- 1. lua Rd Moana Ka`a20 feet from wetland hum limit to edge
ofanuretaining wallSt Waiau Wetland New sidewalkKamehameha Hwys4
culverts under highwaySpringdraining into Waiau SpringsWaiau LEGEND
The Project Wetland Limit Columns Near Streams PEARL HARBOR 0 500
1000Feet Figure 4-64 Waiau Springs and Wetlandthrough Pearlridge
Center, discharging south into shore here, on which supports the
growth of salt- the East Loch of Pearl Harbor.tolerant plants
(mangrove and pickleweed). e sediment is anaerobic. Mud ats in
Pearl Harbor, `Aiea Bay State Recreation Area Wetland such as this
one, are relatively stable, whereas thee Project guideway is
approximately 200 feet narrow riparian mud ats along streams are
subject mauka of the tidal wetland (formally a denseto hydraulic
scouring. Recovery of the mangrove mangal forest) fringing Aiea Bay
(Figure 4-66).removed in 2007 is well underway as juvenile Aiea
Stream has formed a depositional delta o themangrove plants
colonize the tidal at.4-154 CHAPTER 4 Environmental Analysis,
Consequences, and Mitigation
2. i St nohKao 20 feet from wetland limit to edge ofKam
retaining wall ehameh a HwySumida Watercress Farm ngsao Spri i St K
alau Pali Mom Wetland extends Pearlridge beyond limitNew
sidewalkngsamSpri ao StreuaoKalaK alauam Stre uaoKam Kalaeham eha
`Aiea Kai Pl HwyLEGEND The Project Fixed Guideway StationWetland
Limit 0250 500 FeetFigure 4-65 Sumida Watercress Farm Wetland
Aolele Ditch of the three wetlands connects to the tidal reach of
Aolele Ditch is a man-made drainage featureAolele Ditch and harbors
top minnows (poeciliids) constructed to drain stormwater to Keehi
Lagoon and American cray sh, suggesting a permanent from the
northeastern portion of Honolulu Inter- fresh or slightly brackish
wetland that has devel- national Airport and an adjacent light
industrialoped on a thin layer of sediment over the concrete area.
e lower end of the ditch is tidal. However,channel bed in this
segment. the part of the ditch crossed by the guideway is an
intermittently owing (non-RPW), unlined,Marine Waters open ditch
fed by several small drains from the e large coastal surface water
bodies within light industrial area mauka. ese drains provideor
adjacent to the study corridor are listed in su cient freshwater to
establish three small semi- Table 4-28 and illustrated in Figure
4-61. ese permanent wet areas along the bottom of the ditchwater
bodies are all highly urbanized and/or (one under the guideway).
ese wetland features altered from their natural state. Marine areas
support a variety of wetland plants and aquaticnear the Project
include the Middle and East insects, such as dragon ies. e most
downstream Lochs of Pearl Harbor (technically an estuarine June
2010Honolulu High-Capacity Transit Corridor Project Environmental
Impact Statement 4-155 3. LEGENDThe ProjectFixed Guideway
StationMoaPark-and-Ride Facilities and Transit Center naluShoreline
Boundary of a RdEstuary WetlandOrdinary High-water Mark mrea0 500
1000a St Feet`Aie KamehamehaHwy Moanalua Fwy`Aiea Bay State
Recreation Area Mangrove wetlands removed in 2007`AIEA BAY Aloha
Stadium Station Salt Lake Blvd Figure 4-66 `Aiea Bay State
Recreation Area WetlandTable 4-28 Marine Waters2Water Body
ClassAssociated Inlets 303(d) Impaired 1Pearl Harbor 2Inland
water/estuary Point-source discharges; streamsYesKe`ehi
LagoonAMarine embayment Storm drains; streams YesHonolulu
HarborAMarine embayment Storm drains; streams Yes1Pearl Harbor
includes West Loch, Middle Loch, and East Loch2303(d) Impaired
Waterway as de ned by State of Hawai`i Department of Health
(2008).4-156 CHAPTER 4 Environmental Analysis, Consequences, and
Mitigation 4. bay), Keehi Lagoon (an open embayment), and4.14.3
Environmental Consequences Honolulu Harbor. and Mitigation
Environmental Consequences Flood Zones No Build Alternative Flood
Insurance Rate Maps show that the project Under the No Build
Alternative, the Project alignment will cross several oodplains and
twowould not be built and would not have any impactsoodways
associated with Waiau and Waiawa to water resources. e projects in
the ORTP are Streams (Figures 4-57 and 4-58). Floodplainsassumed to
be built, and the consequences of along the project alignment
mostly recharge those projects will be studied and documented in
groundwater levels, convey stormwater toward theseparate
environmental documents. ocean, and help moderate oods when they
occur (Figure 4-67). ese areas also support plants andProject
wildlife within urbanized areas, while maintaining e following
sections discuss possible e ects to areas for outdoor recreation
and enjoyment andsurface and marine waters, wetlands, ood zones,
preserving the lands natural beauty. e ood stormwater, and
groundwater and present coordi- zones and their associated waters
are listed in nation activities and mitigation that will occur to
Table 4-29. address possible e ects. E ects during construc- tion
are discussed in Section 4.18. Stormwatere existing drainage
conditions encountered Surface Waters along the guideway alignment
consist of the Project encroachment into waters of the U.S. is
following: undeveloped or unpaved areas, areassummarized in Tables
4-30 and 4-31. e Project adjacent to paved roadways, landscaped
median will, once constructed, permanently encroach areas of paved
roadways, or a combination ofupon 0.08 acre of waters of the U.S.
(0.02 acre these conditions. Drainage conditions for the as listed
on Table 4-30 and 0.06 acre as listed on Project area west of
Hoopili Station (west Site 4) Table 4-31). ese impacts are from
placing piers are generally undeveloped or unpaved. e drain-in
Waiawa Springs, Moanalua Stream, Kaplama age conditions for the
Project within the City of Canal Stream, and Nuuanu Stream and
improv- Waipahu are landscaped median areas of paveding a culvert
in Waiawa Springs. Although Kaloi roadway. e drainage conditions
for the majority Gulch is not under the jurisdiction of the USACE
of the project alignment are areas adjacent to pavedand not
included in Tables 4-30 or 4-31, it was roadways or a combination
of various conditions.considered in the impact quantities with the
usee existing drainage system consists of drainageof the
preliminary JD approach. e Project at pipes/culverts, structures,
swales, and outfalls to Kaloi Gulch will add 0.009 acre of
permanent tributaries adjacent to Pearl Harbor and Honolulu impact
from the guideway support columns, Harbor. with 27 cubic yards of
impact below OHWM and above the mudline and 1,234 cubic yards below
Groundwater the mudline (linear transportation features). e entire
Project overlies the Southern Oahu e Project will also add 0.39
acre of permanent Basal Aquifer and includes two aquifer sectors. e
impact from a park-and-ride lot, with 953 cubic Pearl Harbor
Aquifer Sector contains the Ewa,yards below OHWM and above the
mudline and Waipahu, Waiawa, and Waimalu Aquifer Systems, 744 cubic
yards below the mudline. and the Honolulu Aquifer Sector contains
the Moanalua, Kalihi, and Nuuanu Aquifer Systems.June 2010 Honolulu
High-Capacity Transit Corridor Project Environmental Impact
Statement 4-157 5. Waiawa WaikeleWaimaluFigure 4-67 Watershed and
Flood ZonesHonouliuli 31Kapakahi 12 13Kalauao 14 11A15 `Aiea 7 9
1016 Hlawa 11B17 186 8194 520 21Moanalua 3Kalihi22 23 2 Waipio
4-158 CHAPTER 4 Environmental Analysis, Consequences, and
Mitigation Ke`ehi 124 26Nu`uanu 25 27 28 KaplamaKalo`i Manuwai29
30Makiki Ala WaiLEGENDWatershed Flood Zones# Wetland and Waters of
the Ala WaiKapakahiNu`uanu Moderate to Low Risk Zones X and
X500U.S. Study SitesHlawa KaplamaWaiawa High Risk Zones A, AE, AH,
and AOFixed Guideway StationHonouliuli Ke`ehiWaikeleHigh Risk
Coastal Zone VEThe Project KalauaoMakikiWaimaluSalt Lake
Alternative Kalihi Manuwai Waipio 0 12Park-and-Ride Access Ramp
Kalo`i Miles Moanalua`Aiea 6. Table 4-29 Streams Having FEMA Mapped
Flood ZonesFlood Zone(s) Traversed byAssociated Water
BodyDevelopedMajor Functions Fixed GuidewayKalo`i GulchYes
Groundwater recharge; stormwater conveyanceAEHonouliuli StreamNo
Groundwater recharge; stormwater conveyanceAWaikele StreamYes
Stormwater conveyance AEF, AEKapakahi Stream1Yes Stormwater
conveyance AEF, AEWaipahu Canal Stream2 Yes Stormwater conveyance
AEF, AEWaiawa Stream Yes Stormwater conveyance AEF, AEKalauao
StreamYes Stormwater conveyanceAEFMoanalua Stream Yes Stormwater
conveyance AEF, AE, AOKalihi Stream Yes Stormwater conveyance AEF,
AE, AOZone A = the ood insurance rate zone that corresponds to the
100-year oodplains that are determined in the Flood Insurance Study
by approximate methods. Because detailedhydraulic analyses are not
performed for such areas, no base ood elevations or depths are
shown within this zone.Zone AE = the ood insurance rate zones that
correspond to the 100-year oodplains that are determined in the
Flood Insurance Study by detailed methods. In most instances, base
ood elevations derived from the detailed hydraulic analyses are
shown at selected intervals within this zone.Zone AEF = the area
within Zone AE reserved to pass the base ood.Zone AO = the ood
insurance rate zone that corresponds to the areas of 100-year
shallow ooding (usually sheet ow on sloping terrain) where average
depths are between 1 and3 feet. The depth should be averaged along
the cross-section and then along the direction of ow to determine
the extent of the zone. Average ood depths derived from the
detailedhydraulic analyses are shown within this zone. In addition,
alluvial fan ood hazards are shown as Zone AO on the Flood
Insurance Rate Map.FEMA referes to this canal as Kapakahi Stream #2
on their FIRM maps (Panel No. 0240F)1 2FEMA referes to this canal
as Wailani Canal on their FIRM maps (Panel No. 0240F)Table 4-30
Permanent Impacts to Waters of the U.S. (Linear Transportation
Features)WaiawaMoanalua KaplamaNu`uanu Stream &Total Impact
Total ImpactStream Canal StreamStreamSprings of Project(Site 27)
(Site 29)(Site 30)(Sites 12 & 13)Area (acres)0.003 0.004
0.010.004 0.02Volume (cubic yards) (below OHWM and above mudline)
10 8 6127105Volume (cubic yards) (below mudline) 8731,454
601,1643,551Table 4-31 Permanent Impacts to Waters of the U.S.
(Other Project Features)Total Impact Waiawa Springs (Existing
Stormwater Culvert Extension)Area (acres)0.06 Volume (cubic yards)
(below OHWM and above mudline) 185 Volume (cubic yards) (below
mudline) 0June 2010 Honolulu High-Capacity Transit Corridor Project
Environmental Impact Statement 4-159 7. As discussed in Section
4.18, during construction derivative adverse impacts resulting from
the of the xed guideway (linear transportation projectProject that
would be overlooked by focusing on features), it is anticipated
that there will be a tem-acreage or that dont scale to acreage.
Kaloi Gulch porary e ect of up to 0.13 acre of waters of the U.S.
is not under the jurisdiction of the USACE and is, Although Kaloi
Gulch is not under the jurisdiction therefore, not listed in Tables
4-30 or 4-31. However, of the USACE and the impacts are not listed
init was considered in the impact quantities with the the tables,
temporary impacts include 0.07 acre use of the preliminary JD
approach. of impact from the guideway support columns with 948
cubic yards of impact below OHWM Kalo`i Gulch and above the
mudline. An additional 0.86 acre ofe lower end of Kaloi Gulch on
the Ewa Plain temporary impact will result from construction of
will be impacted by structural elements of the a park-and-ride lot
at Lower Kaloi Gulch with an Project in two respectsa park-and-ride
lot is additional 1,238 cubic yards below OHWM and proposed for a
parcel crossed by the man-made above the mudline.drainage channel
(Site 1); and support columns for the guideway will be located on
the banks of Of the 20 streams in the study corridor, most the
Kaloi Drainage Channel (Site 2). Although will not be directly a
ected because the Projectshow the drainage channel at the
park-and-ride elevated guideway will clear-span these streams lot
will be designed has yet to be determined, the and there will be no
pier or column constructionmost likely solution will be to replace
the exist- or other construction-related activities within the ing
man-made ditch with a buried box culvert. stream channel below
OHWM. In general, theAnother option would be to redirect the
channel project alignment parallels other bridge
crossingselsewhere, for example via a ditch or culvert more of the
streams and, in many cases, crosses alongdirectly to the Kaloi
Drainage Canal nearby to the median between bridges carrying
opposingthe east. No aquatic resources are associated with lanes of
tra c. In these cases (Categories II this channel, which is
normally dry and cut-o through IV as outlined in Section 4.14.2),
thefrom most of its drainage basin by redirection of only potential
direct e ect of the Project is one upper Kaloi Gulch into the Kaloi
Drainage Canal. of shading of the stream or wetland. Because
theFuture urban development will likely establish guideway is
elevated relative to the surroundingruno conveyances throughout
this area. As noted, roadway crossings, the guideway will only
impartthe Kaloi Drainage Canal will take over much minimal,
additional shading onto the water as of the stormwater runo
contributed by Kaloi compared to the bridges already present in
each Gulch. is approximately 160-foot wide channel location.
Shading impacts are addressed in more is presently under
construction paralleling North- detail for Sumida Watercress Farm,
below. South Road. Neither this channel nor the existing narrow
Kaloi Gulch (Site 2) have aquatic resourcee streams a ected by
structural elements of thevalue. e guideway crosses the new channel
at a Project are described below and in Tables 4-30shallow angle on
a turn, and the span at this point and 4-31. ese are the Category V
sites discussedcannot avoid placing several columns within the
above, most of which are estuarine and con ned to banks of the
channel. Two columns (approximately highly modi ed channels with
little to no ripar-36 square feet constructed on 10-foot drilled
ian values. An acreage approach to quantifyingsha s) are located
near the bottom of the banks impacts was followed since functional
assessment(within the 100-year oodway). methods are typically
calibrated to non-urban, non-hardened areas. ere are no secondary
or 4-160 CHAPTER 4 Environmental Analysis, Consequences, and
Mitigation 8. Waiawa Stream and SpringsStream, all above OHWM. ese
columns were e Project and associated features will have onemoved
away from the stream to avoid impacts. guideway support column and
two station piersWaiawa Stream in this area ows in a natural bed
below OHWM. ere will be some impacts toand banks, although there
are multiple existing riparian areas. Moving the station location,
park- piers in the stream associated with Farrington ing structure,
bus transit center, and other featuresHighway and Kamehameha
Highway bridges. is the only option to avoid impacts to this area.
e Pearl Highlands Station is projected to have thee guideway will
clear-span this stream makai of second-highest passenger volume of
all stations in the Pearl Highlands Station. e Pearl Highlands the
system and will serve as the transfer point forparking and transit
center will be constructed on all users in Central Oahu, whether
they drive tocircular columns close to Waiawa Stream. In this the
station or transfer from eBus. is transitarea, the park-and-ride
structure roughly paral- center and park-and-ride facility are
designed lels Waiawa Stream (Figure 4-62). is structure to provide
easy access to the xed guideway will require approximately six
support columns transit system from the H-1 and H-2
Freeways,(approximately 25 square feet each) to be located in
Kamehameha Highway, and Farrington Highway.the riparian area
outside the OHWM but below the is station location provides the
most convenient top-of-bank (TOB) line. access to the system for
residents of Central Oahu (i.e., locations mauka and Ewa of the
station). Construction of the elevated guideway at Pearl erefore,
elimination of the station and associ-Highlands Station will result
in one guideway ated park-and-ride structure does not satisfy
thesupport column (approximately 36 square feet Projects Purpose
and Need.constructed on a 10-foot drilled sha foundation)and two
station piers (approximately 25 square feet Alternative locations
for the Pearl Highlandseach) being placed close to the OHWM of
Waiawa Station and park-and-ride lot were identi ed atSprings
located beneath the station structure. Leeward Community College
and the Hawaii e impact area and ll for these columns are Laborers
Training Program site. Both of these sitesincluded in Table 4-30
because of their proximity were evaluated in Section 5.4.2 of the
Dra EIS to the springs. e location of the Pearl Highlands that
addressed avoidance alternatives to potential Station is designed
to be in close proximity to the impacts to the historic Solmirin
House (sinceproposed park-and-ride lot as well as surrounding
publication of the Dra EIS, the Solmirin House businesses. e piers
near the Pearl Highlands Sta- was determined to be not eligible for
designationtion cannot be relocated because they are support- as a
historic resource). Locating the park-and-rideing the guideway as
it enters the station, as well as facilities at either of the two
avoidance alternativesupporting a concourse, stairs, and
escalators. sites would cost substantially more and provide less e
cient transportation circulation, as access would e springs (Site
13) in this case is at the end of a be less direct. For these
reasons, these avoidance street drain passing under Kamehameha
Highway. alternatives are not considered feasible.It would best be
modi ed by constructing anextension of the existing pipe culvert to
a pointe construction of the high occupancy vehiclebeyond the
elevated station footprint. is new (HOV) ramp that will connect
inbound H-2 outlet would be located closer to Waiawa Stream Freeway
vehicles with the park-and-ride structurewhere the TOB line and
OHWM closely coincide adjacent to the Pearl Highlands Station will
resultalong an erosion face created by the piers of the in four
columns being constructed close to WaiawaFarrington Highway bridge
forcing the stream owJune 2010Honolulu High-Capacity Transit
Corridor Project Environmental Impact Statement 4-161 9. to the
right (thus eroding the le bank). Extending feet each on 10-foot
drilled sha foundations) will the drains outlet would have no
consequences on need to be constructed in the estuary (Figure
4-68). spring-water contribution to Waiawa Stream and is location
(Site 27) is makai of the H-1 Freeway would reduce potential stream
contamination in ramp to Nimitz Highway. In this area, there an
area that would be too shaded by the stationexists multiple bridge
crossings of Moanalua structure to support plant growth. A cut in
theStream, including Kamehameha Highway, the high bank already
exists where the spring ow H-1 Freeway, Nimitz Highway ramps, and
two joins Waiawa Stream. pedestrian bridges makai of the project
guidewaycrossing. e guideway columns will be aligned Approximately
5 acres near Waiawa Stream with the upstream viaduct piers, as
feasible, to between Kamehameha Highway and Farringtonminimize
obstruction of stream ow. is area Highway will be shaded by
structures (a park-is tidal and near the stream mouth at Keehi
and-ride parking structure, bus transit center,Lagoon. Placement of
the piers is not expected to station and guideway, and various
pedestrian and have any consequences on the Moanalua Stream vehicle
access ramps), roughly one-third of theestuarine environment or its
fauna beyond a loss area (Sites 12 and 13). Direct impacts on the
stream of 0.004 acre of sandy mud bottom. Because the (including
shading) would be minimal; most ofguideway lies immediately south
of the existing the structures are on the north side of the
stream.viaducts and will be elevated 50 feet above the Waiawa
Stream supports some native amphidro- water, shading on the estuary
will be minimal. mous fauna, and no part of the Project is antici-
pated to interfere with the local population of goby Kaplama Canal
Stream observed or migration through the site required bye existing
Dillingham Boulevard bridge over native macrofauna that may breed
upstream. Kaplama Canal Stream will be widened makai. is will allow
for construction of a new median To maintain oodway hydrology, it
will be neces-in line with the guideway to maintain two through
sary to remove ll material from along Waiawa lanes and one
dedicated le -turn lane for both Stream in this area. Approximately
100 feet of the directions of tra c. is will improve safety and
small tributary issuing from an existing drain enhance tra c ow.
ere will be impacts to (Site 13) will be con ned within an
extension of Kaplama Canal Stream to extend the existing that drain
pipe. piers and abutments.Moanalua StreamA design option was
evaluated at this stream To avoid impacts below OHWM in
Moanaluacrossing to avoid impacts below OHWM that Stream (300 feet
wide) substantially di erentconsidered construction of the guideway
on bridge types would be needed to clear span thisstraddle bents
located on each bank of the stream. stream. is stream is beyond the
practical lengthe straddle bents would have been approximately
limit for precast concrete girders (150 feet). Long100 feet long to
completely straddle Dillingham spans could add $5 million to total
project costs. Boulevard. is option was not considered feasible For
this reason, avoiding impacts below OHWM infor the following
reasons: these streams is not considered feasible. Construction of
massive straddle bents wouldbe di cult in this congested corridor
Because of the 300-foot width of the channel e large straddle bents
would require large where the guideway crosses Moanalua Stream,and
expensive drilled sha foundations two guideway columns
(approximately 36 square4-162 CHAPTER 4 Environmental Analysis,
Consequences, and Mitigation 10. Overhead power lines would
complicatelocated outside of Kaplama Canal behind theconstruction
existing bridge abutments, the Dillingham Boule- e size of the
straddle bents would have avard Bridge will need to be widened
approximatelyconsiderable visual impact in this area20 feet makai
to accommodate a new median. In- water work will involve extending
the four existing e Project crosses Kaplama Canal Stream at
thebridge piers and the two existing bridge abutments Dillingham
Boulevard Bridge with the guideway inmakai. Pier extensions will
require eight addi- the median of the Boulevard (Site 29; Figure
4-69). tional piles placed in the stream (approximately Although
the guideway support columns will be 1.36 square feet each). e
abutment and retainingLEGEND The Project Fixed Guideway Station
Columns in Waters of the U.S. Columns near Streams
05001000FeetMiddle StreetTransit CenterMoanaluNim itz Hwya
Streamamre St hi liKa HONOLULUHARBOR Figure 4-68 Moanalua
StreamJune 2010 Honolulu High-Capacity Transit Corridor Project
Environmental Impact Statement 4-163