20240515-005: January Drive Flood Reduction Variance Packet — original pdf

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ITEM FOR ENVIRONMENTAL COMMISSION AGENDA May 15, 2024 January Drive Flood Risk Reduction Project – SP-2022-0531D Claudia Corsetti – Capital Delivery Service Department COMMISSION MEETING DATE: NAME & NUMBER OF PROJECT: NAME OF APPLICANT OR ORGANIZATION: LOCATION: 11605 – 11509 February Drive Austin, Texas 78753 COUNCIL DISTRICT: District 1 ENVIRONMENTAL REVIEW STAFF: Eric Brown, PG – Hydrogeologist – Watershed Protection Department WATERSHED: Walnut Creek, Watershed Regulation Area - Suburban, DDZ REQUEST: To allow construction of drainage infrastructure within 50-feet of seep/spring Critical Environmental Feature (CEF) STAFF RECOMMENDATION: STAFF CONDITION: Recommended with Conditions 1. 2. 3. 4. 5. Repair rill erosion throughout the area, Place Grow Zone signs at 100 ft intervals, 30 ft from back of curb, Expand native planting and seeding throughout the Grow Zone area, and native seeding in the area between the Grow Zone and the curb (no plantings outside of the Grow Zone; sod area for stabilization can remain), Ensure that placement of topsoil, temporary irrigation and weed management are included with the restoration, Remove remaining driveway aprons and replace with curb and gutter. Staff Findings of Fact  Watershed Protection Department Staff Recommendations Concerning Required Findings Project Name & Case Number: January Drive Flood Risk Reduction Project – SP-2022- 0531D Ordinance Standard: Watershed Protection Ordinance Variance Request: LDC 25-8-281(C)(2)(b) - To allow construction within 50 feet of a Rimrock and Seep Critical Environmental Features (CEF) . Include an explanation with each applicable finding of fact. A. Land Use Commission variance determinations from Chapter 25-8-41 of the City Code: 1. The requirement will deprive the applicant of a privilege available to owners of similarly situated property with approximately contemporaneous development subject to similar code requirements. Yes. Watershed Protection Department proposes a project to reduce the risk of flooding for the Four Season Subdivision Neighborhood. The new stormwater drainage system must be installed to direct stormwater flows away from existing properties and into the ROW. The development is necessary for the health and safety of the citizens of the City of Austin. The denial of the requested variance for the proposed project will preclude the construction of a stormwater facility necessary to relieve the neighborhood of flooding. The variance is being requested to allow for drainage improvements and continued maintenance and operation of the stormwater system. The variance: a) Is not necessitated by the scale, layout, construction method, or other design decision made by the applicant, unless the design decision provides greater overall environmental protection than is achievable without the variance. 2. Yes. After numerous discussions with design staff, this was the only way to allow for gravitational flows of the stormwater. Using the existing outfall structure minimizes the overall impact of the construction within the setback of the seep horizon. . b) Is the minimum deviation from the code requirement necessary to allow a reasonable use of the property. Yes. The variance is the minimum deviation from the code requirement to allow for a reasonable use of the property. After numerous discussions with design staff, this was the only way to allow for gravitational flows of the stormwater. Using the existing outfall structure minimizes the overall impact of the construction within the setback of the seep horizon. c) Does not create a significant probability of harmful environmental consequences. Yes. Reducing the storm flows out of the pipe to the 2-year storm to protect from stream erosion and utilizing existing infrastructure to minimize the impacts to the creek bank. 3. Development with the variance will result in water quality that is at least equal to the water quality achievable without the variance. Yes, the variance will result in water quality that is at least equal to the water quality achievable without the variance. Soil rehabilitation, native planting and seeding, and invasive species removal will help stabilize the surrounding soils and promote infiltration of rainwater to reduce sediment discharge into Walnut Creek maintain spring flow at the seep horizon. Staff Recommendation: Staff recommends the variance as the Findings of Fact have been met, with the staff recommended conditions listed below: 1. 2. 3. 4. 5. Repair rill erosion throughout the construction area, Place Grow Zone signs at 100 ft intervals, 30 ft from back of curb, Expand native planting and seeding throughout the Grow Zone area, and native seeding in the area between the Grow Zone and the curb (no plantings outside of the Grow Zone; sod area for stabilization can remain), Ensure that placement of topsoil, temporary irrigation and weed management are included with the restoration, Remove remaining driveway aprons and replace them with curb and gutter. Hydrogeologic Reviewer (WPD) ___________________________ Eric Brown Date: 04/18/2024 Deputy Environmental Officer _____________________________ (WPD) Liz Johnston Date: 05/6/2024 Applicant Form and Findings of Fact Dear Eric Brown, The Watershed Protection Department is seeking a variance from LDC 25-8-281 to construct a drainage outfall within a Seep/Spring Complex Critical Environmental Feature buffer. The January Drive Flood Risk Reduction project (CIP 5789.122) aims to mitigate the risk of flooding in the Four Season Subdivision Neighborhood located in North Austin. The proposed storm drain improvements will redirect runoff flows away from undersized infrastructure in the residential parcels and into the January Drive right-of-way. The construction of the storm drain system is necessary for the safety and well-being of the citizens of the City of Austin, as it will help relieve flooding in the neighborhood. The electronic format (PDF) of the Findings of Facts package consisting of the following: 1. Environmental Commission Variance Application Form 2. Walnut Creek - January Drive Project Map 3. Landscape and Grading Plan Sheets 4. ERI Waiver Approval Letter 5. ERI Location Map 6. ERI Topography Map Please do not hesitate to contact me if you have any questions or concerns. Sincerely, Claudia Corsetti, P.E., CFM, PMP Capital Delivery Project Manager Capital Delivery Service Department February 9, 2024 ENVIRONMENTAL COMMISSION VARIANCE APPLICATION FORM PROJECT DESCRIPTION Applicant Contact Information Name of Applicant Street Address City State ZIP Code Work Phone E-Mail Address Case Name Case Number Address or Location Environmental Reviewer Name Environmental Resource Management Reviewer Name Applicable Ordinance Claudia Corsetti, Capital Delivery Services Dept. 6800 Burleson Road, Building 312, Suite 200 Austin, TX 78744 512-974-7205 Claudia.corsetti@austintexas.gov 11603 February Drive, Austin, TX 78753 SP-2022-0531d Brad Jackson Eric Brown, Hydro Geologist Variance Case Information Walnut Creek - January Dr Flood Risk Reduction LDC 25-8-281 to allow construction within a Seep/Spring Complex Critical Environmental Feature buffer for a drainage outfall. Watershed Name Walnut Creek Watershed Classification Urban City of Austin | Environmental Commission Variance Application 1 February 9, 2024 Edwards Aquifer Recharge Zone Edwards Aquifer Contributing Zone Edwards Aquifer Contributing Zone Distance to Nearest Classified Waterway No Adjacent to the waterway. Water and Waste Water service to be provided by City of Austin The variance request is as follows (Cite code references: LDC 25-8-281 to allow construction within a Seep/Spring Complex CEF buffer Existing ________ ________ ________ Proposed _________ _________ ________ No change in impervious cover is proposed. The following general description is for the portion of the property where the tie-in of the proposed stormwater drainage improvements will be taking place directly behind the existing 6ft by 8ft outfall structure. The existing 30-inch RCP outfall connection will be replaced with a 48-inch RCP. The new upsized 48 - inch stormwater system will tie into an existing headwall to minimize the need to disrupt the seep horizon. Request Impervious cover square footage: acreage: percentage: Provide general description of the property (slope range, elevation range, summary of vegetation / trees, summary of the geology, CWQZ, WQTZ, CEFs, floodplain, heritage trees, any other notable or outstanding characteristics of the property) City of Austin | Environmental Commission Variance Application 2 Construction within a Seep/Spring Complex CEF buffer. February 9, 2024 Clearly indicate in what way the proposed project does not comply with current Code (include maps and exhibits) FINDINGS OF FACT Project: Ordinance: A. As required in LDC Section 25-8-41, in order to grant a variance the Land Use Commission must make the following findings of fact: Include an explanation with each applicable finding of fact. Land Use Commission variance determinations from Chapter 25-8-41 of the City Code: 1. The requirement will deprive the applicant of a privilege available to owners of similarly situated property with approximately contemporaneous development subject to similar code requirements. Yes Watershed Protection Department proposes a project to reduce the risk of flooding for the Four Season Subdivision Neighborhood. The new stormwater drainage system must be installed to direct stormwater flows away from existing properties and into the ROW. The development is necessary for the health and safety of the citizens of the City of Austin. The denial of the requested variance for the proposed project will preclude the construction of a stormwater facility necessary to relieve the neighborhood of flooding. The variance is being requested to allow for drainage improvements and continued maintenance and operation of the stormwater system. 2. The variance: a) Is not necessitated by the scale, layout, construction method, or other design decision made by the applicant, unless the design decision provides greater overall environmental protection than is achievable without the variance; City of Austin | Environmental Commission Variance Application 3 February 9, 2024 Yes b) Yes c) Yes The stormwater improvements are required to reduce the risk of flooding within the Four Season Subdivision Neighborhood. The new system alignment must be installed to direct stormwater runoff flows away from existing properties and into the ROW. The development is necessary for the health and safety of citizens of the City of Austin. The upsized stormwater system release at the existing facility outfall/headwall structure is to minimize impacts to the environment. Due to the environmentally sensitive features in the area, the location of the new upsized system tie-in will be directly behind the existing headwall to prevent disturbance of the seep horizon at Walnut Creek. Is the minimum deviation from the code requirement necessary to allow a reasonable use of the property; The proposed stormwater improvement will provide a safe and controlled method for directing stormwater runoff flows into Walnut Creek. Does not create a significant probability of harmful environmental consequences. The proposed stormwater improvement will maintain the existing outfall structure and reduce the probability of harmful environmental consequences. 3. Development with the variance will result in water quality that is at least equal to the water quality achievable without the variance. Yes The proposed stormwater improvement will redirect runoff flows away from residential structures, reducing the risk of flooding and becoming contaminated with household chemicals like cleaners, and auto/cooking oils. B. Additional Land Use Commission variance determinations for a requirement of Section 25-8-422 (Water Quality Transition Zone), Section 25-8-452 (Water Quality Transition Zone), Article 7, Division 1 (Critical Water Quality Zone Restrictions), or Section 25-8-368 (Restrictions on Development Impacting Lake Austin, Lady Bird Lake, and Lake Walter E. Long): 1. The criteria for granting a variance in Subsection (A) are met; Yes The proposed stormwater improvement will provide a safe and controlled method for directing stormwater runoff flows into Walnut Creek. 2. The requirement for which a variance is requested prevents a reasonable, economic use of the entire property; Yes The proposed stormwater improvement will tie in to the existing facility headwall structure to minimize impacts to the environment and make the best use of the entire property with a minimal increase to the storm drainage system’s footprint. City of Austin | Environmental Commission Variance Application 4 February 9, 2024 3. The variance is the minimum deviation from the code requirement necessary to allow a reasonable, economic use of the entire property. Yes The proposed stormwater improvement will tie-in to the existing facility headwall structure to minimize impacts to the environment and make the best use of the entire property with a minimal increase to the storm drainage system’s footprint. **Variance approval requires all above affirmative findings. City of Austin | Environmental Commission Variance Application 5 February 9, 2024 A Exhibits for Commission Variance o Aerial photos of the site o Site photos o Aerial photos of the vicinity o Context Map—A map illustrating the subject property in relation to developments in the vicinity to include nearby major streets and waterways o Topographic Map - A topographic map is recommended if a significant grade change on the subject site exists or if there is a significant difference in grade in relation to adjacent properties. o For cut/fill variances, a plan sheet showing areas and depth of cut/fill with topographic elevations. o Site plan showing existing conditions if development exists currently on the property o Proposed Site Plan- full size electronic or at least legible 11x17 showing proposed development, include tree survey if required as part of site or subdivision plan o Environmental Map – A map that shows pertinent features including Floodplain, CWQZ, WQTZ, CEFs, Setbacks, Recharge Zone, etc. o An Environmental Resource Inventory pursuant to ECM 1.3.0 (if required by 25-8-121) o Applicant’s variance request letter City of Austin | Environmental Commission Variance Application 6 Exhibits for Commission Variance Aerial Photo of the Site Figure 1 - 2024 Aerial, 11603 February Dr City of Austin | Environmental Commission Variance Application 7 Exhibits for Commission Variance Site Photos Figure 2 - Existing Headwall Structure, View from Walnut Creek Figure 3 - Existing Headwall Structure, View from Top of Headwall City of Austin | Environmental Commission Variance Application 8 Exhibits for Commission Variance Figure 4 – Existing Headwall Structure, View from Top of Headwall to Walnut Creek Figure 5 – View of site near the street inlet, 11603 February Dr City of Austin | Environmental Commission Variance Application 9 Exhibits for Commission Variance Figure 6 - View of site upstream of headwall, 11603 February Dr City of Austin | Environmental Commission Variance Application 10 Exhibits for Commission Variance Aerial Photo of the Vicinity Figure 7 – 2024 Aerial of Project Vicinity, January Drive Flood Risk Reduction City of Austin | Environmental Commission Variance Application 11 RIVER O A KS Legend Proposed Storm Drain (SD) Existing SD to Remain Existing SD to Abandon Existing Inlet Creek Detention Pond COA 100-Year Floodplain " ! ! ! FY23 Drainage Reports Building Yard Street W ALN UT RID G E ! " " ! ! " " ! ! ! ! Y R A U N A J " " " ! " " " ! M A R C H A P R I L BLER TO " " " " W A L N U T C R E E K F E B R U A R Y 0 100 200 400 Feet ® A U G U S T The City of Austin is currently updating floodplain maps citywide. The floodplain shown on this map is used for regulating development only. For questions about the floodplain study in your area, visit ATXfloodplains.com. 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 property boundaries. This product has been produced by the WPD for the sole purpose of geographic reference. No warranty is made by the City of Austin regarding specific accuracy or completeness. S T U G U A Environmental Resource Inventory Waiver Request Form For The City of Austin Related to LDC 25-8-121(D) or City Code 30-5-121(D) GENERAL SITE INFORMATION: 1. SITE/PROJECT NAME: __________________________________________________ Walnut Creek - January Drive Flood Risk Reduction 2. COUNTY APPRAISAL DISTRICT PROPERTY ID (#’s): _________________________ 0247261325-0247261124 3. ADDRESS/LOCATION OF PROJECT: _______________________________________ 11502 to 11614 January Drive 4. WATERSHED: _________________________________________________________ Walnut Creek 5. THIS SITE IS WITHIN THE (Check all that apply) Edwards Aquifer Recharge Zone* (See note below).................. (cid:133)YES (cid:133)No Edwards Aquifer Contributing Zone* .................................. (cid:133)YES (cid:133)No Barton Spring Zone* .......................................................... (cid:133)YES (cid:133)No *(as defined by the City of Austin – LDC 25-8-2 or City Code 30-5-2) ■ ■ ■ 6. DOES THIS PROJECT PROPOSE FLOODPLAIN MODIFICATION? (cid:133)YES** (cid:133)NO IF YES, THEN DO ANY OF THE FOLLOWING CONDITIONS APPLY? (check all that apply): (cid:133) (1) The floodplain modifications proposed are necessary to protect the public health and safety; (cid:133) (2) The floodplain modifications proposed would provide a significant, demonstrable environmental benefit, as determined by a functional assessment of floodplain health as prescribed by the Environmental Criteria Manual(ECM), or (cid:133) (3) The floodplain modifications proposed are necessary for development allowed in the critical water quality zone under LDC 25-8-261or 25-8-262, City Code 30-5-261 or 30-5-262. (cid:133) (4) The floodplain modifications proposed are outside of the Critical Water Quality Zone in an area determined to be in poor or fair condition by a functional assessment of floodplain health. ** If yes, then a Functional Assessment must be completed and attached to the ERI (see ECM 1.7 and Appendix X in the Environmental Criteria Manual for forms and guidance) unless conditions 1 or 3 above apply. 7. DOES THIS PROJECT PROPOSE AN UTILITY LINE PARALLEL TO AND WITHIN THE CRITICAL WATER QUALITY ZONE? ………………………………….(cid:133)YES*** (cid:133)NO ■ ***If yes, then riparian restoration is required by LDC 25-8-261(E) and a Functional Assessment must be completed and attached to the ERI (see ECM 1.5 and Appendix X in the Environmental Criteria Manual for forms and guidance). REQUIRED INFORMATION FOR WAIVER REQUEST: Pursuant to LDC 25-8-121(D) or City Code 30-5-121(D), the Director of the Watershed Protection Department (WPD) may permit an applicant to exclude information that is required in ERI report if the Director determines that the information is unnecessary because of the scope or nature of the proposed development. Please provide the requested information below to WPD for review. Please be advised, if granted, this waiver may be rescinded in the future, if new information is discovered during the review process that requires that an ERI be completed for this site. 1. ____ A NARRATIVE DESCRIPTION of current site conditions and justifications to support the granting of the waiver request are attached at the end of this form. (See attachments) X X 2. . ____ The following MAPS of the site is attached: WPD ERM ERI Waiver-2014-01 Page 1 of 2  (Map Information available at http://www.austintexas.gov/GIS/DevelopmentWebMap/Viewer.aspx) ■ ■ (cid:13) Site Location Map (cid:13) Historic Aerial Photo at least 15 years old (cid:13) Current Aerial Photo (cid:13) Topographic Map with a 2 feet contour interval ■ ■ To the best of my knowledge, the responses to this form accurately and thoroughly reflect all information requested. Digitally signed by Xiaoqin Zhang, P.E. DN: C=US, E=xiaoqin.zhang@austintexas.gov, O=City of Austin, OU=Public Works Engineering Services Division, CN="Xiaoqin Zhang, P.E." Date: 2022.09.02 10:21:24-05'00' xiaoqin.zhang@austintexas.gov Xiaoqin Zhang, P.E. Print Name Xiaoqin Zhang, P.E. Signature City of Austin Name of Company 512.974-3562 Telephone Email Address 07/20/2021 Date WATERSHED PROTECTION DEPARTMENT USE ONLY. The waiver requested from LDC 25-8-121(D) of City Code 30-5-121(D) for the above reference project has been: (cid:19) Denied (cid:19) Approved (cid:19) Rescinded (cid:19) Approved with TCEQ Geologic Assessment ■ Reasoning for denial: (cid:13) Formal and/or administrative variances are required for this proposed development. (cid:13) Critical Environmental Features are present on or within 150 feet of site boundaries. (cid:13) The information provided is incomplete (see comments below). (cid:13) Denied, but the following sections can be omitted (see comments below). (cid:13) Other Reasoning for Approval (This form must be included with submittal materials and referenced in your Engineer’s Report and/or Summary): (cid:134) (cid:13) No Critical Environmental Features are present on or within 150 feet of the site boundaries. (cid:13) The site has existing impervious cover and no significant undisturbed natural areas. (cid:13) No floodplains, slopes >15%, CWQZs, WQTZs, wetlands, and the Edwards Aquifer contributing zone are present on site and TCEQ Geologic Assessment has been completed and will be submitted (Only for sites within the Edwards Aquifer). Comments: ■ (cid:13) Other: Comments: CEFs have already been identified ERM Reviewer (Print Name) Eric Brown 9/9/2022 If you have questions on how to fill out this form, please contact the Watershed Protection Department at 512/974-2550. WPD ERM ERI Waiver-2014-01 Page 2 of 2 POPLAR CVRIVER OAKS TRLTOBLER TRLDEUPREE DRAPRIL DRJANUARY DRWALNUT RIDGE DRMARCH DRFEBRUARY DRJANUARY DRIVE - RIMROCK & SPRINGLOCATION MAPLegendRock OutcropSpring LocationDrainage PipeStormDrainCulvertLateral<all other values>010020030040050FeetEXTRATERRITORIAL JURISDICTION 2 MILE ETJ AGRICULTURAL AGREEMENT Legend Jurisdiction FULL PURPOSE LIMITED PURPOSE OTHER CITY LIMITS OTHER CITIES ETJ TCAD Parcels TCAD Parcel IDs Jurisdiction FULL PURPOSE LIMITED PURPOSE EXTRATERRITORIAL JURISDICTION 2 MILE ETJ AGRICULTURAL AGREEMENT Activity Centers for Redevelopment in Sensitive Environmental Areas OTHER CITY LIMITS OTHER CITIES ETJ UCC Permit Imagine Austin Corridors Imagine Austin Centers Regional Center Town Center Neighborhood Center Job Center Fully Developed Floodplain COA Fully Developed 25-Year COA Fully Developed 100-Year COA Master Plan 25-Year COA Master Plan 100-Year 100-Year (Detailed-AE) 100-Year (Shallow-AO,AH) 100-Year (Approx-A) 0.1 0 0.04 0.1 Miles NAD_1983_StatePlane_Texas_Central_FIPS_4203_Feet Date Printed: 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. 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. 100 Year (Approx-A) X Protected by Levee 500 Year 1: 2,400 FEMA Floodplain Notes 100 Year (Detailed-AE) 100 year (Shallow-AO) Applicant Exhibits