Abstract Submitted to
2014 FLOODPLAIN MANAGEMENT ANNUALCONFERENCE
September 2-5, 2014
Santa Clara, CA
Use of Flood Control Detention Basins as a Regional Stormwater BMP
Andrew Trelease, PE; Clark County Regional Flood Control District
Angela MacKinnon, PE, MBA, PMP, CPSWQ; MWH Americas, Inc.
Las Vegas Valley is the driest large urban area in the United States that has a municipal separate storm sewer system (MS4) permit. The arid environment in Las Vegas Valley (4.2 inches of rainfall and 6-11 days of measurable runoff on an average annual basis) creates unique challenges and opportunities for managing stormwater runoff quality. Poor soils and concerns over water rights constrain the ability to use infiltration measures commonly promoted in other communities. On the other hand, an extensive regional system of flood control detention basins and other infrastructure provides potential opportunities for using existing drainage facilities and plans to address stormwater quality concerns.
Las Vegas Valley MS4 Permittees consisting of Clark County Regional Flood Control District, Clark County, City of Las Vegas, City of North Las Vegas, and City of Henderson adopted a new Storm Water Management Plan (SWMP) that emphasizes use of regional systems including regional flood control basins for stormwater quality management. A process was developed to demonstrate how water quality capture volume principles usually applied at the development level could be applied to larger watersheds of up to 250 square miles. A strategic plan was prepared to use regional detention basins of 50 to 3,400 ac-ft to treat urban runoff through retrofitting existing basins or designing new basins with water quality management as an objective. Addition of water quality outlets and use of detention storage reserved for sediment accumulation as well as other measures were proposed for water quality designs. This regional approach is more cost-effective and politically acceptable in Las Vegas Valley than hundreds of on-site measures, and could serve as a template for MS4 strategies in other similar communities.
Contacts:
Andrew Trelease, , 702-685-0000, Co-Presenter
Angela MacKinnon, , 702-821-4344, Co-Presenter
Bios:
Andrew Trelease, PE (NV); Co-Presenter
Mr. Trelease is a Principal Civil Engineer for the Regional Flood Control District. He joined the District in November 2001, and has been a registered civil engineer in Nevada since 1998. Prior to joining the District, Mr. Trelease worked as a private land development and flood control engineer for 8 years in Nevada and Arizona. Mr. Trelease graduated from Arizona State University in 1994 with a degree in Civil Engineering.
Angela MacKinnon, PE (NV), MBA, PMP, CPSWQ; Co-Presenter
Ms. MacKinnon is a Project Manager at MWH. Ms. MacKinnon holds a BSc in civil engineering and an MBA and Finance Certificate from Colorado State University. She has over 13years of experience in design, planning, and construction of wet infrastructure projects.She has been involved in the design of stormwater conveyance facilities and flood detention structures in Nevada, Utah, California, New York, and in New Zealand. Ms. MacKinnon serves as MWH’s Project Manager for the Las Vegas Valley MS4 Permit.