20210421-003c: Wastewater Service Extension Request 4652 Memo — original pdf

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ITEM FOR ENVIRONMENTAL COMMISSION AGENDA COMMISSION MEETING DATE: NAME & NUMBER OF PROJECT: April 21, 2021 FM 620 and Anderson Mill RD Wastewater SER #4652 NAME OF APPLICANT OR ORGANIZATION: Jewels Cain, Land Development Consultant, Armbrust & Brown, PLLC LOCATION: 11213 FM 620 Road, Austin, TX 78726 COUNCIL DISTRICT: Located partially in Austin’s full-purpose jurisdiction (District 6) and 2-Mile Extraterritorial Jurisdiction PROJECT FILING DATE: March 15, 2021 WPD/ENVIRONMENTAL STAFF: Kaela Champlin, Environmental Program Coordinator (512) 974-3443, kaela.champlin@austintexas.gov WATERSHED: REQUEST: STAFF DETERMINATION: Bull Creek, Water Supply Suburban, Northern Edwards Aquifer Recharge Zone, Drinking Water Protection Zone Wastewater Service Extension Staff do not recommend this service extension request.  MEMORANDUM April 16, 2021 Linda Guerrero, Chair, and Members of the Environmental Commission Kaela Champlin, Environmental Program Coordinator Watershed Protection Department TO: FROM: DATE: SUBJECT: FM 620 and Anderson Mill Road SER #4652 Service Extension Requests (SER) located in the Drinking Water Protection Zone and outside of the City of Austin’s full purpose jurisdiction require Council approval and review by the Environmental Commission. Watershed Protection Department staff have completed the review for FM 620 and Anderson Mill Road Wastewater SER #4652 and do not recommend approval of the request. Site Overview The site consists of a tract of approximately 34.40 acres, located at 11213 FM 620 Road. The site consists of 4 parcels; the northern three parcels consisting of 9.4 acres are located in the City of Austin’s full purpose jurisdiction and the Birden tract, a 25-acre parcel, is located in the City’s 2- Mile ETJ and is adjacent to Council District 6. The site is in the Bull Creek Watershed, Water Supply Suburban, and the Drinking Water Protection Zone, and the Northern Edwards Aquifer Recharge Zone. Service Extension Requests have been made on this site previously and were not recommended by Watershed Protection Department Staff. In 2016, a wastewater service extension request (SER #3880) was made for Broadstone 620/Birden Multi-family, a proposed multifamily development with 336 units on the southern 25-acre portion of the site. The SER was considered by the Environmental Commission on November 16, 2016, and the commission recommended against approval. Subsequently, the Water and Wastewater Commission did not make a recommendation on the SER and the applicant withdrew the service extension request. The staff memo, proposed SER, and Environmental Commission recommendation are attached as Exhibit A. 1 In 2018, water and wastewater SERs #4098 and 4099 were submitted for the 25-acre Birden tract. The applicant proposed to build 138 single family residences with 138 LUEs. Watershed Protection Department did not support the request, and the applicant formally withdrew the request. The current applicant is now proposing to develop a 350-unit multi-family development with 175 LUEs on the 25-acre Birden Tract, and the 9.4 acres of land to the north of it. A site plan is currently in review with the City of Austin (SP-2020-0427C). Development Impacts Water: The site is located in the Austin Water Service Area. Wastewater: The SER proposes that the applicant upgrade the existing Volente Lift Station, upgrade the existing force main that serves the lift station, and upgrade the downstream gravity collection system to provide the capacity necessary to serve the proposed development. The applicant is proposing two wastewater extension options that are described in the Service Extension Request for Consideration (Exhibit B) as follows: Option 1 Applicant shall construct approximately 1,600 feet of 12-inch gravity wastewater main from the existing 8-inch gravity wastewater main (Project no. 80-0629; MH ID #11399) located in El Salido Pkwy., southwest towards Anderson Mill Rd. to the existing 8-inch gravity wastewater main as shown on page 1 of the attached maps. The proposed 12-inch gravity wastewater main shall replace the existing 8-inch gravity wastewater main (Project no. 2002-0552) along this path and all existing services shall be reconnected to the proposed 12-inch gravity wastewater main. Applicant shall also make an appropriately sized wastewater connection to the existing 8-inch gravity wastewater main located south of the Volente Lift Station at the location shown on the attached map. Applicant shall also upgrade the pumping capacity of the existing Volente Lift Station to a firm capacity of approximately 355 gpm in order to adequately serve the additional wastewater flow proposed to be contributed by this development. Upgrades shall include, but are not limited to, replacement of existing pumps, generator, and electrical system (including starters, wiring, service, control panel, etc.) Applicant shall also construct approximately 1,350 feet of appropriately sized force main from the existing Volente Lift Station, north and northwest across the adjacent property, to the existing 6-inch gravity wastewater main located east of N. FM 620 and south of Anderson Mill Rd. The proposed force main shall replace the existing 4-inch force main located along this path. Option 2 Applicant shall construct approximately 1,200 feet of 12-inch gravity wastewater main from the existing 8-inch gravity wastewater main located in El Salido Pkwy., southwest towards Anderson Mill Rd. to the existing 8-inch gravity wastewater main as shown on page 2 of the attached maps. The proposed 12-inch gravity wastewater main shall replace the existing 8-inch gravity wastewater main along this path and all existing services shall be reconnected to the proposed 2 12-inch gravity wastewater main. Applicant shall also construct approximately 650 feet of 12- inch gravity wastewater main from the existing 8-inch gravity wastewater main located in Anderson Mill Rd. and extend southeast and then southwest towards the subject tract to the highest point that can be served by the proposed gravity wastewater main. Applicant shall also make an appropriately sized wastewater connection to the existing 8-inch gravity wastewater main located south of the Volente Lift Station at the location shown on the attached map. Applicant shall also upgrade the pumping capacity of the existing Volente Lift Station to a firm capacity of approximately 355 gpm in order to adequately serve the additional wastewater flow proposed to be contributed by this development. Upgrades shall include, but are not limited to, replacement of existing pumps, generator, and electrical system (including starters, wiring, service, control panel, etc.). Applicant shall construct approximately 950 feet of appropriately sized force main from the existing Volente Lift Station, northeast to the proposed 12-inch gravity wastewater main. Applicant shall also properly abandon the existing 4-inch force main as shown on page 2 of the attached maps. Alternative Wastewater Service: The site is allowed 30.10 acres of net site area and 12.04 acres of allowable impervious cover. 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, the applicant would not be able to develop with a similar density with decentralized service. Environmental Impacts The property is in the Bull Creek Watershed and is classified as Water Supply Suburban. The site is in the Drinking Water Protection Zone and the Northern Edwards Aquifer Recharge Zone. The site contains critical water quality zone and water quality transition zone to the headwaters of Bull Creek. An Environmental Resource Inventory was conducted by the applicant, and two springs, one recharge critical environmental feature, and four wetlands were found onsite. Additionally, this site is in the headwaters of federally-listed threatened Jollyville Plateau salamander (Eurycea sosorum) habitat. Through prior studies, WPD biologists identified a robust population of salamanders in this tributary. The highest salamander occupancy was found in this tributary compared to the other tributaries surveyed in both 2018 and 2019. Runoff from the proposed development would flow downstream into Jollyville Plateau salamander habitat, and thus could negatively impact that salamander population. As the intensity of development on the site increases, the probability of harm to salamanders increases. Recommendation Due to the significant potential environmental impacts to the site with the extension of wastewater service, Watershed Protection Department staff do not recommend support for wastewater SER #4652. 3 The attached information provides further detail on the applicant’s request. Please feel free to contact Kaela Champlin at (512) 974-3443 or kaela.champlin@austintexas.gov if you have any questions or comments about the proposed SER. cc: Colleen Kirk, P.E., Austin Water Cole Huggins, P.E., Austin Water Liz Johnston, Watershed Protection Department Christopher Herrington, P.E., Watershed Protection Department 4