10 SPC-2023-0110C - Stassney Park; District 2 Applicant Variance — original pdf

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April 10, 2024 ENVIRONMENTAL COMMISSION VARIANCE APPLICATION FORM PROJECT DESCRIPTION Applicant Contact Information Variance Case 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 Watershed Name Watershed Classification Nick Brown 10814 Jollyville Rd Building 4, Suite 200 Austin, TX 78759 737-210-1044 Nick.Brown@kimley-horn.com Stassney Park SPC-2023-0110C Enrique A Maiz-Torres Eric Brown 25-8-341 & 25-8-342 Williamson Creek ☐Urban ☐Water Supply Rural 6200 E Stassney Ln, Austin, TX 78744 X Suburban ☐Water Supply Suburban ☐ Barton Springs Zone City of Austin | Environmental Commission Variance Application Guide 1 April 10, 2024 Edwards Aquifer Recharge Zone ☐ Barton Springs Segment ☐ Northern Edwards Segment X Not in Edwards Aquifer Zones Edwards Aquifer Contributing Zone Distance to Nearest Classified Waterway Water and Waste Water service to be provided by Request ☐ Yes X No Austin Water Utility St Elmo Tributary crosses the southwest corner of the subject property; An unnamed stream bisects the property from north to south. The variance request is as follows: 25-8-342 Fill Requirements 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) Existing ____0____ ___0_____ ____0____ Proposed 880347.6 sf 20.21 Ac 37.92% The subject property is approximately 53.291 acres in size with frontage on Stassney Lane. The property ranges in elevation from 528 to 617. The highest point on the property is the northwest corner and the lowest point is along the southern property line where St Elmo Tributary exits the property. 91.15% of the property falls within the 0% to 15% slope category. The remainder property has slopes exceeding 15% slope mainly isolated to the existing drainage channels. Grade 0% - 15% 15% - 25% 25% - 35% > 35% Site Area (Sq Yds) 237842.43 10058.85 4676.20 8369.01 260946.50 % of Site Area 91.15% 3.85% 1.79% 3.21% 100.00% There is an assortment of tree species within the site; only five of the identified trees were measured over 24 caliper inches. On-site soils include Type D Expansive Clays and is identified as Ferris-Heiden City of Austin | Environmental Commission Variance Application Guide 2 April 10, 2024 complex, Heiden clay, and Type B Altoga Silty Clay by the USGS web soil survey. There is a new wetland CEF identified in June 2023 located on the Southeast portion of the property most likely resulting from wastewater line construction allowing ground water to surface. Critical Water Quality Zones exist within the site. Ordinance No. 030605-24 permits a roadway and driveway crossing of the Critical Water Quality Zone. Fully developed 25-year and 100-year floodplains exist within the site. The topography of the site is unique in that the unnamed tributary divides the property into an East side and West side. There are multiple constraints that limit the constructable areas such as the CWQZ, existing steep slopes, and offsite flows entering the property. City of Austin | Environmental Commission Variance Application Guide 3 April 10, 2024 Clearly indicate in what way the proposed project does not comply with current Code (include maps and exhibits) FINDINGS OF FACT Per the attached cut/fill exhibit, there are areas that require cuts/fills greater than 8’. As required in LDC Section 25-8-342, 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. Project: Stassney Park Ordinance: 25-8-341 Cut Requirements & 25-8-342 Fill Requirements Land Use Commission variance determinations from Chapter 25-8-341 and 25-8-342 of the City A. 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 / No 2. The variance: a) Yes / No Numerous other properties along the Burleson Road corridor are developed in a similar manner and fashion as the subject property with large areas of parking and truck courts. At least one of these properties in the nearby vicinity was granted a similar variance to assist in the development of a large warehouse facility at the Park 183 project. 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 Guide 4 April 10, 2024 The existing grades of the subject property would require extensive cut and fill for any scale or type of commercial development. The conceptual plan presented for review presents a configuration that minimizes the required cut and fill while limiting impact around the Critical Water Quality Zones. In addition, the grading of the bridge crossing over the unnamed stream that separates the western portion of the subject property from the access on Stassney Lane reduces site impacts related to grading. Efforts taken to minimize the cut and fill required for these facilities include maximizing allowable grades within the site’s roadways for WB-67 and WB-50 trucks, orienting the buildings to follow the natural contours, sloping the parking and truck loading areas in the same direction as the existing slopes, and constructing walls to meet natural grade rather than sloping 3:1. The project will provide significant environmental benefits to mitigate the impact of cut and fill and to enhance the design of the project including, without limitation: · · · · · · · · State-of-the-art, LEED-certified buildings and site-phased erosion control plans; Reduced building area to adjust grades; Reduced driveway connections to utilize retaining walls in lieu of grading; Enhanced landscaping; Approximately 0.5 mile of offsite-trail connection to regional Austin- to-Manor trail; · Wetland plantings for newly placed wetland; · Proposed rock retaining walls with natural stone look limiting impact to cut; The applicant will work with staff to review the reflective glass product to ensure it is reducing bird strikes onsite. Improved plantings within creek before and after the bypass culvert Improved plantings around bridge abutments b) Is the minimum deviation from the code requirement necessary to allow a reasonable use of the property; Yes / No The requested variance is the minimum amount necessary to achieve appropriate slopes throughout the internal drives and truck courts. The Warehouse Limited Office (W/LO) zoning district permits the warehousing and office type uses that require the large building footprints, truck courts, and City of Austin | Environmental Commission Variance Application Guide 5 April 10, 2024 parking areas. The excessive slopes on the subject property prevent the development of the facilities that serve the use. Approximately 70% of the site is within the area permitting administrative cut- and-fill variances of 8’ or less. Approximately 20% percent of the remaining site will require cut-and-fill of less than 16’, with only approximately 5% of the site to require greater cut and fill. The project has undergone multiple redesigns and reconfigurations in order to reduce the amount of cut and fill to the minimum reasonably necessary. For example, the volume of required cut has been reduced 89% from the original proposal, building footprints have been reduced, and internal drives have been removed, all to reduce the amount of cut and fill. c) Does not create a significant probability of harmful environmental consequences. The proposed slopes on site meet the 3:1 maximum requirement. Where this requirement cannot be met, retaining walls have been placed. The retaining walls and bridge minimize grading encroachment to the CWQZ, additional property, and bisecting creek. Two water quality and detention ponds have been designed to fully capture the runoff created by the proposed improvements and release stormwater to pre-developed conditions flows. One culvert runs through the site to bypass offsite flows and prevent upstream disturbance. 3. Development with the variance will result in water quality that is at least equal to the water quality achievable without the variance. Yes / No Yes / No The proposed design adheres to all water quality requirements outlined within the Land Development Code and Environmental Criteria Manual and as such, will result in water quality that is at least equal to water quality achievable without the variance. Two water quality and detention ponds have been designed to fully capture the runoff created by the proposed improvements and release stormwater to pre-developed conditions flows. One culvert runs through the site to bypass offsite flows and prevent upstream disturbance. Partial biofiltration ponds are proposed with stacked detention to meet the requirements. City of Austin | Environmental Commission Variance Application Guide 6 April 10, 2024 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; N/A to this variance request. The requirement for which a variance is requested prevents a reasonable, economic use of the entire property; 2. 3. N/A to this variance request. N/A to this variance request. The variance is the minimum deviation from the code requirement necessary to allow a reasonable, economic use of the entire property. **Variance approval requires all above affirmative findings. City of Austin | Environmental Commission Variance Application Guide 7 00 100' 200' GRAPHIC SCALE 100' K R A L P R I A 4 4 9 4 K G L O C S 0 , B U D C I F I C I N L O T 2 T I O N 2 A R I- P D O C . N O . 2 T R O P 1 C C S E 1 7 0 T 3 S O U M I S X X X X HERITAGE TREE TO REMAIN TP T P T P D E L O P P E V E D N E : U Z O N I N G : L I- C O - N S D U N A L X TP TP X P T X X X 10697 10698 T P O F F I C E S P A C E 5 7 , 8 3 4 S F 5 9 2 . 6 0 F F E : B U I L D I N G 5 Z O N I N G L I N E C L S 9 E N 4 T L 4 4 R C 7 2 A L O P M E 3 1 C 1 7 T 0 R L 8 . 9 E V E D 4 E L U M D D O C . N O . 2 O P A C C R A P X D U M P S T E R D U M P S T E R L I - C O - N P W / L O - C O - N P T P X X T P X T P X T P X T P 10582 X X X X L I - C O - N P W / L O - C O - N P P T P T X X TP X TP X TP RETAINING WALL T P RETAINING WALL TP X TP X TP L O P D E P E V E D N E : U Z O N I N G : W / L O - C O - N D U S N A L P T OFFICE SPACE BUILDING 3 87,408 SF FFE:577.00 7 7 5 T P 6022 X X 1 2 6 1 4 7 4 . 7 S I G 0 D N 5 7 N E X D O T 2 1 6 5 1 8 7 3 S I G N B T 4 . 5 0 7 6 2 1 9 3 7 7 5 . 3 0 S I G N 8 3 7 8 8 5 . 3 N S I G 0 1 2 6 E I 1 2 6 4 9 7 0 2 3 . 9 S I G N E 0 D N D O T X E T C N A R T N 7 6 2 9 1 4 . 0 S I G N B M A I N E 0 1 2 6 E E E E H O E E T E 1 1 O 3 R T 1 2 6 2 4 1 6 0 1 . 9 N M E 0 S I G W W D D E H O T P O F F I C E S P A C E 8 1 , 8 2 8 S F 5 8 2 . 7 0 F F E : B U I L D I N G 4 D U S Z N A L G R I N U T C O - N P A F U N G : L I- C 6 2 8 . 0 H U C O . 2 P O D 4 E E T B I O C . N O R C A I N 7 1 0 C 1 A S 1 T 0 R E : M A N I N A L X L D O C E S C . 7 0 1 8 T P T P T P L D U M P S T E R P T P T P T T P TP TP TP BRIDGE OVER CREEK TP TP X RETAINING WALL TP TP TP P T TRACT 1 53.292 ACRES 2,321,385 SQ. FT. TP TP TP TP TP TP TP TP 8 R " Ø U G A P I P E 1 C O R T E D T P TP T P OFFICE SPACE BUILDING 2 55,944 SF FFE:561.00 TP RETAINING WALL P T L D U M P S T E R T P T P RETAINING WALL T P T P P T P T DUMPSTER OFFICE SPACE BUILDING 1 30,048 SF FFE:567.80 EXISTING WETLAND CEF P T 1 2 5 3 4 4 4 2 5 . 9 S I G N E N D 9 E S A E S I G N B W O O D / F O R L 3 2 6 . 6 4 9 9 7 1 2 5 D 1 4 S I G N R O U G H R O A 1 5 . 9 8 1 9 1 2 5 D N G N A I L E 1 2 5 7 0 4 4 . 6 G U 9 9 R 3 A D R L A I R E A C I R T C E L E ' 5 1 C I R T C E L E , N O I T U B I R T S I D D N A , S N O I T A C I N U M M O C E L E T T N E M E S A E R E B I F C I R T C E L E P T A I L N G 1 2 5 3 4 R 9 9 3 3 . 4 G U 9 A D R X 2 1 3 6 9 2 . 1 G U A R D R A I L N G 9 1 2 5 T P D I I E H O A I L N G 1 2 5 6 R 2 4 3 9 . 3 G U 8 0 A D R X A I L N G 1 2 5 0 4 3 6 . 8 8 A G U 8 D R 8 R D D P T A I L B N G 1 2 5 3 7 R 9 3 3 4 . 6 G U 8 A D R E H O E N A L Y E N S S A T S E . H E O ) S E I R A V H T D I W W O . R ( . . 7 3 . 5 S I G N T D O T D I R T I O N C S E X 7 2 5 7 1 2 9 1 D E H O D D N G N A I L E 1 2 5 9 3 1 1 . 0 G U 6 A 9 9 R D R D S A I L N G 1 2 5 2 3 1 7 . 4 G U 5 9 R 4 A D R 1 2 1 1 3 3 . 6 G U A R D R A I L B 2 5 1 5 11003 TP TP TP TP TP E N C E E N D 0 E D W I R E F 8 4 2 7 . 8 A R B 8 5 0 5 B D W I R 6 7 . 8 R A 8 4 0 5 5 B 9 E 9 B E N G C N E E F X E B C N E E F D W I R 7 E 5 B 8 0 5 3 6 . 7 R A 5 0 B D D L O P D E P E V E N D E : U Z O N I N G : W / L O - C O - N D U S N A L STASSNEY PARK CUT & FILL ANALYSIS Austin, Texas April 10, 2024 DWG NAME LAST SAVED K:\AUS_CIVIL\BROOKFIELD\067806217 - STASSNEY PARK\CAD\EXHIBITS\PLANSHEETS\STASSNEY CUT AND FILL 2024.04.10.DWG 4/10/2024 1:28 PM 10814 Jollyville Road Campus IV, Suite 200 Austin, TX 78759 512-418-1771 State of Texas Registration No. F-928 NOTE: THIS PLAN IS CONCEPTUAL IN NATURE AND HAS BEEN PRODUCED WITHOUT THE BENEFIT OF A SURVEY, TOPOGRAPHY, UTILITIES, CONTACT WITH THE CITY, ETC.  Case No.: (City use only) Environmental Resource Inventory For the City of Austin Related to LDC 25-8-121, City Code 30-5-121, ECM 1.3.0 & 1.10.0 The ERI is required for projects that meet one or more of the criteria listed in LDC 25-8-121(A), City Code 30-5-121(A). 1. SITE/PROJECT NAME: Stassney Lane 2. COUNTY APPRAISAL DISTRICT PROPERTY ID (#’s): 897007; 897009 3. ADDRESS/LOCATION OF PROJECT: 6200 Block East Stassney Lane, Austin, Texas 78744 4. WATERSHED: Williamson Creek 5. THIS SITE IS WITHIN THE (Check all that apply) Edwards Aquifer Recharge Zone* (See note below) .................. YES No Edwards Aquifer Contributing Zone*.................................. YES No Edwards Aquifer 1500 ft Verification Zone* ....................... YES No Barton Spring Zone* .......................................................... YES No *(as defined by the City of Austin – LDC 25-8-2 or City Code 30-5-2) Note: If the property is over the Edwards Aquifer Recharge zone, the Hydrogeologic Report and karst surveys must be completed and signed by a Professional Geoscientist Licensed in the State of Texas. 6. DOES THIS PROJECT PROPOSE FLOODPLAIN MODIFICATION?.......YES** NO If yes, then check all that apply:     (1) The floodplain modifications proposed are necessary to protect the public health and safety; (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 (3) The floodplain modifications proposed are necessary for development allowed in the critical water quality zone under LDC 25-8-261 or 25-8-262, City Code 30-5-261 or 30-5-262. (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 for forms and guidance) unless conditions 1 or 3 above apply. 7. IF THE SITE IS WITHIN AN URBAN OR SUBURBAN WATERSHED, DOES THIS PROJECT PROPOSE A UTILITY LINE PARALLEL TO AND WITHIN THE CRITICAL WATER QUALITY ZONE? ......................................................... YES*** NO ***If yes, then riparian restoration is required by LDC 25-8-261(E) or City Code 30-5-261(E) and a functional assessment must be completed and attached to the ERI (see ECM1.5 and Appendix X for forms and guidance). 8. There is a total of 0 (#’s) Critical Environmental Feature(s)(CEFs) on or within150 feet of the project site. If CEF(s) are present, attach a detailed DESCRIPTION of the CEF(s), color PHOTOGRAPHS, the CEF WORKSHEET and provide DESCRIPTIONS of the proposed CEF buffer(s) and/or wetland mitigation. Provide the number of each type of CEFs on or within 150 feet of the site (Please provide the number of CEFs ):  0 0 (#’s) Spring(s)/Seep(s) (#’s) Point Recharge Feature(s) 0 (#’s) Bluff(s) (#’s) Canyon Rimrock(s) (#’s) Wetland(s) 0 0 Note: Standard buffers for CEFs are 150 feet, with a maximum of 300 feet for point recharge features. Except for wetlands, if the standard buffer is not provided, you must provide a written request for an administrative variance from LDC 25-8-281(C)(1) and provide written findings of fact to support your request. Request forms for administrative variances from requirements stated in LDC 25-8-281 are available from Watershed Protection Department. 9. The following site maps are attached at the end of this report (Check all that apply and provide): All ERI reports must include:  Site Specific Geologic Map with 2-ft Topography    Historic Aerial Photo of the Site Site Soil Map Critical Environmental Features and Well Location Map on current Aerial Photo with 2-ft Topography Only if present on site (Maps can be combined):  Edwards Aquifer Recharge Zone with the 1500-ft Verification Zone (Only if site is over or within 1500 feet the recharge zone)     Edwards Aquifer Contributing Zone Water Quality Transition Zone (WQTZ) Critical Water Quality Zone (CWQZ) City of Austin Fully Developed Floodplains for all water courses with up to 64-acres of drainage 10. HYDROGEOLOGIC REPORT – Provide a description of site soils, topography, and site specific geology below (Attach additional sheets if needed): Surface Soils on the project site is summarized in the table below and uses the SCS Hydrologic Soil Groups*. If there is more than one soil unit on the project site, show each soil unit on the site soils map. Soil Series Unit Names, Infiltration Characteristics & Thickness *Soil Hydrologic Groups Definitions (Abbreviated) Soil Series Unit Name & Subgroup** Altoga silty clay, 3 to 6 percent slopes (AgC2), Typic Ustochrepts Group* Crockett soils, 2 to 5 percent slopes (CsC2), Udertic Paleustalfs Ferris-Heiden complex, 8 to 20 percent slopes (FhF3), Udorthentic Chromusterts and Udic Chromusterts Lewisville silty clay, 2 to 5 percent slopes (LcB), Typic Haplustolls Patrick soils, 2 to 5 percent slopes (PaC), Typic Calciustolls Thickness (feet) 0 to >6.5 0 to 5 0 to 5 0 to >6.5 0 to >6.5 C D D B B A. Soils having a high infiltration rate when thoroughly wetted. B. Soils having a moderate infiltration rate when thoroughly wetted. C. Soils having a slow infiltration rate when thoroughly wetted. D. Soils having a very slow infiltration rate when thoroughly wetted. **Subgroup Classification – See Classification of Soil Series Table WPD ERM ERI-2014-01 Page 2 of 6  Description of Site Topography and Drainage (Attach additional sheets if needed): The overall topography of the Site was illustrated with slopes oriented northwest-to-southeast toward the southwestern drainage. Multiple areas with “U-” or “V-shaped” contours were present on the hillslopes, suggesting the presence of confined flow. The elevation of the property was between approximately 530 feet and 630 feet above mean sea level (amsl). List surface geologic units below: Geologic Units Exposed at Surface Group Taylor Group Formation Ozan (Sprinkle) Formation Member Quaternary High Gravel Deposits Quaternary High Gravel Deposits Brief description of site geology (Attach additional sheets if needed): The project area is located within the Northern Blackland Prairie ecoregion. The Northern Blackland Prairie is distinguished from surrounding regions by the gently rolling hills and fine-textured, black, clay soils that primarily support prairie vegetation (Griffith et al. 2007). Vertisols dominate the Blackland Prairie ecoregion and consist of high clay content soils with significant shrink-swell potential. Soils in this area are underlain by the Ozan Formation (Ko) and high gravel deposits (Qhg; Proctor et al 1979; USGS 2021; see Geology Map). The Ozan Formation is characterized by gray calcareous clay, silt, and sand (USGS 2021). High gravel deposits within the Austin Sheet feature minor quartzite, milky quartz, sandstone, and mudstone underlying silty clays (Proctor et al. 1979). Griffith, Glenn, Sandy Bryce, James Omernik, and Anne Rogers 2007 Perry, E., F. Schmidt, J. Calvert, M. David, J. Corbett, V. Chandler 1974 2021). U.S. Geological Survey (USGS) 2021 U.S. Department of the Interior Mineral Resources On-Line Spatial Data Website. http://mrdata.usgs.gov/sgmc/tx.html (accessed January 2021). Texas Archeological Sites Atlas. 41TV1284 Archeological Site Form. http://atlas.thc.texas.gov/ (accessed January Ecoregions of Texas. Texas Commission on Environmental Quality, Austin. Wells – Identify all recorded and unrecorded wells on site (test holes, monitoring, water, oil, unplugged, capped and/or abandoned wells, etc.): There are 0 (#) wells present on the project site and the locations are shown and labeled 0 0 0 (#’s)The wells are not in use and have been properly abandoned. (#’s)The wells are not in use and will be properly abandoned. (#’s)The wells are in use and comply with 16 TAC Chapter 76. There are 0 (#’s) wells that are off-site and within 150 feet of this site. WPD ERM ERI-2014-01 Page 3 of 6  11. THE VEGETATION REPORT – Provide the information requested below: Brief description of site plant communities (Attach additional sheets if needed): The survey area was an undeveloped, vacant property with sporadic cleared areas dominated by woody encroachment throughout previous agricultural pastures. Three vegetation communities were identified: live oak/ Ashe juniper stand, forested upland, and forested riparian corridor. The live oak / Ashe juniper stand was recently cleared, leaving sporadic residual overstory trees and a relatively open midstory/understory. The live oak / Ashe juniper stand was dominated by an overstory of live oak (Quercus virginiana) and Ashe juniper (Juniperus ashei) with sporadic cedar elm (Ulmus crassifolia) trees and an understory of Japanese privet (Ligustrum japonicum), Chinese privet (Ligustrum sinense), saw greenbrier (Smilax bona-nox), and silver bluestem (Bothriochloa saccharoides). The forested upland community was dominated by an overstory of Ashe juniper, sugarberry (Celtis laevigata), cedar elm, honey mesquite (Prosopis glandulosa), and Osage-orange (Maclura pomifera) trees, with a midstory/understory comprised of Japanese privet, Chinese privet, King Ranch bluestem (Bothriochloa ischaemum), silver bluestem, Bermudagrass (Cynodon dactylon), Johnsongrass (Sorghum halepense), saw greenbrier, and southern dewberry (Rubus trivialis). The forested riparian corridor community was dominated overstory of American elm (Ulmus americana), green ash (Fraxinus pennsylvanica), cedar elm, and sugarberry with sporadic Ashe juniper trees. The midstory/understory was relatively open, comprised of sporadic Japanese privet, Chinese privet, and saw greenbrier. There is woodland community on site ............................. YES  NO (Check one). If yes, list the dominant species below: Woodland species Common Name Ashe juniper cedar elm American elm sugarberry green ash Scientific Name Juniperus ashei Ulmus crassifolia Ulmus americana Celtis laevigata Fraxinus pennsylvanica There is grassland/prairie/savanna on site ................... YES NO (Check one). If yes, list the dominant species below: Grassland/prairie/savanna species Common Name Scientific Name There is hydrophytic vegetation on site ....................... YES  NO (Check one). If yes, list the dominant species in table below (next page): WPD ERM ERI-2014-01 Page 4 of 6  Hydrophytic plant species Common Name Scientific Name black willow Salix nigra Wetland Indicator Status FACW A tree survey of all trees with a diameter of at least eight inches measured four and one- half feet above natural grade level has been completed on the site. YES  NO (Check one). 12. WASTEWATER REPORT – Provide the information requested below. On-site system(s) Wastewater for the site will be treated by (Check of that Apply):    City of Austin Centralized sewage collection system Other Centralized collection system Note: All sites that receive water or wastewater service from the Austin Water Utility must comply with City Code Chapter 15-12 and wells must be registered with the City of Austin The site sewage collection system is designed and will be constructed to in accordance to all State, County and City standard specifications. YES  NO (Check one). Calculations of the size of the drainfield or wastewater irrigation area(s) are attached at the end of this report or shown on the site plan.  YES  NO  Not Applicable (Check one). Wastewater lines are proposed within the Critical Water Quality Zone?  YES  NO (Check one). If yes, then provide justification below: WPD ERM ERI-2014-01 Page 5 of 6 Is the project site is over the Edwards Aquifer?  YES NO (Check one). If yes, then describe the wastewater disposal systems proposed for the site, its treatment level and effects on receiving watercourses or the Edwards Aquifer. 13. One (1) hard copy and one (1) electronic copy of the completed assessment have been provided. Date(s) ERI Field Assessment was performed: 01/15/2021 Date(s) My signature certifies that to the best of my knowledge, the responses on this form accurately reflect all information requested. Nicholas Schiwitz Print Name Signature 214-998-3029 Telephone nschiwitz@intenvsol.com Email Address Integrated Environmental Solutions, LLC. Name of Company 03/16/2021 Date For project sites within the Edwards Aquifer Recharge Zone, my signature and seal also certifies that I am a licensed Professional Geoscientist in the State of Texas as defined by ECM 1.12.3(A). P.G. Seal WPD ERM ERI-2014-01 Page 6 of 6 City of Austin Environmental Resource Inventory - Critical Environmental Feature Worksheet Project Name: Project Address: Site Visit Date: Stassney Lane 01/15/2021 03/12/2021 Environmental Resource Inventory Date: 6200 Block East Stassney Lane, Austin, Texas 78744 5 6 7 8 Primary Contact Name: Phone Number: Prepared By: Email Address: Nicholas Schiwitz 214-998-3029 Nicholas Schiwitz nschiwitz@intenvsol.com FEATURE TYPE {Wetland,Rimrock, Bluffs,Recharge Feature,Spring} FEATURE ID (eg S-1) FEATURE LONGITUDE (WGS 1984 in Meters) FEATURE LATITUDE (WGS 1984 in Meters) WETLAND DIMENSIONS (ft) RIMROCK/BLUFF DIMENSIONS (ft) coordinate notation coordinate notation X Y Length Avg Height RECHARGE FEATURE DIMENSIONS Z Y Trend X Springs Est. Discharge cfs 1 2 3 4 9 City of Austin Use Only CASE NUMBER: For rimrock, locate the midpoint of the segment that describes the feature. For wetlands, locate the approximate centroid of the feature and the estimated area. For a spring or seep, locate the source of groundwater that feeds a pool or stream. Please state the method of coordinate data collection and the approximate precision and accuracy of the points and the unit of measurement. Method GPS Accuracy sub-meter  □ □ Surveyed Other  □ □ meter > 1 meter Professional Geologists apply seal below WPD ERM ERI-CEF-01 Page 7 of 8 Qhg Ko Qhg Geologic Map Stassney Lane City of Austin Travis County, Texas 1 in = 500 feet Feet 0 500 File Ref. Date: 04.338.005 3/12/2021 - Qt Survey Area 150-foot Buffer Geologic Formation - Central Texas Ko - Ozan Formation Qhg - high gravel deposits LcB AgC2 LcB LcB BsA BsB CsC2 HnA LcA PaC AgC2 GP LcB FhF3 PaC HnA HnC2 HnB HeC2 HeD2 LcB LcB HnA Fr Soils Map Stassney Lane City of Austin Travis County, Texas 1 in = 500 feet Feet 0 500 File Ref. Date: 04.338.005 3/12/2021 - Survey Area 150-foot Buffer Soil Map Units AgC2 - Altoga silty clay, 3 to 6 percent slopes, moderately eroded CsC2 - Crockett soils, 2 to 5 percent slopes, eroded FhF3 - Ferris-Heiden complex, 8 to 20 percent slopes, severely eroded LcB - Lewisville silty clay, 1 to 3 percent slopes PaC - Patrick soils, 2 to 5 percent slopes Soil map units outside survey area Legend Contours Year- 2017 2 Ft Contours 10 Ft Contours 0.2 03/12/2021 NAD_1983_StatePlane_Texas_Central_FIPS_4203_Feet 0 0.08 0.2 Miles 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. 1: 4,800 Notes Topographic map with 2 foot contour intervals Legend Image High : 255 Low : 0 0.2 03/12/2021 NAD_1983_StatePlane_Texas_Central_FIPS_4203_Feet 0 0.08 0.2 Miles 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. 1: 4,800 Notes 1984 Historic Aerial Map Texas Water Development Board Well Report Sites March 11, 2021 The d ata in Wa te r D a ta In ter ac ti ve re pr es en ts th e b e st a va il ab le i nfo rm ati on p ro vid e d b y th e TW D B a nd thi rd -p a rty co o pe ra to rs o f th e TW D B. The TWD B p ro vi de s i n fo rm a ti o n v ia thi s w eb si te a s a pu b li c se rv ice . N ei the r th e S tate of Te xa s n o r the TWD B a ss u me s a ny le g al li ab il ity or r es po n si bi li ty or ma ke s a n y gu a ra nte e s o r w ar ran ti es a s to the a ccu ra cy, co mp l ete n es s o r su ita b ili ty o f th e in for ma tio n fo r a n y pa rti cu la r p u rpo se . The TWD B s yste ma tic a lly re vis e s or r em o ve s d ata d isc ov er ed to b e in co rre ct. If y ou fin d in a ccu ra te i n fo rm a ti o n o r h av e q u es tio n s, pl e as e c on ta ct WD I- Su p po rt @ tw d b .te xa s.g o v. Well Reports 0 0 0.15 0.3 0.25 0.5 1:18,056 0.6 mi 1 km Source: Esri, Maxar, GeoEye, Earthstar Geographics, CNES/Airbus DS, USDA, USGS, AeroGRID, IGN, and the GIS User Community TEXAS WATER DEVELOPMENT BOARD Critical Environmental Features Map Stassney Lane City of Austin Travis County, Texas 1 in = 325 feet Feet 0 325 File Ref. Date: 04.338.005 3/12/2021 - Survey Area 150-foot Buffer *No Critical Environmental Features were identified within the Survey Area and 150-foot buffer* Page 1 April 10, 2024 City of Austin Development Services Department 505 Barton Springs Road Austin, Texas 78704 Re: Environmental Variance Request Letter Stassney Park 6200 E Stassney Ln Austin TX, 78744 Please accept this Environmental Variance Request Letter for the above-mentioned project. A Environmental Variance for cut fill is being requested on this site due to site and design constraints. The Stassney Park project proposes five industrial buildings on the site located at 6200 E Stassney Ln. The site is within the Full-Purpose City Limits of the City of Austin in Travis County, Texas. This site is within the Williamson Creek Watershed, which is classified as a Suburban Watershed and a portion is located in the Federal Emergency Management Agency’s 100-year floodplain per 48453C0605K for Travis County, Texas and Incorporated Areas, dated January 22, 2020. This site is not located in the Edwards Aquifer Recharge Zone. Design constraints pertaining to industrial development include, but are not limited to, large building footprints with one Finished Floor Elevation (FFE), loading docks that are required to be 4ft below building FFE, truck courts limited to 2% slope away from the building, and truck drives limited to 6% slope for safe maneuvering. Due to the 75ft of fall across the site, a cut/fill variance is needed. A cut of 23.97ft and fill of 22.58ft is being requested. The following environmental benefits have been provided with this site: - Retaining walls limiting LOC where needed - Providing more Avg CWQZ than existing conditions require - Maintaining understory trees outside of LOC - Parkland dedication along south side of property line - - Reduced driveway connections to minimize cut/fill and construction on slopes - Construction of bridge over CWQZ and creek to access western portion of property in lieu of LEED certified buildings culverts Improved plantings in creek area before and after bypass culvert Improved plantings in CWQZ around bridge abutments - - kimley-horn.com 10814 Jollyville Road, Building 4, Suite 200, Austin, TX 78759 512 418 1771 Page 2 If you have any questions or comments regarding this request, please contact me at 737-210-1044. Sincerely, KIMLEY-HORN AND ASSOCIATES, INC. Nick Brown, P.E. Senior Project Manager kimley-horn.com 10814 Jollyville Road, Building 4, Suite 200, Austin, TX 78759 512 418 1771 April 10, 2024 ENVIRONMENTAL COMMISSION VARIANCE APPLICATION FORM PROJECT DESCRIPTION Applicant Contact Information Variance Case 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 Watershed Name Watershed Classification Nick Brown 10814 Jollyville Rd Building 4, Suite 200 Austin, TX 78759 737-210-1044 Nick.Brown@kimley-horn.com Stassney Park SPC-2023-0110C Enrique A Maiz-Torres Eric Brown 25-8-341 & 25-8-342 Williamson Creek ☐Urban ☐Water Supply Rural 6200 E Stassney Ln, Austin, TX 78744 X Suburban ☐Water Supply Suburban ☐ Barton Springs Zone City of Austin | Environmental Commission Variance Application Guide 1 April 10, 2024 Edwards Aquifer Contributing Zone Distance to Nearest Classified Waterway 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) Edwards Aquifer Recharge Zone ☐ Barton Springs Segment ☐ Northern Edwards Segment X Not in Edwards Aquifer Zones ☐ Yes X No St Elmo Tributary crosses the southwest corner of the subject property; An unnamed stream bisects the property from north to south. Water and Waste Water service to be provided by Austin Water Utility Request The variance request is as follows: 25-8-341 Cut Requirements Existing ____0____ ___0_____ ____0____ Proposed 880347.6 sf 20.21 Ac 37.92% The subject property is approximately 53.291 acres in size with frontage on Stassney Lane. The property ranges in elevation from 528 to 617. The highest point on the property is the northwest corner and the lowest point is along the southern property line where St Elmo Tributary exits the property. 91.15% of the property falls within the 0% to 15% slope category. The remainder property has slopes exceeding 15% slope mainly isolated to the existing drainage channels. Grade 0% - 15% 15% - 25% 25% - 35% > 35% Site Area (Sq Yds) 237842.43 10058.85 4676.20 8369.01 260946.50 % of Site Area 91.15% 3.85% 1.79% 3.21% 100.00% There is an assortment of tree species within the site; only five of the identified trees were measured over 24 caliper inches. On-site soils include Type D Expansive Clays and is identified as Ferris-Heiden City of Austin | Environmental Commission Variance Application Guide 2 April 10, 2024 complex, Heiden clay, and Type B Altoga Silty Clay by the USGS web soil survey. There is a new wetland CEF identified in June 2023 located on the Southeast portion of the property most likely resulting from wastewater line construction allowing ground water to surface. Critical Water Quality Zones exist within the site. Ordinance No. 030605-24 permits a roadway and driveway crossing of the Critical Water Quality Zone. Fully developed 25-year and 100-year floodplains exist within the site. The topography of the site is unique in that the unnamed tributary divides the property into an East side and West side. There are multiple constraints that limit the constructable areas such as the CWQZ, existing steep slopes, and offsite flows entering the property. City of Austin | Environmental Commission Variance Application Guide 3 April 10, 2024 Clearly indicate in what way the proposed project does not comply with current Code (include maps and exhibits) FINDINGS OF FACT Per the attached cut/fill exhibit, there are areas that require cuts/fills greater than 8’. As required in LDC Section 25-8-341, 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. Project: Stassney Park Ordinance: 25-8-341 Cut Requirements & 25-8-342 Fill Requirements Land Use Commission variance determinations from Chapter 25-8-341 and 25-8-342 of the City A. 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 / No 2. The variance: a) Yes / No Numerous other properties along the Burleson Road corridor are developed in a similar manner and fashion as the subject property with large areas of parking and truck courts. At least one of these properties in the nearby vicinity was granted a similar variance to assist in the development of a large warehouse facility at the Park 183 project. 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 Guide 4 April 10, 2024 The existing grades of the subject property would require extensive cut and fill for any scale or type of commercial development. The conceptual plan presented for review presents a configuration that minimizes the required cut and fill while limiting impact around the Critical Water Quality Zones. In addition, the grading of the bridge crossing over the unnamed stream that separates the western portion of the subject property from the access on Stassney Lane reduces site impacts related to grading. Efforts taken to minimize the cut and fill required for these facilities include maximizing allowable grades within the site’s roadways for WB-67 and WB-50 trucks, orienting the buildings to follow the natural contours, sloping the parking and truck loading areas in the same direction as the existing slopes, and constructing walls to meet natural grade rather than sloping 3:1. The project will provide significant environmental benefits to mitigate the impact of cut and fill and to enhance the design of the project including, without limitation: · · · · · · · · State-of-the-art, LEED-certified buildings and site-phased erosion control plans; Reduced building area to adjust grades; Reduced driveway connections to utilize retaining walls in lieu of grading; Enhanced landscaping; Approximately 0.5 mile of offsite-trail connection to regional Austin- to-Manor trail; · Wetland plantings for newly placed wetland; · Proposed rock retaining walls with natural stone look limiting impact to cut; The applicant will work with staff to review the reflective glass product to ensure it is reducing bird strikes onsite. Improved plantings within creek before and after the bypass culvert Improved plantings around bridge abutments b) Is the minimum deviation from the code requirement necessary to allow a reasonable use of the property; Yes / No The requested variance is the minimum amount necessary to achieve appropriate slopes throughout the internal drives and truck courts. The Warehouse Limited Office (W/LO) zoning district permits the warehousing and office type uses that require the large building footprints, truck courts, and City of Austin | Environmental Commission Variance Application Guide 5 April 10, 2024 parking areas. The excessive slopes on the subject property prevent the development of the facilities that serve the use. Approximately 70% of the site is within the area permitting administrative cut- and-fill variances of 8’ or less. Approximately 20% percent of the remaining site will require cut-and-fill of less than 16’, with only approximately 5% of the site to require greater cut and fill. The project has undergone multiple redesigns and reconfigurations in order to reduce the amount of cut and fill to the minimum reasonably necessary. For example, the volume of required cut has been reduced 89% from the original proposal, building footprints have been reduced, and internal drives have been removed, all to reduce the amount of cut and fill. c) Does not create a significant probability of harmful environmental consequences. The proposed slopes on site meet the 3:1 maximum requirement. Where this requirement cannot be met, retaining walls have been placed. The retaining walls and bridge minimize grading encroachment to the CWQZ, additional property, and bisecting creek. Two water quality and detention ponds have been designed to fully capture the runoff created by the proposed improvements and release stormwater to pre-developed conditions flows. One culvert runs through the site to bypass offsite flows and prevent upstream disturbance. 3. Development with the variance will result in water quality that is at least equal to the water quality achievable without the variance. Yes / No Yes / No The proposed design adheres to all water quality requirements outlined within the Land Development Code and Environmental Criteria Manual and as such, will result in water quality that is at least equal to water quality achievable without the variance. Two water quality and detention ponds have been designed to fully capture the runoff created by the proposed improvements and release stormwater to pre-developed conditions flows. One culvert runs through the site to bypass offsite flows and prevent upstream disturbance. Partial biofiltration ponds are proposed with stacked detention to meet the requirements. City of Austin | Environmental Commission Variance Application Guide 6 April 10, 2024 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; N/A to this variance request. The requirement for which a variance is requested prevents a reasonable, economic use of the entire property; 2. 3. N/A to this variance request. N/A to this variance request. The variance is the minimum deviation from the code requirement necessary to allow a reasonable, economic use of the entire property. **Variance approval requires all above affirmative findings. City of Austin | Environmental Commission Variance Application Guide 7 00 100' 200' GRAPHIC SCALE 100' K R A L P R I A 4 4 9 4 K G L O C S 0 , B U D C I F I C I N L O T 2 T I O N 2 A R I- P D O C . N O . 2 T R O P 1 C C S E 0 1 7 T 3 S O U M I S X X X X HERITAGE TREE TO REMAIN TP T P T P D E L O P P E V E N D E : U Z O N I N G : L I- C O - N S D U N A L X TP TP X P T X X X 10697 10698 T P O F F I C E S P A C E 5 7 , 8 3 4 S F 5 9 2 . 6 0 F F E : B U I L D I N G 5 Z O N I N G L I N E C L S 9 E N 4 T L 4 4 R C 7 2 A L O P M E 3 1 C 1 7 T 0 R L 8 . 9 E V E D 4 E L U M D D O C . N O . 2 O P A C C R A P X D U M P S T E R D U M P S T E R L I - C O - N P W / L O - C O - N P T P X X T P X T P X T P X T P 10582 X X X X L I - C O - N P W / L O - C O - N P P T P T X X TP X TP X TP RETAINING WALL T P RETAINING WALL TP X TP X TP L O P D E P E V E D N E : U Z O N I N G : W / L O - C O - N D U S N A L P T OFFICE SPACE BUILDING 3 87,408 SF FFE:577.00 7 7 5 T P 6022 X X 1 2 6 1 4 7 4 . 7 S I G 0 D N 5 7 N E X D O T 2 1 6 5 1 8 7 3 S I G N B T 4 . 5 0 7 6 2 1 9 3 7 7 5 . 3 0 S I G N 8 3 7 8 8 5 . 3 N S I G 0 1 2 6 E I 1 2 6 9 4 7 0 2 3 . 9 S I G N E 0 D N D O T X E T C N A R T N 7 2 6 9 1 4 . 0 S I G N B M A I N E 0 1 2 6 E E E E H O E E T E 1 1 O 3 R T 1 2 6 2 4 1 6 0 1 . 9 N M E 0 S I G W W D D E H O T P O F F I C E S P A C E 8 1 , 8 2 8 S F 5 8 2 . 7 0 F F E : B U I L D I N G 4 D U S Z N A L G R I N U T C O - N P A F U N G : L I- C 6 2 8 . 0 H U C O . 2 P O D 4 E E T B I O C . N O R C A I N 7 1 0 C 1 A S 1 T 0 R E : M A N I N A L X L D O C E S C . 7 0 1 8 T P T P T P L D U M P S T E R P T P T P T T P TP TP TP BRIDGE OVER CREEK TP TP X RETAINING WALL TP TP TP P T TRACT 1 53.292 ACRES 2,321,385 SQ. FT. TP TP TP TP TP TP TP TP 8 R " Ø U G A P I P E 1 C O R T E D T P TP T P OFFICE SPACE BUILDING 2 55,944 SF FFE:561.00 TP RETAINING WALL P T L D U M P S T E R T P T P RETAINING WALL T P T P P T P T DUMPSTER OFFICE SPACE BUILDING 1 30,048 SF FFE:567.80 EXISTING WETLAND CEF P T 1 2 5 4 3 4 4 2 5 . 9 S I G N E N D 9 E S A E S I G N B W O O D / F O R L 3 2 6 . 6 4 9 9 7 1 2 5 D 4 1 S I G N R O U G H R O A 1 5 . 9 9 1 8 1 2 5 D N G N A I L E 1 2 5 7 0 4 4 . 6 G U 9 9 R 3 A D R L A I R E A C I R T C E L E ' 5 1 C I R T C E L E , N O I T U B I R T S I D D N A , S N O I T A C I N U M M O C E L E T T N E M E S A E R E B I F C I R T C E L E P T A I L N G 1 2 5 3 4 R 9 9 3 3 . 4 G U 9 A D R X 2 1 3 6 9 2 . 1 G U A R D R A I L N G 9 1 2 5 T P D I I E H O A I L N G 1 2 5 6 R 2 4 3 9 . 3 G U 8 0 A D R X A I L N G 1 2 5 0 4 3 6 . 8 8 A G U 8 D R 8 R D D P T A I L B N G 1 2 5 3 7 R 9 3 3 4 . 6 G U 8 A D R E H O E N A L Y E N S S A T S E . H E O ) S E I R A V H T D I W W O . R ( . . 7 3 . 5 S I G N T D O T D I R T I O N C S X E 7 5 2 7 2 1 9 1 D E H O D D N G N A I L E 1 2 5 9 3 1 1 . 0 G U 6 A 9 9 R D R D S A I L N G 1 2 5 2 3 1 7 . 4 G U 5 9 R 4 A D R 1 2 1 1 3 3 . 6 G U A R D R A I L B 2 5 1 5 11003 TP TP TP TP TP E N C E E N D 0 E D W I R E F 8 4 2 7 . 8 A R B 8 5 0 5 B D W I R 6 7 . 8 R A 8 4 0 5 5 B 9 E 9 B E N G C N E E F X E B C N E E F D W I R 7 E 5 B 8 0 5 3 6 . 7 R A 5 0 B D D L O P D E P E V E N D E : U Z O N I N G : W / L O - C O - N D U S N A L STASSNEY PARK CUT & FILL ANALYSIS Austin, Texas April 10, 2024 DWG NAME LAST SAVED K:\AUS_CIVIL\BROOKFIELD\067806217 - STASSNEY PARK\CAD\EXHIBITS\PLANSHEETS\STASSNEY CUT AND FILL 2024.04.10.DWG 4/10/2024 1:28 PM 10814 Jollyville Road Campus IV, Suite 200 Austin, TX 78759 512-418-1771 State of Texas Registration No. F-928 NOTE: THIS PLAN IS CONCEPTUAL IN NATURE AND HAS BEEN PRODUCED WITHOUT THE BENEFIT OF A SURVEY, TOPOGRAPHY, UTILITIES, CONTACT WITH THE CITY, ETC.  Case No.: (City use only) Environmental Resource Inventory For the City of Austin Related to LDC 25-8-121, City Code 30-5-121, ECM 1.3.0 & 1.10.0 The ERI is required for projects that meet one or more of the criteria listed in LDC 25-8-121(A), City Code 30-5-121(A). 1. SITE/PROJECT NAME: Stassney Lane 2. COUNTY APPRAISAL DISTRICT PROPERTY ID (#’s): 897007; 897009 3. ADDRESS/LOCATION OF PROJECT: 6200 Block East Stassney Lane, Austin, Texas 78744 4. WATERSHED: Williamson Creek 5. THIS SITE IS WITHIN THE (Check all that apply) Edwards Aquifer Recharge Zone* (See note below) .................. YES No Edwards Aquifer Contributing Zone*.................................. YES No Edwards Aquifer 1500 ft Verification Zone* ....................... YES No Barton Spring Zone* .......................................................... YES No *(as defined by the City of Austin – LDC 25-8-2 or City Code 30-5-2) Note: If the property is over the Edwards Aquifer Recharge zone, the Hydrogeologic Report and karst surveys must be completed and signed by a Professional Geoscientist Licensed in the State of Texas. 6. DOES THIS PROJECT PROPOSE FLOODPLAIN MODIFICATION?.......YES** NO If yes, then check all that apply:     (1) The floodplain modifications proposed are necessary to protect the public health and safety; (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 (3) The floodplain modifications proposed are necessary for development allowed in the critical water quality zone under LDC 25-8-261 or 25-8-262, City Code 30-5-261 or 30-5-262. (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 for forms and guidance) unless conditions 1 or 3 above apply. 7. IF THE SITE IS WITHIN AN URBAN OR SUBURBAN WATERSHED, DOES THIS PROJECT PROPOSE A UTILITY LINE PARALLEL TO AND WITHIN THE CRITICAL WATER QUALITY ZONE? ......................................................... YES*** NO ***If yes, then riparian restoration is required by LDC 25-8-261(E) or City Code 30-5-261(E) and a functional assessment must be completed and attached to the ERI (see ECM1.5 and Appendix X for forms and guidance). 8. There is a total of 0 (#’s) Critical Environmental Feature(s)(CEFs) on or within150 feet of the project site. If CEF(s) are present, attach a detailed DESCRIPTION of the CEF(s), color PHOTOGRAPHS, the CEF WORKSHEET and provide DESCRIPTIONS of the proposed CEF buffer(s) and/or wetland mitigation. Provide the number of each type of CEFs on or within 150 feet of the site (Please provide the number of CEFs ):  0 0 (#’s) Spring(s)/Seep(s) (#’s) Point Recharge Feature(s) 0 (#’s) Bluff(s) (#’s) Canyon Rimrock(s) (#’s) Wetland(s) 0 0 Note: Standard buffers for CEFs are 150 feet, with a maximum of 300 feet for point recharge features. Except for wetlands, if the standard buffer is not provided, you must provide a written request for an administrative variance from LDC 25-8-281(C)(1) and provide written findings of fact to support your request. Request forms for administrative variances from requirements stated in LDC 25-8-281 are available from Watershed Protection Department. 9. The following site maps are attached at the end of this report (Check all that apply and provide): All ERI reports must include:  Site Specific Geologic Map with 2-ft Topography    Historic Aerial Photo of the Site Site Soil Map Critical Environmental Features and Well Location Map on current Aerial Photo with 2-ft Topography Only if present on site (Maps can be combined):  Edwards Aquifer Recharge Zone with the 1500-ft Verification Zone (Only if site is over or within 1500 feet the recharge zone)     Edwards Aquifer Contributing Zone Water Quality Transition Zone (WQTZ) Critical Water Quality Zone (CWQZ) City of Austin Fully Developed Floodplains for all water courses with up to 64-acres of drainage 10. HYDROGEOLOGIC REPORT – Provide a description of site soils, topography, and site specific geology below (Attach additional sheets if needed): Surface Soils on the project site is summarized in the table below and uses the SCS Hydrologic Soil Groups*. If there is more than one soil unit on the project site, show each soil unit on the site soils map. Soil Series Unit Names, Infiltration Characteristics & Thickness *Soil Hydrologic Groups Definitions (Abbreviated) Soil Series Unit Name & Subgroup** Altoga silty clay, 3 to 6 percent slopes (AgC2), Typic Ustochrepts Group* Crockett soils, 2 to 5 percent slopes (CsC2), Udertic Paleustalfs Ferris-Heiden complex, 8 to 20 percent slopes (FhF3), Udorthentic Chromusterts and Udic Chromusterts Lewisville silty clay, 2 to 5 percent slopes (LcB), Typic Haplustolls Patrick soils, 2 to 5 percent slopes (PaC), Typic Calciustolls Thickness (feet) 0 to >6.5 0 to 5 0 to 5 0 to >6.5 0 to >6.5 C D D B B A. Soils having a high infiltration rate when thoroughly wetted. B. Soils having a moderate infiltration rate when thoroughly wetted. C. Soils having a slow infiltration rate when thoroughly wetted. D. Soils having a very slow infiltration rate when thoroughly wetted. **Subgroup Classification – See Classification of Soil Series Table WPD ERM ERI-2014-01 Page 2 of 6  Description of Site Topography and Drainage (Attach additional sheets if needed): The overall topography of the Site was illustrated with slopes oriented northwest-to-southeast toward the southwestern drainage. Multiple areas with “U-” or “V-shaped” contours were present on the hillslopes, suggesting the presence of confined flow. The elevation of the property was between approximately 530 feet and 630 feet above mean sea level (amsl). List surface geologic units below: Geologic Units Exposed at Surface Group Taylor Group Formation Ozan (Sprinkle) Formation Member Quaternary High Gravel Deposits Quaternary High Gravel Deposits Brief description of site geology (Attach additional sheets if needed): The project area is located within the Northern Blackland Prairie ecoregion. The Northern Blackland Prairie is distinguished from surrounding regions by the gently rolling hills and fine-textured, black, clay soils that primarily support prairie vegetation (Griffith et al. 2007). Vertisols dominate the Blackland Prairie ecoregion and consist of high clay content soils with significant shrink-swell potential. Soils in this area are underlain by the Ozan Formation (Ko) and high gravel deposits (Qhg; Proctor et al 1979; USGS 2021; see Geology Map). The Ozan Formation is characterized by gray calcareous clay, silt, and sand (USGS 2021). High gravel deposits within the Austin Sheet feature minor quartzite, milky quartz, sandstone, and mudstone underlying silty clays (Proctor et al. 1979). Griffith, Glenn, Sandy Bryce, James Omernik, and Anne Rogers 2007 Perry, E., F. Schmidt, J. Calvert, M. David, J. Corbett, V. Chandler 1974 2021). U.S. Geological Survey (USGS) 2021 U.S. Department of the Interior Mineral Resources On-Line Spatial Data Website. http://mrdata.usgs.gov/sgmc/tx.html (accessed January 2021). Texas Archeological Sites Atlas. 41TV1284 Archeological Site Form. http://atlas.thc.texas.gov/ (accessed January Ecoregions of Texas. Texas Commission on Environmental Quality, Austin. Wells – Identify all recorded and unrecorded wells on site (test holes, monitoring, water, oil, unplugged, capped and/or abandoned wells, etc.): There are 0 (#) wells present on the project site and the locations are shown and labeled 0 0 0 (#’s)The wells are not in use and have been properly abandoned. (#’s)The wells are not in use and will be properly abandoned. (#’s)The wells are in use and comply with 16 TAC Chapter 76. There are 0 (#’s) wells that are off-site and within 150 feet of this site. WPD ERM ERI-2014-01 Page 3 of 6  11. THE VEGETATION REPORT – Provide the information requested below: Brief description of site plant communities (Attach additional sheets if needed): The survey area was an undeveloped, vacant property with sporadic cleared areas dominated by woody encroachment throughout previous agricultural pastures. Three vegetation communities were identified: live oak/ Ashe juniper stand, forested upland, and forested riparian corridor. The live oak / Ashe juniper stand was recently cleared, leaving sporadic residual overstory trees and a relatively open midstory/understory. The live oak / Ashe juniper stand was dominated by an overstory of live oak (Quercus virginiana) and Ashe juniper (Juniperus ashei) with sporadic cedar elm (Ulmus crassifolia) trees and an understory of Japanese privet (Ligustrum japonicum), Chinese privet (Ligustrum sinense), saw greenbrier (Smilax bona-nox), and silver bluestem (Bothriochloa saccharoides). The forested upland community was dominated by an overstory of Ashe juniper, sugarberry (Celtis laevigata), cedar elm, honey mesquite (Prosopis glandulosa), and Osage-orange (Maclura pomifera) trees, with a midstory/understory comprised of Japanese privet, Chinese privet, King Ranch bluestem (Bothriochloa ischaemum), silver bluestem, Bermudagrass (Cynodon dactylon), Johnsongrass (Sorghum halepense), saw greenbrier, and southern dewberry (Rubus trivialis). The forested riparian corridor community was dominated overstory of American elm (Ulmus americana), green ash (Fraxinus pennsylvanica), cedar elm, and sugarberry with sporadic Ashe juniper trees. The midstory/understory was relatively open, comprised of sporadic Japanese privet, Chinese privet, and saw greenbrier. There is woodland community on site ............................. YES  NO (Check one). If yes, list the dominant species below: Woodland species Common Name Ashe juniper cedar elm American elm sugarberry green ash Scientific Name Juniperus ashei Ulmus crassifolia Ulmus americana Celtis laevigata Fraxinus pennsylvanica There is grassland/prairie/savanna on site ................... YES NO (Check one). If yes, list the dominant species below: Grassland/prairie/savanna species Common Name Scientific Name There is hydrophytic vegetation on site ....................... YES  NO (Check one). If yes, list the dominant species in table below (next page): WPD ERM ERI-2014-01 Page 4 of 6  Hydrophytic plant species Common Name Scientific Name black willow Salix nigra Wetland Indicator Status FACW A tree survey of all trees with a diameter of at least eight inches measured four and one- half feet above natural grade level has been completed on the site. YES  NO (Check one). 12. WASTEWATER REPORT – Provide the information requested below. On-site system(s) Wastewater for the site will be treated by (Check of that Apply):    City of Austin Centralized sewage collection system Other Centralized collection system Note: All sites that receive water or wastewater service from the Austin Water Utility must comply with City Code Chapter 15-12 and wells must be registered with the City of Austin The site sewage collection system is designed and will be constructed to in accordance to all State, County and City standard specifications. YES  NO (Check one). Calculations of the size of the drainfield or wastewater irrigation area(s) are attached at the end of this report or shown on the site plan.  YES  NO  Not Applicable (Check one). Wastewater lines are proposed within the Critical Water Quality Zone?  YES  NO (Check one). If yes, then provide justification below: WPD ERM ERI-2014-01 Page 5 of 6 Is the project site is over the Edwards Aquifer?  YES NO (Check one). If yes, then describe the wastewater disposal systems proposed for the site, its treatment level and effects on receiving watercourses or the Edwards Aquifer. 13. One (1) hard copy and one (1) electronic copy of the completed assessment have been provided. Date(s) ERI Field Assessment was performed: 01/15/2021 Date(s) My signature certifies that to the best of my knowledge, the responses on this form accurately reflect all information requested. Nicholas Schiwitz Print Name Signature 214-998-3029 Telephone nschiwitz@intenvsol.com Email Address Integrated Environmental Solutions, LLC. Name of Company 03/16/2021 Date For project sites within the Edwards Aquifer Recharge Zone, my signature and seal also certifies that I am a licensed Professional Geoscientist in the State of Texas as defined by ECM 1.12.3(A). P.G. Seal WPD ERM ERI-2014-01 Page 6 of 6 City of Austin Environmental Resource Inventory - Critical Environmental Feature Worksheet Project Name: Project Address: Site Visit Date: Stassney Lane 01/15/2021 03/12/2021 Environmental Resource Inventory Date: 6200 Block East Stassney Lane, Austin, Texas 78744 5 6 7 8 Primary Contact Name: Phone Number: Prepared By: Email Address: Nicholas Schiwitz 214-998-3029 Nicholas Schiwitz nschiwitz@intenvsol.com FEATURE TYPE {Wetland,Rimrock, Bluffs,Recharge Feature,Spring} FEATURE ID (eg S-1) FEATURE LONGITUDE (WGS 1984 in Meters) FEATURE LATITUDE (WGS 1984 in Meters) WETLAND DIMENSIONS (ft) RIMROCK/BLUFF DIMENSIONS (ft) coordinate notation coordinate notation X Y Length Avg Height RECHARGE FEATURE DIMENSIONS Z Y Trend X Springs Est. Discharge cfs 1 2 3 4 9 City of Austin Use Only CASE NUMBER: For rimrock, locate the midpoint of the segment that describes the feature. For wetlands, locate the approximate centroid of the feature and the estimated area. For a spring or seep, locate the source of groundwater that feeds a pool or stream. Please state the method of coordinate data collection and the approximate precision and accuracy of the points and the unit of measurement. Method GPS Accuracy sub-meter  □ □ Surveyed Other  □ □ meter > 1 meter Professional Geologists apply seal below WPD ERM ERI-CEF-01 Page 7 of 8 Qhg Ko Qhg Geologic Map Stassney Lane City of Austin Travis County, Texas 1 in = 500 feet Feet 0 500 File Ref. Date: 04.338.005 3/12/2021 - Qt Survey Area 150-foot Buffer Geologic Formation - Central Texas Ko - Ozan Formation Qhg - high gravel deposits LcB AgC2 LcB LcB BsA BsB CsC2 HnA LcA PaC AgC2 GP LcB FhF3 PaC HnA HnC2 HnB HeC2 HeD2 LcB LcB HnA Fr Soils Map Stassney Lane City of Austin Travis County, Texas 1 in = 500 feet Feet 0 500 File Ref. Date: 04.338.005 3/12/2021 - Survey Area 150-foot Buffer Soil Map Units AgC2 - Altoga silty clay, 3 to 6 percent slopes, moderately eroded CsC2 - Crockett soils, 2 to 5 percent slopes, eroded FhF3 - Ferris-Heiden complex, 8 to 20 percent slopes, severely eroded LcB - Lewisville silty clay, 1 to 3 percent slopes PaC - Patrick soils, 2 to 5 percent slopes Soil map units outside survey area Legend Contours Year- 2017 2 Ft Contours 10 Ft Contours 0.2 03/12/2021 NAD_1983_StatePlane_Texas_Central_FIPS_4203_Feet 0 0.08 0.2 Miles 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. 1: 4,800 Notes Topographic map with 2 foot contour intervals Legend Image High : 255 Low : 0 0.2 03/12/2021 NAD_1983_StatePlane_Texas_Central_FIPS_4203_Feet 0 0.08 0.2 Miles 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. 1: 4,800 Notes 1984 Historic Aerial Map Texas Water Development Board Well Report Sites March 11, 2021 The d ata in Wa te r D a ta In ter ac ti ve re pr es en ts th e b e st a va il ab le i nfo rm ati on p ro vid e d b y th e TW D B a nd thi rd -p a rty co o pe ra to rs o f th e TW D B. The TWD B p ro vi de s i n fo rm a ti o n v ia thi s w eb si te a s a pu b li c se rv ice . N ei the r th e S tate of Te xa s n o r the TWD B a ss u me s a ny le g al li ab il ity or r es po n si bi li ty or ma ke s a n y gu a ra nte e s o r w ar ran ti es a s to the a ccu ra cy, co mp l ete n es s o r su ita b ili ty o f th e in for ma tio n fo r a n y pa rti cu la r p u rpo se . The TWD B s yste ma tic a lly re vis e s or r em o ve s d ata d isc ov er ed to b e in co rre ct. If y ou fin d in a ccu ra te i n fo rm a ti o n o r h av e q u es tio n s, pl e as e c on ta ct WD I- Su p po rt @ tw d b .te xa s.g o v. Well Reports 0 0 0.15 0.3 0.25 0.5 1:18,056 0.6 mi 1 km Source: Esri, Maxar, GeoEye, Earthstar Geographics, CNES/Airbus DS, USDA, USGS, AeroGRID, IGN, and the GIS User Community TEXAS WATER DEVELOPMENT BOARD Critical Environmental Features Map Stassney Lane City of Austin Travis County, Texas 1 in = 325 feet Feet 0 325 File Ref. Date: 04.338.005 3/12/2021 - Survey Area 150-foot Buffer *No Critical Environmental Features were identified within the Survey Area and 150-foot buffer* Page 1 April 10, 2024 City of Austin Development Services Department 505 Barton Springs Road Austin, Texas 78704 Re: Environmental Variance Request Letter Stassney Park 6200 E Stassney Ln Austin TX, 78744 Please accept this Environmental Variance Request Letter for the above-mentioned project. A Environmental Variance for cut fill is being requested on this site due to site and design constraints. The Stassney Park project proposes five industrial buildings on the site located at 6200 E Stassney Ln. The site is within the Full-Purpose City Limits of the City of Austin in Travis County, Texas. This site is within the Williamson Creek Watershed, which is classified as a Suburban Watershed and a portion is located in the Federal Emergency Management Agency’s 100-year floodplain per 48453C0605K for Travis County, Texas and Incorporated Areas, dated January 22, 2020. This site is not located in the Edwards Aquifer Recharge Zone. Design constraints pertaining to industrial development include, but are not limited to, large building footprints with one Finished Floor Elevation (FFE), loading docks that are required to be 4ft below building FFE, truck courts limited to 2% slope away from the building, and truck drives limited to 6% slope for safe maneuvering. Due to the 75ft of fall across the site, a cut/fill variance is needed. A cut of 23.97ft and fill of 22.58ft is being requested. The following environmental benefits have been provided with this site: - Retaining walls limiting LOC where needed - Providing more Avg CWQZ than existing conditions require - Maintaining understory trees outside of LOC - Parkland dedication along south side of property line - - Reduced driveway connections to minimize cut/fill and construction on slopes - Construction of bridge over CWQZ and creek to access western portion of property in lieu of LEED certified buildings culverts Improved plantings in creek area before and after bypass culvert Improved plantings in CWQZ around bridge abutments - - kimley-horn.com 10814 Jollyville Road, Building 4, Suite 200, Austin, TX 78759 512 418 1771 Page 2 If you have any questions or comments regarding this request, please contact me at 737-210-1044. Sincerely, KIMLEY-HORN AND ASSOCIATES, INC. Nick Brown, P.E. Senior Project Manager kimley-horn.com 10814 Jollyville Road, Building 4, Suite 200, Austin, TX 78759 512 418 1771 April 10, 2024 ENVIRONMENTAL COMMISSION VARIANCE APPLICATION FORM PROJECT DESCRIPTION Applicant Contact Information Variance Case 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 Watershed Name Watershed Classification Nick Brown 10814 Jollyville Rd Building 4, Suite 200 Austin, TX 78759 737-210-1044 Nick.Brown@kimley-horn.com Stassney Park SPC-2023-0110C Enrique A Maiz-Torres Eric Brown 25-8-301 and 25-8-302 Williamson Creek ☐Urban ☐Water Supply Rural 6200 E Stassney Ln, Austin, TX 78744 X Suburban ☐Water Supply Suburban ☐ Barton Springs Zone City of Austin | Environmental Commission Variance Application Guide 1 April 10, 2024 Edwards Aquifer Contributing Zone Distance to Nearest Classified Waterway 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) Edwards Aquifer Recharge Zone ☐ Barton Springs Segment ☐ Northern Edwards Segment X Not in Edwards Aquifer Zones ☐ Yes X No St Elmo Tributary crosses the southwest corner of the subject property; An unnamed stream bisects the property from north to south. Water and Waste Water service to be provided by Austin Water Utility Request The variance request is as follows: 25-8-301 and 25-8- 302 Construction on Slopes Existing ____0____ ___0_____ ____0____ Proposed 880347.6 sf 20.21 Ac 37.92% The subject property is approximately 53.291 acres in size with frontage on Stassney Lane. The property ranges in elevation from 528 to 617. The highest point on the property is the northwest corner and the lowest point is along the southern property line where St Elmo Tributary exits the property. 91.15% of the property falls within the 0% to 15% slope category. The remainder property has slopes exceeding 15% slope mainly isolated to the existing drainage channels. Grade 0% - 15% 15% - 25% 25% - 35% > 35% Site Area (Sq Yds) 237842.43 10058.85 4676.20 8369.01 260946.50 % of Site Area 91.15% 3.85% 1.79% 3.21% 100.00% There is an assortment of tree species within the site; only five of the identified trees were measured over 24 caliper inches. City of Austin | Environmental Commission Variance Application Guide 2 April 10, 2024 On-site soils include Type D Expansive Clays and is identified as Ferris-Heiden complex, Heiden clay, and Type B Altoga Silty Clay by the USGS web soil survey. There is a new wetland CEF identified in June 2023 located on the Southeast portion of the property most likely resulting from wastewater line construction allowing ground water to surface. Critical Water Quality Zones exist within the site. Ordinance No. 030605-24 permits a roadway and driveway crossing of the Critical Water Quality Zone. Fully developed 25-year and 100-year floodplains exist within the site. The topography of the site is unique in that the unnamed tributary divides the property into an East side and West side. There are multiple constraints that limit the constructable areas such as the CWQZ, existing steep slopes, and offsite flows entering the property. City of Austin | Environmental Commission Variance Application Guide 3 April 10, 2024 Clearly indicate in what way the proposed project does not comply with current Code (include maps and exhibits) FINDINGS OF FACT Per the attached slope analysis, there is construction on slopes greater than 15%. As required in LDC Section 25-8-341, 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. Project: Stassney Park Ordinance: 25-8-341 Cut Requirements & 25-8-342 Fill Requirements Land Use Commission variance determinations from Chapter 25-8-341 and 25-8-342 of the City A. 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 / No 2. The variance: a) Yes / No Numerous other properties along the Burleson Road corridor are developed in a similar manner and fashion as the subject property with large areas of parking and truck courts. At least one of these properties in the nearby vicinity was granted a similar variance to assist in the development of a large warehouse facility at the Park 183 project. 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 Guide 4 April 10, 2024 The existing grades of the subject property would require construction on slopes greater than 15% for any scale or type of commercial development. The conceptual plan presented for review presents a configuration that minimizes the construction on slopes and creek disturbance while limiting impact around the Critical Water Quality Zones. In addition, the grading of the bridge crossing over the unnamed stream that separates the western portion of the subject property from the access on Stassney Lane reduces site impacts related to construction on slopes. Efforts taken to minimize the construction on slopes for these facilities include proposing a singular main drive entering the site, orienting the smallest building over the existing creek on the eastern side of the property, and constructing walls to meet natural grade rather than sloping 3:1. The project will provide significant environmental benefits to mitigate the impact of construction on slopes and to enhance the design of the project including, without limitation: · · · · · · · · State-of-the-art, LEED-certified buildings and site-phased erosion control plans; Reduced building area to adjust grades; Reduced driveway connections to utilize retaining walls in lieu of grading; Enhanced landscaping; Approximately 0.5 mile of offsite-trail connection to regional Austin- to-Manor trail; · Wetland plantings for newly placed wetland; · Proposed rock retaining walls with natural stone look limiting impact to slopes; The applicant will work with staff to review the reflective glass product to ensure it is reducing bird strikes onsite. Improved plantings within creek before and after the bypass culvert Improved plantings around bridge abutments b) Is the minimum deviation from the code requirement necessary to allow a reasonable use of the property; Yes / No The requested variance is the minimum amount necessary to achieve appropriate connectivity and functionality throughout the site while minimizing construction on slopes. The Warehouse Limited Office (W/LO) zoning district permits the warehousing and office type uses that require the large building City of Austin | Environmental Commission Variance Application Guide 5 April 10, 2024 footprints, truck courts, and parking areas. The excessive slopes on the subject property prevent the development of the facilities that serve the use. Approximately 91% of the site has slopes less than 15%. Approximately 1.4% percent of the entire site will require construction on slopes greater than 15%. The project has undergone multiple redesigns and reconfigurations to reduce the amount of construction on slopes and maintain functionality within the site. For example, the driveway entering the site has been reconfigured and regraded, building footprints have been reduced, and internal drives have been removed, all to reduce the amount of construction on slopes. c) Does not create a significant probability of harmful environmental consequences. The proposed slopes on site meet the 3:1 maximum requirement. Where this requirement cannot be met, retaining walls have been placed. The retaining walls and bridge minimize the Limit of Construction encroachment to the CWQZ, additional property, and bisecting creek. Two water quality and detention ponds have been designed to fully capture the runoff created by the proposed improvements and release stormwater to pre-developed conditions flows. One culvert runs through the site to bypass offsite flows. This culvert provides a direct path for the existing flows from the bisecting creek to travel through the site with minimal disturbance to the upstream and downstream areas. 3. Development with the variance will result in water quality that is at least equal to the water quality achievable without the variance. Yes / No Yes / No The proposed design adheres to all water quality requirements outlined within the Land Development Code and Environmental Criteria Manual and as such, will result in water quality that is at least equal to water quality achievable without the variance. Two water quality and detention ponds have been designed to fully capture the runoff created by the proposed improvements and release stormwater to pre-developed conditions flows. One culvert runs through the site to bypass offsite flows and prevent upstream disturbance. Partial biofiltration ponds are proposed with stacked detention to meet the requirements. City of Austin | Environmental Commission Variance Application Guide 6 April 10, 2024 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; N/A to this variance request. The requirement for which a variance is requested prevents a reasonable, economic use of the entire property; 2. 3. N/A to this variance request. N/A to this variance request. The variance is the minimum deviation from the code requirement necessary to allow a reasonable, economic use of the entire property. **Variance approval requires all above affirmative findings. City of Austin | Environmental Commission Variance Application Guide 7 00 100' 200' GRAPHIC SCALE 100' K R A L P R I A 4 4 9 4 K G L O C S 0 , B U D C I F I C I N L O T 2 T I O N 2 A R I- P D O C . N O . 2 T R O P 1 C C S E 7 1 0 T 3 S O U M I S X X D E L O P P E V E D N E : U Z O N I N G : L I- C O - N S D U N A L X TP TP X P T LIMIT OF FULLY DEVELOPED100-YEAR FLOODPLAIN X X T P T P X 10697 10698 T P O F F I C E S P A C E 5 7 , 8 3 4 S F 5 9 2 . 6 0 F F E : B U I L D I N G 5 Z O N I N G L I N E C L S 9 E N 4 T L 4 4 R C 7 2 A L O P M E 3 1 C 1 7 T 0 R L 8 . 9 E V E D 4 E L U M D D O C . N O . 2 O P A C C R A P X TP D U M P S T E R D U M P S T E R X X X X X X X L I - C O - N P W / L O - C O - N P T P X X T P X T P X T P T P 10582 X F.E.M.A. ZONE X (UNSHADED) Z Q W C L I - C O - N P W / L O - C O - N P P T G V A P T Z Q W C G V A P T Z Q W C G V A P T Z Q W C G V A T P T P T P Z Q W C G V A TP Z Q W C G V A T P P T TP TP AVG CWQZ TP BRIDGE OVER CREEK TP Z Q W C G V A P T T P X X TP Z Q W C G V A T P X TP X TP TP X TP X TP L O P D E P E V E D N E : U Z O N I N G : W / L O - C O - N D U S N A L BUILDING 3 87,408 SF FFE:577.00 OFFICE SPACE T P 6022 X X 1 2 6 1 4 7 4 . 7 S I G 0 D N 5 7 N E X D O T 2 1 6 5 8 1 7 3 S I G N B T 4 . 5 0 7 6 2 1 9 3 7 7 5 . 3 0 S I G N 8 3 7 8 8 5 . 3 N S I G 0 1 2 6 E I 1 2 6 9 4 7 0 2 3 . 9 S I G N E 0 D N D O T X E T C N A R T N 7 2 6 9 1 4 . 0 S I G N B M A I N E 0 1 2 6 E E E E H O E E T E T P T P T P P T P T DUMPSTER OFFICE SPACE BUILDING 1 30,048 SF FFE:567.80 EXISTING WETLAND CEF 1 1 O 3 R T 1 2 6 2 4 1 6 0 1 . 9 N M E 0 S I G W W D D E H O P T 1 2 5 4 3 4 4 2 5 . 9 S I G N E N D 9 E S A E S I G N B W O O D / F O R L 3 2 6 . 6 4 9 7 9 1 2 5 D 1 4 S I G N R O U G H R O A 1 5 . 9 9 1 8 1 2 5 D N G N A I L E 1 2 5 7 0 4 4 . 6 G U 9 9 R 3 A D R D E T A C I D E D Y B T N E E R M E E S A H E R . W E B I F O C . I R R T C E L E P T . 6 9 2 . 1 1 2 3 5 9 1 2 L A I R E A C I R T C E L E ' 5 1 C I R T C E L E , N O I T U B I R T S I D D N A , S N O I T A C I N U M M O C E L E T A I L N G 1 2 5 3 4 R 9 9 3 3 . 4 G U 9 A D R X G U A R D R A I L N G T P D I I E H O A I L N G 1 2 5 6 R 2 4 3 9 . 3 G U 8 0 A D R X A I L N G 1 2 5 0 4 3 6 . 8 8 A G U 8 D R 8 R D D P T A I L B N G 1 2 5 3 7 R 9 3 3 4 . 6 G U 8 A D R E H O E N A L Y E N S S A T S E . H E O ) S E I R A V H T D I W W O . R ( . . 7 3 . 5 S I G N T D O T D I R T I O N C X E S 5 7 7 2 1 2 1 9 D E T A C I D E D Y B E R E H . W O . R . D E H O D D N G N A I L E 1 2 5 9 3 1 1 . 0 G U 6 A 9 9 R D R D S A I L N G 1 2 5 2 3 1 7 . 4 G U 5 9 R 4 A D R 2 1 1 1 3 3 . 6 G U A R D R A I L B 2 5 1 5 TP TP TP TP E N C E E N D 0 E D W I R E F 8 4 2 7 . 8 A R B 8 5 0 5 B D W I R 6 7 . 8 R A 8 4 0 5 5 B 9 E 9 B E N G C N E E F X E B C N E E F D W I R 7 E 5 B 8 0 5 3 6 . 7 R A 5 0 B D D 5016 H TP L O P D E P E V E D N E : U Z O N I N G : W / L O - C O - N D U S N A L APPROXIMATE LIMIT OF F.E.M.A. 100-YEAR FLOODPLAIN L D U M P S T E R OFFICE SPACE D U M P S T E R T P APPROXIMATE LIMIT OF COA 100-YEAR FLOODPLAIN TP TP TP P T TP TP TP TP APPROXIMATE LIMIT OF F.E.M.A. 100-YEAR FLOODPLAIN APPROXIMATE LIMIT OF COA 100-YEAR FLOODPLAIN TP TP TP TP T P TP TP P T BUILDING 2 55,944 SF FFE:561.00 L APPROXIMATE LIMIT OF COA 100-YEAR FLOODPLAIN APPROXIMATE LIMIT OF F.E.M.A. 100-YEAR FLOODPLAIN 11003 T P O F F I C E S P A C E 8 1 , 8 2 8 S F 5 8 2 . 7 0 F F E : B U I L D I N G 4 D U S Z N A L G R I N U T C O - N P A F U N G : L I- C 6 2 8 . 0 H U C O . 2 P O D 4 E E T B I O C . N O R C A I N 7 1 0 C 1 A S 1 T 0 R E : M A N I N A L X L D O C E S C . 7 0 1 8 STASSNEY PARK SLOPE ANALYSIS Austin, Texas April 10, 2024 DWG NAME LAST SAVED K:\AUS_CIVIL\BROOKFIELD\067806217 - STASSNEY PARK\CAD\EXHIBITS\PLANSHEETS\STASSNEY SLOPE ANALYSIS 2024.04.10.DWG 4/10/2024 1:32 PM 10814 Jollyville Road Campus IV, Suite 200 Austin, TX 78759 512-418-1771 State of Texas Registration No. F-928 NOTE: THIS PLAN IS CONCEPTUAL IN NATURE AND HAS BEEN PRODUCED WITHOUT THE BENEFIT OF A SURVEY, TOPOGRAPHY, UTILITIES, CONTACT WITH THE CITY, ETC.  Case No.: (City use only) Environmental Resource Inventory For the City of Austin Related to LDC 25-8-121, City Code 30-5-121, ECM 1.3.0 & 1.10.0 The ERI is required for projects that meet one or more of the criteria listed in LDC 25-8-121(A), City Code 30-5-121(A). 1. SITE/PROJECT NAME: Stassney Lane 2. COUNTY APPRAISAL DISTRICT PROPERTY ID (#’s): 897007; 897009 3. ADDRESS/LOCATION OF PROJECT: 6200 Block East Stassney Lane, Austin, Texas 78744 4. WATERSHED: Williamson Creek 5. THIS SITE IS WITHIN THE (Check all that apply) Edwards Aquifer Recharge Zone* (See note below) .................. YES No Edwards Aquifer Contributing Zone*.................................. YES No Edwards Aquifer 1500 ft Verification Zone* ....................... YES No Barton Spring Zone* .......................................................... YES No *(as defined by the City of Austin – LDC 25-8-2 or City Code 30-5-2) Note: If the property is over the Edwards Aquifer Recharge zone, the Hydrogeologic Report and karst surveys must be completed and signed by a Professional Geoscientist Licensed in the State of Texas. 6. DOES THIS PROJECT PROPOSE FLOODPLAIN MODIFICATION?.......YES** NO If yes, then check all that apply:     (1) The floodplain modifications proposed are necessary to protect the public health and safety; (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 (3) The floodplain modifications proposed are necessary for development allowed in the critical water quality zone under LDC 25-8-261 or 25-8-262, City Code 30-5-261 or 30-5-262. (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 for forms and guidance) unless conditions 1 or 3 above apply. 7. IF THE SITE IS WITHIN AN URBAN OR SUBURBAN WATERSHED, DOES THIS PROJECT PROPOSE A UTILITY LINE PARALLEL TO AND WITHIN THE CRITICAL WATER QUALITY ZONE? ......................................................... YES*** NO ***If yes, then riparian restoration is required by LDC 25-8-261(E) or City Code 30-5-261(E) and a functional assessment must be completed and attached to the ERI (see ECM1.5 and Appendix X for forms and guidance). 8. There is a total of 0 (#’s) Critical Environmental Feature(s)(CEFs) on or within150 feet of the project site. If CEF(s) are present, attach a detailed DESCRIPTION of the CEF(s), color PHOTOGRAPHS, the CEF WORKSHEET and provide DESCRIPTIONS of the proposed CEF buffer(s) and/or wetland mitigation. Provide the number of each type of CEFs on or within 150 feet of the site (Please provide the number of CEFs ):  0 0 (#’s) Spring(s)/Seep(s) (#’s) Point Recharge Feature(s) 0 (#’s) Bluff(s) (#’s) Canyon Rimrock(s) (#’s) Wetland(s) 0 0 Note: Standard buffers for CEFs are 150 feet, with a maximum of 300 feet for point recharge features. Except for wetlands, if the standard buffer is not provided, you must provide a written request for an administrative variance from LDC 25-8-281(C)(1) and provide written findings of fact to support your request. Request forms for administrative variances from requirements stated in LDC 25-8-281 are available from Watershed Protection Department. 9. The following site maps are attached at the end of this report (Check all that apply and provide): All ERI reports must include:  Site Specific Geologic Map with 2-ft Topography    Historic Aerial Photo of the Site Site Soil Map Critical Environmental Features and Well Location Map on current Aerial Photo with 2-ft Topography Only if present on site (Maps can be combined):  Edwards Aquifer Recharge Zone with the 1500-ft Verification Zone (Only if site is over or within 1500 feet the recharge zone)     Edwards Aquifer Contributing Zone Water Quality Transition Zone (WQTZ) Critical Water Quality Zone (CWQZ) City of Austin Fully Developed Floodplains for all water courses with up to 64-acres of drainage 10. HYDROGEOLOGIC REPORT – Provide a description of site soils, topography, and site specific geology below (Attach additional sheets if needed): Surface Soils on the project site is summarized in the table below and uses the SCS Hydrologic Soil Groups*. If there is more than one soil unit on the project site, show each soil unit on the site soils map. Soil Series Unit Names, Infiltration Characteristics & Thickness *Soil Hydrologic Groups Definitions (Abbreviated) Soil Series Unit Name & Subgroup** Altoga silty clay, 3 to 6 percent slopes (AgC2), Typic Ustochrepts Group* Crockett soils, 2 to 5 percent slopes (CsC2), Udertic Paleustalfs Ferris-Heiden complex, 8 to 20 percent slopes (FhF3), Udorthentic Chromusterts and Udic Chromusterts Lewisville silty clay, 2 to 5 percent slopes (LcB), Typic Haplustolls Patrick soils, 2 to 5 percent slopes (PaC), Typic Calciustolls Thickness (feet) 0 to >6.5 0 to 5 0 to 5 0 to >6.5 0 to >6.5 C D D B B A. Soils having a high infiltration rate when thoroughly wetted. B. Soils having a moderate infiltration rate when thoroughly wetted. C. Soils having a slow infiltration rate when thoroughly wetted. D. Soils having a very slow infiltration rate when thoroughly wetted. **Subgroup Classification – See Classification of Soil Series Table WPD ERM ERI-2014-01 Page 2 of 6  Description of Site Topography and Drainage (Attach additional sheets if needed): The overall topography of the Site was illustrated with slopes oriented northwest-to-southeast toward the southwestern drainage. Multiple areas with “U-” or “V-shaped” contours were present on the hillslopes, suggesting the presence of confined flow. The elevation of the property was between approximately 530 feet and 630 feet above mean sea level (amsl). List surface geologic units below: Geologic Units Exposed at Surface Group Taylor Group Formation Ozan (Sprinkle) Formation Member Quaternary High Gravel Deposits Quaternary High Gravel Deposits Brief description of site geology (Attach additional sheets if needed): The project area is located within the Northern Blackland Prairie ecoregion. The Northern Blackland Prairie is distinguished from surrounding regions by the gently rolling hills and fine-textured, black, clay soils that primarily support prairie vegetation (Griffith et al. 2007). Vertisols dominate the Blackland Prairie ecoregion and consist of high clay content soils with significant shrink-swell potential. Soils in this area are underlain by the Ozan Formation (Ko) and high gravel deposits (Qhg; Proctor et al 1979; USGS 2021; see Geology Map). The Ozan Formation is characterized by gray calcareous clay, silt, and sand (USGS 2021). High gravel deposits within the Austin Sheet feature minor quartzite, milky quartz, sandstone, and mudstone underlying silty clays (Proctor et al. 1979). Griffith, Glenn, Sandy Bryce, James Omernik, and Anne Rogers 2007 Perry, E., F. Schmidt, J. Calvert, M. David, J. Corbett, V. Chandler 1974 2021). U.S. Geological Survey (USGS) 2021 U.S. Department of the Interior Mineral Resources On-Line Spatial Data Website. http://mrdata.usgs.gov/sgmc/tx.html (accessed January 2021). Texas Archeological Sites Atlas. 41TV1284 Archeological Site Form. http://atlas.thc.texas.gov/ (accessed January Ecoregions of Texas. Texas Commission on Environmental Quality, Austin. Wells – Identify all recorded and unrecorded wells on site (test holes, monitoring, water, oil, unplugged, capped and/or abandoned wells, etc.): There are 0 (#) wells present on the project site and the locations are shown and labeled 0 0 0 (#’s)The wells are not in use and have been properly abandoned. (#’s)The wells are not in use and will be properly abandoned. (#’s)The wells are in use and comply with 16 TAC Chapter 76. There are 0 (#’s) wells that are off-site and within 150 feet of this site. WPD ERM ERI-2014-01 Page 3 of 6  11. THE VEGETATION REPORT – Provide the information requested below: Brief description of site plant communities (Attach additional sheets if needed): The survey area was an undeveloped, vacant property with sporadic cleared areas dominated by woody encroachment throughout previous agricultural pastures. Three vegetation communities were identified: live oak/ Ashe juniper stand, forested upland, and forested riparian corridor. The live oak / Ashe juniper stand was recently cleared, leaving sporadic residual overstory trees and a relatively open midstory/understory. The live oak / Ashe juniper stand was dominated by an overstory of live oak (Quercus virginiana) and Ashe juniper (Juniperus ashei) with sporadic cedar elm (Ulmus crassifolia) trees and an understory of Japanese privet (Ligustrum japonicum), Chinese privet (Ligustrum sinense), saw greenbrier (Smilax bona-nox), and silver bluestem (Bothriochloa saccharoides). The forested upland community was dominated by an overstory of Ashe juniper, sugarberry (Celtis laevigata), cedar elm, honey mesquite (Prosopis glandulosa), and Osage-orange (Maclura pomifera) trees, with a midstory/understory comprised of Japanese privet, Chinese privet, King Ranch bluestem (Bothriochloa ischaemum), silver bluestem, Bermudagrass (Cynodon dactylon), Johnsongrass (Sorghum halepense), saw greenbrier, and southern dewberry (Rubus trivialis). The forested riparian corridor community was dominated overstory of American elm (Ulmus americana), green ash (Fraxinus pennsylvanica), cedar elm, and sugarberry with sporadic Ashe juniper trees. The midstory/understory was relatively open, comprised of sporadic Japanese privet, Chinese privet, and saw greenbrier. There is woodland community on site ............................. YES  NO (Check one). If yes, list the dominant species below: Woodland species Common Name Ashe juniper cedar elm American elm sugarberry green ash Scientific Name Juniperus ashei Ulmus crassifolia Ulmus americana Celtis laevigata Fraxinus pennsylvanica There is grassland/prairie/savanna on site ................... YES NO (Check one). If yes, list the dominant species below: Grassland/prairie/savanna species Common Name Scientific Name There is hydrophytic vegetation on site ....................... YES  NO (Check one). If yes, list the dominant species in table below (next page): WPD ERM ERI-2014-01 Page 4 of 6  Hydrophytic plant species Common Name Scientific Name black willow Salix nigra Wetland Indicator Status FACW A tree survey of all trees with a diameter of at least eight inches measured four and one- half feet above natural grade level has been completed on the site. YES  NO (Check one). 12. WASTEWATER REPORT – Provide the information requested below. On-site system(s) Wastewater for the site will be treated by (Check of that Apply):    City of Austin Centralized sewage collection system Other Centralized collection system Note: All sites that receive water or wastewater service from the Austin Water Utility must comply with City Code Chapter 15-12 and wells must be registered with the City of Austin The site sewage collection system is designed and will be constructed to in accordance to all State, County and City standard specifications. YES  NO (Check one). Calculations of the size of the drainfield or wastewater irrigation area(s) are attached at the end of this report or shown on the site plan.  YES  NO  Not Applicable (Check one). Wastewater lines are proposed within the Critical Water Quality Zone?  YES  NO (Check one). If yes, then provide justification below: WPD ERM ERI-2014-01 Page 5 of 6 Is the project site is over the Edwards Aquifer?  YES NO (Check one). If yes, then describe the wastewater disposal systems proposed for the site, its treatment level and effects on receiving watercourses or the Edwards Aquifer. 13. One (1) hard copy and one (1) electronic copy of the completed assessment have been provided. Date(s) ERI Field Assessment was performed: 01/15/2021 Date(s) My signature certifies that to the best of my knowledge, the responses on this form accurately reflect all information requested. Nicholas Schiwitz Print Name Signature 214-998-3029 Telephone nschiwitz@intenvsol.com Email Address Integrated Environmental Solutions, LLC. Name of Company 03/16/2021 Date For project sites within the Edwards Aquifer Recharge Zone, my signature and seal also certifies that I am a licensed Professional Geoscientist in the State of Texas as defined by ECM 1.12.3(A). P.G. Seal WPD ERM ERI-2014-01 Page 6 of 6 City of Austin Environmental Resource Inventory - Critical Environmental Feature Worksheet Project Name: Project Address: Site Visit Date: Stassney Lane 01/15/2021 03/12/2021 Environmental Resource Inventory Date: 6200 Block East Stassney Lane, Austin, Texas 78744 5 6 7 8 Primary Contact Name: Phone Number: Prepared By: Email Address: Nicholas Schiwitz 214-998-3029 Nicholas Schiwitz nschiwitz@intenvsol.com FEATURE TYPE {Wetland,Rimrock, Bluffs,Recharge Feature,Spring} FEATURE ID (eg S-1) FEATURE LONGITUDE (WGS 1984 in Meters) FEATURE LATITUDE (WGS 1984 in Meters) WETLAND DIMENSIONS (ft) RIMROCK/BLUFF DIMENSIONS (ft) coordinate notation coordinate notation X Y Length Avg Height RECHARGE FEATURE DIMENSIONS Z Y Trend X Springs Est. Discharge cfs 1 2 3 4 9 City of Austin Use Only CASE NUMBER: For rimrock, locate the midpoint of the segment that describes the feature. For wetlands, locate the approximate centroid of the feature and the estimated area. For a spring or seep, locate the source of groundwater that feeds a pool or stream. Please state the method of coordinate data collection and the approximate precision and accuracy of the points and the unit of measurement. Method GPS Accuracy sub-meter  □ □ Surveyed Other  □ □ meter > 1 meter Professional Geologists apply seal below WPD ERM ERI-CEF-01 Page 7 of 8 Qhg Ko Qhg Geologic Map Stassney Lane City of Austin Travis County, Texas 1 in = 500 feet Feet 0 500 File Ref. Date: 04.338.005 3/12/2021 - Qt Survey Area 150-foot Buffer Geologic Formation - Central Texas Ko - Ozan Formation Qhg - high gravel deposits LcB AgC2 LcB LcB BsA BsB CsC2 HnA LcA PaC AgC2 GP LcB FhF3 PaC HnA HnC2 HnB HeC2 HeD2 LcB LcB HnA Fr Soils Map Stassney Lane City of Austin Travis County, Texas 1 in = 500 feet Feet 0 500 File Ref. Date: 04.338.005 3/12/2021 - Survey Area 150-foot Buffer Soil Map Units AgC2 - Altoga silty clay, 3 to 6 percent slopes, moderately eroded CsC2 - Crockett soils, 2 to 5 percent slopes, eroded FhF3 - Ferris-Heiden complex, 8 to 20 percent slopes, severely eroded LcB - Lewisville silty clay, 1 to 3 percent slopes PaC - Patrick soils, 2 to 5 percent slopes Soil map units outside survey area Legend Contours Year- 2017 2 Ft Contours 10 Ft Contours 0.2 03/12/2021 NAD_1983_StatePlane_Texas_Central_FIPS_4203_Feet 0 0.08 0.2 Miles 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. 1: 4,800 Notes Topographic map with 2 foot contour intervals Legend Image High : 255 Low : 0 0.2 03/12/2021 NAD_1983_StatePlane_Texas_Central_FIPS_4203_Feet 0 0.08 0.2 Miles 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. 1: 4,800 Notes 1984 Historic Aerial Map Texas Water Development Board Well Report Sites March 11, 2021 The d ata in Wa te r D a ta In ter ac ti ve re pr es en ts th e b e st a va il ab le i nfo rm ati on p ro vid e d b y th e TW D B a nd thi rd -p a rty co o pe ra to rs o f th e TW D B. The TWD B p ro vi de s i n fo rm a ti o n v ia thi s w eb si te a s a pu b li c se rv ice . N ei the r th e S tate of Te xa s n o r the TWD B a ss u me s a ny le g al li ab il ity or r es po n si bi li ty or ma ke s a n y gu a ra nte e s o r w ar ran ti es a s to the a ccu ra cy, co mp l ete n es s o r su ita b ili ty o f th e in for ma tio n fo r a n y pa rti cu la r p u rpo se . The TWD B s yste ma tic a lly re vis e s or r em o ve s d ata d isc ov er ed to b e in co rre ct. If y ou fin d in a ccu ra te i n fo rm a ti o n o r h av e q u es tio n s, pl e as e c on ta ct WD I- Su p po rt @ tw d b .te xa s.g o v. Well Reports 0 0 0.15 0.3 0.25 0.5 1:18,056 0.6 mi 1 km Source: Esri, Maxar, GeoEye, Earthstar Geographics, CNES/Airbus DS, USDA, USGS, AeroGRID, IGN, and the GIS User Community TEXAS WATER DEVELOPMENT BOARD Critical Environmental Features Map Stassney Lane City of Austin Travis County, Texas 1 in = 325 feet Feet 0 325 File Ref. Date: 04.338.005 3/12/2021 - Survey Area 150-foot Buffer *No Critical Environmental Features were identified within the Survey Area and 150-foot buffer* Page 1 April 10, 2024 City of Austin Development Services Department 505 Barton Springs Road Austin, Texas 78704 Re: Environmental Variance Request Letter Stassney Park 6200 E Stassney Ln Austin TX, 78744 Please accept this Environmental Variance Request Letter for the above-mentioned project. A Environmental Variance for construction on slopes greater than 15% is being requested on this site due to site and design constraints. The Stassney Park project proposes five industrial buildings on the site located at 6200 E Stassney Ln. The site is within the Full-Purpose City Limits of the City of Austin in Travis County, Texas. This site is within the Williamson Creek Watershed, which is classified as a Suburban Watershed and a portion is located in the Federal Emergency Management Agency’s 100-year floodplain per 48453C0605K for Travis County, Texas and Incorporated Areas, dated January 22, 2020. This site is not located in the Edwards Aquifer Recharge Zone. Design constraints pertaining to industrial development include, two (2) creeks running north/south through the property. One located near the eastern side adjacent to Stassney Lane, and the other traversing the middle of the property. The one through the middle of the property has a Critical Water Quality Zone associated with it, but the eastern one does not. To mitigate impact to the slopes greater than 15% located on the middle tributary, a bridge is proposed. The bridge will span the 100-year storm water surface elevation to maintain existing drainage patterns through the tributary. In addition to the bridge, enhanced plantings are proposed around the bridge abutments. These plantings will help reduce erosion. Due to the nature of the development with large single story buildings with truck courts, we are proposing development on the 15% slopes associated with the eastern tributary. Impacts to the tributary have been reduced throughout the permitting process to limit crossings and improvements. The existing drainage will be conveyed through the property with an underground storm pipe. Vegetation enhancements to the upstream and downstream areas of the storm bypass are being proposed. These plantings and enhancements will help reduce stormwater velocity and mitigate erosion. In addition to the items listed above, the following environmental benefits have been provided with this site: · Retaining walls limiting LOC where needed · Providing more Avg CWQZ than existing conditions require · Maintaining understory trees outside of LOC · Parkland dedication along south side of property line · LEED certified buildings · Reduced driveway connections to minimize construction on slopes · Construction of bridge over CWQZ and creek to access western portion of property in lieu of culverts kimley-horn.com 10814 Jollyville Road, Building 4, Suite 200, Austin, TX 78759 512 418 1771 Page 2 · · Improved plantings in creek area before and after bypass culvert Improved plantings in CWQZ around bridge abutments If you have any questions or comments regarding this request, please contact me at 737-210-1044. Sincerely, KIMLEY-HORN AND ASSOCIATES, INC. Nick Brown, P.E. Senior Project Manager kimley-horn.com 10814 Jollyville Road, Building 4, Suite 200, Austin, TX 78759 512 418 1771