20211103-002c: 8921 US 290 Hwy West Wastewater SER #4796 staff 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 140 Land Use Equivalents (LUEs) SER #4796 Site Location Austin City Limits Austin ETJ Edwards Aquifer Recharge Zone Edwards Aquifer Contributing Zone Site Location Devils Pen Creek Honeycomb Dr Devils Pen Creek Ledgestone Multifamily SER #4622 8921 US Hwy 290 W SER #4976 SER #4796 Environmental Impacts • Contains Devils Pen Creek and associated critical water quality zone (CWQZ) and water quality transition zone (WQTZ) • Seven wetland critical environmental features • One seep critical environmental feature • Does not drain to occupied salamander habitat. Devils Pen Creek SER #4796 Lift Station & Force Main Improvements • Due to the approved Ledgestone Multifamily SER on the adjacent property, there are two possible scenarios for development: – Scenario 1: Both developers build one lift station & force main to serve both properties • Due to cost & limited allowable space in ROW, this is the most likely scenario. – Scenario 2: Developer builds lift station & force main for this property only. Ledgestone Multifamily development will be responsible to upgrade existing lift station & force main or build their own on the adjacent property. SER #4796 Water Service • The site is in the water service area of the West Travis County Public Utility Agency (PUA). SER #4796 Proposed Wastewater Extension Map provided by AWU Map provided by Austin Water Ledgestone SER #4622 Approved Wastewater Extension Map provided by Austin Water SER #4796 Development Impacts • Construction of the wastewater main and lift station are required to be located outside of the WQTZ and CWQZ. • The layout of the proposed lift station will be reviewed when the project is submitted for site plan review and must comply with City Code. SER #4796 Alternative Wastewater Service • If service is not extended to the site and wastewater disposal is required, the applicant would likely apply for a Subsurface Area Drip Dispersal System (SADDS) issued by the Texas Commission on Environmental Quality (TCEQ) • Net site area impervious cover = 25% • An estimated 8.3 acres would be deducted from the net site area calculations for the impervious cover limits for a dispersal field, on-site storage, & on-site treatment plant • This scenario would disturb over 8 acres of uplands. Staff Recommendation Staff recommends approval. • The approved Ledgestone Multifamily SER will eventually allow for construction of new public wastewater infrastructure & the proposed infrastructure is similar to that which has been previously approved for the Ledgestone Multifamily SER on the adjacent property. Staff Recommendation Staff recommends approval. • • The existing parcel already has an approved site plan for an athletic complex. The level of development associated with the proposed apartment buildings will be similar to the amount already allowed due to site development regulations. The area that would be required for subsurface irrigation under an alternative wastewater treatment scenario would disturb over an estimated 8 acres of uplands. Contact Information Kaela Champlin Watershed Protection Department City of Austin (512) 974-3443 kaela.champlin@austintexas.gov