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