DEPARTMENT: Development Services
SUBJECT: TPV 20-048 Tree Preservation Variance for SAWS WRIP Phase 2
SUMMARY:
Request by Mr. Robert Jenkins 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 along the proposed alignment of the SAWS Segment 2C and Segment 3 pipelines and within the Anderson and Old Pearsall pump stations. Staff recommends approval. (Herminio Griego, (210) 207 - 6042, herminio.griego@sanantonio.gov, Development Services Department)
BACKGROUND INFORMATION:
Project A/P# 2400168
Council Districts: Inside and in the ETJ adjacent to Districts 4 and 5
Consultant: Mr. Robert Jenkins
Staff Coordinator: Herminio Griego, Assistant City Arborist 210-207-6042
ANALYSIS:
The Development Services Department (DSD) reviewed the information presented in Mr. Robert Jenkins letter dated June 30, 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 stand delineated trees and heritage trees in the Environmentally Sensitive Areas (ESA) and floodplain in excess of 80% minimum preservation of tree stand and 100% minimum preservation of heritage trees in place under the 2010 Tree Preservation Ordinance for development of the San Antonio Water Systems Water Resource Integration Program (WRIP) Phase 2 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 stand determined to be below 80% tree stand preservation and 100% heritage tree preservation in the ESA and floodplain for the following reasons:
Existing site conditions - The Project includes three projects that encompasses 266.6 acres and is designed to deliver water from the SAWS Aquifer and Storage Facility (ASR), Local Carrizo, Expanded Carrizo and Brackish Desalination operations to new and existing facilities in western Bexar County. The Project will accomplish this with Anderson and Old Pearsall pump station improvements, and installation of the Segment 2C and the Segment 3 pipelines. The Segment 2C and Segment 3 pipelines are 48 inches in diameter and will be constructed in an 80-foot SAWS owned easement paralleling Loop 1604 (see attached figure). The design incorporated the following activities to minimize tree impacts and enhance reclamation efforts:
1) Boring 778 linear feet in strategic areas to maximize heritage tree preservation;
2) Reducing the working area in the 80-foot easement to 60 feet. This effort preserved 25% of the easement and the collocated canopy and heritage trees;
3) The Project will also save an additional 8.7 acres (equivalent to 7,196.8 inches) of tree stand in temporary construction preservation areas;
4) Reclaiming 118 acres of disturbed areas by drill seeding native seed mix and ensuring 85% establishment.
5) Incorporating cultural and archeological resources and hazardous waste investigations;
Overall the Project will preserve:
1) 1,058 of 1,504 heritage tree inches for a combined ESA and floodplain preservation of 71%, and
2) 7.78 of 22.3 tree stand acres for a combined ESA and floodplain tree stand preservation of 34.9%.
The preservation, removal and mitigation details are presented below.
|
|
Shade Value |
Total Canopy Area (acre) / (Dia In) |
% Required to be Preserved Excluding Heritage Trees |
Percent Preserved |
Area Required to be Mitigated (acre) / (Dia In) |
Area to be Mitigated (3 Times for Heritage) |
Diameter to be Mitigated / Preserved |
|
Floodplain Canopy |
|
Heritage Tree |
N/A |
1222.0 |
100.0% |
70.0% |
366.6 |
1099.8 |
1099.8 |
|
Non-Heritage Tree |
875.0 |
18.8 |
80.0% |
36.6% |
8.2 |
8.2 |
6801.0 |
|
Environmentally Sensitive Canopy |
|
Heritage Tree |
N/A |
282.0 |
100.0% |
72.0% |
79.0 |
237.0 |
237.0 |
|
Non-Heritage Tree |
875.0 |
3.5 |
80.0% |
25.7% |
1.9 |
1.9 |
1567.3 |
|
Temporary Construction Preservation Area |
|
Non-Heritage Tree |
875.0 |
8.7 |
0.0% |
100.0% |
0.0 |
0.0 |
7196.8 |
|
Total Mitigation Required (Dia In) = |
2508.0 |
Tree mitigation and canopy diversity - The applicant proposes to meet the ESA and Floodplain Tree Stand Delineation mitigation requirements as follows:
1. Reducing the construction width within the permanent easement from 80 feet to 60 feet to minimize tree impacts;
2. Boring 778 linear feet of waterline to save additional heritage trees;
3. Saving an additional 8.7 acres (equivalent to 7,196.8 inches) of tree stand in temporary construction preservation areas;
4. Reclaiming 118 acres of disturbed areas by drill seeding native seed mix and ensuring 85% establishment.
5. Mitigation Evaluation:
a. Total mitigation = 2,508 equivalent inches.
b. Mitigation balance for items 1, 2, 3, and 4 above = 1,254 equivalent inches
c. Tree Mitigation Fund Payment = 1,254 inches @ $200.00 per inch = $250,830.00
DSD staff supports the applicant’s Variance request to fall below 80% Tree Stand and 100% Heritage Tree requirements in the ESA and floodplain based on the conditions of the site, the need to improve San Antonio’s water delivery systems and payment to the Tree Mitigation Fund. The proposed Variance Request meets the intent and spirit of the Tree Ordinance therefore, staff recommends approval.