20200916-004b: 8921 US Hwy 290 West wastewater SER #4796 Presentation — original pdf

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8921 US Hwy 290 West Wastewater Service Extension Request #4796 Request Summary • 69.12 acres • 2-Mile ETJ • Slaughter Creek Watershed, Barton Springs Zone • Located in the Edwards Aquifer Contributing Zone • Drinking Water Protection Zone (DWPZ) • Applicant is proposing to develop a 280-unit multi- family project with 14- Land Use Equivalents (LUEs) SER #4622 Site Location Austin City Limits Austin ETJ Edwards Aquifer Recharge Zone Edwards Aquifer Contributing Zone Austin City LimitsETJRechargeContributingAustin City LimitsETJRechargeContributingSite Location Devils Pen Creek Honeycomb Dr Devils Pen Creek Ledgestone Multifamily SER #4622 8921 US Hwy 290 W SER #4976 Devils Pen Creek SER #4796 Proposed Wastewater Extension Map provided by AWU SER #4796 Wastewater Summary • 1,000 feet of 8-inch gravity wastewater main in Circle Dr and extend south along Circle Dr and then west along US 290 to the highest point that can be served by the proposed gravity wastewater main. • 6,000 feet of appropriately sized force main from the proposed lift station and extend north through the subject tract and northeast along US 290 Hwy to the proposed 8-inch gravity wastewater main in US 290 Hwy. • 1,800 feet of 15-inch gravity wastewater main from the existing 15- inch gravity wastewater main along Williamson Creek, and extend west to the existing 12-inch gravity wastewater main located west of Covered Bridge Dr. • 2,250 feet of 12-inch gravity wastewater main (minimum 1.0% slope) from the existing 8-inch gravity wastewater main located north of Towana Trl, and extend south towards Towana Trl, west along Towana Trl, and then south along Mowinkle Dr to the existing 8-inch gravity wastewater main in Mowinkle Dr. SER #4796 Summary Lift station • Construction of the wastewater main and lift station are required to be located outside of the water quality transition zone and critical water quality zone. • The appropriately sized lift station and force main shall be sized to provide service to the subject tract only. • The adjacent tract (Ledgestone SER #4622) also requires a lift station and force main, and the applicant has indicated that it is preferable that only one lift station be constructed to serve both tracts. SER #4796 Summary • Approximately 1,600 feet of the 1,800 feet of 15-inch gravity wastewater main is also proposed to be constructed by Granada Ridge (SP-2018-0138, SER #3299). – If the applicant’s project timeline needs these wastewater improvements prior to the completion of them by others, then the design and construction of these improvements are the responsibility of the applicant. • The proposed 1,800 feet of 15-inch gravity wastewater main, 2,500 feet of 12-inch gravity wastewater main, 1,000 feet of 8-inch gravity wastewater main, and a portion of the 6,000 feet of appropriately sized force main is also proposed to be constructed by Ledgestone SER #4622. – If the applicant’s project timeline needs these wastewater improvements prior to the completion of them by others, then the design and construction of these improvements are the responsibility of the applicant. SER #4796 Summary Alternative Wastewater Service: • If service is not extended to the site and wastewater disposal is required under a Texas Land Application Permit (TLAP) issued by the Texas Commission on Environmental Quality, wastewater irrigation fields would be required on the site. Due to the environmental sensitivity of this tract, staff recommends the SER extension as opposed to a TLAP. Water: • The site is located in West Travis County Public Utility Agency (PUA) for water service. Staff Recommendation Staff recommends approval. Basis for recommendation: Based on the approved site plan and vested rights on the property, and if service were not extended, alternative wastewater service could create negative environmental conditions on the site; WPD staff recommend approval of Service Extension Request #4796. Contact Information Kaela Champlin Watershed Protection Department City of Austin (512) 974-3443 kaela.champlin@austintexas.gov