DEPARTMENT: Development Services
SUBJECT: TPV 20-010 Tree Preservation Variance for SAWS E-16 Wurzbach Parkway Sanitary Sewer Project
SUMMARY:
Request by Mr. Mario Valdez for approval 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”, located from the southwest corner of Wurzbach Parkway and North Loop Road along Salado Creek. Staff recommends approval. (Mark C Bird, (210) 207-0278, mark.bird@sanantonio.gov, Development Services Department)
BACKGROUND INFORMATION:
Project A/P# 2547450
Council District: 9
Consultant: Mr. Mario Valdez
Staff Coordinator: Mark C Bird, City Arborist, (210) 207-0278
ANALYSIS:
The Development Services Department (DSD) reviewed the information presented in Mr. Mario Valdez’s letter dated February 17, 2020.
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 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 an Environmental Variance to mitigate for the removal of tree survey delineated trees in the floodplain in excess of 100% minimum preservation of heritage trees in place under the 2010 Tree Preservation Ordinance for development of San Antonio Water System (SAWS) E-16 Wurzbach Parkway Sewer Project Highway 281 project (the Project). DSD staff does agree with the applicant’s request to mitigate via enhanced revegetation and payment into the Tree Mitigation Fund for tree survey determined to be below 100% heritage tree survey preservation in the floodplain for the following reasons:
Existing site conditions - The E-16 Wurzbach Parkway Sewer Project Highway 281 project (the Project) is required pursuant to the agreement between the City of San Antonio and the United States Environmental Protection Agency to address capacity constrained sewer infrastructure across the City of San Antonio (CoSA). The Project is essential for the health and welfare of San Antonio’s citizenry. The Project consists of replacing 6,700 linear feet of sewer lines from the southwest corner of Wurzbach Parkway and North Loop Road along Salado Creek. The existing 18 and 27 inch sewer lines will be upgraded to 24, 27, 36 and 78 inch sewer lines. The Project is constrained by the existing sewer alignment and connections, topography, the future location of the CoSA Senior Center, and permanent easements. The Project encompasses 543,410 square feet of disturbed area, and includes permanent easements raging in width from thirteen (13) to fifty (50) feet and temporary easements from ten to one-hundred and twenty (10’ to 120’) feet wide. Multiple alignments were evaluated to optimize design and budget while minimizing tree impacts. Efforts to minimize tree impacts included routing two segments of the sewer line outside of the floodplain and buffer area and tunneling multiple segments within the floodplain and buffer areas. Approximately 752 linear feet of the project will be tunneled to minimize tree impacts. Conflicts with the future CoSA Senior Center location caused rerouting of the sewer line through the floodplain. This rerouting resulted in the removal of a large number of trees. The final design resulted in the removal of 583 inches of heritage floodplain trees and mitigation of 1597 inches. Preservation requirements were achieved for significant floodplain trees and in the upland and environmentally sensitive areas.
The Tree Survey Delineation Plan indicates that eighty percent (80.1%) of the floodplain heritage trees will be preserved.
1. Tree mitigation and canopy diversity - The applicant proposes to meet the Floodplain Tree Survey Delineation mitigation requirements as follows:
a. Boring 752 linear feet at multiple locations to minimize tree impacts;
b. Relocating the sewer line outside of the floodplain and environmentally sensitive areas to minimize tree impacts and minimize the variance area;
c. Re-seeding 247,311 square feet of CoSA owned right of way disturbed area, both inside and outside of the floodplain; and
d. Reclaiming disturbed areas by drill seeding with a native seed mix and ensuring 85% establishment; and
e. Mitigation Evaluation:
i. Total Floodplain mitigation = 1597 inches (mixed 3:1 and 1:1 heritage trees)
ii. Mitigation balance for implementing items a, b, c and d = 798.5 inches
iii. Tree Mitigation Fund Payment = 798.5 inches @ $200.00 per inch $159,700.00.
DSD staff supports the applicant’s request to fall below 100% Heritage Tree Survey preservation requirements in the floodplain based on the conditions of the site, the need to address the current capacity constrained sewer lines, and payment into the Tree Mitigation fund. The proposed Variance Request meets the intent and spirit of the Tree Ordinance therefore, staff recommends approval.