Orland Pit Wetland Mitigation Project

Orland Pit Wetland Mitigation Project

This streambed alteration agreement pertains to work to be performed within the floodplain of Stony Creek and to an unnamed drainage tributary to Stony Creek. This work is part of a larger project that will create/enhance 3.48 acres of fresh emergent/riparian wetland habitat. The wetland creation/enhancement areas consist of three district areas of uplands situated immediately adjacent to existing wetlands. The wetland creation/enhancement activities will have very limited effects on the low flow channel. The wetland creation areas are currently upland and will be excavated to a depth that is slightly higher (about 6 inches higher) than the bank of the low flow channel. The wetland creation areas will flood during higher flows and their hydrology will also be supported by groundwater (similar to the existing wetlands adjacent to the channel). Non-native invasive plant species, such as giant reed (Arundo donax) and tamarish (Tamarix parviflora) would be eradicated from areas proposed for creation of wetland and upland riparian habitats. Following construction, the wetland areas would be monitored and maintained in accordance with the project's Wetland Mitigation and Monitoring Plan. Wetland Creation Area #1 is the only unit where construction will involve work affecting the bank of the low flow channel. Wetland Creation Area #1 will include two drainage ways that will route flow through the wetland unit. Connecting the upstream extent of each of these proposed drainages to the low flow channel will involve breaching approximately 6 feet of the bank of the low flow channel. The downstream connection of the proposed drainages will not require any channel work. Wetland Creation Areas #2 and #3 will not require any channel work. Additional work potentially affecting the channel will include two temporary crossings by bridge space (e.g., railcar bridge), culvert with clean gravel, or similar method. Construction of each temporary crossing will temporary affect approximately 15 linear feet of the low flow channel. The crossings will be removed up completion of construction activities and the stream bank restored to preconstruction conditions. Total impacts to stream bank are anticipated to be 42 linear feet (12 feet for connection of Wetland Creation Area #1 drainage ways and 30 feet for temporary crossings. Appropriate areas will be planted with wetland and riparian upland vegetation.

Orland

Glenn