DEPARTMENT: Development Services
SUBJECT: TPV 19-019 Tree Preservation Variance for SAWS E-20 Wurzbach Parkway Segment 1
SUMMARY:
Request by Mr. Kendall NeSmith, 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”, general located off of Nacogdoches Road and Salado Cliff Drive. Staff recommends approval. (Herminio Griego, (210) 207-6042, herminio.griego@sanantonio.gov <mailto:herminio.griego@sanantonio.gov>, Development Services Department)
BACKGROUND INFORMATION:
Project A/P# 2458102
Council District: 10
Consultant: Kendall NeSmith, P.E. with Kimley-Horn and Associates
Staff Coordinator: Herminio Griego, Assistant City Arborist, (210) 207-6042
ANALYSIS:
The Development Services Department (DSD) reviewed the information presented in Mr. Kendall NeSmith letter dated April 2, 2019.
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 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 to mitigate for removal of surveyed trees within the 100-year floodplain below the minimum preservation of protected significant and heritage trees in place under the 2015 Tree Preservation Ordinance for the installation of the San Antonio Waster System E-20 Wurzbach Parkway Segment 1 sanitary sewer line (the Project). DSD staff does agree with the applicant’s request to mitigate via enhanced revegetation and paying into the Tree Mitigation Fund for the removal of tree survey inches determined to be below 80% significant and 100% heritage tree preservation for the following reasons:
1. Existing site conditions: The project is comprised of constructing 13,350 linear feet of 54 inch diameter sanitary sewer line encompassing a project area of 804,672 square feet (18.5 acres). The sewer line crosses upland, environmentally sensitive and floodplain areas. Multiple alignments and construction techniques were evaluated to minimize impacts to significant and heritage trees before selecting the final design. The project includes boring 1,300 feet to avoid tree impacts. However, since this is a sewer line replacement project some impacts were unavoidable.
2. Due to existing site conditions, the size of the sewer line, design constraint’s and the aliment of the original sewer line through floodplain areas the Project is unable to preserve the minimum 80% of significant and 100% of heritage trees surveyed within the Project boundary. Significant and heritage tree preservation is projected to be 79.70% and 87.84% respectively in the floodplain.
3. Required floodplain mitigation for the tree survey is 146.6 inches comprised of 5.6 inches of significant trees and 141 inches of heritage trees as depicted in sheet TP1 (see attached).
4. Tree mitigation and canopy diversity - The applicant requests a 50% mitigation requirement reduction from 146 inches to 73 inches for achieving mitigation above and beyond the minimum required in the UDC as identified below:
a. Revegetation of 804,672 square feet as follows:
i. Planting of the disturbed areas with native seed mix;
ii. Planting of the native seed mix using the drill-seeding technique;
iii. Achieving 85% establishment of the planted seed mix; and
b. Payment of $14,600.00 into the Tree Mitigation Find.
DSD staff supports the applicant’s request to fall below 80% significant tree and 100% heritage tree preservation requirements in the floodplain based on the conditions of the site, size of the sewer, design constraints, location of the original sewer line, and achieving the mitigation and tree survey requirements and exceeding revegetation requirements. The proposed Variance Request meets the intent and spirit of the Tree Ordinance therefore, staff recommends approval.