20210120-003d: Blue Bluff at Wildhorse Ranch C8-2020-0033 staff presentation — original pdf

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Pamela Abee-Taulli Environmental Review Specialist Senior Development Services Department BLUE BLUFF AT WILDHORSE RANCH 10621 BLUE BLUFF RD C8-2020-0033 PROJECT LOCATION Site Location Austin ETJ Austin City Limits Edwards Aquifer Recharge Zone Edwards Aquifer Contributing Zone This product is for informational purposes and may not have been prepared for or be suitable for legal, engineering, or surveying purposes. It does not represent an on-the- ground survey and represents only the approximate relative location of property boundaries. This product has been produced by the Watershed Protection Department for the sole purpose of geographic reference. No warranty is made by the City of Austin regarding specific accuracy or completeness. 0510Miles[PROPERTY DATA • Gilleland Creek Watershed • Suburban Classification • Desired Development Zone • Full Purpose Jurisdiction • Critical Water Quality Zone & Water Quality Transition Zone • Council District 1 [DEVELOPMENT DATA • Comprehensive Watershed Ordinance • Wildhorse Planned Unit Development Agreement (PUD) • The PUD requires buffers for waterways draining 64-320 ac.: • CWQZ (boundary coincides with the 100-year floodplain, except that the minimum width is 50’ from centerline) • WQTZ (50’) • Waterway buffers: • Major waterway buffer for Gilleland Creek • Minor waterway for tributary of Gilleland Creek (per PUD) • Slopes > 15% VARIANCE REQUEST • Vary from 25-8-341 to cut to 15 feet • Vary from 25-8-342 to fill to 15 feet FINDINGS OF FACT (1) Blue Bluff Rd. Buffers & Floodplain (1) The requirement will deprive the applicant of a privilege available to owners of other similarly situated property with approximately contemporaneous development subject to similar code requirements; ✓Grading variances have been deemed appropriate under similar development circumstances for sites with multiple constraints. Constraints of this site include pronounced changes in elevation, an adjacent existing roadway to which the development must connect, and the fact that approximately one third of the property consists of creek buffers, floodplain, & greenways. Greenways Property line [FINDINGS OF FACT (2)(A) (2) The variance: (a) is not necessitated by the scale, layout, construction method, or other design decision made by the applicant, unless the design decision provides greater overall environmental protection than is achievable without the variance; ✓The site elevation drops off to the east of existing Blue Bluff Rd., making it a challenge to meet Transportation Criteria Manual vertical roadway design criteria and to provide for accessible routes and crossings in compliance with the Americans with Disabilities Act. ✓Multiple rain gardens and ponds are proposed so that the site does not have to be severely leveled to achieve drainage to the main, biofiltration pond. 3 Rain Gardens 3 Water Quality / Detention Ponds Property line Property line [FINDINGS OF FACT (2)(B) Retaining Walls (2) The variance: (b) is the minimum deviation from the code requirement necessary to allow a reasonable use of the property; ✓The roadway network within the proposed single-family subdivision has been designed to minimize the number of cross streets in order to reduce the amount of cut and fill and to maintain compliance with the Transportation Criteria Manual block-length requirement. ✓At staff request, the applicant has decreased the length of some lots, decreasing the area that needs to be leveled, and terraced some lots, reducing the steepness of fill. They have also increased the number of retaining walls to minimize the footprint of grading. Terracing Property line [FINDINGS OF FACT (2)(C) (2) The variance: (c) does not create a significant probability of harmful environmental consequences; ✓With appropriate erosion and sedimentation controls provided in accordance with Code and Criteria, the proposed cut and fill can be managed during construction, despite the slopes and proximity to waterways. Neither will the completed project create a probability of harmful environmental consequences. FINDINGS OF FACT (3) (3) Development with the variance will result in water quality that is at least equal to the water quality achievable without the variance. ✓Water quality for the completed project will be code compliant and equal to the water quality achievable without the variance. STAFF DETERMINATION & CONDITIONS Staff determines that the findings of fact have been met. The Applicant will protect three natural, unclassified drainages. These small waterways with less than 64 acres of drainage will be preserved in a natural state with foot-path trails for pedestrian access to the Critical Water Quality Zone buffers for an unnamed tributary of Gilleland Creek and for Gilleland Creek. Development within these drainage areas will be limited to park amenities such as trails and trail appurtenances (buildings and parking will not be allowed). Greenways