HomeMy WebLinkAboutCOM 0176.111 2006-2008
Wedn®aday, May 30, 20071:15 PM Nancy Burns (808) 325-1065 01
?NANCY E. BLTR:~S. P.E,. LLC
73-1487 Hao Street
hailua-bona, HI 96'740
Tel: 325-3182 - Fay: 325-1065 ~~J7 (~(1'~' 3(1 f'iri ? ? r
`C;_ a
Recipient; Council Testimony Sent By: Nancy Burns
Company: Company: Nancy E. Burns. f .E. _L.
Fax Number: 9618912 Fax Number: (808) 325-11:fi;~
Voice Number: Voice Number:
Date: 5/30/2007
Time: 1;15:06 PM
Total No. Pages: 3
Subject: Comments on Bill 51
Message:
II hope that the council and con::nunity can work together to res~~lw~
;drainage and floodplain management issues. There ere many ri~y~:~:~lf:
'out there there with lots of experience in these matters that are re;:~r,Py,
willing and able to assist you in any way we can.
Nancy
!I '
ii
ii
Comm. tip. 11~• ~~t
Ref. To: e
Ref. Date~~ ~
Wednesday, May 30, 2007 1:15 PM Nancy Burns (808) 325-1065 p 02
May 30, 2007
1
Honorable Pete IIoffmann, Chairperson
Hawaii Cotutty Council
25 Waupun St. ~ t'.'
Hilo, Hawaii'i 9(i72U
'lcstimany on Rill 51,1)xaft 3 Pro~tisecF Amendment; to Chatrter 27 of the HCC
L)eaz Chairperson Tloffmann and Members of the Hawaii County Council,
There have been many statements made at C.`ounty Council committee meetu,gs ahn r. flu ~d'urg. o.u tlra
island of hlawaii. Has anyone investigatul the reasons for the Il<xrding? Is it trail}~ iu:: br i vtctequaG;
codes oc could it be that l'<tlks have constructed homes and businesses in areas tksat a, :'f i1 ur a1
watercourses ~ 13cforc we make sweeping changes W the codes that ali'ect all lar.+<I:I `;r 5r.~~ her or nut they
have drainage problems, perhaps we should investigate further the causes of"the Fl~:ic:, i.n.,;.
We should also look at whether the entire island has flood problems or if it is onl`- .r ?:p. xitic lur,,:.tior.:~.
if frequent flooding only occurs at specific locations, perhaps those locations neevi x r.;. tlale<i
dit~erently front areas that do nal experience flooding. i was under the imprr~ssi+,, fl.+a. I;luxptcs- 2'7 v+ae er
code that was meant to mguiate areas shat experience fregfrenl flooding. 'Phe am:ui:3 r u:r t„ proposed turn
this code into a regulation that tncats all areas as flaod plains with no technical, c:o:,,r,•:i; ter sc.:rntif:c
basis.
If floodwaters arc coming from mauka areas such ac the vast watersheds above t- l i:lu 31~;u ~ ~ ur~l
Kealakekuft, requiring developments to coutsin al), their runoff from the 100-year, ~ m~ at storm on-site
will not prevent flood datnagc. These containments will not handle the vast quau~.itire; ~ 7aar from tl,r•.
mauka watersheds and could very well lxe:u:h causing more harm than good. "fhc hu; ;l aeu,lition o1'
water from the upstreattt watersheds cannot be stoppexi. What would pn:vent ftutllea• !+u<; bletns is to
clearly map stream channels and make sftre that they are allowed to flow unimpe: a i.
1 bclicvc that Chapter 27 was originally meant to be a code that assures that no strt rl t rcu trf built within
floodways. A gotxl effort has been made to hY to determine the location of strewn _,tm;uas and r,any
of the major stream channels are shown on the current Fli2M maps. It appears ob v:.o ~ s t in: ~ t e F'i R~ N
maps need to be updated to identify additional fl~xxiways. i bclicvc that the ident licatlan oi's~~catn
channels along with good drainage design (no structures in these areas) is what i:~ rr.a+l ,+x;e sutry'[o
prevent flood issues.
In locations where folks have already unknowingly constructed hurtles and husines~e3 in r tKics f.~.aod
prone areas, mitigation to protect these structures is required. This needs to be ~~~c:.+rh :a+led ry
govenunutt agencies through Flood C'onArol projects as hati been done in the past in sf rvi rat fu~eas ~+i+fi.in.
the County of Hawaii. Relying on future private developments to remedy the cxisti r.? I'fl3' ur regxntnl
Flood problems will not resolve these ongoing flooding problems and they will n::al::fi a zis :la.us quo `nrilJt
the potential for future damage hoing unchanged. In some inntanceti where the ftoc:aiif.,v~ s tniuar,
Wednesday, May 30, 2007 1:15 PM Nancy Burns (808) 325-1065 O3.
modificafions to individtuzl properties that are curnntly experiencing tlooding could ;as'. l;r,and
economically he made I:o solve the problem.
There are many locations throughout North utd South Kona that experience hca~;, al ; l.ow during
high intensity tropical storms. Mom alai mitre Irequently folks are building slssh-uri-,ir::~;e ,>tmchzres irn.
the patlt of this sheet (low with no provisions for diverting the Ilow around the str.us. t r;;:. '1't, restdt. is
flooding of homes and businesses. This could txw prevented by elevating stntcturce a l d t.r; a ing
diversion swales around [he buildings. to some instarwes, a simple trench drain ins~:a I'.a: ir, 'rout of a
building ur garage could. roily and economically rernedy flood issues for homes cu'¢I b,e.i~t:,^ses. The
proposed atnendtnent requiring all rtntoff {whether gcnv~raled by the development. i~ : t cat; 1 c be cordainx.~l
vn-site is unrealistic, cost prohibitive, and most importantly it is unnatural.
Aill 5 t includes amendments to change the "design storm" for alt drainage to the 10~: - yr: u , :4 hoax
stottn. This does not comport with criteria rued inmost an.as of the Country. For e~ t nz e, acrordirr;
to'1'able 12-2 Minor Structure DesiXrz Frequencies frnmd on page 582 of Iptxodu~.; a, ii du 'sdrnlc!py,
Second i3dition by warren vicssman, Jr„ John w. Knapp, Cary L. Lewis, the Iatr,1."c r;a:~ x: h. k:rruauc;ir,
Harper an<I Row, Publishers, hie. 1977, design sn~ttn liequencies used across the c. fur u•~ in storm
drainage c:alculaiions very from 2 to 10 years. The Cjvil Lneingering Handlxx>k.,,3~s.c~_r,,c_,dition, t:ditec!
by W.F. Chen, J.Y. Licw, CRC Press, 2003, slates vn page 32-1 that rainfall witki S to I1: pctr r~occm,nce
intervals arc. used most often in the sizing and design ol'thc urban stotmwater dnir.;tl aid convr,.rancc:
systems. The County of Hawaii Storm Drainage Standard specilies the l p-year iI<u~ i,_r r'sorrt. whir:Ja s
on the high end ofthe scale. `1'he County currently requires higher design slonn Ii+~~q tLn~:ies fir largrr
watersheds and requires the ] 00-year, 24 hour storm for all FL'MA watercourses. 'I h ~ p;; i' its
inl'ormalion is helpful in the Counch's evaluation of the adequacy of the C ounty of h: r~r; ri i e Kistir. t;
storm drainage staruiards.
i ur~*e the County Council to investigate firrther the causes of specific tlooding iss,t~,,,: unr l ;'e+a: ,m nx,•zrrr
opinion as to whether the proposed amendments will really cure the problem. There :t v et,r re;a1
possibilit}~ that the proposed amendrnont will nut selve the problem at all but fined: ,u~i u:~ssi„rrily
contribute to the already high cast of living here in Hawaii.
i recommend approval of the amendments proposed by the Department ofYubllc Vhsncs a the caal:ie:,t
possible date so that the County remains incompliance with FIMA rc-gniremetrts.
1 sincerely appreciate the itppinlunily to provide testimony on the subject of Chal:a,:::• ? 7.
Respectfully Subtrti{t~/te{~d,
Nancy l;. Burns, Y.L.
cc 13nzce McClure, .f)irector, Department of public Works
Galen Kuba, Divisipn Head, Departrnent ol'Puhlie Works, Engineering Divi:~.i~.n