20240918-002: Williamson Creek Interceptor Staff Presentation — original pdf

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Williamson Creek Interceptor SP-2022-1368D Located between 5111 S. 1st Street and 5404 E. William Cannon Drive along Williamson Creek Brad Jackson Environmental Compliance Specialist Senior Development Services Department 2 Property Data  Williamson Creek Watershed  Suburban Watershed Classification  Desired Development Zone  Not located over Edwards Aquifer Recharge Zone  Approximately 3.5-mile-long wastewater interceptor 3 Synopsis  Project proposes replacement of existing 36-inch and 42-inch wastewater interceptors with a new 72-inch interceptor  Interceptor will be constructed by tunnel boring methods with limited surface disturbance  20 “Cutover” connections proposed to new interceptor Variance Requests 4 To allow development in the CWQZ for a wastewater interceptor per LDC 25-8-261 To allow cut up to 9 feet for removal of a building foundation per LDC 25-8-341 Interceptor Overview 5 Interceptor Overview 6 Interceptor Overview 7 Interceptor Overview 8 Interceptor LOC and Slope Map 9 Interceptor LOC and Slope Map 10 Interceptor LOC and Slope Map 11 Interceptor LOC and Slope Map 12 Interceptor LOC and Slope Map 13 Variance Recommendation 14 Staff recommends the variances, having determined that the required findings of fact have been met. Staff also recommends and supports the following five conditions: 1. Payment into the Water Supply Mitigation Fund as per Appendix Q-7: Riparian Zone Mitigation of the ECM in the amount of $606,850 for 15.7 acres of required mitigation for a utility line installed parallel to a creek centerline. 2. All areas of the Limits of Construction (LOC) within the CWQZ will be restored with 609S Native Seeding and Planting per restoration plan sheets. Variance Recommendation & Conditions Continued 15 3. Previously identified portions of the exposed infrastructure for the existing and to be abandoned wastewater interceptor will be removed from the CWQZ and restored to natural conditions as per approved plans. 4. The abandoned wastewater interceptor diversion building will be demolished and the hill underneath it will be removed to provide additional floodwater storage and a consistent grade for the CWQZ and restoration of the riparian area at S. Pleasant Valley Road and Williamson Creek. 5. An odor control facility will be installed as part of the project to reduce impacts to adjacent properties. Access Shaft Site and Odor Control Facility 16 17 Portions of project located within the Williamson Creek Greenbelt and Parkland Williamson Creek Interceptor Route Restoration Plans 18 Restoration Plans 19 Location of Cut Variance Restoration Plans 20 Restoration Plans 21 Restoration Plans 22 23 THANK YOU