DEPARTMENT: Development Services
SUBJECT: TPV 17-013 Tree Preservation Variance for Stillwater Ranch Phase 3 MDP
SUMMARY:
Request by Mr. Jon Robinson, 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.” Due to existing site conditions, design and layout constraints, and the contractor not following the previously approved tree plan, the project is unable to preserve the minimum 80% of significant trees within the Environmentally Sensitive Area (ESA). The required mitigation for the Environmentally Sensitive Area will be met by planting 29, 3”-4” trees back within the environmentally sensitive area and installing Low Impact Development features throughout the site. (Herminio Griego, (210) 207-6042, herminio.griego@sanantonio.gov, Development Services Department)
BACKGROUND INFORMATION:
Project A/P# 2105096
Council District: Outside City Limits
Consultant: Jon Robinson of Horizon Design
Staff Coordinator: Herminio Griego, Assistant City Arborist, (210) 207-6042
ANALYSIS:
The Development Services Department (DSD) has reviewed the information presented in Mr. Jon Robinson’s letter dated June 27, 2017.
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 floodplain 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 trees in excess of the 80% significant tree within the environmentally sensitive area in place under the 2015 Tree Preservation Ordinance for construction of Stillwater Ranch Phase 3 Subdivision. DSD staff does agree with the applicant’s request to mitigate for significant below 80% preservation for the following reasons:
1. Existing site conditions - Due to existing site conditions, design and layout constraints, and the contractor not following the previously approved tree plan, the project is unable to preserve the minimum 80% of significant trees within the Environmentally Sensitive Area (ESA). The ESA located onsite is a 30’ riparian buffer parallel to the current floodplain limits. Only 47.4% of the ESA can be preserved due to the grading required to prepare and level the site for the new residential lots and roads servicing the development.
2. Low Impact Development Features - Vegetative Filter Strips will provide a total of 435.5 inches of Tree Mitigation that will be applied to the Environmentally Sensitive Area preservation shortfall. Vegetative Filter Strips are designed to provide pretreatment of runoff generated from impervious areas such as roads and highways. They are implemented for improving stormwater quality and reducing runoff flow velocity.
3. Tree mitigation and canopy diversity - In addition to the Vegetated Filter Strips, 29 proposed 3”- 4” trees will be planted back within the ESA. These trees will raise the post-development preservation in the ESA from 47.4% back to the initially approved 93.9% and will help alleviate adverse impacts from the removal of ESA required to prepare and level the site. The proposed planting plan provides added species diversity to include medium to large native tree species per Appendix E “San Antonio Recommended Plant List.” Recommended trees proposed to be planted for mitigation include: Live Oak, Mexican Sycamore, Burr Oak, Chinquapin Oak, and Cedar Elm.
DSD staff supports the applicant’s request to fall below 80% of the tree preservation requirements in the Environmentally Sensitive Area (ESA) based on the conditions of the site, design constraints, and exceeding mitigation and canopy requirements. The proposed Variance Request meets the intent and spirit of the Tree Ordinance therefore, staff recommends approval.