Water Resources Integration Program Update: Water Delivery and Operational Flexibility with a 60-inch, 45-mile Pipeline

摘要

Over the last several decades, San Antonio has experienced rapid population growth. The San Antonio Water System (SAWS) currently serves more than 1.6 million people in Bexar County Texas as well as parts of Medina and Atascosa Counties, and has over 460,000 water customers. With the integration of the Bexar Metropolitan Water District, regulatory withdrawal limitations, and increasing drought restrictions that have put a strain on the Edwards Aquifer, SAWS has had to increase its water supply and system flexibility. SAWS has been working to meet the increased water demand through a strategy of conservation, reuse, and investments in new water supply resources, and will increase system flexibility with the Water Resources Integration Plan (WRIP). Currently, the Twin Oaks Aquifer Storage and Recovery (ASR) facility in South Bexar County allows SAWS to store excess Edwards Aquifer water from the east side of San Antonio. That water can then be recovered from the ASR during periods of high demand, significantly increasing SAWS operational flexibility. The ASR Pipeline, completed in 2004, is currently the only conduit between the ASR and SAWS' distribution system; moving water into the distribution system during production mode and reversing flow to inject water into the ASR well field in recharge mode. Since future water supply facilities will produce a constant base flow, additional flexibility is needed for continued recharge of the ASR. The WRIP will provide that flexibility. The WRIP consists of approximately 45 miles of 48" to 60" diameter steel pipe and two associated pump stations, extending from the ASR to west San Antonio. The WRIP will be constructed in two phases and will ultimately convey up to 75 MGD of potable water from four different sources: treated water from the Brackish Groundwater Desalination Facility (Wilcox Aquifer), Local and Expanded Carrizo Wells (Carrizo Aquifer), and recovered ASR water (Edwards Aquifer). Similar to the ASR pipeline, the WRIP pipeline will also be used to recharge the ASR well field using reverse gravity flow. The WRIP pipeline will work in tandem with the ASR pipeline to offer operational flexibility and provide water where San Antonio needs it most. This paper will describe the WRIP and specifically discuss design concepts that allow the WRIP to give SAWS additional flexibility in managing their water supply.