to May 5, 1982 and where roadway and site improvement construction and grading plans had received all necessary agency approvals by May 5,1982. (3) Camtvals,l'u`aus,fairs,and camping tents of a temporary nature which are not in a floodway. (4) Nonfenwd,at grade outdoor swimming pools. (5) Signs which are not in a floodway. (6) Domolilion, (1993,Ord.No,93-78,sec.3;Am.2001,Ord.No.01-108,sec.1;Am.2007,Ord,No.07-169,sec.4.) Section 27-6. Basis. The areas of special flood hazard identified by the Federal Emergency Management Agency in the Flood Insurance Study dated April 2, 2004, along with all subsequent revisions and amendments, and the Flood Insurance Rate Maps, dated April 2.2004, May 16, 1994,July 16, 1990,and September 16, 1988, and all fulure changes,revisions.and amcndmcnts to these documents,arc hereby adopted and declared to be a part of this chapter.the Flood Insurance Study and Flood Insurance Rale\gaps,and all future changes,revisions,and amendments to these documents,are on file at the Aupuni Center,DepMmem of Public Works, 101 Pauahi Strucl.Suite 7,Hilo,Hawaii 96720. (1993,Ord,No.93-78,sec.3;Am.1994,Ord.No.94-74,sec.3;Am.1995.Ord.No.95-86,sec.3;Am.2007. Ord.No.07-169,sec.5.) SUPP 5 (1-2008) 27-2 1 0A-4 Hawaii County Multi-Hazard Mitigation Plan Chapter-10 Appendix FLOODPLAIN MANAGEMENT 27-7 Section 27-7. Compliance. No structure or land shall hereafter be constructer) located.extended, converted,or altered without full compliance with the terms of this chapter and other applicable regulations.The terms of this chapter shall be enforced by the standards set forth in article 6. (1993,turd.No.93-78,sec.3.) Section 27-8. Other laws and regulations. All construction and improvements subject to this chapter shall comply with other applicable laws and regulations including,but not limited to,the zoning,building,electricity,plumbing,subdivision,erosion and sedimentation control chapters of the Hawaii County Code,and the storm drainage standards,October 1970 edition,or later revisions,of the County of Hawaii.This chapter,designed to reduce flood losses,shall talc precedence over any less restrictive,conflicting laws,ordinances.and regulations.Thus chapter is not intended to mpeal, abrogate, or impair any existing casements. covenants,or deed restriction.However,where this chapter and another c:haptcr,casement,covenant,or dead restriction conflict or overlap,whichever imposes the more stringent restrictions shall prevail. In the event of a conflict between this chapter and the National Flood Insurancc Program and Related Regulations(NFIP),as amended,file more restrictive provision will govern. (1993,Ord.No.93-78,sec_3;Am.2007,Ord No.07-169,sec,0.) Section 27-9. interpretation. In the interpretation and application of this chapter,all provisions shall be: (a) Considered as minimum requirements; (b) Liberally construed in favor of the County afHawai'i:and (c) Dcemed neither to limit nor repeal any other powers granted to the County of Hawaii under State of Ilawai`i statutes. (1993,Ord.No.93-78,sec.3.) Section 27-10. Warning and disclaimer of liability. The degree of flood protection required by this chapter is considered reasonable for regulatory purposes and is based on scientific and engineering considerations.Larger floods can and will occur on rare occasions. Flood heights may be increased by man-made or natural causes.This chapter does not imply that land outside the areas of special flood hazards and areas of llood-related erasion hazards,or uses permiucd within such areas will be free from flooding or flood damages. This chapter shall not creale liabibty on the part of the County of Hawaii, any officer or employee thereof, or the Federal insurance Administration, Federal Emergency U--magcment Agency, for anv flood damages drat result from reliance on ilus chapter or anv administrative decision lawfully madethereundcr. (1993,Ord,Nu.93-78,sec.3.) Section 27-11. Severablldty. 'lltis chapter and the various parts thereof are hereby declared to be severable.Should any section of this chapter b,:declared by the courts to be unconstitutional or invalid,such decision shall not affect the validity of the chapter as a whole, or any portion thereof other than the section so declared to be unconstitutional or imand. (1993,Ord.No.93-78,scc.3.) 27-3 SUPP,5 (1-2008) 1 0A-5 Hawaii County Multi-Hazard Mitigation Plan Chapter-10 Appendix §27-12 IIAW AI'l COUNTY CODE Section 27-12. Definitions. Unless specifically dcftned below,words nr phrases used in this chapter shall be interpreted so as to give them the meaning they have in common usage and to give this chapter its most reasonable application. "Accessory use"means a use which is incidental and subordinate to the principal use of the parcel of land on which it is located. "Appeal" means a request for a review of the floodplain adminisirator's interpretation of any provision of this chapter or denial of a request for a variance. "Area of shallow flooding"means a designated AU or All tone on the Flood Insurance state blap (1-MI).'Ilie base flood depths range from one to three feet;a clearly defmal channel does not exist: the path of flooding is unpredictable and indeterminate: and velocity flow may he evident. Such flooding is characterized by ponding or sheet flow. "BackfUl"means the placement of 511 material within a specified depression,hole or excavation pit below the surrounding adjacent ground level as a means of improving floodwater conveyance or to reslore the land to the natural contours existing prior to excavation. "Base flood"means the flood having a one percent chance of being equaled or exceeded in any given year(also called the"one-hundred-year flood"). "Base flood elevation"means the water surface elevation of the base flood. "Basement" mean.%any area of the building having its flour subgrade(below ground level)on all sides. "Breakaway walls" are any type of walls, whether solid or lattice. and whether constructed of concrete,masonry,wood,metal,plastic nr any other suitable building material which is not part of the structural support of the building and which is designed to break away under abnormally high tides or wave action without causing any damage to the structural integrity of the building on which they are used or any buildings to which they night be carried by floodwaters.A breakaway wall shall have a safe design loading resistance of not less than ten and no more than twenty pounds per square foot.Use of breakaway walls must be certified by a Gccnscd structural engineer or architect and shall meet the following conditions: (1) Breakaway wall collapse shall result from a water load less than that which would occur during the base flood;and (2) 'lime elevated portion of the building shall not incur any structural damage due to the effects of wind and water loads acting simultaneously in the event of the base flood. "Buffer zones"are areas bordering and within 50 feet of special flood hazard areas with base flood elevations, depth numbers spccified in feet on the FIRNI or other areas that have boon studied and identified with base flood elevations or depth numbers. 'icomtal high hazard area'-See"Zone V"and Zone VL." "Development"means any man-made change to improved or unimproved real estate,including bill not limited to buildings or other structures,mining, dredging, tilling,grading,paving,excavation or drilling operations or storage of equipment or materials. "Drainage fadlity"-See"Watercourse." "Encroachment" means the advance or infringement of uses, plant growth, fill, excavation, buildings,permanent structures or development into a floodplain which may impede or alter the flow capacity of a floodplain_ "Existing manufactured home park or subdivision' means a manufactured home park or subdivision for which the construction of facilities for servicing the lots on which the manufactured homes are to he affixed(including,at a minimum.the installation of utilities,the construction of shreds, and either final site grading or the pouring of concn:le pads)is completed before May 5,1982. SUPP 5 (1-2008) 27-4 1 0A-6 Hawaii County Multi-Hazard Mitigation Plan Chapter 10 Appendix 1'LOODPLAiN MANAGEMENT §27-12 "Fill"iS the placement of fill material at a ipocified location to bring die ground surface up to a desired elevation. "Fill material"can he natural sand,dirt.soil or rock.For the purposes of floodplain management, fill material may include concrete, cement,soil cement, brick, or similar material as approved on a case-try-case basis. "Flood elevation determination"means a determination by the Federal Emergency Management Agency of the water surface elevations of the bash flood,that is,the flood level that has a one percent or greater chance of occurrence in any given year. -Flood elevation study"or"flood study"moans an examination, evaluation,and determination of flood hazards and, if appropriate, corresponding water surface elevations, or an examination, evaluation and dotern ination of flood-rolated erosion hazards. "Hood,flooding,or floodwater"means: (1) A general and temporary condition of partial or complete inundation of normally dry land areas from: (A) The overflow of inland or tidal waters: (l3) 'the unusual and rapid accumulation of runoff or surface waters from any source which arc approximately caused by flooding as defined in paragraph(A)(ii)of this definition and are akin to a river of water on the surfaces of normally dry land areas,as when earth is carried by a current of water and deposited along the path of the current:and (2) The collapse or subsidence of land along the shore of a lake or other body of water as a result of erosion or undermining caused by waves or currents of water exceeding anticipated cyclical levels or suddenly caused by an unusually high water level in a natural body of water,accompanied by a severe start.or by an unanticipated force of nature,such as flash flood or an abnormal tidal Surge,or by some similarly unusual and unforeseeable event which results in flooding as defined in paragraph (1)(A) of this definition. "Flood Insurance Rate Xtap(11RIM)" means the official map on which the Federal Lmergency, Management Agency has delineated both the areas of special flood hazards and the risk premium zones applicable to the community. "Rood Insurance Study" means the official report provided by the federal Emergency Management Agency that includes flood profiles,the Flood Insurance Rate Map.and the water surface clevafion of the base flood. "Flood protection system" means those physical structural works for which funds have been authorized. appropriated, and expended and which have been constructed specifically to modify flooding in order to reduce the extent of the area within a community subject to a "special flood hazard"and the extent of the depths of associated flooding.Such a system typically includes hurricane tidal harriers, dams reservoirs,levees, or dikes.These specialized flood modifying works are those constructed to conform with sound engineering standards. "Floodplain administrator"is the individual appointed to administe7 and enforce the floodplain management regulations.'this person shall be the director ofpublic works of the County of Ifawai`i or the director's duly authorized representative who shall be a currently licensed professional engineer in the Stale of Hawaii. "lloodplain management"means the operation of an overall program of corrective and preventive measures for reducing flood damage,including but not limited to emergency preparedness plans,flood control works and lloodplain management regulations. 27-5 SUPP s (1-2008) 1 0A-7 Hawaii County Multi-Hazard Mitigation Plan Chapter-10 Appendix §27-12 MW.AI'l COUNTY CODE "Floodpluin management regulations-means zoning ordinances,subdivision regulations,building codes,hcallh regulations,and special purpose ordinances(such as a floodplain ordinance or an erosion and sedimentation control nrdinanec)and other applications of police power. The term doscribes such state or local regulations,in any combination thereof.which provide standards for the purpose of flood damage prevention and reduction. "Floodplain or flood-prone area"means any land area susceptible to being inundated by water from any sourze(sev definition of"fluodirtg"). "Iloodproofing" means any combination of structural and nonstructural additions, changes, or adjustments to structures which reduce or eliminate flood damage to real estate or improved real property.water and sanitary facilities,xtruclures,and their contents. "Hoodway fringe" is the areas of a floodplain on either side of the designated floodway where encroachment may be permitted. "floodway" or"regulatory floodway"meats the channel of a river or other watercourse and the adjacent land areas that most be reserved in order to discharge the base flood without cumulatively increasing the water surface elevation. "Fraud and victimization"related to article 5,variances,of this chapter means that the variance granted must not cause fraud on or victimization of the public.In examining this requirement, the director of public works will consider the fact that ever' newly constructed structure adds to government responsibilities and remains a part of the community for filly to one hundred years. Structures that are permitted to be constructed below the base flood elevation are subject during all those years to increased risk of damage from floods,wimile future owners of the structure(s)and the community as a whole are subject to all the costs, inconvenience, danger, and suflating that those increased flood damages bring.in addition,future owners may purchase the sinmcture(s),unaware that it is subject to pmenlial flood damage, and the structure(s) call be insured only at very high flood insurance rates. "Freeboard"means a factor of safely usually expressed in feet above a flood level for purposes of floodplain management. "Freeboard" tends to compensate for the many unknown factors that could contribute to flood heights greater than the height calculated for a selected size flood and floodway conditions.such as wave action,bridge openings.and the hydrological effect of urbanization of the watershed- "Functionally dependent use means a use which cannot perform its intended purpose unless it is located or carried out in close proximity to water, The, term includes only docking facilities, port facilities that arc necessary for the loading and unloading of cargo or passengers,and strip building and ship repair facilities,but does not include long-term storage or related manufacturing facihtics_ "General floodplain"-Sue"Zone A." "Hardship"as related to article 5,variances,of this chapter means the hanIsi ip that would result from a failure to grant the requested variance.The director of public works requirus that the variance be exceptional,unusual,and peculiar to the property involved.Meru economic or financial hardship alone is not exceptional.Inconvenience,aesthetic considerations,physical disabilities,personal preferences, or the disapproval of one's neighbont likewise cannot as a rule,qualify as exceptional hardships.All of these problems can he resolved through other means,without granting a variance.'11tis is so even if the allctrtativc means are more expensive or complicated than building with a variance.or if they require the property owner to put the parcel to a different use than originally intended,or to build clsewhere. "Highest adjacent grade" means the highest natural elevation of lire ground surface prior to construction next to the proposed walls of a structure. "Ifistoric structure"means any structure that is: (1) Listed individually in the National Register of llistoric Places(a listing maintained by the Department of Interior)or preliminarily determined by the Sceretary of the Interior as meeting the requirements for individual listing on the National Register. SUPP 5 (1-2008) 27-6 10A-8 Hawaii County Multi-Hazard Mitigation Plan Chapter 10 Appendix T'LOODPLAiN MANAGEMENT §27-12 (2) Cati fied or preliminarily determined by the Secretary of the Interior as contributing to the historical significance of a rcgislcrcd historic district or a district preliminarily dcturmincd by the Secretary of'lhe Interior to qualify as a rcgislcrcd historic district.. (3) Individually listed on a Slate of Ilawai'i inventory of historic places where the historic preservation program has been approved by the Secretary of the interior;or (4) Individually listed on a local inventory of historic places in communities with historic preservation programs that have been certified either, (A) By an approved Stale program as determined by the Secretary ofthe Interior,or (B) Diractly by the Sccrctary of the Interior in states without approved programs. `Lcvice'means a man-made structure,usually an earthen embankment designed and constructed in accordance with sound engineering practices to contain control. or divert the flow of water so as to provide protection from temporary flooding, "Levee system" means a flood protection system which consists of a levee, or levees, and associated stmetures, such as closure and drainage devices, which are constructed and operatud in accord with sound engineering practices. "Lowest floor" means the lowest floor of the lowest enclosed area (including basement). An unfinished or flood resistant enclosure.usable solely for parking of vehicles.building access,or storage in an area other than a basement area is not considered a building's lowest floor provided that such enclosure is not built so as to render the structure in violation of the applicable noncicvation design requirements of this chapter. `Manufactured home-means a structure,transportable in one or more sections,which is built on a permanent chassis and is designed flor use with or without a permanent foundation when attached to the required utilities. 'lhe lerm "manufactured home"includes a "mobile home' but does not include a "recreational vehicle." "Manufactured home park or subdivision"means a parcel(or contiguous parcels)of land divided into two or more manufactured home lots for rent or sale. "Market value."For the purposes of determining substantial improvement,market value pertains only to the structure in question.It does not pertain to the land,landscaping,or detached accessory structures on the property.For determining substantial improvement.the value of the land must always be subttactcd.Acceptable estimates of market value can be obtained from the following sources: (1) Independent appraisals by a professional appraiser licensed by file State. (2) Property appraisals used for tax assessment purposes by 1ha County department of finance,real property lax office. (3) The value of buildings taken from National Flood Insurallec Program claims data. This value shall be used as a screening tool to identify those structures where the substantial improvement ratio is less than forty percent or greater than sixty percent. "Mean sea level" means, for purposes of the National Flood Insurance Program. the National Gcodclic Vertical Datum of 1929 or other datum, to which hasc flood elevations shown on a community's Flood Insurance[fate Map are referenced. "Minimum necessarv"related to article 5,variances,of this chapter mcam the minimum necessary to afford relief to the applicant of a variance with a minimum deviation from the requirements of this chapter.in the case of variances to an elevation requiroment,this means the director of public works need not grant permission for the applicant to build al grade,for example,or even to whatever elevation the applicant proposes,but only that level that the director of public works believes will bout provide relief and preserve the integrity of this chapter. "New construction"for floodplain management purposes,means structures for which the-start of construction"comtnenced on or alter May i. 1982,and includes any subsequent improvements to such structures. 27.7 SUPP 5 (1-2008) 1 0A-9 Hawaii County Multi-Hazard Mitigation Plan Chapter-10 Appendix §27-12 MW:AI't COUNTY CODE "New manufactured home park or subdivision"means a manufactured home park or subdivision for which the construction of facilities f'or servicing the lots on which the manufactured(tomes are to he affixed(including at a minimum.the installation of utilities,the construction of streets,and either final site grrading or the pouring of concrete pads)is completed on or after May 5,1982. "Obstruction"includes but is not funned to any darn.wall, wharf;embankment,levee,dike,(rile. abutment,protection,excavation,channcfization,bridge_conduit,culvert,building,wire.fence, rock, gravel,refuse, fill, structure, vegetation, or other material in, along, across. or projecting into any walemourse which may alter,impede, retard, or change the direction and/or velocity of the flow of water,or due to its location,its propensity to snare or collect debris carried by the flow of water or its likelihood of being carried downstream- "Ono-hundred-year flood" means a flood which has a one pet"nt annual probability of being equaled or exceeded.11 is identical to the"base flood," "Ono-hundred-year floodplain" means any area of land susceptible to being inundated by water from any source generated by the one-hundred-year flood. `Primary frontal dune" means a continuous or nearly continuous mound or ridge of sand with relatively steep seaward and landward slopes immediately landward and adjacent to the beach and subject to crnsion and overtopping from high tides and waves during major coastal storms.The inland limit of the primary frontal dune occurs at the point where there is a distinct change from a relatively mild slope. "Principal structure"means a structure used for the principal use of the property as distinguished from an accessory use. "Recreational vchield"means a vehicle which is: (1) Bud on a single chassis: (2) Pour hundred square feet or less when measured at the largest horizontal projection; (3) Designed to be self-propelled or permanently lovable by a light duty truck:and (4) Designed primarily not for use as a permanent dwelling but as temporary living quarters forrecrcadonal,camping,travel,or seasonal use. "Regulatory floodway"means the channel of a river or other watercourse and the adjacent land areas flint must be reserved in order to discharge the base flood without cumulatively increasing the water surface elevation. "Repetitive loss structure-means home or business that was damaged by flood two times in the past ten vears, where the cost of fully repairing the flood damage to the building, on Cite average, equaled or exceeded hventy-five percent of its market value at the time of each flood. "Riverine" means relating to, formed by, or resembling a aver(including tributaries), stream, brook,etc. "Sand dunes"means naturally occurring accumulations of sand in ridges or mounds landward of the beach. "Sheer flow aura"-Sec••arcs of shallow Ilooding." "Special flood hazard area"means an area having special flood or flood-related erosion hazards. and shown on the Flood Insurance Rate Maps as Zones A,AO,AE,A99,AK VF or V. "Start of construction"includes substantial improvement and other proposed new development and means the dale the building permit was issued, provided the act" start of construction. repair, reconstruction, rehabilitation, addition, placement, or other improvement was within one hundred- eighty days from the date of the permit.'The actual start means either rite foal placement of permanent construction of a structure on a site,such as the pouting of slab or footings.the installation of piles,the construction of columns, or any work beyond the stage of excavation; or the placement oh a SUPP 5 (1-2008) 27-8 1 OA-10 Hawaii County Multi-Hazard Mitigation Plan Chapter-10 Appendix T'LOODPLAiN MANAGEMENT §27-12 manufactured home on a foundation.Permanent construction does not include land preparation,such as clearing.grading and filling;nor does it include the installation of streets and/or walkways:nor does it include excavation for a basement, (outings,piers,or foundations,or the erection of temporary forms; nor does it include the installation on the property of accessory buildings.such as garages or sheds not occupied as dwelling units or not part of the main structure.For a substantial improvement,the actual start of construction means the first alteration of any wall,coiling,floor.or other structural pail of a building,whether or not that alteration affects the external dimensions of*the building. "State`tream fire State of l lawai`i. -Structure" moans a walled and motod building, including a gas or liquid storage lank, that is principally above ground,as well as a manufactured home. "Substantial damage"means damage of any origin sustained by a structure whereby file cost of restoring the structure to its before damaged condition would equal ur exceed fifty percent of the market value of the structure before the damage occurred. "Substantial improvement." For the purposes of this chapter, the determination of whelhcr any improvements constitute substantial improvements is applicable only to structures built prior to May 9, 1982 or buildings constructed after May 5.1982 which were not within a special flood hazard area at the time of issuing the building permiL "Substantial improvement" means any repair,reconstruction. rehabilitation.addition,or other proposed new development of a structure,the cost of which equals or exceeds Cully percent of the market value of the structure before the -start of construction" of the improvement which shall be die stint of all costs of all such work performed in the previous ten years including the cost of the current work being considered.The value of the structure including previous ten year improvements,shall be certified by a contractor,engineer,or architect licensed by the State and the property owner as may be required on a form provided by the County. 11tis term includes structures which have incurred"substantial damage,"regardless of the actual repair work performed. The term does not,however,include either: (1) Any project for improvement of a structure to correct existing violations of stale or local health,sanitary,or safety coda specifications which have been identified by the local code enforcement oOicial and which are the minimum necessary to assure safe living conditions;or (2) Any alteration of a `historic structure;' provided that the alteration will not proclnde,the tructure's continued designation as a"historic structure." "Variance"means a grant ofrehof from the roquu•ements of this chapter which permits construction in a manner that would otherwise be prohibited by this chapter. "Violation"means the failure of a structure or other development to be Cully compliant with the community's floodplain management regulations. A structure or other development without the elevation certificate,other certifications,or other evidence of compliance with this chapter is presumed to be in violation until such time as that documentation is providcd- "Water surface elevation"means the height,in relation to the National geodetic Vertical Datum at' 1929. (or other datum, when: specified) of floods of various magnitudes and frequencies in the floodplairis of coastal or riverine areas. "Watercourse" means a lake, river, creek. stream, wash, arroyo,channel. or other topographic feature on or over which water;flow at least periodically.Watercourse includes specifically designated arias in which substantial damage may occur. -Zone A"is the special flood hazard area that corresponds to the one hundred-year floodplains that are determined in the hood Insurance Study by approximate methods. Because detailed hydraulic analyses are not performed for such areas,base flood elevations or depths have not been determined within this zone. "'Zone A99"is the special flood hazard area where enough progress has been made on a protective system,such as dikes,dams,and levees, to consider it complete tar insurance rating purposes.Base flood elevations have not been determined for areas designated as Zone A99, "Zone AG"is the special flood hazard area that corresponds In the one hundred-year floodplains that are determined in the Hood Insurance Study by detailed methods.Whole-fool base flood elevations 27-9 SUPP,5 (1-2008) 10A-11 Hawaii County Multi-Hazard Mitigation Plan Chapter 10 Appendix §27-12 HAWAII COUNTY CODE derived from the detailed hydraulic analyses have been determined at selected intervals within this zone. "7onc AH" is the special flood hazard area that corresponds to the areas of one-hundred-year shallow flooding(usually areas of ponding) where average depths are between one and three feel. Miole-foot base flood elevations derived from the detailed hydraulic analyses have been determined at selected intervals within this zonc. "Zone AO" is the special flood hazard area that corresponds to the areas of ono-hundred-year shallow flooding(usually sheet flow on sloping terrain)where average depths are between one and three feet. Average whole-foot depths derived fiam the detailed hvdraulic analvsCR have been determined within this zonc. "Zone D"corresponds to unstudied areas where flood hazards are undetermined.but possible. '•Zone V" is the special flood hazard area that corresponds to the one hundred-year coastal floodplains extending from offshore to the inland limit of a primary frontal dune along an open coast and any other area subject to high velocity wave action from storms or seismic sources,ll is an arca subject to high velocity waters, including coastal and tidal inundation or tsunamis. Base flood elevations have not been determined for areas designated as Zone V. -Zone VF." is the special flood hazard area that corresponds to the one hundred-year coastal lloodplains extending firm offshore to the inland limit of•a priman,liontal dune along an open coast and any other ara subjecl to high velocity wave action from storms or seismic sources.11 is an arca subject to]sigh velocity waters, including coastal and tidal inundation or tsunamis. Whole-fool base flood elevations derived from the detailed hydraulic analyses have been determined at selected intervals within this zone. "Zone\(shaded)"are areas of moderate flood hazard corresponding to areas of the five-hundred- year floodplain,areas of one-hundred-year flooding where average depths are less than one foot,areas of one-hundrtd-year flooding where the contributing drainage area is I.ss than one square mile,and areas protected from the one-hundred-year flood by levcos. 'Zone N(unshaded)"are areas of*minimal flood hazard corresponding to areas outside of the five- hundred-year floodplain.Base flood elevations or depths have not been determined for Lone X. (1993,Ord.No.93-78,sec.3:Am.1997,Ord.No.97-116,sec l;Am.2001,Ord.No.01-108,sues.1 and 9; Am.2007,Ord.No.07-169,scc.7.) Section 27-13. Nonconforming structures. Any nonconforming structure existing on clay 5,1982 or made nonconforming by a change in the special flood hazard area may continue,subject to the following conditions: (a) Any repair,reconstruction,improvement,or addition to a nonconforming structure.if it is considercd to be substantial improvement,shall comply with the applicable standards of this chapter. (b) All relocated structures shall comply with the applicable standards of this chapter. (c) Substantial improvement of a damaged,dcstroyod,or demolished structure located in a lloodway shall not be allowed unless a variance from the flood requirements is obtained. (1993,Ord.No.93-78,scc.3:Am.1997,Ord,No.97-116,sec.2.) Article 3.Administration. Section 27-14. Director of public works approval. No building permit, certificate of occupancy, or grading permit shall be issued, no structure shall be occupied,and no development or subdivision shall be approved without the approval of die director of public works with respect to compliance with the provisions of this chapter. (1993,Ord.No.93-78,sec.3:Am.2001,Ord,No.01-10R,sec.1;Am.2007.Ord.No.07-169.sec.R,) SUPP 5 (1-2008) 27-10 1 0A-12 Hawaii County Multi-Hazard Mitigation Plan Chapter'10 Appendix FLOODPLAiN MANAGEMENT §27-15 Section 27-15. Designation of the tloodplain administrator. The dinclor of public works of-the County of Hawaii is hereby appointed to administer,implement,and enforce this chapter in accord with the provisions of this chapter. (1993.Ord No.93-78,sec.3;Am.2001,Ord.No.01-108,sec.1,) Section 27-16. Duties and responsibilities of the Iloodplain administrator. The lloodplain administralnr, with the cooperation and assistance of other County departments, shall administer this chapter.'llre duties and responsibilities of the floodplain administrator shall include.but not be limited to: (a) PenrdI review. (1) All building pamtils,certificates of occupancy,grading permits, and development or subdivision proposals shall be reviewed to determine whether lire requnCmen(s of this chapter have been satisfied; (2) All other development permits referred by other governmental departments and agencies shall be reviewed for consistency with the mquirement_a of this chapter, (3) All permits and proposals shall be reviewed to determine that the proposed building %td is reasonably safe from flooding; (4) For proposed building sites in flood-prone areas where special flood hazard areas have not been defined,water surface elevations have not been provided,and there is insufficient data to identify the floodway or coastal high hazard areas but the flood plain administrator has determined that there are verifiable physical indications that such hazards are present,all new construction improvements to repetitive loss structures and substantial irnprovcmcnts(including the placement of manufactured homes)shall be: (A) Designed and adequately anchored to prevent flotation,collapse,or lateral movement: (Il) Constructed offlood-resistant materials; (C) Constructed by methods and practices that minimize flood damage:and (D) Constructed with electrical, heating, ventilation, plumbing, and air conditioning equipment and other service facilities (hal are designed and or located so as to prevent water from entering or accumulating within the components during conditions of flooding; (E) Be reviewed to assure that all necessary permits have beun received from those governmental agencies from which approval is required by Federal or State law,including section 404 of the Federal Water Pollution Control Act Amendments of 1972,33 U.S.C.1334; (F) New and replacement utilities shall comply with the requirements of section 27-19;and (5) All permits shall be reviewed to dow mine that the proposed dcvclopment when combined with all other existing and anticipated development will not increase lie water surface elevation of the base flood at any point. (b) Ittforrnation to be maintained. (1) The Flood Insurance Study and Flood insuranou Rate Maps for thn County of Hawaili; (2) The certification of lowesl floor elevation: (3) The certification of flu odproofine for spaces below the base flood elevation, (4) line certification oflinal pad elevation where a site is filled above the base flood elevation; (5) The certification that an encroachment in the floodwav will not result in anv increase in flood levels during base flood discharge;and (6) 'the certification of elevation and structural support for structures In the coastal high hazard area. (c) Interpretation ofmaps. The director of public works shall make interpmIafions where nceded,as to the exact location of the boundaries of the areas of special flood hazards (rur axampte, whcr: there appears to be a conflict between a mapped boundary and actual field conditions). A person contesting the location of the boundary shall be given a reasonable opportunity to appeal the interpretation as provided in article 5. 27-11 SUPP 5 (1-2008) 1 0A-13 Hawaii County Multi-Hazard Mitigation Plan Chapter-10 Appendix §27-16 IIAWAI't Cl)U1VTY CODE (d) Change in base flood elevations. Whenever base flood elevations increase or decrease or'result in a mappable alteration of the boundaries of any special flood hazard area,as a result of physical changes affecting flooding conditions, as soon as practical. but no later than six months aflor the date such information becomes available. the floodplain administrator shall notify the Federal Lmergency Management Agency of the changes by submitting technical or scientific data through the Letter of Map Revision process. Such a submission is necessary so that upon confirmation of those physical changes affecting flooding conditions,risk premium rates and floodplain management requirements will be based upon current data. (e) Use of other base flood data.When base flood elevation data has not been provided in accordance with section 27-6, the floodplain administrator shall obtain, review, and reasonably utilize any base flood elevation and floodway data available from a federal or State agency, or other source, in order to administer article 4.Anv such information shall be submitted to the County of Ilawaiti for adoption. (f) Whenever a watercourse is to be altered or relocated: (1) Require that the flood carving capacity of the altered or relocated portion of said watercourse is maintained: (2) For riverine situations, notify die State of llawai`i department of land and natural resources (commission an water resource management) and all adjacent property owners, prior to such alteration or relocation of a watercourse, and submit evidence of such notification to the Federal Emergency Management Agency. (3) Whenever a proposed alteration or relocation occurs that would significantly change the base flood elevation or result in a mappable alteration of the boundaries of anv special flood hazard area, technical and scientific data through the Conditional Letter of Map Revision(CLOMR) shall be submitted to and approved by the Federal L•me>Qency Management Agency.Such a submission is necessary so that upon completion of those physical changes affecting flooding conditions, risk premium rates and floodplain management requirements will he based upon current data.Work to be performed under an approved Conditional Lefler of Map Revision(CLOMR)shall be subject to the following: (A) Work shall not begin any on-site development affecting or impacting the floodplain until an approved Conditional i.etter of Map Revision is received from the Federal Emergency Management Agency: (B) Within sixty days of receiving final approval from director of public works for the completion of the alteration or relocation of a watercourse, the request for a Letter of Map Revision (LOMR),and all other information required by the 1-crier of Map Revision(i OMR)process shall be submitted to the flood plain administrator_ (g) Take action to remedy violations of this chapter as specified in article 6. (1993,Ord.No.93-78,sec.3;Ant.3001,Ord.No.01-108,sec.1;Am 2007,Ord.No.07-169,sec.9.) Article 4.Standards. Section 27-17. Certification standards. Pre-construction and post-construction certification of elevafion and floodproofing of new constructions, improvements to repetitive loss structures,development,and substantial improvements within areas of special flood hazards and buffer zones slmll be submitted to the director of public works and shall he maintained its a matter of public record. (a) Pre-construction certification. Requirements for approval of the building permit shall include the following items,as applicable, and any additional items as required by the director of public works to promote public welfare and safety; (1) Certification of building plans.Each set of building plans shall be wrtilied by a structural engineer or architect,currently licensed in the State ofllawai`i,to be in compliance with the requirements of this chapter. SUPP 5 (1-2008) 27-12 1 0A-14 Hawaii County Multi-Hazard Mitigation Plan Chapter 10 Appendix 1'LOODPLAIN MANAGEMLTtT §27-17 (2) Elevation certification on building plans.Tlw elevation of the lowest floor shall be certified on each set of the building plans by a civil engineer or land surveyor currently licensed in the State of Hawai•i. (3) Special flood hazards area certification. the County of Ilawai'i -Special P1ood Hazard Area Certification" form, as amended, shall be completed and certified by a structural engineer or architect currently licensed in the State of Hawaii. The completed "Special Flood Hazard Certification"shall be submitted 1or approval with the building plans, (4) Iloodproofing certification. For all new nonresidential construction and substantial improvement with enclosed areas below the base flood elevation.the Federal Fmcrgcncy Management Agency "Floodproofing Certificate"form,as amended shall be completed and certified by an engineer or architect currently licensed in the State of Ilawai`i and shall be submitted for approval with the building plans. The director of public works may require additional information regarding the floodproofing design from the permit applicant and the applicant shall provide it.'lhe information required may include the design data and calculations used in the lloodprooling design,a detailed flood elevatiun study, a drainage report, and other information as determined necessary by the director of public works to establish compliance with the provisions of thus chapter and to promote public welfare and safety. (b) Post-construction certification.Requirements for approval of the certificate of occupancy shall include the following items,as applicable.and any additional items as required by the director of public works(o promote public welfare and safety: (1) Elevation certification. 7'lie Federal Emergency Management Agency"Elevation Certificate," as amended,shall he completed and certified by a land surveyor.civil engineer.or architect currently licensed in the State of Ilawai'i and submitted for approval with the application for the certificate of occupancy. The information certified within the"Llevation Certificate" shall be based on actual construction. (2) Compliance with other requirements of this chapter. (1993,Ord.No.93-79,scc_3;Am.2001-Ord No.M-10R,sec.1;Ain,2007,Ord.No.07-169,sec.1Q) Section 27-18. Standards ror construction. Standards for construction within areas of special flood hazards and buffer zones am established as follows: (a) Anchoring. (1) Now construction,improvements to repetitive loss structures,and substantial improvements shall be adequately anclimcd to resist flotation,collapse or lateral movement of the structuro resulting from hydrodynamic and hydrostatic loads,including the effects of buoyancy. (2) All manufactured homes,including mobile homes,shall meet all standards for structures. (b) Construction materials and methods. (1) New construction,improvements to repetitive loss structures,and substantial improvcmont shall be constructed with materials and utility equipment resistant to flood damage. (2) New construction.improvements to repetitive loss structures,and substantial improvement shall be constructed using methods and practices that minimize flood damage. (3) New construction,improvements to repetitive loss structures,and substantial improvement shall he designed and constructed with electrical, heating, ventilation, plumbing. air-conditioning equipment,and other service facilities including, but not limited to, furnaces,heat pumps, water heaters, washers, dryers, elevator lift equipment, electrical junction boxes,circuit breaker boxes. and food freezers located above the base flood elevation plus any required freeboard (4) Within Zones V and '�T, new construction, improvements to rcpetitivc loss structures, and substantial improvements shall comply with the standards of seolion 27-23. 27-13 SUPP,5 (1-2008) 1 0A-15 Hawaii County Multi-Hazard Mitigation Plan Chapter 10 Appendix §27-18 MWAI't COUNTY CODE (5) Rcercational vehicles placed on sites within Zones AH and AF,on the FIRM shall be elevated and anchored or be on the site for less than one hundred eighty consecutive days or be fully licensed and highway ready- ic) Encroachments. (1) Within a floodway, encroachments(including fill),new construction,improvements to repetitive loss structures, substantial improvements, and other developments, shall he prohibited unless certified by a professional civil engineer licensed in the Slate of Hawaii,with supporting data,that the encroachment will not cause any increase in base flood elevations during the occurrence of the base flood discharge. (?) Require, until a regulaloty floodway is designated, that no new construction, improvements to repetitive loss structures,substantial improvements,or other development(including fill),shall be permitted within Zones AL on the MRAL unless demonstrated that the cumulative effect of the proposed development, when combined with all other existing and anticipated development, will not increase the water surface elevation of the base flood A any point. (3) Within all tones ofspecial flood hazurds,but not including floodways,filling which would resrdl in the blockage or impediment of flow and/or induce or aggravate flooding shall be prohibited unless certified by a professional civil engineer licensed in the State of Hawaii,with supporting data,that the encroachment will not cause any increase in base flood elevations during the occurrence of the base flood discharge. (4) Within floodway fringe areas, filling to elevate the lowest floor of a nonresidential structure may only he permitted where the structure: (A) is floodproofcd so that below the base flood elevation plus any requirod freeboard the structure is watertight with walls substantially impermeable to the passage of water,and (13) Has structural components capable of msisting hydrostatic and hydrodynamic loads and the effects ol'buoyancy. (5) In Zones V and VE.filling shall be prohibited. (d) Elevation and floodprouling. (1) Within Zones rti and AIL (A) For rasidmtial new construction, improvements to repetitive loss structures, and substantial improvements,the lowest floor shall be cicvalad to or above the base flood cicvafion plus a fivoboard of at least one foot. (II) For nomesidential new construction, improvements to repetitive loss structures, and subslantal improvements,the lowest floor shall be elevated or Iloodproafed to or above the base flood elevation plus a freeboard of at least one foot_ if the lowest floor is below the base flood elevation plus the required fieeboard,then the structure together with attendant utilih and sanitary facilities shall be designed constructed,and certified by a currently licensed professional engineer or architect in the State of Hawai`i such that: (i) The suuetvrc is watertight below the base flood elevation plus the rcgtircd freeboard_ (ii) 'Me walls are substantially impermeable to the passage ofwater. (iii)71ic structural components are capable of resisting hydrostatic and hvdmdynamic loads and the effects of buoyancy. (C) Within Zone AH,new construction,improvements to repetitive loss structures,and substantial improvement shall be required to provide adequate drainage paths around structures on slopes to guide floodwaters around and away from proposed structures. (I)) Fully enclosed areas below the lowest floor that are useable solely for parking of vehicles, building access,or storage in an area other than a basement and which are subject to flooding, shall be designed to automatically equalize hydrostatic flood forces on exterior walls by SUPP 5 (1-2008) 27-14 10A-16 Hawaii County Multi-Hazard Mitigation Plan Chapter 10 Appendix T'LOODPLAiN MANAGEMENT §27-18 allowing for the entry and exit of floodwaters. Designs for tnceting this requirement must either be certified by a currently licensed prolcssional engineer or architect or meet or exceed the following criteria: A minimum of two openings having a Iota)net area of nol less than one square inch for every square foot of enclosed area subject to flooding shall be provided. Bach opening must he on different sides of the enclosed area. The bottom of all openings shall be no higher than one foot above grade. Openings may he equipped with screens, louvers, valves,or other coverings or devices provided that they permit the automatic entry and exit of floodwaters. (2) Within:,one AO: (A) For residential new construction, improvements to repetitive loss structums, and substantial improvements,the lowest floor shall be elevated above the highest adiacent grade at least one fool above the depth number specified in feet on the FIRK or at least three feet if no depth number is specified. (B) For nonresidential new construction, improvement% to refidi ivc loss structures, and substantial improvements,the lowest floor shall be elevated or completely floudproofed above the highest adjacent grade at least one foot above the depth number specified in feet on the RRNI, or at least three feet if no depth number is specified. if the lowest floor is to be completely floodprooled, then a currently licensed prolcssional engineer or architect in the State of Hawaii shall develop and/or review structural design.spceificalions and plans far construction and shall certify that the design and methods of construction are in accordance with accepted standards of practice for the stricture together with attendant utility and sanitary facilities such that, (i) The structure is watertight below the referenced flood elevation. (ii) the walls are substantially impermeable to the passage ofivater. (iii)Tlic structural components are capable of'resisting hydrostatic and hydrodynamic loads and the effects of buoyancy. (C) New construction, improvements to repetitive loss structures, and substantial improvement: shall be required to provide adequate drainage paths around structures on slopes to guide floodwaters around and away from proposed structures. (3) Within Zones V and Vli_ New construction, improvements to repetitive loss structures, and substantial improvement shall comply with the standards of section 27-23. (4) Within Zone A: New cormiruction, improvements to repetitive loss structures. and substantial improvement shall comply with the standards of%eetion 27-23_ (5) Buffer zones: Areas bordering and within fifty feet of a special flood hazard areas with base flood elevations.depth numbers specified in feel on the FMX1 or other areas that have been studied and identified with base flood elevatioms or depth nurnbets'. (A) For residential new construction, improvements to repetitive loss structures, and substantial improvements,the lowest floor shall be elevated to the borderine base flood elevation or depth number plus a freeboard of at least one foot. V (A) For nonresidential new uonstruction, improvements to repetitive loss structurtis, and substantial improvements,the lowest floor shall he elevated or floodproofed to the bordering base flood elevation or depth number plus a reeboard of at[cast one foot. If the lowest floor is below the bordering baso flood elevation or depth number plus the required freeboard,then a currently licensed professional engineer or architect in the State of liawaN shall develop endior review structural design,specifications and plans for construction and shall certify that the design and methods of construction are in accordance with accepted standards of practice for the structure together with attendant utility and sanitary facilities such that: (i) The structure is watertight below the bordering base flood elevation or depth number plus the required freeboard. 27-15 SUPP 5 (1-2008) 1 OA-17 Hawaii County Multi-Hazard Mitigation Plan Chapter 10 Appendix §27-18 IIAWAI't CC)UN rr CODE (ii) The walls arc substantially impermeable to the passage ofwaler. (iii) The structural component,;arc capable of resisting hydrostatic and hvdmdynamic loads and the cffccls nl-buoyancv- (C) New construction.improvements to repetitive loss structures_and substantial improvements. shall be required to provide a drainage path around and away from proposed structures. (D) When topographical or ground elevation data,submitted by a civil engineer or land surveyor currently licensed in the State of Hawai=i.shows that the proposed building site is higher than the elevation requirements of paragraph 27-18(d)(5)(A)and 27-18(d)(5)(13), the flood plain regulations of this chapter shall not be applicable. (c) Certification requirements. All new construction, improvements to repetitive loss structures, and substantial improvement within.areas of special flood hazard and buffer zones shall be certified as required by the standards of section 27-17, (1993.Ord.No.93-78.sea 3:Am.1997,Ord,No.97-116,sec.3;Am.2007,Ord,No.07-169,sec.11.) Section 27-19. Standards for utilities. (a) New and replacement water supply and sanitary sewage systems shall be designed to minimize or eliminate infiltration of flood waters into the system and discharge from systems into flood waters. (b) On-sire cesspools and septic svAcims shall be located to avoid impairment to them or contamination from them during flooding_ (1993,Ord.No.93-78,sea 3.) Section 27-20. Standards for subdivisions and other developments. (a) All subdivisions and other developments within am:as of special flood hazards and flood prone areas where special flood hazard areas have not been dcl3ned,realer surface elevations have nut been provided, and there is insufficient data to identify the floodway or coastal high hazird areas but there are verifiable physical indications that such hazards are present as determined by the flood plain administrator.shall: (1) Be consistent with the need to minimize flood damage; (2) Have public utilities and facilities, such as sewer,gas,electrical,and water systems.located and constructed to minimize flood damage.and (3) Have adequate drainage provided to reduce cxpnsum to flood damage. (b) All subdivision and other development applications shall identify the areas of special flood hazards and basc flood elevations on the proposed site.if such information is not provided by The Flood Insurance Ratc Maps,the director of public works may request and the applicant shall provide such information. (e) Finally approved subdivision plats for subdivisions within areas of special flood hazards shall provide basc flood elevations within the lots. (d) All new subdivision proposals and other proposed developments within areas designated as Gone A or a flood prone area where special flood hazard areas have not been defined.water surface elevations have not been provided,and there is insufficient data to identify the floodway or coastal]high hazard areas but die flood plain administrator has determined that there arc verifiable physical indications [lint such hazards arc present shall comply with the following: (1) Be reviewed to assure that all necessary permits have been received from those governmental agencies from which approval is required by Fuleral or State law,including section 404 of the Federal Water Pollution Control Act Amendments of 1972.33 U.S.C.1334; (2) For all proposed developments and/or subdivisions greater than either fifty lots or five acres,the developer and/or subdivider shall include base flood elevation data within their proposal. (3) Comply with the requirements of section 27-24. SUPP 5 (1-2008) 27-16 1 0A-18 Hawaii County Multi-Hazard Mitigation Plan Chapter'10 Appendix FLOODPLAfN MANAGEMENT §27-20 (e) All developments requiring a site drainage plan under section 25-2-72(3)shall submit such a plan for review and approval by the director of public works. The site drainage plan shall comply with sections 27-20(a)and(h)and section 27-24,and shall include a storm water disposal system to contain run-off caused by the proposed development,within the site boundaries.up to the expected one-hour.ten year storm event,as shown in the department of public works"Storm Drainage Standards." dated October 1970,or any approved revision.unless those standards specify a greater recurrence interval. The amount of expected runoff shall be calculated according to the department of public works "Storm Drainage Standards," dated October 1970, or any approved revision, or by any nationally-recognized method meeting with the approval of the director of public works, Runoff calculations shal I include the effects of all impmvcmcnts. (f) Stonn water shall be disposed into drywells.infiltration basins,or other approved infiltration methods. Ibe development shall not alter the general drainage pattern above or behm die development. (1993,Ord.No.93-78,sec.3;Am.2001,Ord.No.01-108,sec.1;Am.2007,Ord.No.07-169,sec.12.) Section 27-21. Standards for manufactured homes. Alanufactured homes that are placed or substantially improved on sites outside of a manufactured home park or subdivision. in a now manufactured home park or subdivision, in an expansion to an existing manufactured home park or subdivision,or in an existing manufactured home park or subdivision on which a manufactured home has incurred"substantial damage"as the result ofa flood shall: (a) Within'Zones AL or Alf,be elevated so that either: (1) The lowest floor of the manufactured home is at or above the base flood elevation,or (2) The manufactured home chassis is supported by reinforced piers or other foundation elements of at least equivalent stronglh that are no less than thirty-six inches in height above grade and be securely anchored to an adequately anchored foundation system to resist flotation, collapse, and lateral movement. (b) Within Zone AO,be elevated such that the lowest floor of the manufactured[tome is elevated at least as high as the depth number specified in feet on the FIRM, or at least two feel if no depth number is specified and be securely anchored to an adequately anchored foundation system to resist flotation collapse,and lateral movement. (e) Within Zone A,comply with the standards orsection 27-24. (d) Within Zones V or VL,comply with the standards of section 27-23. (1993,Ord.No.93-78,sec.3.) Section 27-22. Standards for Iloodways. The floodway identilicd on the Flood Insurance Rate Maps and located within areas of spocial flood hazard is the watercourse reserved to discharge the base flood,Since the floodway is an extremely hazardous area due to the velocity of floodwaters which carry debris, potential projectiles, and erosion potential. site following provisions apply: (a) Encroachments,including fill,new construction, improvements to repetitive loss structures,substantial improvement,and other now development shall be prohibited unless ecrtificalion and supporting data is provided by a licensed professional engineer or architect demonstrating that the encroachment will not cause any increase in base flood elevations doling the occurrence of the base flood discharge. (b) If an encroachment within a floodway is allowed under the conditions of paragraph 27-22(a), all new construction.improvements to repetitive loss structures,substantial improvement and other proposed new development shall comply with all applicable flood hazard reduction provisions established in this chapter. 27-17 SUPP 5 (1-2008) 1 OA-19 Hawaii County Multi-Hazard Mitigation Plan Chapter-10 Appendix §27-22 IIAwnl'I COUNTY CODE (c) The following uses,not involving fill,shall be evaluated on a case-by-case basis to establish that the use does not cause any increase in hale flood elevations: (1) Public and private outdoor nonstructural rccrcalional lacililios,lawn_garden,and play areas: (2) Agricultural uses,including farm.grazing,pasture,and outdoor plant nurseries:and (3) Drainage'improvements,such as channels and stream crossings. (1993,Ord.No.93-78,sec.3:Am.2007,Ord.No.07-169,see.13.) Section 27-23. Standards for coastal high hazard areas. Coastal high hazard areas,more commonly known as tsunami inundation areas,are identified as'Lone V or Zone VE on the Hood hisurance Rate Maps.Within coastal high hazard areas,the following standards shall apply: (a) .411 new construction, improvements to repetitive loss structures, and substantial improvements in a coastal high hazard area shall be constructed with materials and utility equipment resistant to flood damage and using methods and practices that minimize flood damage. (b) New construction, improvements In repetitive loss structures, and substantial improvement shall be elevated on adequately anchored pilings or columns and securely anchored to such pilings or columns so that the lowest horizontal portion of the structural mcmbent of the lowest floor,excluding the pilings and columns, is elevated to or above the base flood level. The pile or column foundation and structure attached t=ft)shall be anchored to resist flotation,collapse,and lateral movement due to the etTecls of- wind and water loads acting simultaneously on all building components.the wind and water loading values shall each have a one percent chance of being equaled or exceeded in any given year. (c) New construction-improvements to repetitive loss structures,and other development shall be located on the landward side of the reach of mean high tide. (d) New construction,improvements to repetitive loss structural,and substantial improvement shall have the enclosed space,if any,below the lowest floor Gee of obstructions and constructed with breakaway walls as defined in section 27-12. Such enclosed space shall not be used for human habitation and will be useable solely for parking of vehicles, building access, or storage. Machinery and equipment which service the building.such as fumaces,air conditioners,heat pumps.hot water heaters,washers.dryers, elevator lift equipment,electrical junction and circuit boxes,and food freezers are not permitted in such enclosed spaces. The unclosed space must only ire achieved wilh breakaway walls. open wood latticework,or insect screening intended to collapse under wind and water loads without causing collapse, displacement,or other structural damage to the elevated portion of the building or supporting foundation system. A breakaway wall shall have a design safe loading resistance of not less than tan and no more than twenty pounds per square foot. Ilse of breakaway walls which exceed a design safe loading resistance of twenty pounds per square foot may be purmitted only if a licensed professional structural engineer certifies that the design proposed meets the following conditions: (1) Breakaway war collapse shall result from a water load less than that which would occur dining the base Bond;and (2) The elevated portion of the building and supporting foundation system shall not be subject to collapse,displacement.or other structural damage due to the effects of wind and water loads acting simultaneously on all building components (structural and nonstructural). lvlaximum wind and water loading values to be used in this determination shall each have a one percent chance of being equaled or exceeded in any given year(uric-hundred-year mean recurrence interval). (e) Pill shall not be used. (f) Man-made alteration of sand dunes which would increase potential flood damage is prohibited. (g) All new conslruclinm improvemenL% to repetitive loss structures, development and substantial improvement within coastal high hazard areas shall be certified as required by section 27-17. SUPP 5 (1-2008) 27-18 1 0A-20 Hawaii County Multi-Hazard Mitigation Plan Chapter 10 Appendix FLOODPLAiN MANAGEMENT §27-23 (h) Recreational vchiclos placed on site within Zones V and XrE on the FiRM shall be elevated and anchored or be on the site for less than one hundred eighty consecutive days or be fully licensed and highway ready. (1993.Ord.No.93-78,sec.3;Am.2007.Ord.No.07-169,sec.14.) Seellon 27-24. Standards for general floodplain. Tlic general floodplain,identified as Zone A on the Flood Insurance Rate Maps,are areas of special flood hazards for which detailed engineering studies are not performed by the federal Emergency ivlanagement Agency to determine the base flood elevations and to identify,the floodways, (a) To determine base flood elevations and the locations of floodways within the gencral floodplain The director of public works may obtain, review. and reasonably utilize any base flood elevation and floodway data available from a Federal, Slate, or other sourer, including informatiun requrstrd of a permit applicant. (b) Development or subdivision proposals shall conform with the requirements of section 27-20. (c) The following information shall be provided by a permit applicant to the director of public works to evaluate the proposed construction or improvement site within a general floodplain area: (1) Project location and silo plan showing dimensions. (2) Relationship to floodwav and floodway fringes as determined by flood elevation study. (3) Contour map showing the topography of existing ground based on elevation refervrice marks on flood maps.The scale and contours are to be appropriate to the work in question. (4) Existing and proposed base flood elevations. (5) Existing and proposed floodproofing and flood control measures. The director of public works may waive informational requirements il'the director of public works has sufficient information to make an evaluation and determination regarding flood elevation or may request further information,including a detailed flood elevation study and a drainage report,to evaluate flood risks and determine the applicability of flood construction and development standards. (d) Now construction, improvements to repetitive lass structures,and substantial improvements within the general floodplain shall satisfy the requirements set forth for Zones AE. All,AU_or VE as is determined to be applicable by the director of public works based on base flood information and floodway data obtained through subsections 27-24(a)and 27-24(b). (c) All new construction, improvements to repetitive loss structures, development, and substantial imprm+ement within die general floodplain shall be certified as required by section 27-17. (f) All manufactured homes shall be elevated and anchored to resist flotation collapse,or lateral movement- (1993,Ord.No.93-78,sec.3;Am.2001.Ord.No.01-108,sec.);Am.2007,Ord.No.07-169,sec.15.) Section 27-25, Standards for improvements adjacent.to drainage facilities, New construction, improvements to repetitive loss structures, and substantial improvements proposed adjacent to drainage facilities outside of the special flood hazard areas identified on the ITood Insurance Rate Maps shall be subject to review and approval of the director of public works. (a) Upon request by the director of public works, further information concerning base flood elevation, floodways, surface water runoff. existing and proposed drainage patterns, and other information, including a detailed flood elevation study, drainage report, and findings and opinions by a licensed profbssional civil engineer,shall be provided to evaluate potential flooding. (b) The director of public works shall determine the applicability of the various development and construction standards provided in this chapter based upon information available from a Federal,State,or other source,including information provided by the permit applicant. (c) A drainage facility shall not be modified,constructed, lined,or altered in am•way to accommodate the improvement without the approval of the director of public works. (1993,Ord.No.93-78,sec.3;Am.2001.Ord.No.01-108,sec.1;Am.2007,Ord.No.07-169,sec.16.) 27-19 SUPP 5 (1-2008) 1 0A-21 Hawaii County Multi-Hazard Mitigation Plan Chapter-10 Appendix §27-26 IIAW AI'[COUNTY CODE Section 27-26. Storm drainage standards. The department of public works,County of Hawai`i's"Storm Drainage Standard,"October 1970 edition, or lutes(revision,is incorporated into and made a part of this chapter.These standards have been prepared to guide County engineers and personnel,engineers for subdivision and other developers,consultants employed by tlx:department of public works.and other interested parties in the general features required for the design of storm drainage facilities, preparation of flood hazard studies, and other related work in the County of Hawaii. (1993,Ord-No.93.78,sec.3;Arm.2007,Ord.No.07-169,sec.17.) Article 5.Variances and Appeals. Section 27-27. Criteria for variances. A variance from this chapter may be issued by the director of public works only upon the applicant matting the variance criteria of this section. The variance criterion sot forth in this section are based on the general principle of zoning law that variances pertain to a piece of property and arc not personal in nature. ,4 properly issued variance is granted for a parcel of propurly with physical characteristics so unusual that complying with the requirements of this chapter would create an exceptional hardship to the applicant or the surrounding property ownem. the characteristics must be unique to The property and not be shared by adjacent parcels. The unique characteristic must pertain to the land itself, not to the structure, its inhabitants,or the property owners. It is the duty of the County of Ilawai`i to help protect its citizens from flooding. 'this need is so compelling and the implications of the cost of insuring a structure built below flood level are so serious that variances from the flood elevation or from other requirements or this chapter are quite rare. The variancc guidelines are detailed and contain multiple provisions that must be met before a variance can be properly granted.The following criterion are designed to screen out those situations in which alternatives other than a variance are more appropriate: (a) Generally-variances may be issued for new construction,improvements to repetitive loss structures, substantial improvement•and other proposed new development to be erected on a lot of one-half acre or less in size contiguous to and surrounded by lots with existing structures constructed below the base flood level,providing that the procedures of articles 3 and 4 of this chapter have been fully considered. As the lot size increases beyond one-half acre,the technical justification required for issuing the variance increases_ (b) Variances shall not be issued within any designated floodway if any increase in flood levels during the base flood discharge would result. (c) Variances shall only be issued upon: (1) A showing of good and sufficient cause.Under[his criterion,the applicant must demonstrate that the variance request is for land which has physical characteristics so unusual that complying to flood requirements will create exceptional hardship to llte applicant or surrounding landowners.Thc unique characteristic must pertain to the land itself and not the structure,its inhabitants,or the properly owner. Under this criterion, only exceptional instances should arise where Cite physical oharacteristics of properties create a hardship sufficient to justify granting a variance.Even in a fairly common situation where an undeveloped lot is surrounded by properties with structures built at grade and/or below flood levels, a variance cannot be justified since an applicant can erect the concerned structure on pilings,etc.; (2) A determination that failure to grant the variance would result in exceptional"hardship°(as defined in section 27-12)to the applicant,Under this criterion.the hardship that would result from failure to grant a requested variance must be exceptional, unusual, and peculiar to the property involved. Economic or financial hardship alone is not exceptional. Inconvenience, aesthotic considerations,physical disabilities,personal preferences.or the disapproval of one's ncighburs cannot,generally,qualify as exceptional hardship.Under this criterion,for example, SUPP 5 (1-2008) 27-20 1 OA-22 Hawaii County Multi-Hazard Mitigation Plan Chapter 10 Appendix FLOODPLAiN MANAGEMENT §27-27 a member ofa household has a physical disability and wants a variance:to build the dwelling at grade or at a lower level for access purposes.A variance should not be issued because the owner can cnnslruet a ramp or elevator to meet flood requirements.Elevation will allow the infirm or persons with disabilities to be evacuated in the early stage of flooding,and,if there is insufficient warning or help in evacuating that person,then,in all likelihood,he can survive the flood by simply remaining in the home safely above the levels of floodwaters: (3) A determination that the variance is the"minimum necessary"(as defined in section 27-12), considering the flood hazard,to afford relief Under this criterion,the variance that is granted should be for the minimum deviation from the flood requirements that will still alleviate the hardship.In the case of variance to an elevation requirement, this does not mean approval to build at grade level or to whatever elevation an applicant proposes,but rather to a level that the director of public works determines will provide relief and preserve the integrity of the flood ordinance:and (4) A determination that the granting of a variance will not result in increased Flood heights_ additional threats to public safety, extraordinary public expense, create nuisances, cause `fraud or victimization"(as defined in section 27-12)of the public,or conflict with existing local laws or ordinances.Under this criterion,an applicant must demonstrate that flood levels will not be raised above the base flood elevations. (d) Variance% may be issued for new construction, improvements to repetitive loss structures, substantial improvement, and other proposed new development necessary for the conduct of a "functionally dependent use" (as defined in section 27-12) provided that the provisions of paragraphs 27-27(a)through 27-27(c)are satisfied and that the structure or other dcvelopmeni is protected by methods that minimize flood damages during the base flood and create no additional threats to public safety, (c) Variances may be issued for the repair or rehabilitalion of historic structures upon a determination that lire proposed repair or rehabilitation will not preclude the structure's continued designation as a historic structure and the variance is the minimum necessary_ to preserve the historic character and design of the structure. (f) Variances may be issued for improvement of a structure to correct existing violations of State or local health,sanitary,or safety code specifications which have been idcnlilicd by the local code enforcement official and which are the minimum necessary to assure safe living conditions. (g) Variances may be approved with conditions.Such conditions may include: (1) Modification of the construction or substantial improvement,including the sewer and water facilities. (2) Limitations on periods of use and operation. (3) Imposition of operational conlrols,sureties,and deed restrictions. (4) Requirements for construction of channels, dikes, ditches,swales, levees, and other flood- protective measures- (5) Floodproofing measures designed consistent with the regulatory flood elevation, flood velocities, hvdrostatic and hvdrodvnamic forces, and other factors associated with the base flood. (G) Other conditions as may he required by the director nfpublic works to promote public welfare and safety. (1993,Ord.No.93-78,sec.3;Am.2001,Or&No.01-108,sec.1:Am.2007,Gird.No.07-169.sec.18.) Section 27-28. Application I'ar variance. An application for a variance shall be submitted to the director of public works,signed and stamped by a licensed professional engineer or architect, and shall include three sets of documents with the following information as may be applicable: 27-21 SUPP 5 (1-2008) 1 0A-23 Hawaii County Multi-Hazard Mitigation Plan Chapter'10 Appendix §27-28 MWAI1 COUNTY CODE (a) Plans and specifications showing the site and location:dimensions of all property lines and topographic elevation of the lot;existing and proposed structures and impmvcmcn(s, fill.storage area;locations and elevations of existing and proposcd strcols and utilities;floodproofing measures:relationship of the site to the location of the flood boundary:floodway:and the existing and proposed flood control measures and improvements. (b) Cross-sections and profile of the area and the regulatory flood elevation and profile based on cicvation reference marks on flood maps. (c) hood study and drainage report in areas where a study and report have not been reviewed and accepted by the County of Hawaii. (d) mscriplion of surrounding properties and existing structures and uses and the effect of the regulatory flood on them caused by'the valiance. (e) Evaluation and supporting information for the variance with respect to the factors lobe considered by the director of public works as listed in paragraphs 27-27(a)through 27-27(f). (t) An agreement that a covenant will be inserted in the decd and other conveyance documents of the property and recorded with the bureau of conveyances of the Stale of Ilawai'i,stating that the property is located in a flood hazard area subject to flooding and flood damage;that a flood hazard variance to construct a structure below the base flood elevation will result in increased flood insurance rates and increases flood risks to life and properly; that the properly owners will not file any lawsuit or action against the County ofHawai'i for costs or damages or any claim:that the property owners will indcmnifv and hold)harmless the County of flawai'i from liability when such loss,damage,injury,or death results due to any flood hazard variance and flooding of the property;and that upon approval of the variance,the covenants shall be fully executed and proof of recording with the bureau of conveyances shall be submitted to llhc dirculor of public works prior to the issuance of a building permit. (g) Such other information as may be relevant and requested by the du•ector of public works. (1993,Ord.No.93.78,sec.3:Am.2001,Ord.No.01-108,sec.I;Am.2007,Ord.No.U7-169.sec.19.) Section 27-29. Review orvar)ance applications. The director of public works shall review variance applications and shall consider all technical evaluations,relevant factors,standards specified in other sections of this chapter.and: (a) The danger that materials may be swept onto other lands to the injury of others; (b) '17te danger of life and property due to flooding or erosion damage; (e) The susceptibility of the proposed facility and its contorts to flood damage and the effect of such damage on the existing individual owner and future owners of the property; (d) The importance of the services provided by the proposed facility to the community; (c) The necessity to the facility of a waterfront location,when:applicable; (f) 1-he availability of alternative locations for the proposed use which are not subject to flooding or erosion damage; (g) Thu compatibility of the proposed use with existing and anticipated development; (h) The relationship of the proposed use to the comprehensive plan and Iloodplain management program.if airy,for that area; (i) The safety of access to the property,in time of flood for ordinary and emergency vehicles; 0) The expected heights.velocity,duration,rate of rise,and sediment transport of the flood waters expected at the site;and (k) 'Ilhe costs of providing governmental services during and after flood conditions,including maintenance and repair of public utilities and facilities such as sewer.gas,electrical.and water system,and streets and bridges. (1) Upon consideration of the factors of paragraphs 27-29(a) through 27-29(k) and the purposes of this chapter,the director of public works may attach such conditions to the granting of variances as it deems necessary to further the purposes of this chapter. (1993,Ord-No.93-78,sec_3;Am.2001,Ord_No-01-108,sec_1.) SUPP 5 (1-2008) 27-22 1 OA-24 Hawaii County Multi-Hazard Mitigation Plan Chapter 10 Appendix T'LOODPLAiN MANAGEMENT §27-30 Section 27-30. Recording and reporting ot'variances. (a) Any applicant to whom a variance is granted shall be given written notice over the signature of The director of public works that: (1) The issuance of a variance to construct a structure at elevations balow the base flood level will result in increased premium rates for flood insurance up to amounts as high as$25 for$100 of insurance coverage; (2) Such construction below the base flood level increases risks to life and property;and (3) A copy of the notice shall be recorded with the State of Hawaii bureau of conveyances and shall be recorded in a manner so that it appears in the chain oftitle of the affected parcel of land. (h) A record of all variance actions,including justifications for issuance of any variance and written notices, shall be maintained by the director of public works.A report of the variances issued shall be included in the biennial report submitted to The federal Lmergency Management Agency, (1993,Ord.No.93-78,sec.3;Am.2001,Ord.No,01-108,sec.1;Am.2007,Ord.No.07-169,sec.211,) Section 2731. Appeals. The circuit court of the third circuit,County of IlawaN. Stale of llawaN shall hear and decide appeals when it is alleged that there is an error in any requirement,decision,or determination made by the floodplain admitdslrator in the administration or enforcement of this chapter. (1993,Ord.No.93-78,sec.3.) Article 6.Enforcement. Section 27-32. Right to enter. Authorized representatives of the County of Hawaii arc empowered to enter and inspect properties,both public and private, for the purposes of investigating compliance with the provisions of this chapter, The representatives shall,upon request,provide proper identification and state the purpose of the investigation. (1993,Ord.No.93-78,sec.3.) Section 27-33. Notice of violation. Whenever any person,firm.or corporation violates any provision of this chapter,the director of public works shall serve, either through certified mail or try' hand delivery, a notice of violation to the parties responsible for the violation. (a) The notice of'violation shall identify the violation and require the responsible party to correct the violation and comply with applicable requirements of tliis chapter, (b) The notice ofviolation shall include at least the following information: (1) 'fhe date of the notice; (2) The name and address of the person served with the notice; (3) The tar'key number of the properly where the violation has been identified; (4) The section number of the chapter or other law which has been violated; (5) The nature of the violation; (6) The corrective meastues required to comply with this chapter: (7) The deadline date for compliance with the notice. (1993,Ord.No,93-78.sec.3,.Am,2001,Ord.No.01-108,sec.I,) Section 27-34. Administrative order. (a) In lieu of or in addition to section 27-33,if the director of public works determines that any person,firm. or corporation is not complying with the requirements of this chapter or a notice of violation for a violation of this chapter,the director of public works may have the party responsible for the violation served,by certified mail or delivory,with an order pursuant to this section 27-23 SUPP,5 (1-2008) 10A-25 Hawaii County Multi-Hazard Mitigation Plan Chapter-10 Appendix §27-34 MWAI't COUNTY CODE (b) The order may require the party responsible for the violation to do am or all of the following: (1) Correcl the violation within the time specified in the order; (2) Pay a civi) fine of not Icss than 5500 and not more than $1,000 in the manner,at the place,and before the dale specified in the order. (3) Pay a civil fine of not less than$300 per day and not more than 51,000 per day for each day that the violation persists,in tie manner and at the time and place specified in the order. (c) The order shall become final thirty days from the date of service utdess Ilse party served requests a hearing under chapter 91, ilawai'i Revised Statutes.If a hearing is requested,no fine shall be imposed except upon completion of the hearing. In determining the amount of the fine, the director of public works shall consider the seriousness of the violations, any history of such violations, any good-faith efforts to comply with the applicable requirements.the economic impact of the fine on the violator.and such other considerations that have a beating on the amount of the fine. (d) '17te director of public works may institute a civil action in anv court of competent jurisdiction for the enforcement of any order issued pursuant to this section- Where the civil action has been instituted to enforce the civil fine imposed by said order,the director of public works need only show that the notice of violation and order were served,that a civil fine was imposed.the amount of the civil fine imposed, and that the tine has not been paid. (1993,Ord.No.93-78,sec.3;Am.2001,Ord.No.01-108,sec.l;Am.2007,Ord.No.07-169,soc.21.) Section 27-35. Injunctive relief. Whenever a person,firm.or corporation has violated or continues to violate the provisions of this chapter, notice of violation,or administrative order issued relevant to this article,the County of Hawaii may petition the circuit court of the third district,Stale of Hawai'i,or rte United Stales District Court. Slate of Hawaii, through the County of Ilawai`i's corporation counsel,for the issuance of a temporary or permanent injunction, as appropriate,which restrains or compels the specific performance of the provisions of this chapter,notice of violation,or administrative order.Such outer action as appropriate for legal and/or equitable relief may also be sought by the County of Hawaii. A petition for injunctive relief nocd not he filed as a prerequisilo to taking any other action against a user. (1993,Ord.No.93-78,sec.3.) Section 27-36. Criminal enforcement. A violation of the requin:menls of this chapter shall constitute a misdemeanor.Any person violating the provisions of this chapter shall upon conviction be punished by a fine of x1.000 or by, imprisonment not exceeding one year,or both,except that in cases where such offense shall continue after due notice,each day's continuance of the same shall constitute a separate offense. (1993,Ord.No,93.78,sec,3,) Section 27-37. Removal of encroachment and/or obstruction notices. In addition to any other section,if any encroaclunent and/or obstruction exists,under,over or through any portion of a drainaocway,Iloodway. twee system or watercourse within the County and the eneroachmcni and/or obstruction is observed. or a complaint made to the department of public works of the County of Ilawai'i, then the department of public works shall investigate and forthwith,give notice to the owner to remove the encroachment and/or obstruction in the manner provided in Ibis article- (1997,Ord.97-128,see.1;Ann,2(107,Ord.No.07-169.sec.22.) SUPP 5 (1-2008) 27-24 1 0A-26 Hawaii County Multi-Hazard Mitigation Plan Chapter-10 Appendix T'LOODPLAiN MANAGEMENT §27-38 Section 27-38. Removal by County;costs. If the encroachment and/or obstruction is not removed or its removal is not commenced and diligently prosecuted prior to the expiration of thirty days alter mailing of notice,the department of public works may proceed to remove the encroachment anther obstruction by itself or contract for its removal.All costs incurred in ilia course of removing the encroachment and/or obstruction shall be paid by owner and the County may institute an action to recover costs and expcnsLx for removal o1'the encroachment and/or obstruction.The County may also place a lien against the encroaching and/or obstructing parcel for any uncollected costs. (1997.Ord.97-128.sec.1.) 27-25 SUPP 5 (1-2008) 10A-27 Hawaii County Multi-Hazard Mitigation Plan