DEPARTMENT: Development Services Department
SUBJECT: TPV 21-038 SAWS 20-4508 Multiple Sewer Package 18
SUMMARY:
Request by Mr. Michael Persyn for approval on behalf of San Antonio Water Systems of a tree preservation variance request from Unified Development Code Section 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”, at two locations. The locations are northwest of the SAWS Medio Creek Treatment Plant and along Rosillo Creek between Hwy 87 and Sinclair Road. Staff recommends approval. (Charles Johnson, (210) 207-0170, charles.johnson2@sanantonio.gov, Development Services Department)
BACKGROUND INFORMATION:
Project TER-APP-APP21-38800121
Council Districts: 2 and 4
Consultant: Mr. Michael Persyn
Staff Coordinator: Mark C Bird, City Arborist, (210) 207-0265
ANALYSIS:
The Development Services Department (DSD) reviewed the information presented in Mr. Michael Persyn’s letter submitted April 19, 2021.
The Unified Development Code (UDC) - Article V, Section 35-523 (h), 100-Year Floodplain(s) 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.”
Applicant Hardship: SAWS, in compliance with the Environmental Protection Agency’s (EPA’s) Consent Decree (Decree), proposes to replace 17,903 linear feet of sewer pipe between 10” and 72” inches in diameter located in six locations. Two of the locations, northwest of the SAWS Medio Creek Treatment Plant and along Rosillo Creek between Hwy 87 and Sinclair Road, require an environmental variance to the requirements of Section 35-523(h) of the Unified Development Code (UDC).
The applicant wishes to remove significant tree canopy in excess of the minimum preservation requirements for the floodplain. However, the applicant will preserve 100% of the heritage trees within the entire project limits, including the floodplain, environmentally sensitive areas and upland areas. DSD staff does agree with the applicant’s request to mitigate below minimum preservation of significant tree canopy and heritage trees in the floodplain for the following reasons:
1. SAWS has no choice but comply with the EPA’s Decree and replace or repair the deteriorated sewer lines. Repairing the deteriorated pipe is essential to protecting the health and welfare of San Antonio’s citizenry.
2. Mitigation via planting is not permitted within the floodplain due to the flood water’s erosional forces.
3. The project is constrained by in-place infrastructure including, but not limited to:
a. existing sewer lines;
b. existing easements; and
c. existing manholes, and connections to upstream and downstream sewer appurtenances.
Establishing new infrastructure elements would be cost prohibitive.
4. SAWS minimized tree impacts by:
a. Repairing the sewer pipes using the Cast-In-Place Pipe (CIPP) technique. This technique essentially slip-lines the existing pipe and significantly reduces the need for trenching or using large trenching equipment, and
b. Using existing SAWS easements.
These efforts helped to minimize the amount of tree canopy removed and preserved 100% of the 369 inches of heritage trees.
5. The tree preservation data is as follows:
6. Mitigation and Tree Preservation Balance: SAWS will
a. Preserve 38.8% more canopy than required in the non-floodplain and non-buffer areas.
b. Preserve 75% more upland heritage trees than required.
c. Reclaim disturbed areas via drill seeding with native grasses and ensuring 85% establishment.
d. Revegetate and establish natural vegetation added to all disturbed areas (416,000 SF) equal to 492 inches mitigation.
e. Tree Mitigation Fund Payment: $98,530.00 = 492.65” * $200.00/inch
DSD staff agrees with the applicants’ analysis and supports the request to remove significant tree canopy below the minimum preservation requirements for the Floodplain. The Variance Request meets the intent and spirit of the Tree Ordinance therefore, staff recommends approval.