DEPARTMENT: Development Services
SUBJECT: TPV 18-022 Tree Preservation Variance for Overlook Town Center Off-Site Sanitary Sewer
SUMMARY:
Request by Mr. Jose Canty, P.E., for approval of a tree preservation variance request from Unified Development Code 35-523 (h), “significant trees shall be preserved at eighty (80) percent and heritage trees at one hundred (100) percent preservation within both the 100-year floodplains and environmentally sensitive areas.” Staff recommends approval. (Herminio Griego, (210) 207-6042, herminio.griego@sanantonio.gov, Development Services Department)
BACKGROUND INFORMATION:
Project A/P# 2321303
Council District: Outside City Limits
Consultant: Jose Cantu, P.E. of 6S Engineers
Staff Coordinator: Herminio Griego, Assistant City Arborist, (210) 207-6042
ANALYSIS:
The Development Services Department (DSD) has reviewed the information presented in Mr. Jose Cantu’s letter dated June 5, 2018.
The Unified Development Code (UDC) - Article V, Section 35-523 (h), 100-Year Floodplain(s) and Environmentally Sensitive Areas states that, “Significant trees shall be preserved at eighty (80) percent preservation within both the 100-year floodplains and environmentally sensitive areas. Heritage trees shall be preserved at one hundred (100) percent preservation within both the 100-year floodplains and environmentally sensitive areas. Mitigation shall be prohibited in floodplains and environmentally sensitive area except when a variance is granted by the Planning Commission.”
The applicant is requesting a Variance Request to mitigate for removal of significant trees within the 100-year floodplain in excess of the 80% minimum preservation of significant trees in place under the 2010 Tree Preservation Ordinance for construction of an off-site sewer for Overlook Town Center project. DSD staff does agree with the applicant’s request to mitigate for significant trees below 80% preservation for the following reasons:
1. Tree Preservation - Due to the proposed scope of work, the project is unable to preserve the minimum 80% of significant trees within the 100-year floodplain. The alignment shown on the proposed plans was the most feasible location to tie into an existing manhole with a gravity main, and maintain minimum cover beneath Elm Waterhole Creek. This alignment is located within the 100 year floodplain of Elm Waterhole Creek. The construction of the main would require removal of significant trees within the proposed and temporary easements. With the current alignment 70% of trees would be preserved, however, this is below the 80% requirement for floodplain preservation. Additional measures will be taken to protect remaining existing trees during construction. Trenchless methods of construction such as pipe boring will be utilized to minimize the impact to the root protection zone for nearby heritage trees located adjacent to the easement. The required mitigation for falling below 80% preservation is 101 inches.
2. Tree mitigation - A total of 101 diameter inches of trees will be mitigated by paying in to the Tree Mitigation Fund $20,200.00 (101 inches x $200 per inch). In addition, the contractor will be required to seed all disturbed areas with a native rural grass seed mix per TXDOT Specification Item 164. Where trees have been removed, the contractor is required to forgo using hydromulching in favor of a more robust drilled seed method to establish the native seed mix.
DSD staff supports the applicant’s request to mitigate for significant trees below 80% preservation requirements based on the conditions of the site, design constraints, and exceeding mitigation requirements. The proposed Variance Request meets the intent and spirit of the Tree Ordinance therefore, staff recommends approval.