DEPARTMENT: Development Services
SUBJECT: TPV 20-034 Tree Preservation Variance for Dickerson Tract SF community
SUMMARY:
Request by Mr. Jon Robinson 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 at west Grosenbacher Road west of Canthree Drive. Staff recommends approval. (Herminio Griego, (210) 207 - 6042, herminio.griego@sanantonio.gov, Development Services Department)
BACKGROUND INFORMATION:
Project A/P# 2524907
Council District: Outside of District 4 in ETJ
Consultant: Mr. Jon Robinson
Staff Coordinator: Herminio Griego, Assistant City Arborist 210-207-6042
ANALYSIS:
The Development Services Department (DSD) reviewed the information presented in Mr. Jon Robinson's letter dated April 20, 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 Environmentally Sensitive Areas (ESA) and floodplain in excess of 80% minimum preservation of significant trees in place under the 2010 Tree Preservation Ordinance for development of the Dickerson Tract SF Community project (the Property). DSD staff does agree with the applicant's request to mitigate via planting additional trees and upsizing required trees on 162 lots for tree survey determined to be below 80% significant tree preservation in the ESA and floodplain and for the following reasons:
Existing site conditions - The Dickerson Tract SF Community is located on West Grosenbacher Road west of Canthree Drive. The Property consists of 31.027 acres of which 6.317 is located within a regulatory floodplain. The planned development will include 162 new single-family lots. The Property will also include two new entrances onto West Grosenbacher Road, which will also be improved.
Currently water in the area drains from the north to the south of West Grosenbacher Road via an undersized drainage channel along the east side of the Property into the regional stormwater conveyance system. As conditions of development the Owner is required to improve both West Grosenbacher Road and the existing drainage along the east side of the Property. The drainage improvement to allow offsite stormwater to flow into the regional stormwater conveyance system requires a substantial amount of earthwork. The earthwork related tree removal will result in less than 80% preservation of surveyed significant trees in the ESA and the floodplain resulting in 585 inches of mitigation. There are no heritage trees located in either the ESA or the floodplain. The Tree Survey Delineation Plan also indicates that 569 inches of mitigation is required for existing Right of Way tree removal associated with the roadway improvements. The Upland areas mitigation is 4 inches.
The Tree Survey Delineation Plan indicates that 53.3% and 32.3% of the significant trees will be Preserved in the floodplain and ESA respectively as noted in the table below:
I
1. Tree mitigation and canopy diversity- The applicant proposes to meet the ESA and Floodplain Tree Survey Delineation mitigation requirements as follows:
a. Upsizing the two UDC required trees to 3 inches on 162 lots = 486 inches.
b. Planting two additional 3 caliper inch trees on 162 lots = 972 Inches.
c. Total inches planted= 486 inches+ 972 inches= 1458 inches
d. Excess mitigation= 1458 inches - 569 inches (ROW)- 585 (ESA & Floodplain) inches - 4 Upland inches = 300 inches excess
In addition, the total property planting will yield 792,955 square feet of canopy. The project requires only 409,008 square feet of final canopy cover. Therefore, the Property planting will yield 383,947 square feet of excess final canopy cover.
DSD staff supports the applicant's request to fall below 80% Significant Tree Survey preservation requirements in the ESA and floodplain based on the conditions of the site and the required roadway and drainage improvements. The proposed Variance Request meets the intent and spirit of the Tree Ordinance therefore, staff recommends approval.