20250507-005: SER 6139 5140 McLemore Tract Staff Presentation — original pdf

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McLemore Tract Multifamily Water and Wastewater Service Extension Request #6139 and 6140 What is a Service Extension Request? • A service extension request (SER) is an application for City water or wastewater service from a property owner or developer. • Required when: – a property is more than 100 ft from accessible water/wastewater system – existing infrastructure isn't adequate for the proposed project demands • May involve the construction of a new line/associated facility or upgrades to existing lines/facilities. • Applicant pays for the associated infrastructure, as outlined in the SER. SER Process • Requires Council approval if property: – is in Drinking Water Protection Zone and – outside of the City's full purpose jurisdiction • Environmental Commission & Water & Wastewater Commission make recommendations for support/denial • No conditions can be put on SERs. Request Summary • Wastewater Service Request • 10656 N FM 620 • 10 acres • Lake Travis Watershed • Located in the North Edwards Aquifer Recharge Zone • Drinking Water Protection Zone (DWPZ) • Property removed from City of Austin’s jurisdiction in September 2024 SER #6139 & 6140 Site Location Austin City Limits Austin ETJ Edwards Aquifer Recharge Zone Edwards Aquifer Contributing Zone Site Location Proposed Development Intended Uses • • • 300 multifamily units with 150 Living Unit Equivalents (LUEs) 10-acre development with 59% impervious cover Parking covers approximately 34% of property SER #6319 Proposed Water Extension Option 1 Map provided by AWU SER #6139 Proposed Water Extension Option 1 • Construct approximately 950 feet of 12-inch water main from the existing 12-inch water main located in North FM 620 south of the Foundation Road intersection • Extend southwest along North FM 620 to the subject tract. SER #6319 Proposed Water Extension Option 2 Map provided by AWU SER #6139 Proposed Water Extension Option 2 • A second water SER option has been proposed if the first option is not feasible due to spacing constraints with other utilities • Construct 1,400 feet of 12-inch water main from the existing 12-inch water main crossing North FM 620 north of the Boulder Lane intersection • Extend northeast along North FM 620 to the subject tract, as shown on the attached map. SER #6140 Proposed Wastewater Extension Map provided by AWU SER #6140 Proposed Wastewater Extension • Construct 1,300 feet of 8-inch gravity wastewater main from the existing 8-inch gravity wastewater main located in N FM 620 to the subject tract • Construct an appropriately sized upgrade to the existing Volente Lift station. Alternative Wastewater Service • Option 1: Texas Land Application Permit (TLAP) (land application) – Subsurface Area Dispersal System (SADDS) – Issued by Texas Commission on Environmental Quality (TCEQ) – Requires 9.3 acres or 10.1 acres for spray irrigation system & storage pond – TLAP is not feasible without drastically scaling back the number of LUEs planned – Native soils onsite are limited due to depth of bedrock and number of course fragments. Alternative Wastewater Service • Option 2: Onsite Sewage Facility (OSSF) – Travis County rules require 0.75 acre lots for development with public water supply & 1 acre lots for development without public water supply – Number of LUEs possible using OSSF would be 10 to 13 – Tarrant soils onsite have severe limitations for OSSF and other soil- based systems (TLAPs) – Imported soils would have to be used – Does not eliminate potential for adverse impacts as preferential flowpaths can form more easily in imported soil and the interface with native soils can provide a horizontal plane for effluent to travel offsite. Alternative Wastewater Service • Option 3: Texas Pollutant Discharge Elimination System (TPDES) (direct discharge) – Issued by the Texas Commission on Environmental Quality (TCEQ) – TCEQ prohibits wastewater discharges within 10 miles from the pool elevation of Lake Travis at 681 ft mean sea level – Property is 2.9 miles above this location in Cypress Creek – Therefore, TPDES permit would not be possible (30 TAC 311.1(3)) ETJ Regulations • Following passage of SB 2038, property owner received a valid petition to be removed from Austin’s ETJ in September 2024 • Allows properties to be removed on a lot-by-lot basis • Negatively affects Austin’s ability to regulate environmental and water quality protection requirements • No requirement to comply with City of Austin’s environmental regulations once released. Jurisdictional Boundaries 2-Mile ETJ Full Purpose Jurisdiction Limited Purpose Jurisdiction Outside Extraterritorial Jurisdiction Environmental Impacts • Upstream of known Jollyville Plateau salamander habitat • Portions of the site contain slopes greater than 15% • No critical environmental features (CEFs) identified by applicant • COA database shows a seep CEF on the western corner of the property • No critical water quality zone/water quality transition zone  Spring Critical Environmental Feature Buffer Property boundary Environmental Impacts, continued • If property had remained in COA ETJ: – Subject to Watershed Protections Ordinance (WPO) – Impervious cover limited to 20% net site area – 40% of downstream portion of the site would have been required to be preserved within a natural state – Construction on slopes greater than 15 % are limited. • Subject to Travis County Code 482.216(a)(1)(a): – No impervious cover limits for commercial subdivision on a tract with primary driveway access on a state road (such as FM 620) WPD Recommendation Staff does not recommend approval for the following reasons: • Property owner received a valid petition to be removed from COA ETJ and is not subject to COA environmental regs, which would limit footprint of development within this environmentally sensitive area that drains to Austin’s drinking water supply. The project would not be required to meet the following regulations: – – – – – 20% NSA impervious cover limit 40% downstream natural area Protections for slopes greater than 15% COA water quality treatment standards COA CEF protections • The site drains to occupied Jollyville Plateau salamander habitat and is sensitive to impacts of development.