D&K updated the Dam Safety and Surveillance Monitoring Plan (DSSMP) for a 390kW 30-ft-high run-of-the-river hydroelectric dam (FERC No. 5261-VT). D&K reviewed the existing DSSMP for the facility; participated in a site visit with facility staff to complete the revised first quarter checklist; and reviewed existing data including FERC correspondence, plans, Dam Safety and Surveillance Monitoring Reports, Potential Failure Mode Analysis report, FERC Part 12 inspection data, and Supporting Technical Information Documents.
Low Level Outlet Repair, Enel Green Power
DuBois & King designed structural repairs to the existing low level outlet structure at the Hoague-Sprague/EHC Hydro Plant (FERC No. 4337-NH) on the Contoocook River to return the structure to a sound and watertight condition. The low level outlet structure is adjacent to the right abutment of an existing rock filled timber crib dam. D&K’s scope of work for this project includes a visit to the site, providing preliminary design, incorporating the owner and FERC’s comments on the design, and completing a final design package suitable for bidding and construction.
Dam Safety and Surveillance Monitoring Reports (DSSMR), Enel Green Power
DuBois & King prepared Dam Safety and Surveillance Monitoring Reports (DSSMRs) for four hydroelectric projects in Barnet (FERC No. 5702-VT), Newbury (FERC No. 5261-VT), and Sheldon Springs (FERC No. 7186-VT), Vermont; and Woodsville (FERC No. 5307-NH), New Hampshire. D&K reviewed available drawings and data for each project, visited the project sites, completed quarterly inspection checklists in accordance with Dam Safety and Surveillance Monitoring Plans (DSSMPs) and prepared a DSSMR for each facility.
Pine Lane Farm, NRCS NH
D&K engineers, through an assignment for on-call Soil Conservation services with NRCS, designed a retention structure and disposal field for 2,000-gallons-per-day of milking center wastewater. The retention structure consists of a multi-chamber reinforced concrete tank with a Clearspan fabric structure cover and was designed to be accessible by standard farming equipment for removal of accumulated sediment, fat cake, and sludge. D&K engineers designed disposal of wastewater utilizing a Presby Advance Environmental System (AES) subsurface disposal field, including 2,500 ft of AES piping. The wastewater disposal system includes gravity and forced mains for transferring wastewater. The existing manhole pump station was reused to serve as a new retention structure and the existing sediment basin and disposal lagoon were retained as an emergency back-up system.
Sugar River, NRCS NH
D&K engineers, through an assignment for on-call Soil Conservation services with NRCS, performed site investigation, design, permitting support, and construction observation for river bank stabilization and installation of a shallow wildlife pond on and adjacent to the Sugar River. Riverbank stabilization included the use of natural sub-angular boulders to armor the toe of slope, while providing pockets of shelter for aquatic organisms. Riparian vegetation was restored on the upper bank. Project was completed under the Wildlife Habitat Incentives Program (WHIP).
The pond was designed and built with zones of varied depth and vegetation. A rounded L-shape was designed to blend naturally into the landscape and avoid an adjacent wetland. Wetland delineation was performed for avoidance, minimization, permitting, and mitigation purposes. A landscape plan was developed to help stabilize and restore the riverbank and to provide native vegetation that provided wildlife value at the pond. The scope of services included field survey, wetland delineation, soil test pits, hydraulic modeling, plans, specifications, cost estimate, permitting support, construction quality assurance guidance, and an operation and maintenance plan.