20200603-006c: Ledgestone WW SER #4622 REVISED Memo — original pdf

Backup

ITEM FOR ENVIRONMENTAL COMMISSION AGENDA COMMISSION MEETING DATE: June 3, 2020 NAME & NUMBER OF PROJECT: Ledgestone Wastewater Service Extension Request #4622 NAME OF APPLICANT OR ORGANIZATION: Daniel Ryan, P.E. LJA Engineering, Inc. LOCATION: 9021 W US 290 Hwy, Austin, TX 78737 COUNCIL DISTRICT: Austin 2-Mile Extraterritorial Jurisdiction PROJECT FILING DATE: October 17, 2019 WPD/ENVIRONMENTAL STAFF: Kaela Champlin, Environmental Officer’s Office (512) 974-3443, kaela.champlin@austintexas.gov Slaughter Creek Watershed, Barton Springs Zone, Edwards Aquifer Contributing Zone, Drinking Water Protection Zone WATERSHED: REQUEST: STAFF DETERMINATION: Wastewater Service Extension Recommended 1  MEMORANDUM May 21, 2020 Linda Guerrero, Chair, and Members of the Environmental Commission Kaela Champlin, Environmental Officer’s Office Watershed Protection Department TO: FROM: DATE: SUBJECT: Ledgestone Wastewater SER #4622 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 Ledgestone Wastewater SER #4622 and recommend approval of the request. Site Overview The site consists of one tract of approximately 77.78 acres, located at 9021 W US 290 Hwy. The site is in the City of Austin’s Limited Purpose Jurisdiction, the Slaughter Creek Watershed, the Barton Springs Zone, and the Drinking Water Protection Zone. The site is also within the Edwards Aquifer Contributing Zone and is subject to the Save Our Springs (SOS) Ordinance. An Environmental Resource Inventory submitted by the applicant identified no critical environmental features within the property. The applicant is proposing to develop a 550-unit multi-family development. A site plan has not yet been submitted to the City of Austin. Development Impacts Water: The site is located in the water service area of the West Travis County Public Utility Agency (PUA). Wastewater: The applicant shall construct approximately 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, as approximately shown on the attached map. Applicant shall also construct an appropriately sized public lift station at the approximate location shown on the attached map. Applicant shall construct approximately 6,150 feet of 2  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. Applicant shall dedicate appropriately sized wastewater easements from the proposed lift station west to Ledgestone Terrace and north to W US 290 Hwy. Applicant shall construct approximately 1,800 feet of 15-inch gravity wastewater main (minimum 0.4% slope) 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, as approximately shown on the attached map. The proposed 15-inch gravity wastewater main shall replace the existing 12-inch gravity wastewater main in its path. Applicant shall reconnect all existing wastewater services from the existing 12-inch gravity wastewater main to the proposed 15-inch gravity wastewater main. Applicant shall construct approximately 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, as approximately shown on the attached map. The proposed 12-inch gravity wastewater main shall replace the existing 8-inch gravity wastewater main along its path. Applicant shall reconnect all existing wastewater services from the existing 8-inch gravity wastewater main to the proposed 12-inch gravity wastewater main. Alternative Wastewater Service: The applicant has stated that the site could develop with a similar density with decentralized service approved by a Texas Land Application Permit (TLAP) issued by the Texas Commission on Environmental Quality. Environmental Impacts The property is in the Slaughter Creek Watershed and classified as the Barton Springs Zone. The site is in the Drinking Water Protection Zone, the Edwards Aquifer Contributing Zone, and is subject to the Save Our Springs (SOS) Ordinance. The southwestern and eastern corners of the site are within the Devils Pen Creek critical water quality zone and water quality transition zone. An Environmental Resource Inventory was conducted by the applicant, and no known recharge environmental features or critical environmental features were found onsite. The site does not drain to occupied salamander habitat. Based on the information provided by the applicant, the site contains 74.88 of net site area. Therefore, the site contains 18.72 acres of allowable impervious cover. If service is not extended to the site and wastewater disposal is required under a Texas Land Application Permit with the Texas Commission on Environmental Quality, the allowable impervious cover would likely reduce to 15.1 acres based on staff’s estimation of the irrigation area. By staff’s estimation, the site could develop without any required Land Use Commission variances to the City of Austin Land Development Code. Recommendation Staff review determined that there are no significant environmental risks to extend service to the site and therefore recommends approval of Service Extension Request #4622. 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: Kevin Critendon, P.E., Austin Water Colleen Kirk, P.E., Austin Water Christopher Herrington, P.E., Watershed Protection Department 4  WATER AND WASTEWATER SERVICE EXTENSION REQUEST FOR CONSIDERATION Name: Ledgestone Service Requested: Wastewater SER-4622 Hansen Service Request Number 823568 Date Received: 10/17/2019 Location: 9021 W US 290 HWY AUSTIN TX 78737 Acres: 77.78 Land Use: MULTI FAMILY LUE: 275 Alt. Utility Service or S.E.R. Number: West Travis County Public Utility Agency - Water Quad(s): WZ18 WZ19 Reclaimed Pressure Zone: N/A DDZ: NO Drainage Basin: SLAUGHTER Pressure Zone: DWPZ: YES Flow (Estimated Peak Wet Weather): 219 GPM Cost Participation: $0.00 % Within City Limits: 0 % Within Limited Purpose: 0 Description of Improvements: Applicant shall construct approximately 1,000 feet of 8-inch gravity wastewater main from the existing 8-inch gravity wastewater main (Project No. 2009-0588; MH ID #240187) in Circle Dr, and extend south along Circle Dr and then west along US 290 Hwy to the highest point that can be served by the proposed gravity wastewater main, as approximately shown on the attached map. Applicant shall also construct an appropriately sized public lift station at the approximate location shown on the attached map. Applicant shall construct approximately 6,150 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. Applicant shall dedicate appropriately sized wastewater easements from the proposed lift station west to Ledgestone Terrace and north to W US 290 Hwy. Applicant shall construct approximately 1,800 feet of 15-inch gravity wastewater main (minimum 0.4% slope) from the existing 15-inch gravity wastewater main (Project No. 2015-0938; MH ID #124875) along Williamson Creek, and extend west to the existing 12-inch gravity wastewater main (Project No. 2001-0681; MH ID #124869) located west of Covered Bridge Dr, as approximately shown on the attached map. The proposed 15-inch gravity wastewater main shall replace the existing 12-inch gravity wastewater main (Project No. 2001-0681) along its path. Applicant shall reconnect all existing wastewater services from the existing 12-inch gravity wastewater main to the proposed 15-inch gravity wastewater main. Applicant shall construct approximately 2,250 feet of 12-inch gravity wastewater main (minimum 1.0% slope) from the existing 8-inch gravity wastewater main (Project No. 2004-0632; MH ID #200276) 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 (Project No. 2009-0589; MH ID #240017) in Mowinkle Dr, as approximately shown on the attached map. The proposed 12-inch gravity wastewater main shall replace the existing 8-inch gravity wastewater main (Project Nos. 2009-0589 and 2004-0632) along its path. Applicant shall reconnect all existing wastewater services from the existing 8-inch gravity wastewater main to the proposed 12-inch gravity wastewater main. NOTES: 1) Wastewater flow based on engineering calculations received from Daniel Ryan, P.E. of LJA Engineering, Inc. on 10/17/2019. 2) Approximately 1,600 feet of the proposed 1,800 feet of 15-inch gravity wastewater main (between MH ID #124875 – 124870) is also proposed to be constructed by others (Granada Ridge; SP-2018-0138D; 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. Approval of this Service Extension Request is subject to completion and acceptance of the improvements described above and the conditions set forth below: 1) Construction of all Service Extensions is subject to all environmental and planning ordinances. 2) Service Extensions are subject to the guidelines established in the Land Development Code, Chapter 25-9, Water and Wastewater Utility Service. 3) An approved Service Extension is not a reservation of capacity in the system, but is an acknowledgment of the intent to serve. Available capacity shall be confirmed at the time a development application is submitted. 4) The level of service approved by this document does not imply commitment for land use. 5) If West Travis County PUA will provide water service, then for wastewater billing purposes, West Travis County PUA must agree to provide winter months (November through February) water readings to the City of Austin within 5 business days of the City’s request. Prior to construction plan approval, an agreement shall be executed between West Travis County PUA, the developer, and the City of Austin regarding this billing arrangement. 6) Public utility mains must meet City of Austin Design and Construction Criteria and must be approved by Austin Water Engineering Review. 7) Proposed public wastewater improvements will be dedicated to the City of Austin for ownership, operation, and maintenance. 8) Proposed public wastewater improvements must be placed in the public right-of-way or approved utility easements. Utility easements must SER-4622, Page 1 of 2 be approved by Austin Water Engineering Review and must be in place prior to construction plan approval. 9) The approved Service Extension will automatically expire 180 days after date of approval unless a development application has been accepted by the Development Services Department. The Service Extension expires on the date the development expires, or if approved, on the date the development application approval expires. 10) Approval by the City Council will be required based on Austin City Code § 25-9-35. SER-4622, Page 2 of 2 1 0 5 0 1 1 2 0 0 1 0 1 1 0 3 0 9 8 0 9 6 0 9 9 0 1 0 6 0 1110 1100 WZ21 1100 1 1 1 0 A22 0 8 9 970 1 0 1 0 1020 1 0 5 0 1 0 0 0 A21 1 0 5 0 1 0 8 0 M AS SPRIN GS RD 1 0 0 0 1 0 4 0 0 2 0 1 1 0 7 0 1 1 0 0 1 0 9 0 1100 1 0 1 0 7 TH O 0 6 0 1 STAFF PROPOSED APPROXIMATLEY 2,250 FEET OF 12-INCH GRAVITY WASTEWATER MAIN (MINIMUM 1.0% SLOPE) STREA 1 0 9 0 0 1 0 1 M L U A 0 8 0 0 1 1 1 C SIDE D MURMURING CREEK DR WZ20 1 0 8 0 C I R C L E D R 1 0 3 0 9 9 0 W S H 7 1 % % A N C H U 1050 0 2 0 1 960 950 9 3 0 9 4 0 1 0 1 4 0 0 2 0 0 0 1 1 % % 8 9 0 2 0 1 % % 990 % 1030 % %% % C % % % % %%% V LANDMARK CONSERVANCY LS % % C % % % " P C % %% %% % V V % % " P % " P 8 % % %%% % % % % % 8 %% % % %%% 8 %% % %% % %% % % % % % % B21 % %% % % % 9 6 0 0 6 9 970 % % % % % % % 9 % % % % 0 0 6 9 \ \ 0 3 \ % \ \ \ \ \ \ \ \ %\ %\ [7L \ %\ \ %\ \ %\ \ \ \ \ \ \ \ \ \ % % % % % L T \ % S % R A \ % \ R A H R % % % % % % % LE % % % % \ %\ % % % T D % % % % % % 0 7 9 \ %\ % % % % 0 4 0 1 R NIG [7L % %\% SUMMER SKY DR STAFF PROPOSED APPROXIMATELY 1,800 FEET OF 15-INCH GRAVITY WASTEWATER MAIN (MINIMUM 0.4% SLOPE) %%%% %% % %% % 124869 % %% %% % %%%% % %% %%%%%%%%%%%%%%% R % % % E D % %% G %% %%%% %% % % % RID % % % 8" PVC % D B %%% % % % 950 % 0 % %%%%%% %% %%% % 7 E 9 ER % %% % C OV % % 8" PVC %%% V % %%% %%%%% 8" P % % %%%% % % % % %% % % %% %% % % %%% % %% % %% C % % % % % C V % % V 8" P % % % % 8" P %% % % %% % % % %%% % % % DERBIRD R %% % 8" C % % % % % % % % % % % % % 8" PVC % % % % R E D L K WIN O 200276 M C V 8" P % C V 8" P % % % % % 8" PVC % % % % % % % % C %% % % 124875 % % % % % % % % %%% 8" P 8" P THUN 240017 % % 0 3 9 930 % N D % % % % % % % % % % % % % % % % % % % % % % % % % % % % % N C O V % V C % % D X A R T O R % % % C % % % % % % % %% % % 8" PVC % % % % %% % % % % % % % % % % % % 9 1 0 % 9 2 0 % % % 6" P % % C V % 890 % % % !% % %%% 880 !% % % % 9 % % % 8 7 % % % 0 !% % % 0 0 % % % % % % %!% %!%% % % % % % % % % % % % % B20 % % % % ABND PRIVATE LIFT STATION [7L % % % AB % % % % % % % % % 920 % % 0 7 9 % % % % % % % % % % % % % 0 94 % % % % % % % % % % % % % % % % % % % % % % % % % WZ19 9 9 0 1 0 1 0 1 0 1 0 2 0 0 0 1 0 9 9 PRIVATE LIFT STATION C L R A L A N D W A N A T R L A20 T O L L A R L N A M C K A T H D O LE R E S E N D N T L A R P E T PIT 1090 %\\ \ % 1070 \ \ \ [7L \\ \ \\ % 0 1 1 1 0 8 0 1 \ \ \ \\ A19 A R T E R D R 240187 % % %%% \\\% % % \ \ 1080 \ %%%%% %% %%% \\\\ \\\\\\ %%%%% % %%% % %%%% % %% 1 0 0 0 % %%%% % 0 7 0 1 1 0 6 0 9 9 0 A18 D E V I L S 9 6 0 P E N 0 6 9 C R E E K \ % % \ % 1 0 7 0 W US 290 HWY %%%%% %% %%%% %%%% \\ [7L %% % % % \ % RIDGEVIEW LS %%%%%% %%%%%%%%% \ \ 1040 0 6 0 1 9 9 0 STAFF PROPOSED APPROXIMATELY 6,150 FEET OF APPROPRIATELY SIZED FORCE MAIN % 8" P % V % C % % % B19 9 2 %%%%%%%%%%%%%% %% % 970 0 9 0 8 % \ \ \ \ \ \ % 9 %\ % % % % % % % % STAFF PROPOSED % % % % % %\%\%\%\%\\ %\\ %\\\ %\\%\%\%\%\ \%\ %\%\ APPROXIMATELY %\%\%\ 1,000 FEET OF 8-INCH GRAVITY WASTEWATER MAIN % % % \%%%\ % %%%%% %% % \ 6 12" PVC % 0 \ %\ 9 4 0 %\ %%%% % %%% % %% 920 % % % % PRIVATE LIFT STATION [7L % % % % % %% % VIA RICCODR % % % % % % 0 7 %% 960 % % 9 % %% % N % 9 8 0 % N L R %%% %% % % % Y D %% %% %% %%% % % O %% %% %% S T %%% % D T % A R E A % % % % %%% B W % % % % D E % % % !% !% % % % % % % Subject Tract B18 % %% % B17 % % % % % % % % % \ \ %\ 930 0 1 9 BIO N D % A T % % % % % % % % % % % % % % % % % % % %\ G A R % L T R % % . 8 8 0 %\ \ \ 1 0 1 0 \ \ 9 5 0 5 0 9 C " T T % 9 3 0 Y E ! P V ! A D R B % 5 1 ! ! ! ! ! % 980 100-yr FEMA Floodplain Full-Purpose City Limit 2-Mile ETJ Limited-Purpose City Limit STAFF PROPOSED APPROPRIATELY SIZED LIFT STATION Y O U N G L N A17 0 3 9 0 2 9 0 1 9 0 4 9 B E L L A VIS 0 1,000 2,000 4,000 6,000 Feet 0 7 0 0 5 0 1 1 0 6 0 1060 R E E T N O T S E G D E L 1 0 4 0 0 2 0 1 "J WZ18 1 0 4 0 0 4 0 1 SANDSTONE ST 1030 980 970 . W.W. S.E.R. Name: Ledgestone W.W. S.E.R. Number: 4622 Utility Development Services Plotted 11/27/2019 This product is for informational purposes and may not have been prepared for or be suitable for legal, engineering, or surveying purposes. It does not represent an on-the-ground survey and represents only the approximate relative location of the property boundaries. This product has been produced by the City of Austin for the sole purpose of geographic reference. No warranty is made by the City of Austin regarding specific accuracy or completeness. DRAFT