HomeMy WebLinkAboutNaalehu Collection System Final Technical Memorandum 05-01-20Memorandum
Naalehu Collection System Improvements
May 1, 2020
Page 2
2. GENERAL CRITERIA
The COH will be the owner of the collection system; therefore, the sewer system will meet COH
standards and be accessible for maintenance. Preference is to construct sewers within the County
ROW as much as possible unless other factors make placing the pipes within easements on private
property or in the State ROW much more practical from economic and engineering standpoints. The
COH prefers sewers not be within easements due to future access challenges when maintenance and
repairs are needed. It is also recommended that the collection system not be located in a State ROW if
possible due to the lengthy review and approval time needed for the Use and Occupancy Agreement
(UOA). This was emphasized by the State Department of Transportation Highways Division (DOT-
H) in their Environmental Assessment (EA) pre-consultation comment to stay out of the State ROW
unless there is no other feasible means of routing the sewer. The collection system will require a
crossing of the State ROW to convey the sewage from the community Mauka of the highway to the
WWTP site that is Makai of the highway; however, DOT-H tends to take less time when reviewing
ROW crossings, especially if they are done using trenchless installation techniques.
3. TOPOGRAPHY
The topography of the Naalehu area is presented in Figure 2. The proposed location of the
wastewater treatment plant is upgradient of the lowest of the former Brewer properties. The ground
elevation of the WWTP site is approximately 690 ft MSL while the ground elevation of the lowest
Brewer house lot is about 645 ft MSL, an elevation difference of 45 feet. A gravity sewer at this depth
is technologically possible using micro tunneling techniques for construction; however, a wastewater
pump station will be more feasible to convey the wastewater to the WWTP due to the cost of micro
tunneling a relatively short distance. The micro tunneling option can be investigated in the event that
an acceptable wastewater pump station location cannot be found.
4. POTENTIAL WASTEWATER PUMP STATION LOCATIONS
As noted in the previous section, the former Brewer properties in Naalehu would most likely be
served by a pump station due to the topography. When investigating potential sites for a wastewater
pump station (WWPS), priority was placed on sites that are on County or State lands to minimize
land acquisition issues, or large private parcels where a portion can be purchased by the County in
hopes of minimizing impact to the landowner. The potential WWPS sites are listed in Table 1, and
shown on Figure 3.
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Naalehu Collection System Improvements
May 1, 2020
Page 3
Table 1: Potential WWPS Sites
TMK Owner Current
Use
Class Size
(sq ft)
Notes
9-5-008:012 Chinese
Society
Church
Church Agricultural 186,001 Requires land from the owner and/or
easement for WWPS site, utilities and road.
Requires sewer and force main in State
ROW.
WWPS can be set back away from houses.
Located at lowest point of the collection
system.
Within 550 feet of school property line.
Longest distance for transmission to
proposed WWTP location.
9-5-008:048 Kuahiwi
Contractors
Inc.
Storage/
Baseyard
Agricultural 534,307 Requires land from the owner and/or
easement for WWPS site, utilities and road.
WWPS can be set back away from most
residents.
Within 300 feet of school property line.
Located near lowest point of the collection
system requiring approx. 15 foot wet well.
9-5-009:006 State of
Hawaii
Naalehu
School
Residential 534,481 Site is frequented by the public.
Residents have indicated sensitivity to
wastewater facility at a school.
Located at lowest point of the collection
system.
9-5-021:023 County of
Hawaii
Naalehu
Park
Residential 279,176 Site is frequented by the public.
Residents may be sensitive to wastewater
facility at a park.
Requires sewer in State ROW.
Located upgradient of some of the former
Brewer properties.
9-5-021:035 Thy Word
Ministries
– Waikoloa
Faith Ctr
Vacant Residential 134,949 Requires land acquisition from the owner
and access easement or dedicated County
road.
Routing would most likely have sewer
within State ROW.
WWPS can be set back away from most
houses.
9-5-024:007 ‘O Ka’u
Kakou Inc.
Senior
Center
Residential/
Commercial
84,680 Facility currently in construction, timing to
coordinate location could be difficult.
Residents may be sensitive to wastewater
facility within senior center campus.
9-5-024:011 County of
Hawaii
LCC
Location
Residential 10,347 Site is surrounded by houses.
Facilities will be relatively close to property
line.
Residents may be sensitive to wastewater
facility in residential area.
Located up-gradient of the lowest Brewer
properties requiring 30+ foot deep wet well.
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Naalehu Collection System Improvements
May 1, 2020
Page 4
Two of the potential sites appear to be more favorable than the others, the County site located within
the former Brewer house lots (TMK 9-5-024:011) and the Kuahiwi Contractors site (TMK 9-5-
008:048). The remaining parcels were eliminated from consideration at this time but can be re-visited
in the future if needed. The Naalehu School and Naalehu Park sites would likely face the most public
opposition due to proximity to areas frequented by the general population for recreation and
education. The Chinese Society Church and Thy Word Ministries sites would require land acquisition
after negotiation with the landowner and a UOA within the State ROW. Both processes would be
time consuming and the land acquisition depends on the landowner’s willingness to cede some of
their land to the County. The new senior center parcel is currently in construction, making the timing
to negotiate the WWPS site difficult and may possibly incur construction delays that would also
factor into the land negotiations.
A. Pump Station on County Parcel TMK 9-5-024:011
The County site would be the most favorable from a timing standpoint. It does not require land
acquisition and would minimize work in the State ROW by limiting construction to a single
crossing of Mamalahoa Highway. However, since this site is up-gradient from the collection
system low point, this site will require deeper sewers and a very deep pump station wet well.
Construction on this site would be more challenging due to the narrow site and the existing
sewers and LCC that would have to remain in operation until the collection system and WWTP
are completed. These utilities, especially the existing sewer pipes, would have to be protected
during construction as heavy vehicles and machinery enter and leave the site. The condition of the
existing pipes may require additional protection such as supplemental concrete cover and/or
partial replacement depending on condition. A proposed layout of a pump station on the County
parcel is shown in Figure 4.
The need to trench for the deep influent sewer and the deep wet well may result in flow from the
LCC being diverted to these trenches due to the lower resistance to flow through the ground to
those excavated areas. Using mud walls for groundwater control would hinder the flow of sewage
from the LCC into the ground and probably reduce the capacity of the LCC. Therefore, septage
pumping for the duration of the pump station construction would most likely be required until the
collection system and WWTP are complete. This would be a significant cost to the construction.
In addition, should there be unforeseen delays in completion of the collection system and/or
WWTP, the additional septage handling due to the delay could result in a significant construction
change order for the additional pumping.
The on-site stormwater may be more difficult to contain due to the small area. Pervious
pavement, if geotechnical investigation shows this type of pavement is permissible, would be
used to minimize hard surfaces on the site. The only hard pavement area required would be the
area designated for refueling of the generator. The grade of the site would be adjusted to
minimize flow of off-site stormwater. Grade adjustment walls are anticipated along the property
lines on the south and west sides of the parcel to raise the ground elevation.
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Naalehu Collection System Improvements
May 1, 2020
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This site is surrounded by residences directly adjacent to the property line on the east, south and
west. The north side is bordered by Opukea Street. Due to the narrow site, the house structures
are only about 60 feet from the proposed pump station location. The ambient noise from odor
control ventilation fans and electrical switches could be a nuisance to the residents if not
mitigated. The standby generator would also produce noise during testing and operation. This
would require additional sound insulation for the generator and other equipment on the site.
A passive odor control system can be used to eliminate the need for a mechanical fan; however,
passive systems rely on the collection system to be at a higher pressure than atmosphere to force
the foul air through the odor control system. When the collection system becomes pressurized,
odors can begin to leak out of the wet well hatches and nearby manholes so they must also be
gasketed or sealed. A forced-air odor control system using a mechanical fan to draw air out of the
pump station would keep the wet well and collection system at negative pressure, thus
minimizing the chance that odors escape from nearby manholes and hatches.
Electrical and water utilities are located just off-site on Opukea Road. The HELCo transformer
for the site can be located within an easement just off the County road. Water for fire protection
could be from existing hydrants (pending analysis by a fire protection engineer). Water service is
anticipated to be similar to a residential unit to provide wash down and general housekeeping
hose bibbs.
This site poses several risks during construction that could add significantly to the cost and time
to construct the pump station. The site is also narrow and cannot be configured optimally to
mitigate noise, which could be significant to the homeowners directly adjacent to the site.
B. Pump Station on Portion of Kuahiwi Contractors, Inc. Parcel TMK 9-5-008:048
The Kuahiwi Contractors site is private property and would require time to negotiate the
subdivision or easement for the WWPS site and access roadway; however, similar to the County
site, work in the State ROW can be limited to a single crossing of the highway. The anticipated
size of the site is about 8000 to 9000 square feet. A proposed pump station layout and site are
presented in Figure 5. A larger area may be needed if soil conditions require a larger area to
mitigate on-site stormwater flows. This is smaller than the County parcel above but the
dimensions can be optimized to provide the area needed for the facility. This site is located at the
low point of the collection system, which would keep the sewers and pump station wet well at
more typical depths. Locating the WWPS on a portion of the Kuahiwi Contractors site would
allow sewering of the Iglesia ni Cristo Church that requested connection but will place it at the
farthest point from the WWTP, thus increasing the force main and sewer lengths required. An
access road or driveway would also be needed to the site. A gravel drive would minimize the
impervious surface area but can be susceptible to erosion during heavy rains.
The pump station would be placed close to the south property line, the low side of the parcel. The
far south east or Hilo corner of the parcel is the lowest point where stormwater from this parcel
and possibly some adjacent parcels collect before entering a drainage culvert under Mamalahoa
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Naalehu Collection System Improvements
May 1, 2020
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Highway. Anecdotal reports from residents indicate the highway floods at the storm drain during
heavy or sustained rains. There is also a swale that appears to divert stormwater from cattle and
horse pens on the site toward the far south east corner. It is recommended that the County not
encroach into the far south east corner to maintain the current storm drainage pattern from the
site. An aerial view of the area is shown in Figure 6. On-site stormwater can be contained by
making the site large enough for impoundments and by using pervious pavement where possible
depending on geotechnical investigation data. The only road area requiring hard surfacing is the
area designated for re-fueling the generator. Grade adjustment walls are anticipated along the
perimeter of the pump station site to raise the grade on the south side and lower the grade on the
north side to even out the elevation of the site and minimize inflow of off-site storm water.
The site would be bordered on the south by residences unless the pump station is moved further
interior of the parcel. If the pump station site is located against the south property line, the pump
station could be as close as 80 feet from the house structures. Similar to the County parcel, the
ambient noise from equipment could be a nuisance to the residents if not mitigated. This parcel
would allow the County to obtain a more optimally configured site that would allow an additional
motor control center (MCC) room that would not only mitigate noise issues from electrical
switches, but also allow the valuable electrical equipment to be secured in a locked room. The
MCC room can be integrated into the generator building. Noise from the odor control system
could also be an issue, especially from the fan that would operate continuously. However, the site
can be optimally sized to allow sound attenuating enclosures around the fan or around the entire
odor control system. Therefore, a passive odor control system as discussed above for the County
parcel site is probably not needed at this site.
Running electrical utility and communication lines would be more costly for this site since the
closest pole would be on Ohai Road. HELCo would charge the County to run utility lines to their
transformer near the pump station site. As an alternative, the HELCo transformer and meter can
be placed within an easement near Ohai Road and the County would own the power lines going
into the site. This option is mentioned in case HELCo prefers not to own the power lines going
into the site or requires road improvements that would not be favorable to the County. This would
require discussion with and approval by HELCo and would have to be analyzed further by an
electrical engineer.
A potable water line would be required at the site for wash down and general housekeeping. In
addition, a hydrant for fire protection would be needed. The potable water pipe in Naalehu appear
to be 6-inch diameter. The new potable water line to the site would maintain the 6-inch size to
maximize the water flow in case of fire or other emergency requiring water.
This site is preferred from an engineering standpoint because it is at the low side of the collection
system and does not entail unknowns during construction such as breakage of existing utilities or
need for septage pumping for unknown duration. It can also be optimally configured to mitigate
noise and odors.
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Naalehu Collection System Improvements
May 1, 2020
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5 COLLECTION SYSTEM DESIGN
The town of Naalehu is divided by a concrete flood control canal into an east side (Hilo side) where
the majority of the properties are residences, and a west side (Kona side) where the majority of the
properties are commercial. The town is also divided in the Mauka (mountain) and Makai (ocean)
directions by the Mamalahoa Highway. The collection system will convey the wastewater to the
proposed WWTP that is located on the Makai-Kona side of Naalehu. The Naalehu collection system
will be analyzed as two distinct systems, one serving the former Brewer house lots located on the
Mauka-Hilo side to allow closure of the LCCs, and the gravity sewer located on the Kona side to
transport the sewage to the proposed WWTP. An added benefit would be provision of sewer service
to the two restaurants requesting connection. The church on the Hilo side that requested service falls
outside of this area. The County has expressed a desire to accommodate their request; however,
depending on the location of the WWPS, connection of the church may have to be deferred.
C. Former Brewer House Lots
The former Brewer house lots are located on the Mauka-Hilo side as shown in Figure 7. The
houses are on a hillside with a slope of 8% to 9%, ranging in elevation from about 780 ft MSL to
645 ft MSL. The steep hillside results in houses located on the downhill side of the street being
below the elevation of the street. Sewage from houses on the uphill side can flow easily by
gravity to a sewer in the street. On the downhill side; however, the lateral serving the home is
lower than a typical depth sewer (typically designed with 4 feet to 5 feet cover). Four options
were investigated to address the low-lying properties; use of easements on private property,
vacuum sewers, individual grinder pump stations at low-lying properties, and deep sewers to
allow gravity flow from the low-lying properties.
i. Easements
The use of easements was eliminated as a viable option at this time. An initial investigation of
the house lots along the backyard property lines where an easement would be most beneficial
revealed extensive homeowner improvements. As part of sewer construction and easement
terms, the improvements can be removed and the homeowners can be ordered to keep
improvements off of the easements. However, over time it is likely that the homeowners’
memory of the easement locations would fade and various improvements may be placed over
the easement, hindering access by the County for repairs and maintenance.
ii. Vacuum Sewers
The use of vacuum sewers was also eliminated at this time. Vacuum sewers use a sealed
sewer system that produces suction to move the wastewater from low or flat areas. Research
into these types of systems revealed that it is not cost effective to sewer the uphill houses by
gravity and the downhill houses by vacuum because of the need for a sealed piping system
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May 1, 2020
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for vacuum service. Serving some house by conventional gravity and some by vacuum would
require two sewer collection systems in the County ROW.
The vacuum interface valve that would be located on each property requires frequent
maintenance checks to ensure proper operation. These checks should be done by trained
maintenance personnel but since these valves would be on private property, the responsibility
would fall on the homeowner to hire trained personnel or obtain training on the system.
Another drawback is that the vacuum interface valves typically fail open to minimize the
chance of spills. A failed valve will therefore result in the County-owned vacuum pumping
system to run constantly (normal operation would be intermittent to save energy). County
maintenance personnel would not be able to readily find the faulty valve since they would not
have right-of-entry onto the individual properties. Also, since there is no spill or “problem”
with the sewer at the individual property with the faulty valve, there is no incentive to correct
the problem in a timely manner. Remote telemetry can be added to the vacuum interface
valves to monitor the valves via SCADA but these would also require periodic maintenance
on private property and would add to the cost of the system for monitoring at every property.
iii. Individual Grinder Pump Stations
The original concept developed for Brewer before the company dissolved was to have
individual grinder pump stations at the low-lying properties. This type of system consists of a
small pump station at each downhill home. As the pump station fills with sewage, the high
wastewater level starts a pump that evacuates the station and discharges into the gravity
sewer system on the street. Houses on the uphill side of the street would discharge sewage by
gravity into the collection system. The advantage of individual grinder pump stations is the
ability to keep the collection system as shallow as possible.
Disadvantages of this system are the need to maintain the pumps and valves on private
property and the energy used to pump the wastewater. Another disadvantage is the potential
for spills when there are mechanical failures such as, power outages, pump breakdowns, level
switch malfunctions, and clogs within the pump. Similar to the vacuum sewer system, the
mechanically intensive nature of individual grinder pump stations requires trained
maintenance personnel to perform regular checks on the system. However, since the system
belongs to the homeowner, it is their responsibility to either hire a maintenance service or
obtain the necessary training. Unlike the vacuum system, the pump stations are not “fail safe”
and will result in sewage backup in the home or a spill on the homeowner’s property that
would prompt them to seek corrective action. A rough life-cycle cost analysis of an individual
grinder pump unit resulted in an annual cost burden of $850 per house on the homeowners.
The subsurface conditions of the area at the depths required for the sewers is yet to be
investigated. If the deep gravity sewers (see below) are not feasible due to unfavorable
conditions; such as, lava tubes, then the sewers may have to be kept as shallow as possible.
This option is feasible and will be kept in consideration in the event that subsurface
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May 1, 2020
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conditions require it, but is not the preferred option due to the disadvantages, especially the
cost burden on the homeowners.
iv. Deep Gravity Sewers
The majority of the collection system sewer mains can be kept within the County or State
ROW and fed by gravity if the pipes are deep below the low point of the low-lying parcels.
Sewers constructed in the County of Hawaii must adhere to the Wastewater System Design
Standards of the City and County of Honolulu, which requires review and approval for sewers
deeper than 15 feet due to higher soil loading and potential difficulty when repairs are
needed. A preliminary layout of a gravity sewer system, as shown in Figure 7, resulted in
sewer depths of about 20 to 25 feet at the deepest point on the upper portions of Ohai Road
and Nahele Street, and 15 to 18 feet at the deepest point on Lokelani Street and Kilika Street.
These depths are based on running a lateral from the lowest point on a house lot up to the
street. This was used as the basis because there are houses with sinks and outhouses at the
back of the lot that are assumed to be connected to the existing collection system. The soil
depth to rock in the area as reported by USGS and verified by past geotechnical
investigations is 40 to 60 inches; therefore, excavation for the deep gravity sewers would be
mainly in rock.
A sewer along the highway or easements would be needed to service the houses on the State
highway between Kukui Road and Ohai Road. The depth, length and direction of flow for
this sewer would depend on the location of a pump station. The depth of the sewer on Opukea
Street depends on the location of a sewage pump station (see Section 4). As a worse case, the
manhole fronting the County-owned parcel (TMK 9-5-024:011) on Opukea Street would
have an invert about 30 feet deep if a pump station is constructed on that site due to the
elevation of the house at the corner of Ohai Road and Mamalahoa Hwy (TMK 9-5-024:001),
the lowest point of the former Brewer community. Although 30 feet is rather deep, it is not
unheard of at the entrance to pump stations in Honolulu which are often 3 stories deep. At the
Kuahiwi Contractors site (TMK 9-5-008:048) the ground elevation is about the same as the
house at Ohai Road and Mamalahoa Hwy resulting in sewers that are at a more reasonable
depth of about 15 feet.
This option is feasible and will be considered further. Despite the depth of the sewers in the
County ROW, the advantage of not burdening the homeowners with the cost of maintaining
the pumping system in Section 5-A-iii, above, makes this option preferred over the individual
grinder pump option.
D. Gravity Sewer from Force Main to WWTP
The primary purpose of the sewer on the Kona side of Naalehu is to convey the wastewater from
the Brewer house lots to the WWTP. A gravity sewer on Kaalaiki Road can be used to collect the
wastewater discharged from a pump station servicing the housing area on the Hilo side of the
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May 1, 2020
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drainage canal at either the County parcel on Opukea Street or the Kuahiwi Contractors site. The
force main can be run entirely Mauka of the highway, cross the drainage canal, and discharge into
a manhole when it reaches Kaalaiki Road. An easement would be required from the drainage
canal to the County road. There is an existing access and utility easement located on a parcel
owned by La’i LLC (TMK 9-5-025:039) that goes from Kaalaiki Road to the canal. This would
be the recommended method of conveying the sewage to the WWTP to keep construction in the
State ROW to a minimum. The force main route is discussed further in the next section.
Two commercial properties requested connection to the new collection system. These were the
Punaluu Bake Shop (TMK 9-5-025:037) and Hana Hou Restaurant (TMK 9-5-021:005). These
properties can be connected to the collection system via the gravity sewer running down Kaalaiki
Road, across the highway, and down Naalehu Spur Road to the WWTP site. There are potentially
an additional eight properties that would be newly accessible along this sewer route depending on
the disposition of Naalehu Spur Road, which is privately owned by Kuahiwi Contractors, Inc. If
the road is dedicated to the County or an easement in favor of the County spans the entire road
width, then both sides of Naalehu Spur Road would be newly accessible. If the sewer easement is
only on one side of the road, assumed to be the Hilo side to allow connection of Hana Hou
Restaurant (TMK 9-5-021:005), then only the Hilo-side properties would be newly accessible.
The proposed Kona-side collection system is presented in Figure 8.
E. Force Main from Brewer House Lots to Gravity Sewer on Kona Side
A force main will be needed to convey the wastewater from the WWPS that serves the former
Brewer house lots to the gravity sewer going to the WWTP on the Kona side. The force main can
be kept out of the State ROW by running the pipe along easements and County roads. Figure 8
shows the possible force main routes from the County parcel and the Kuahiwi Contractors sites.
The approximate force main lengths from the County parcel and Kuahiwi Contractors parcel are
1300 LF and 2800 LF, respectively.
Both WWPS options will require crossing the concrete drainage canal that divides the Kona side
of Naalehu from the Hilo side. The force main can go either above the canal on a support
structure, or under the canal. There is an existing pedestrian bridge crossing the canal that can be
reconstructed and used to support the new force main; however, the County DEM is not in favor
of this option due to the possibility of the structure impeding flow through the canal and
ownership of the bridge structure being a burden on DEM personnel who are not set up for bridge
inspection and maintenance duties. Routing the force main under the canal can be done by either
cutting the concrete canal structure and laying the pipe in an open trench or tunneling under the
canal. Cutting the structure poses some risk should a rain storm occur while the trench is open or
repaired concrete is curing. Tunneling would be costly due to the depth and equipment needed to
micro-tunnel or the shoring required to excavate under the structure. Further discussions with a
geotechnical engineer will be needed to determine the best method to cross the canal while
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May 1, 2020
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limiting risk during construction. For planning purposes, it will be assumed that the canal
crossing will be approximately 100 LF using micro-tunneling as a worse case.
6 COLLECTION SYSTEM COSTS AND RECOMMENDATIONS
Planning level capital costs were developed for the collection system options developed above. The
costs are presented in Table 2. Basis for the costs are presented in Table 3. Cost basis numbers are
from recent past project construction and bid costs inflated to the current year.
Table 2: Collection System Costs
Table 3: Cost Basis
Unit Cost
Deep WWPS at County Parcel $7.1 million
Typical WWPS at Kuahiwi Contractors Parcel $4.9 million
Gravity Sewers $1100/LF
Deep Gravity Sewers in Rock $1600/LF
Deep Sewers (Tunneled) $7000/LF
Sewer Force Mains (not including tunneled section under canal) $1000/LF
Note: Cost of individual grinder pump system based on design cost estimate of $5.6 million prepared in 2012 inflated to
2020 at 6% average inflation ($5.6m x 1.06^(2020-2012) = $9 million)
The overall recommendation for the collection system is to use deep gravity sewers for the former
Brewer housing area. Two backyard easements would be used to connect four properties to the
collection system. These easements have already been surveyed and are located on the south side of
TMK 9-5-024:009 and TMK 9-5-024:010. These easements would expedite implementation by
avoiding the need for a sewer in the State ROW to serve three of the properties. Two commercial
properties requested connection to the new collection system. These were the Punaluu Bake Shop
(TMK 9-5-025:037) and Hana Hou Restaurant (TMK 9-5-021:005). These properties can be
connected to the collection system via a gravity sewer running down Kaalaiki Road, across the
highway, and down Naalehu Spur Road. There are up to an additional fifteen properties that would be
newly accessible along this sewer route. The newly accessible house lots along with the newly
accessible properties along the sewer to serve the commercial lots brings the total newly accessible
properties to 39, exceeding the number identified in the Consent Order. If the WWPS is located on
the County parcel, the overall estimated cost of the system would be $24.4 million. If the the WWPS
Deep Gravity Sewer at House Lots $12 million
Individual Grinder Pumps at House Lots $9 million
WWPS at County Parcel $7.1 million + $1.3 million FM = $8.4 million
WWPS at Kuahiwi Contractors $4.9 million + $2.8 million FM = $7.7 million
Canal Crossing (Tunneled) $0.7 million
Gravity Sewer from FM to Proposed WWTP $3.3 million
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is located on the Kuahiwi Contractors site, overall estimated cost would be $23.7 million. The
recommended collection system options are presented in Figure 9 and 10.
If using deep sewers in the former Brewer house lots is not feasible due to subsurface conditions, the
estimated cost of the collection system would be $21.4 million if the WWPS is on the County parcel,
and $20.7 million if the WWPS is on the Kuahiwi Contractors site. However, there would be added
cost for the homeowners with parcels below the road of approximately $850 per year per house to
maintain the pumps. A summary of the overall costs is presented in Table 4.
Table 4: Overall Planning Level Cost Estimates
Deep Gravity Sewers Individual Pumps
County WWPS at County Parcel $24.4 million $21.4 million
County WWPS at Kuahiwi Contractors Site $23.7 million $20.7 million
7 COLLECTION SYSTEM PHASING
The collection system can be constructed in phases to expedite the closure of the LCCs. As a
minimum, the collection system would have to intercept the existing sewers entering the LCCs and
convey the sewage to a pump station. To minimize the need for temporary facilities that would be
removed when the collection system is completed in a second phase, it would be beneficial to
construct the permanent WWPS as part of Phase 1. Phase 1 would therefore consist of the following:
a. Construct Gravity Sewer on Kaalaiki Road and Naalehu Spur Road to the WWTP
b. Construct the WWPS and force main
c. Construct the gravity sewer on Opukea Street and Ohai Road to intercept existing sewers and
connect to the WWPS
The sewer system for the proposed Phase 1 is presented in Figures 11 and 12. Sub-phases “a” and
“b” can be done concurrently; however, intercepting the existing sewer system should be done at the
end of Phase 1. This is so that the if there are issues encountered when constructing the sewers, the
main WWPS and means of conveying the flow to the WWTP will be in place so that bypass pumping
to the WWPS can be used if needed. If the main WWPS and conveyance sewers to the WWTP were
not in place, the contractor would have a more difficult time with bypass pumping to the WWTP or
would have to truck sewage if a problem occurs. The new WWPS would be close enough to allow
temporary piping to be routed from the problem area into the wet well.
The cost to implement Phase 1 would be about $15.3 million with the WWPS on the County parcel,
and about $15.1 million with the WWPS on the Kuahiwi Contractors site (not including land
acquisition costs). A phased cost summary is presented in Table 5.
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Table 5: Phased Cost Summary
Deep Gravity Sewers Individual Pumps
County Parcel Kuahiwi Parcel County Parcel Kuahiwi Parcel
Phase 1 $15.3 million $15.1 million $12.3 million $12.1 million
Phase 2 $9.1 million $8.6 million $6.1 million $5.6 million
Total $24.4 million $23.7 million $18.4 million $17.7 million
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JOB NO.: 151494
NAALEHU WASTEWATER TREATMENT PLANT
Existing Naalehu Wastewater System
FIGURE
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Existing Large Capacity
Cesspool (LCC 4)
Existing Large Capacity
Cesspool (LCC 3)
Existing Large Capacity
Cesspool (LCC 5)
Naalehu
Cemetery
Naalehu
Elementary
School
Naalehu
Park
Naalehu
Hongwanji
Figure2:NaalehuTopographyElev 760± HighPointElev 660± KukuiInt.Elev 690± WWTPElev 650± Niu Int.Elev 640± Niu/PohaInt.Elev 645± Ohai IntElev 640± ChurchSource:OnsiteSewageDisposalSystemsHawaii[arcgis_rest_services_Infrastructure_MapServer_26
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Existing Service Area
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JOB NO.: 151494
NAALEHU WASTEWATER TREATMENT PLANT
Existing Naalehu Wastewater System
FIGURE
1-1
Existing Large Capacity
Cesspool (LCC 4)
Existing Large Capacity
Cesspool (LCC 3)
Existing Large Capacity
Cesspool (LCC 5)
Naalehu
Cemetery
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Elementary
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NAALEHU WASTEWATER TREATMENT PLANT
Existing Naalehu Wastewater System
FIGURE
1-1
Existing Large Capacity
Cesspool (LCC 4)
Existing Large Capacity
Cesspool (LCC 3)
Existing Large Capacity
Cesspool (LCC 5)
Naalehu
Cemetery
Naalehu
Elementary
School
Naalehu
Park
Naalehu
Hongwanji
Appendix
Pump Station Cost Estimates
PumpStationOptionSummaryTableCountyParcelVerticalShaftMachine 7,700,000$*CountyParcelDigandShore 7,100,000$KuahiwiSiteMinimumVSM 6,100,000$*#KuahiwiSiteMinimumDigandShore 4,900,000$#KuahiwiSiteLarge,DigandShore 5,600,000$#Notes:*IncludesfullcostofmobilizingVSMtoHawaii.IfVSMisusedforanyotherpurposes(e.g.,trenchlesspipeinstallation,deepSMHsetc.)thenmobilizationcostwillgetdistributed,#DoesnotincludecostofstormwatercontrolthatmayberequiredduetofloodingissuesatSEcornerofsite
CountyParcelVerticalShaftMachine(HerrenknechtVSM8000at4.5mdiameter)DESCRIPTION QTY UM MATERIAL LABOR EQUIPMENTUNITCOSTTOTALMobilization 1 LS 800,000.00$800,000$Clearingandgrubbing10,000 sf 8.00$3.00$11.00$110,000$Machinesetup 1 LS 60,000.00$60,000$Wetwellshaft 35 ft 15,000.00$12,000.00$3,000.00$30,000.00$1,050,000$HaulSpoils 230 cy 13.00$8.00$21.00$4,830$Septagepumping(keepLCClow)2 mo 6,000.00$4,800.00$1,500.00$12,300.00$24,600$Septagehauling2 mo 14,400.00$3,000.00$17,400.00$34,800$Concretematfoundation 20 cy 750.00$225.00$12.00$987.00$19,740$Wetwellstructure;8'dia,9"wall 31 ft 500.00$100.00$250.00$850.00$26,350$Wetwellbase 1 ea 1,750.00$800.00$300.00$2,850.00$2,850$Wetwelltopslab,12'x12'x10"thk 4 cy 950.00$450.00$85.00$1,485.00$5,940$Wetwellhatch,ssandaluminum 1 ea 2,300.00$500.00$90.00$2,890.00$2,890$Wetwellinteriorcoating 1000 sf 85.00$20.00$10.00$115.00$115,000$Wetwellexteriormoistureprot 1045 sf 12.00$10.00$2.00$24.00$25,080$Engineeredbackfill 140 cy 47.00$42.00$20.00$109.00$15,260$SubmPumps,400gpm,80ftTDH 2 ea 3,000.00$1,800.00$180.00$4,980.00$9,960$Dischelbowsandguides 2 ea 1,500.00$1,200.00$180.00$2,880.00$5,760$Valvevaultstructure 1 ea 925.00$250.00$180.00$1,355.00$1,355$Emergencypumpconnvault 1 ea 925.00$250.00$180.00$1,355.00$1,355$GateValve,6" 5 ea 910.00$175.00$85.00$1,170.00$5,850$Checkvalve,6" 2 ea 1,050.00$175.00$85.00$1,310.00$2,620$Quickconnecthosecoupling 1 ea 400.00$100.00$85.00$585.00$585$90bend,FExFE,6" 3 ea 1,005.00$150.00$85.00$1,240.00$3,720$Tee,FExFE,6" 1 ea 1,250.00$225.00$85.00$1,560.00$1,560$45bend,MJ,6" 4 ea 935.00$150.00$85.00$1,170.00$4,680$Wye,MJ,6" 2 ea 1,270.00$225.00$85.00$1,580.00$3,160$Plug,MJ,6" 1 ea 685.00$75.00$85.00$845.00$845$DIpipe,FE,6" 80 LF 185.00$25.00$15.00$225.00$18,000$
DIpipe,MJ,6" 150 LF 180.00$25.00$15.00$220.00$33,000$Sewertrenchexcavation,soft270 cy 25.00$7.00$32.00$8,640$Sewertrenchexcavation,rock110 cy 175.00$35.00$210.00$23,100$HaulSpoils380 cy 13.00$8.00$21.00$7,980$TrenchShoring,010ft2200 sf 2.00$5.00$3.00$10.00$22,000$TrenchShoring1020ft2200 sf 2.50$7.00$3.00$12.50$27,500$TrenchShoring2027ft,rock1540 sf 3.50$9.00$5.00$17.50$26,950$Septagepumping(keepLCClow)1.5 mo 6,000.00$4,800.00$1,500.00$12,300.00$18,450$Septagehauling1.5 mo 14,400.00$3,000.00$17,400.00$26,100$Influentsewer,14"DI,lined110 LF 260.00$45.00$25.00$330.00$36,300$Reinfconcjkt6.3 cy 950.00$350.00$55.00$1,355.00$8,537$CLSMBackfill285 cy 300.00$5.00$10.00$315.00$89,775$Backfill41 cy 20.00$42.00$10.00$72.00$2,952$Deepmanhole(27ft)1 ea 7,500.00$3,300.00$1,500.00$12,300.00$12,300$Manholeinteriorcoating355 sf 85.00$20.00$10.00$115.00$40,825$SMHexteriormoistureprotection410 sf 12.00$10.00$2.00$24.00$9,840$Odorcontrolunit 1 ea 7,150.00$6,000.00$400.00$13,550.00$13,550$GeneratorBldg 320 sf 250.00$265.00$10.00$525.00$168,000$Roofingmembrane 5.8 sq 3,000.00$2,000.00$170.00$5,170.00$29,986$Blocksealantandpaint 700 sf 11.00$10.00$4.00$25.00$17,500$Acousticinsulation 700 sf 90.00$20.00$5.00$115.00$80,500$Acousticlouvers 144 sf 245.00$50.00$60.00$355.00$51,120$Generatorw/basemountedtank 1 ea 127,000.00$35,000.00$800.00$162,800.00$162,800$Concinertiapadforgenerator 6 cy 950.00$450.00$85.00$1,485.00$8,910$Concfuelingpad 3.5 cy 750.00$225.00$12.00$987.00$3,455$Perviouspavementroad5000 sf 50.00$30.00$9.00$89.00$445,000$3'Gradeadjustmentwall360 LF 625.00$475.00$5.00$1,105.00$397,800$Fence 426 LF 45.00$35.00$5.00$85.00$36,210$Gate 1 ea 950.00$500.00$30.00$1,480.00$1,480$2"waterservice120 LF 75.00$9.00$2.00$86.00$10,320$2"watermeterbox1 ea 250.00$200.00$15.00$465.00$465$Watermeter1 LS 1,500.00$1,500$
Generalcivilsitework 10000 sf 20.00$200,000$HELCOxfrmrandfees 1 LS 125,000.00$125,000$SCADAandsecuritysystem 1 LS 95,000.00$95,000$Electrical,inclinstrumentation 1 LS 377,310.60$377,311$Adderfordeepersewers2000 lf 105.00$235.00$125.00$465.00$930,000$SUBTOTAL 5,906,945$CONTINGENCY(30%) 1,772,083$TOTAL 7,679,028$
CountyParcelConventionalDigandShoreDESCRIPTION QTY UM MATERIAL LABOR EQUIPMENTUNITCOSTTOTALMobilization 1 LS$$Clearingandgrubbing10,000 sf 8.00$3.00$11.00$110,000$Mudwallsforwatercontrol 75 cy 600.00$200.00$200.00$1,000.00$75,000$Excavationsoftmaterial 296 cy 164.71$85.00$249.71$73,914$Excavationrock 80 cy 500.00$175.00$675.00$54,000$HaulSpoils 376 cy 13.00$8.00$21.00$7,896$Septagepumping(keepLCClow)4 mo 6,000.00$4,800.00$1,500.00$12,300.00$49,200$Septagehauling4 mo 14,400.00$3,000.00$17,400.00$69,600$Shoring,010ft 800 sf 45.00$200.00$120.00$365.00$292,000$Shoring1020ft 640 sf 65.00$320.00$200.00$585.00$374,400$Shoring2035ft,rock 720 sf 160.00$320.00$225.00$705.00$507,600$Concretematfoundation 20 cy 750.00$225.00$12.00$987.00$19,740$Wetwellstructure;8'dia,9"wall 31 ft 500.00$100.00$250.00$850.00$26,350$Wetwellbase 1 ea 1,750.00$800.00$300.00$2,850.00$2,850$Wetwelltopslab,12'x12'x10"thk 4 cy 950.00$450.00$85.00$1,485.00$5,940$Wetwellhatch,ssandaluminum 1 ea 2,300.00$500.00$90.00$2,890.00$2,890$Wetwellinteriorcoating 1000 sf 85.00$20.00$10.00$115.00$115,000$Wetwellexteriormoistureprot 1045 sf 12.00$10.00$2.00$24.00$25,080$Engineeredbackfill 295 cy 47.00$42.00$20.00$109.00$32,155$SubmPumps,400gpm,80ftTDH 2 ea 3,000.00$1,800.00$180.00$4,980.00$9,960$Dischelbowsandguides 2 ea 1,500.00$1,200.00$180.00$2,880.00$5,760$Valvevaultstructure 1 ea 925.00$250.00$180.00$1,355.00$1,355$Emergencypumpconnvault 1 ea 925.00$250.00$180.00$1,355.00$1,355$GateValve,6" 5 ea 910.00$175.00$85.00$1,170.00$5,850$Checkvalve,6" 2 ea 1,050.00$175.00$85.00$1,310.00$2,620$Quickconnecthosecoupling 1 ea 400.00$100.00$85.00$585.00$585$90bend,FExFE,6" 3 ea 1,005.00$150.00$85.00$1,240.00$3,720$Tee,FExFE,6" 1 ea 1,250.00$225.00$85.00$1,560.00$1,560$
45bend,MJ,6" 4 ea 935.00$150.00$85.00$1,170.00$4,680$Wye,MJ,6" 2 ea 1,270.00$225.00$85.00$1,580.00$3,160$Plug,MJ,6" 1 ea 685.00$75.00$85.00$845.00$845$DIpipe,FE,6" 80 LF 185.00$25.00$15.00$225.00$18,000$DIpipe,MJ,6" 150 LF 180.00$25.00$15.00$220.00$33,000$Sewertrenchexcavation,soft270 cy 25.00$7.00$32.00$8,640$Sewertrenchexcavation,rock110 cy 175.00$35.00$210.00$23,100$HaulSpoils380 cy 13.00$8.00$21.00$7,980$TrenchShoring,010ft2200 sf 2.00$5.00$3.00$10.00$22,000$TrenchShoring1020ft2200 sf 2.50$7.00$3.00$12.50$27,500$TrenchShoring2027ft,rock1540 sf 3.50$9.00$5.00$17.50$26,950$Septagepumping(keepLCClow)1.5 mo 6,000.00$4,800.00$1,500.00$12,300.00$18,450$Septagehauling1.5 mo 14,400.00$3,000.00$17,400.00$26,100$Influentsewer,14"DI,lined110 LF 260.00$45.00$25.00$330.00$36,300$Reinfconcjkt6.3 cy 950.00$350.00$55.00$1,355.00$8,537$CLSMBackfill285 cy 300.00$5.00$10.00$315.00$89,775$Backfill41 cy 20.00$42.00$10.00$72.00$2,952$Deepmanhole(27ft)1 ea 7,500.00$3,300.00$1,500.00$12,300.00$12,300$Manholeinteriorcoating355 sf 85.00$20.00$10.00$115.00$40,825$SMHexteriormoistureprotection410 sf 12.00$10.00$2.00$24.00$9,840$Odorcontrolunit 1 ea 7,150.00$6,000.00$400.00$13,550.00$13,550$GeneratorBldg 320 sf 250.00$265.00$10.00$525.00$168,000$Roofingmembrane 5.8 sq 3,000.00$2,000.00$170.00$5,170.00$29,986$Blocksealantandpaint 700 sf 11.00$10.00$4.00$25.00$17,500$Acousticinsulation 700 sf 90.00$20.00$5.00$115.00$80,500$Acousticlouvers 144 sf 245.00$50.00$60.00$355.00$51,120$Generatorw/basemountedtank 1 ea 127,000.00$35,000.00$800.00$162,800.00$162,800$Concinertiapadforgenerator 6 cy 950.00$450.00$85.00$1,485.00$8,910$Concfuelingpad 3.5 cy 750.00$225.00$12.00$987.00$3,455$Perviouspavementroad5000 sf 50.00$30.00$9.00$89.00$445,000$3'Gradeadjustmentwall360 LF 625.00$475.00$5.00$1,105.00$397,800$Fence 426 LF 45.00$35.00$5.00$85.00$36,210$
Gate 1 ea 950.00$500.00$30.00$1,480.00$1,480$2"waterservice120 LF 75.00$9.00$2.00$86.00$10,320$2"watermeterbox1 ea 250.00$200.00$15.00$465.00$465$Watermeter1 LS 1,500.00$1,500$Generalcivilsitework 10000 sf 20.00$200,000$HELCOxfrmrandfees 1 LS 125,000.00$125,000$SCADAandsecuritysystem 1 LS 95,000.00$95,000$Electrical,inclinstrumentation 1 LS 379,844.85$379,845$Adderfordeepersewers2000 lf 105.00$235.00$125.00$465.00$930,000$SUBTOTAL 5,455,754$CONTINGENCY(30%) 1,636,726$TOTAL 7,092,480$
KuahiwiContractorsSite,MinimumVerticalShaftMachine(HerrenknechtVSM8000at4.5mdiameter)DESCRIPTION QTY UM MATERIAL LABOR EQUIPMENTUNITCOSTTOTALMobilization 1 LS $800,000.00 $800,000Clearingandgrubbing8,000 sf $8.00 $3.00 $11.00 $88,000Machinesetup 1 LS $60,000.00 $60,000Wetwellshaft 18 ft $15,000.00 $12,000.00 $3,000.00 $30,000.00 $540,000HaulSpoils 103 cy $13.00 $8.00 $21.00 $2,163Concretematfoundation 20 cy $750.00 $225.00 $12.00 $987.00 $19,740Wetwellstructure;8'dia,9"wall 15 ft $500.00 $100.00 $250.00 $850.00 $12,750Wetwellbase 1 ea $1,750.00 $800.00 $300.00 $2,850.00 $2,850Wetwelltopslab,12'x12'x10"thk 4 cy $950.00 $450.00 $85.00 $1,485.00 $5,940Wetwellhatch,ssandaluminum 1 ea $2,300.00 $500.00 $90.00 $2,890.00 $2,890Wetwellinteriorcoating 500 sf $85.00 $20.00 $10.00 $115.00 $57,500Wetwellexteriormoistureprot 440 sf $12.00 $10.00 $2.00 $24.00 $10,560Engineeredbackfill 64 cy $47.00 $42.00 $20.00 $109.00 $6,976SubmPumps,400gpm,80ftTDH 2 ea $3,000.00 $1,800.00 $180.00 $4,980.00 $9,960Dischelbowsandguides 2 ea $1,500.00 $1,200.00 $180.00 $2,880.00 $5,760Valvevaultstructure 1 ea $925.00 $250.00 $180.00 $1,355.00 $1,355Emergencypumpconnvault 1 ea $925.00 $250.00 $180.00 $1,355.00 $1,355GateValve,6" 5 ea $910.00 $175.00 $85.00 $1,170.00 $5,850Checkvalve,6" 2 ea $1,050.00 $175.00 $85.00 $1,310.00 $2,620Quickconnecthosecoupling 1 ea $400.00 $100.00 $85.00 $585.00 $58590bend,FExFE,6" 3 ea $1,005.00 $150.00 $85.00 $1,240.00 $3,720Tee,FExFE,6" 1 ea $1,250.00 $225.00 $85.00 $1,560.00 $1,56045bend,MJ,6" 4 ea $935.00 $150.00 $85.00 $1,170.00 $4,680Wye,MJ,6" 2 ea $1,270.00 $225.00 $85.00 $1,580.00 $3,160Plug,MJ,6" 1 ea $685.00 $75.00 $85.00 $845.00 $845DIpipe,FE,6" 80 LF $185.00 $25.00 $15.00 $225.00 $18,000DIpipe,MJ,6" 150 LF $180.00 $25.00 $15.00 $220.00 $33,000
Sewertrenchexcavation,soft700 cy 25.00$7.00$32.00$22,400$Sewertrenchexcavation,rock0 cy 175.00$35.00$210.00$$HaulSpoils700 cy 13.00$8.00$21.00$14,700$TrenchShoring,010ft9400 sf 2.00$5.00$3.00$10.00$94,000$TrenchShoring1020ft1880 sf 2.50$7.00$3.00$12.50$23,500$TrenchShoring2027ft,rock0 sf 3.50$9.00$5.00$17.50$$Septagepumping(keepLCClow)0 mo 6,000.00$4,800.00$1,500.00$12,300.00$$Septagehauling0 mo 14,400.00$3,000.00$17,400.00$$Influentsewer,14"DI,lined470 LF 260.00$45.00$25.00$330.00$155,100$Reinfconcjkt0 cy 950.00$350.00$55.00$1,355.00$$CLSMBackfill0 cy 300.00$5.00$10.00$315.00$$EngineeredBackfill41 cy 47.00$42.00$20.00$109.00$4,469$Manhole(10ft)3 ea 3,900.00$1,800.00$600.00$6,300.00$18,900$Manholeinteriorcoating180 sf 85.00$20.00$10.00$115.00$20,700$SMHexteriormoistureprotection152 sf 12.00$10.00$2.00$24.00$3,648$SFMtrenchexcavation,soft0 cy 25.00$7.00$32.00$$HaulSpoils0 cy 13.00$8.00$21.00$$TrenchShoring,010ft0 sf 2.00$5.00$3.00$10.00$$SFM,6"DI,coatedandlined0 LF 180.00$25.00$15.00$220.00$$EngineeredBackfill0 cy 47.00$42.00$20.00$109.00$$Odorcontrolunit 1 ea $7,150.00 $6,000.00 $400.00 $13,550.00 $13,550GeneratorBldg 520 sf $250.00 $265.00 $10.00 $525.00 $273,000Roofingmembrane 8.4 sq $3,000.00 $2,000.00 $170.00 $5,170.00 $43,428Blocksealantandpaint 1105 sf $11.00 $10.00 $4.00 $25.00 $27,625Acousticinsulation 700 sf $90.00 $20.00 $5.00 $115.00 $80,500Acousticlouvers 144 sf $245.00 $50.00 $60.00 $355.00 $51,120Generatorw/basemountedtank 1 ea $127,000.00 $35,000.00 $800.00 $162,800.00 $162,800Concinertiapadforgenerator 6 cy $950.00 $450.00 $85.00 $1,485.00 $8,910Concfuelingpad 3.5 cy $750.00 $225.00 $12.00 $987.00 $3,455Perviouspavementroad5000 sf 50.00$30.00$9.00$$89.00 $445,0003'Gradeadjustmentwall370 LF 625.00$475.00$5.00$$1,105.00 $408,850Fence 360 LF $45.00 $35.00 $5.00 $85.00 $30,600
Gate 1 ea $950.00 $500.00 $30.00 $1,480.00 $1,4806"waterservice500 LF 120.00$25.00$15.00$160.00$80,000$6"detectorcheckinvault1 ea 8,000.00$6,000.00$1,000.00$15,000.00$15,000$Firestandpipe1 ea 1,500.00$900.00$20.00$2,420.00$2,420$2"waterservice120 LF 75.00$9.00$2.00$86.00$10,320$2"watermeterbox1 ea 250.00$200.00$15.00$465.00$465$Watermeter1 LS 1,500.00$1,500$Generalcivilsitework 8000 sf $20.00 $160,000HELCOxfrmrandfees 1 LS $225,000.00 $225,000SCADAandsecuritysystem 1 LS $95,000.00 $95,000Electrical,inclinstrumentation 1 LS $406,364.33 $406,364Additionalgravelroad 17,000 sf $1.75 $1.60 $0.75 $4.10 $69,700SUBTOTAL $4,675,323CONTINGENCY(30%) $1,402,597TOTAL $6,077,920
KuahiwiContractorsSite,MinimumConventionalDigandShoreDESCRIPTION QTY UM MATERIAL LABOR EQUIPMENTUNITCOSTTOTALMobilization 1 LS$$Clearingandgrubbing8,000 sf 8.00$3.00$11.00$88,000$Excavationsoftmaterial 175 cy 164.71$85.00$249.71$43,699$Excavationrock 0 cy 500.00$175.00$675.00$$HaulSpoils 175 cy 13.00$8.00$21.00$3,675$Shoring,010ft 640 sf 45.00$200.00$120.00$365.00$233,600$Shoring1018ft 384 sf 65.00$320.00$200.00$585.00$224,640$Shoring2035ft,rock 0 sf 160.00$320.00$225.00$705.00$$Concretematfoundation 20 cy 750.00$225.00$12.00$987.00$19,740$Wetwellstructure;8'dia,9"wall 15 ft 500.00$100.00$250.00$850.00$12,750$Wetwellbase 1 ea 1,750.00$800.00$300.00$2,850.00$2,850$Wetwelltopslab,12'x12'x10"thk 4 cy 950.00$450.00$85.00$1,485.00$5,940$Wetwellhatch,ssandaluminum 1 ea 2,300.00$500.00$90.00$2,890.00$2,890$Wetwellinteriorcoating 480 sf 85.00$20.00$10.00$115.00$55,200$Wetwellexteriormoistureprot 445 sf 12.00$10.00$2.00$24.00$10,680$Engineeredbackfill 136 cy 47.00$42.00$20.00$109.00$14,824$SubmPumps,400gpm,80ftTDH 2 ea 3,000.00$1,800.00$180.00$4,980.00$9,960$Dischelbowsandguides 2 ea 1,500.00$1,200.00$180.00$2,880.00$5,760$Valvevaultstructure 1 ea 925.00$250.00$180.00$1,355.00$1,355$Emergencypumpconnvault 1 ea 925.00$250.00$180.00$1,355.00$1,355$GateValve,6" 5 ea 910.00$175.00$85.00$1,170.00$5,850$Checkvalve,6" 2 ea 1,050.00$175.00$85.00$1,310.00$2,620$Quickconnecthosecoupling 1 ea 400.00$100.00$85.00$585.00$585$90bend,FExFE,6" 3 ea 1,005.00$150.00$85.00$1,240.00$3,720$Tee,FExFE,6" 1 ea 1,250.00$225.00$85.00$1,560.00$1,560$45bend,MJ,6" 4 ea 935.00$150.00$85.00$1,170.00$4,680$Wye,MJ,6" 2 ea 1,270.00$225.00$85.00$1,580.00$3,160$Plug,MJ,6" 1 ea 685.00$75.00$85.00$845.00$845$
DIpipe,FE,6" 80 LF 185.00$25.00$15.00$225.00$18,000$DIpipe,MJ,6" 150 LF 180.00$25.00$15.00$220.00$33,000$Sewertrenchexcavation,soft700 cy 25.00$7.00$32.00$22,400$Sewertrenchexcavation,rock0 cy 175.00$35.00$210.00$$HaulSpoils700 cy 13.00$8.00$21.00$14,700$TrenchShoring,010ft9400 sf 2.00$5.00$3.00$10.00$94,000$TrenchShoring1020ft1880 sf 2.50$7.00$3.00$12.50$23,500$TrenchShoring2027ft,rock0 sf 3.50$9.00$5.00$17.50$$Septagepumping(keepLCClow)0 mo 6,000.00$4,800.00$1,500.00$12,300.00$$Septagehauling0 mo 14,400.00$3,000.00$17,400.00$$Influentsewer,14"DI,lined470 LF 260.00$45.00$25.00$330.00$155,100$Reinfconcjkt0 cy 950.00$350.00$55.00$1,355.00$$CLSMBackfill0 cy 300.00$5.00$10.00$315.00$$EngineeredBackfill41 cy 47.00$42.00$20.00$109.00$4,469$Manhole(10ft)3 ea 3,900.00$1,800.00$600.00$6,300.00$18,900$Manholeinteriorcoating180 sf 85.00$20.00$10.00$115.00$20,700$SMHexteriormoistureprotection152 sf 12.00$10.00$2.00$24.00$3,648$SFMtrenchexcavation,soft0 cy 25.00$7.00$32.00$$HaulSpoils0 cy 13.00$8.00$21.00$$TrenchShoring,010ft0 sf 2.00$5.00$3.00$10.00$$SFM,6"DI,coatedandlined0 LF 180.00$25.00$15.00$220.00$$EngineeredBackfill0 cy 47.00$42.00$20.00$109.00$$Odorcontrolunit 1 ea 7,150.00$6,000.00$400.00$13,550.00$13,550$GeneratorBldg 520 sf 250.00$265.00$10.00$525.00$273,000$Roofingmembrane 8.4 sq 3,000.00$2,000.00$170.00$5,170.00$43,428$Blocksealantandpaint 1105 sf 11.00$10.00$4.00$25.00$27,625$Acousticinsulation 700 sf 90.00$20.00$5.00$115.00$80,500$Acousticlouvers 144 sf 245.00$50.00$60.00$355.00$51,120$Generatorw/basemountedtank 1 ea 127,000.00$35,000.00$800.00$162,800.00$162,800$Concinertiapadforgenerator 6 cy 950.00$450.00$85.00$1,485.00$8,910$Concfuelingpad 3.5 cy 750.00$225.00$12.00$987.00$3,455$
Perviouspavementroad5000 sf 50.00$30.00$9.00$$89.00 $445,0003'Gradeadjustmentwall370 LF 625.00$475.00$5.00$$1,105.00 $408,850Fence 360 LF 45.00$35.00$5.00$85.00$30,600$Gate 1 ea 950.00$500.00$30.00$1,480.00$1,480$6"waterservice500 LF 120.00$25.00$15.00$160.00$80,000$6"detectorcheckinvault1 ea 8,000.00$6,000.00$1,000.00$15,000.00$15,000$Firestandpipe1 ea 1,500.00$900.00$20.00$2,420.00$2,420$2"waterservice120 LF 75.00$9.00$2.00$86.00$10,320$2"watermeterbox1 ea 250.00$200.00$15.00$465.00$465$Watermeter1 LS 1,500.00$1,500$Generalcivilsitework 8000 sf 20.00$160,000$HELCOxfrmrandfees 1 LS 225,000.00$225,000$SCADAandsecuritysystem 1 LS 95,000.00$95,000$Electrical,inclinstrumentation 1 LS 407,214.53$407,215$Additionalgravelroad 17,000 sf 1.75$1.60$0.75$4.10$69,700$SUBTOTAL 3,785,292$CONTINGENCY(30%) 1,135,588$TOTAL 4,920,880$
KuahiwiContractorsSite,LargeConventionalDigandShoreDESCRIPTION QTY UM MATERIAL LABOR EQUIPMENTUNITCOSTTOTALMobilization 1 LS $0.00$Clearingandgrubbing8,000 sf $8.00 $3.00 $11.00 88,000$Excavationsoftmaterial 175 cy $164.71 $85.00 $249.71 43,699$Excavationrock 0 cy $500.00 $175.00 $675.00$HaulSpoils 175 cy $13.00 $8.00 $21.00 3,675$Shoring,010ft 640 sf $45.00 $200.00 $120.00 $365.00 233,600$Shoring1018ft 384 sf $65.00 $320.00 $200.00 $585.00 224,640$Shoring2035ft,rock 0 sf $160.00 $320.00 $225.00 $705.00$Concretematfoundation 20 cy $750.00 $225.00 $12.00 $987.00 19,740$Wetwellstructure;8'dia,9"wall 15 ft $500.00 $100.00 $250.00 $850.00 12,750$Wetwellbase 1 ea $1,750.00 $800.00 $300.00 $2,850.00 2,850$Wetwelltopslab,12'x12'x10"thk 4 cy $950.00 $450.00 $85.00 $1,485.00 5,940$Wetwellhatch,ssandaluminum 1 ea $2,300.00 $500.00 $90.00 $2,890.00 2,890$Wetwellinteriorcoating 480 sf $85.00 $20.00 $10.00 $115.00 55,200$Wetwellexteriormoistureprot 445 sf $12.00 $10.00 $2.00 $24.00 10,680$Engineeredbackfill 136 cy $47.00 $42.00 $20.00 $109.00 14,824$SubmPumps,400gpm,80ftTDH 2 ea $3,000.00 $1,800.00 $180.00 $4,980.00 9,960$Dischelbowsandguides 2 ea $1,500.00 $1,200.00 $180.00 $2,880.00 5,760$Valvevaultstructure 1 ea $925.00 $250.00 $180.00 $1,355.00 1,355$Emergencypumpconnvault 1 ea $925.00 $250.00 $180.00 $1,355.00 1,355$GateValve,6" 5 ea $910.00 $175.00 $85.00 $1,170.00 5,850$Checkvalve,6" 2 ea $1,050.00 $175.00 $85.00 $1,310.00 2,620$Quickconnecthosecoupling 1 ea $400.00 $100.00 $85.00 $585.00 585$90bend,FExFE,6" 3 ea $1,005.00 $150.00 $85.00 $1,240.00 3,720$Tee,FExFE,6" 1 ea $1,250.00 $225.00 $85.00 $1,560.00 1,560$45bend,MJ,6" 4 ea $935.00 $150.00 $85.00 $1,170.00 4,680$Wye,MJ,6" 2 ea $1,270.00 $225.00 $85.00 $1,580.00 3,160$Plug,MJ,6" 1 ea $685.00 $75.00 $85.00 $845.00 845$DIpipe,FE,6" 80 LF $185.00 $25.00 $15.00 $225.00 18,000$
DIpipe,MJ,6" 150 LF $180.00 $25.00 $15.00 $220.00 33,000$Sewertrenchexcavation,soft700 cy 25.00$7.00$32.00$22,400$Sewertrenchexcavation,rock0 cy 175.00$35.00$210.00$$HaulSpoils700 cy 13.00$8.00$21.00$14,700$TrenchShoring,010ft9400 sf 2.00$5.00$3.00$10.00$94,000$TrenchShoring1020ft1880 sf 2.50$7.00$3.00$12.50$23,500$TrenchShoring2027ft,rock0 sf 3.50$9.00$5.00$17.50$$Septagepumping(keepLCClow)0 mo 6,000.00$4,800.00$1,500.00$12,300.00$$Septagehauling0 mo 14,400.00$3,000.00$17,400.00$$Influentsewer,14"DI,lined470 LF 260.00$45.00$25.00$330.00$155,100$Reinfconcjkt0 cy 950.00$350.00$55.00$1,355.00$$CLSMBackfill0 cy 300.00$5.00$10.00$315.00$$EngineeredBackfill41 cy 47.00$42.00$20.00$109.00$4,469$Manhole(10ft)3 ea 3,900.00$1,800.00$600.00$6,300.00$18,900$Manholeinteriorcoating180 sf 85.00$20.00$10.00$115.00$20,700$SMHexteriormoistureprotection152 sf 12.00$10.00$2.00$24.00$3,648$SFMtrenchexcavation,soft0 cy 25.00$7.00$32.00$$HaulSpoils0 cy 13.00$8.00$21.00$$TrenchShoring,010ft0 sf 2.00$5.00$3.00$10.00$$SFM,6"DI,coatedandlined0 LF 180.00$25.00$15.00$220.00$$EngineeredBackfill0 cy 47.00$42.00$20.00$109.00$$Odorcontrolunit 1 ea $7,150.00 $6,000.00 $400.00 $13,550.00 13,550$GeneratorBldg 520 sf $250.00 $265.00 $10.00 $525.00 273,000$Roofingmembrane 8.4 sq $3,000.00 $2,000.00 $170.00 $5,170.00 43,428$Blocksealantandpaint 1105 sf $11.00 $10.00 $4.00 $25.00 27,625$Acousticinsulation 700 sf $90.00 $20.00 $5.00 $115.00 80,500$Acousticlouvers 144 sf $245.00 $50.00 $60.00 $355.00 51,120$Generatorw/basemountedtank 1 ea $127,000.00 $35,000.00 $800.00 $162,800.00 162,800$Concinertiapadforgenerator 6 cy $950.00 $450.00 $85.00 $1,485.00 8,910$Concfuelingpad 3.5 cy $750.00 $225.00 $12.00 $987.00 3,455$Perviouspavementroad7000 sf 50.00$30.00$9.00$$89.00 $623,000
3'Gradeadjustmentwall484 LF 625.00$475.00$5.00$$1,105.00 $534,820Fence 480 LF $45.00 $35.00 $5.00 $85.00 40,800$Gate 1 ea $950.00 $500.00 $30.00 $1,480.00 1,480$6"waterservice500 LF 120.00$25.00$15.00$160.00$80,000$6"detectorcheckinvault1 ea 8,000.00$6,000.00$1,000.00$15,000.00$15,000$Firestandpipe1 ea 1,500.00$900.00$20.00$2,420.00$2,420$2"waterservice120 LF 75.00$9.00$2.00$86.00$10,320$2"watermeterbox1 ea 250.00$200.00$15.00$465.00$465$Watermeter1 LS 1,500.00$1,500$Generalcivilsitework 15000 sf $20.00 300,000$HELCOxfrmrandfees 1 LS $225,000.00 225,000$SCADAandsecuritysystem 1 LS $95,000.00 95,000$Electrical,inclinstrumentation 1 LS $475,340.03 475,340$Additionalgravelroad 17,000 sf $1.75 $1.60 $0.75 $4.10 69,700$SUBTOTAL 4,307,588$CONTINGENCY(30%) 1,292,276$TOTAL 5,599,864$