08-21-2002 Committee Meeting - Laserfiche WebLink

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i W i 5 a b 1Ze v 1 sr "Y Port of Houston Authority Wetland Mitigation Plan MITIGATION PROJECT DESIGN The mitigation project is designed to offset the loss of approximately 18.3 acres of USACE jurisdictional wetlands. The mitigation site supports a variety of vegetation communities ranging from coastal prairie to oak forest. Much of the prairie habitat west of the drainage canal i,s�.«� is)including existing wetland areas, is dominated by Chinese tallow and was classified as tallow/shrub habitat. The area to the east of the drainage canal contains open prairie habitat with some tallow infestation occurring, particularly in wetland areas. The primary components of the mitigation project are: • Wetland creation, • Wetland enhancement • Coastal prairie enhancement, and, • Wetland and upland habitat protection under a permanent conservation easement. Wetland Creation The wetland creation portion of the project will consist of constructing 66.8 acres of emergent wetland to offset injury to 18.3 acres of jurisdictional wetland at the Bayport Site at a mitigation ratio of more than 3.65:1. Approximately 4 acres of existing wetlands fall within the footprint of the proposed created wetland,. increasing the total wetland footprint to 70.8 acres The existing wetlands that fall within the footprint of the proposed created marsh will be enhanced by the increased frequency and duration of flooding resulting from the construction of the wetland project, as well as Chinese tallow removal. shows a typical cross sectional view of the wetland The Wetland Design consists of two interacting freshwater wetlands separated by a narrow strip of coastal prairie (S�.es+18). The southern most wetland includes 36.4 acres of emergent freshwater marsh and 25.2 acres of coastal prairie adjacent to Red Bluff Road. The north wetland, which is downslope from the south wetland, includes 34.4 acres of emergent marsh supported by a 14.7 acre band of coastal prairie watershed. At full pool, water depth in the south marsh will range from 0 to 1.2 feet, while maximum depth in the north marsh will be 1.6 feet Benchmark Ecological Services, Inc. June 2002 SLi