Low-Head Hydropower Decommissioning/Site Reclamation: Resource Requirements and Impact Sources
Decommissioning and site reclamation activities include facility removal and revegetation.
Decommissioning of a low-headhydropower facility would include removal of the powerhouse and foundation, and the excavation and removal of the intake, tailrace, and buried components. Underground components would be removed to a depth of at least three feet to ensure an unobstructed root zone for revegetation. Decommissioning of pipelines would range from the removal of only the aboveground components to removal of the entire pipeline and ancillary components. More deeply buried components might be abandoned in place. Any dam or weir could either be removed or left to maintain the head pond for adapted aquatic biota and for recreational activities. Following removal of site components, site reclamation and revegetation would mitigate some impacts, such as soil erosion, habitat fragmentation, and visual impacts.
The following describes the factors that could affect whether an environmental impact could occur and whether it would be considered an adverse effect.
Acreage — If the head pond is left in place, only a small portion of the site would be impacted by decommissioning and deconstruction activities. Transmission lines would probably remain in place as part of the transmission grid.
Emissions — Decommissioning and reclamation activities would produce fugitive dust emissions caused by vehicle traffic and breaking up of concrete foundations, vehicular and equipment emissions, and volatile organic compounds (VOCs) from storage and use of fuels for equipment.
Waste Generation — Wastes generated would include solid and industrial wastes similar to those from construction, broken concrete, pipelines, plant components, electronic equipment, and transformers.
Water Needs — Water would be needed for dust suppression, fire-fighting contingency, and potable supply for the workforce.
Workforce — Decommissioning and reclamation activities would require approximately one-half to two-thirds of the construction workforce for a period lasting about half as long as construction, and could require specialty crews for some operations.