Dam Engineering/Removal

Camp Killooleet Dam Repair

Camp Killooleet Dam is a privately owned timber and concrete dam originally constructed approximately 100 years ago on the Hancock Branch. The dam suffered extensive damage during a storm event. The Hancock Branch over-topped its banks and overwhelmed the dam’s spillway. Damage to the dam included an erosion failure of the right abutment in the vicinity of the low-level drain pipe, over-topping of the timber walkway that spans the top of the spillway, and a slope erosion failure on the left embankment. DuBois & King dam engineers designed and oversaw the repair and modifications to the dam. Services include:

Dam inspection
Topographic field survey of dam and reservoir
Hydrologic analysis
Identification and evaluation of repair alternatives
Geotechnical and structural engineering
Permitting
Construction observation and field engineering

Blueberry Lake Dam Rehabilitation

Blueberry Lake is a 45-acre recreational impoundment. A portion of Plunkton Road, located on the crest of the dam, provides access to the Green Mountain National Forest and local residences beyond the dam. Vermont dam safety engineers identified deficiencies with the primary and emergency outlets, which would require a drawdown to repair.

Repairing the dam required closing the roadway to vehicular traffic, which would cause residents to travel a seven-mile detour; this provided concerns for emergency response time. Project investigations revealed that an old road, submerged six feet below water, was suitable to serve as a temporary detour. The old roadway became a cost-effective alternative detour for the Town.

The dam embankment is 38 ft high and 530 ft long. The existing principal spillway and low level drain were removed and replaced with one new conduit at the maximum section requiring very deep cuts and steep slopes. 8,600 cubic yards of embankment had to be excavated. The excavated material, stored on site, created a 30-ft-high by 100-ft-long mound of earth. Ninety five percent of the excavated material was reused for the dam and roadway reconstruction. Due to the pristine environment surrounding the dam, special provisions were required for sediment control to minimize impacts to natural ecosystem habitats. The Erosion Control Plan developed for the project, was unique in that it accommodated both the roadway and dam reconstruction and satisfied the requirements of the Dam Safety Permit.

Ann Jackson Dam Removal

DuBois & King designed and planned the removal of a 12-ft tall aging concrete and masonry dam and restoration of the stream channel through the former impoundment. Owned by the Girl Scouts of the Green and White Mountains, the dam was deemed structurally deficient by State regulators and the owners could not justify the expense of reconstructing it. D&K connected the owners with the Natural Resource Conservation Service (NRCS), who funded the construction. Design included removal and disposal of the dam and restoration of 180 ft of stream channel that had been previously obliterated. Restored stream channel to mimic existing channel upstream and downstream of the dam. Design included imported cobble and gravel substrate and constructed wood clusters to promote stability and habitat. Design also included passive restoration areas where the channel was populated with woody material to facilitate habitat features while the streamside woody vegetation establishes. Professional services included:

Dam and site inspection
Stream channel geomorphic assessment
Topographic and cross section survey
Coordination with stakeholders and project partners
State wetland permit
Coordination with Section 106 historic consultant
Design of dam removal and channel restoration
Plans and specifications
Bid phase services
Construction observation and administration

DuBois & King provides investigation, analysis, planning, design, and construction phase services to dam owners throughout the northeast. Firm professionals have developed a common-sense approach that provides dam owners cost-effective solutions for maintaining and rehabilitating their dams. D&K’s dam engineers are supported by in-house surveyors, wetland scientists, and permitting specialists that contribute to providing dam owners a full complement of dam and related services. Firm professionals help dam owners address issues identified by state dam safety programs. We investigate the dam site, meet with the owner, and provide a plan to address the issues and help identify contractor resources to assist the dam owner in carrying out rehabilitation activities.

Services

Dam Safety Inspections
Deficiency Assessments
Subsurface Investigations
Stability Analysis
Seepage Analysis
Hazard Classification
Evaluation of Concrete, Steel, Stone, Timber, and Earth Components
Hydroelectric Facility Inspections
Hydraulic and Hydrologic Studies
Repair and Rehabilitation Design
Dam Breach Analysis and Flooding Analysis
Operation and Maintenance (O&M) Plans
Emergency Action Plans (EAPs)
Dam Removal Evaluation and Design
Fish Passage
State and USACE Permitting
Construction Cost Estimates
Bid and Construction Phase Services

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