Northern Nevada Water Planning Commission

Transcription

1 : NNWPC Agenda Item 6 Northern Nevada Water Planning Commission DATE: November 29, 2011 STAFF REPORT TO: FROM: SUBJECT: Chairman and Members, Northern Nevada Water Planning Commission Jim Smitherman, Water Resources Program Manager Report by the Regional Transportation Commission ( RTC ) on its SouthEast Connector project, including issues related to Steamboat Creek and flood management; and, possible direction to staff SUMMARY RTC Project Manager Garth Oksol has prepared a PowerPoint presentation to provide an update on the SouthEast Connector ( SEC ). The SEC will be a 6 lane arterial roadway with two new at-grade signalized intersections. The new intersections will be at Mira Loma Drive and Pembroke Drive. The SEC will originate at the existing intersection of South Meadows Parkway and Veterans Parkway on the south end and will terminate at the existing intersection of Greg Street and Sparks Boulevard on the north end. In regard to the Truckee River Flood Project and Steamboat Creek, the SEC has been integrated into the US Army Corps of Engineers Flood Model. The RTC s goal was to abide by the draft flood mitigation ordinances of the three local governments and: Not raise the water surface elevation of a 117-year flood event Not cause any adverse impact to any improvements as part of the flood control project Not increase flows Provide at least 1:1 mitigation adjacent to the alignment. The RTC submitted the preliminary design and proposed mitigation to the Truckee River Flood Project staff in In a letter dated November 12, 2008, the Flood Project staff found that the proposed mitigation as part of the preliminary design is acceptable. The SEC will adhere to all federal, state, and local requirements. Recent design efforts have provided a 1.2 to 1 ratio for flood mitigation. That means for every one shovel full of dirt being placed in the flood pool for the roadway, 1.2 shovels full of dirt are being removed for flood volume mitigation. The Steamboat Creek restoration plan is being planned in a synergistic manner with the flood volume mitigation. Please refer to the SouthEast Connector Environmental Aspects attachment for more information. BACKGROUND A north-south roadway connecting the southern part of the Truckee Meadows to the eastern part of the Truckee Meadows has been planned for more than 35 years. This arterial is proposed to reduce traffic congestion on I-80, US 395/I-580, Virginia Street, southeast McCarran Boulevard, Double R Boulevard, and Longley Lane.

2 : NNWPC Agenda Item 6 The southeastern part of the Truckee Meadows is underserved by regional roadways. Comparing the west and east sides of the Truckee Meadows, 13 regional roads on the west side carry 130,000 trips per day, while only three east side regional roads carry 102,000 trips a day, that is almost 80% of the west-side trips on just under 25% of the regional roads. RECOMMENDATION Staff recommends that the NNWPC accept this report on the SouthEast Connector project and provide direction as appropriate. JS:jd Page 2 of 2

3 SouthEast Connector Environmental Aspects The SouthEast Connector (SEC) will have numerous environmental benefits attributed to the final, complete project. Among these will be improved air quality, increased acreage of wetlands, restored Steamboat Creek, and recreational opportunities among others. The following information will briefly touch on these benefits. Air Quality Vehicular emissions contribute to degradation in air quality. Idling vehicles add more pollution to the environment than moving vehicles. With the completion of the SEC, regional traffic congestion will reduce on the existing transportation network and will therefore reduce carbon dioxide and dust pollution by 260,000 pounds, or 130 tons. Wetlands Creation and Enhancement acres of Waters of the US (ponds, creeks, rivers, and wetlands) have been identified within the project boundaries. Early avoidance measures as part of the project development showed the SEC roadway would have a direct impact to approximately 10 acres of Waters of the US. At that time, the team established a goal of a 2:1 ratio for mitigation. Meaning that for every one acre of impact, two acres would be constructed, giving a total of 20 acres of constructed wetlands. The next step was to look at minimization efforts to further reduce impacts to Waters of the US. The minimization efforts reduced the direct roadway impacts from 10 acres to 3.14 acres. Of these 3.14 acres, 1.96 acres are wetlands. The project team has maintained the original proposal of 20 acres of wetlands creation for a wetlands ratio of 10:1, instead of the original proposed ratio of 2:1. In addition to the 20 acres of wetlands to be created, 19 acres of Season Wetland Whitetop will be restored to a mosaic of emergent marsh, seasonal wetland meadow and open water aquatic bed habitats. The area of this proposed restoration exists along the eastern edge of the Rosewood Lakes Golf Course and extends from Mira Loma Drive, north to the open pond south of Pembroke Drive. This area is totally dominated by whitetop. The whitetop domination has resulted in very little plant diversity and very low value of habitat. The restoration plan is set up so that the area is no longer conducive for whitetop growth and will promote a more native, diverse plant environment. Restored Steamboat Creek The entire length of the SEC resides within the boundaries of Critical Flood Zone 1. In order to mitigate for the construction of the roadway, the project team has proposed a fill to excavation ratio of 1:1.2. In essence, for every 1 shovelful of material placed within the Flood Zone, 1.2 shovelfuls will be removed. In order to accommodate the removal, the project team will construct a mitigation channel parallel to the SEC roadway. This mitigation channel allows an

4 opportunity to restore Steamboat Creek by relocating the creek to the mitigation channel. This relocation allows for enhancement and restoration of the creek. By relocating Steamboat Creek to the mitigation channel multiple benefits will be realized. Those benefits include: Restoring channel sinuosity, i.e. meander Reducing channel flow energy which will reduce bank erosion Add approximately 5,000 linear feet to the centerline length of Steamboat Creek Increasing dissolved oxygen levels in the creek water Moderate ph levels and temperatures of the creek water, improving water quality for aquatic and vegetative life Constructed riffles to improve aquatic and vegetative life Promoting and enhancing biodiversity Constructing a more natural flood plain for the Steamboat Creek; this currently does not exist. Recreational Opportunities As a basic plan the SEC will have a 10 foot wide multi-use path parallel to the 5.5 mile roadway. This multi-use path will be used in-lieu of the more traditional sidewalks and bike lanes and will be located on one side of the roadway on existing ground. Once completed, the multi-use path will connect the Truckee River Trail to the network of trails in Double Diamond, Damonte Ranch, and Curti Ranch. The decision to use this multi-use path concept was multipurpose driven. The shared multi-use path reduces fill in the Flood Zone, reduces the project s impact to Waters of the US, allows a safer environment for pedestrians and bicyclists, and allows for opportunities to connect to other recreational features. These other recreational features are conceptual and still in development stages. Funding for each and every item has not been completely identified and/or secured. Additional funding opportunities and partnerships will be sought after. The Resource Team and the Stakeholders Team have discussed the possibilities of incorporating the following items into the overall project: Interpretive trails along the wetlands and the restored Steamboat Creek Photography blinds Canoe Trail Fitness Trail Benches Avian habitat and perches Aquatic habitats As well as other opportunities not yet realized

5 Please contact Garth Oksol, Project Manager if you are interested in assisting with the possible recreational opportunities. SouthEast Connector Flood Mitigation The RTC has been working in concert with the Truckee River Flood Management Agency (TRFMA). From the beginning the RTC has had the following goals as it relates to the Flood Project: Not increase the water surface elevation of a 1997 flood event (117 year flood) Not increase flows Allow water to get from one side of the SEC to the other Not adversely impact any improvements that are part of the Flood Project s Locally Preferred Plan. In September 2008, the RTC submitted a preliminary flood model of the SEC with the project mitigation efforts. On November 12, 2008, Director Naomi Duerr wrote the RTC a letter stating This mitigation has been included by Mr. Oksol in the preliminary design of the roadway and is acceptable to this office. Recent engineering efforts have focused on advancing our preliminary design efforts while keeping the final outcome the same or better as it relates to the four items listed above. The RTC anticipates submitting an updated model with the roadway and mitigation efforts in the most recent flood model to the TRFMA by the fall of 2011.