Cresta Reservoir

Cresta River Dredging Project The Cresta Reservoir, located on the North Fork Feather River in Plumas County, California has accumulated approximately 2.3 million cubic meters of sediment, filling almost half its total capacity since it was placed in service in 1949.

For the EDDY Pump demonstration, approximately 7,833 cubic meters of sandy sediment deposits near Cresta Dam were dredged and returned to the reservoir bottom 600 meters upstream. Turbidity, suspended solids, dissolved oxygen, flow, density of the slurry, and production rate were monitored. It was concluded that the dredge performance exceeded the manufacturer's production specifications and easily complied with restrictive water quality standards.

Slurry densities greater than 70 percent solids by weight were sustained, while peaks over 90 percent were achieved. Production rates of over 230 cubic meters per hour were observed. The maximum turbidity of the discharge plume was only 12 Nephelometric Turbidity Units (NTU) over ambient. Depths to over 50 feet were dredged with no problem.

Conclusions:

EDDY Pump slurry suction dredging provides an environmentally superior dredging method to meet strict water quality standards.
Very little turbidity or re-suspension of sediments occurred at the suction head.
The EDDY Pump is capable of high production rates comparable to much larger conventional suction dredges.
The EDDY Pump dredge is capable of passing large volumes of woody debris and other foreign material in sediments without clogging.
High slurry density minimizes the volume of effluent to be treated and disposed of for upland deposition of sediments.
The capability of the technology to pump dense slurries long distances provides a pipeline -alternative for transporting sediment to distant disposal sites.
Following solution of initial -start-up problems, the prototype dredge proved capable of sustained reliable operation.
The discharge of sediment slurry into the water column resulted in low levels of turbidity and total suspended solids (TSS), well within the limits of stringent water quality standards, without the use of a sediment containment curtain.

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	Cresta Reservoir The Cresta Reservoir, located on the North Fork Feather River in Plumas County, California has accumulated approximately 2.3 million cubic meters of sediment, filling almost half its total capacity since it was placed in service in 1949. For the EDDY Pump demonstration, approximately 7,833 cubic meters of sandy sediment deposits near Cresta Dam were dredged and returned to the reservoir bottom 600 meters upstream. Turbidity, suspended solids, dissolved oxygen, flow, density of the slurry, and production rate were monitored. It was concluded that the dredge performance exceeded the manufacturer's production specifications and easily complied with restrictive water quality standards. Slurry densities greater than 70 percent solids by weight were sustained, while peaks over 90 percent were achieved. Production rates of over 230 cubic meters per hour were observed. The maximum turbidity of the discharge plume was only 12 Nephelometric Turbidity Units (NTU) over ambient. Depths to over 50 feet were dredged with no problem. Conclusions: EDDY Pump slurry suction dredging provides an environmentally superior dredging method to meet strict water quality standards. Very little turbidity or re-suspension of sediments occurred at the suction head. The EDDY Pump is capable of high production rates comparable to much larger conventional suction dredges. The EDDY Pump dredge is capable of passing large volumes of woody debris and other foreign material in sediments without clogging. High slurry density minimizes the volume of effluent to be treated and disposed of for upland deposition of sediments. The capability of the technology to pump dense slurries long distances provides a pipeline -alternative for transporting sediment to distant disposal sites. Following solution of initial -start-up problems, the prototype dredge proved capable of sustained reliable operation. The discharge of sediment slurry into the water column resulted in low levels of turbidity and total suspended solids (TSS), well within the limits of stringent water quality standards, without the use of a sediment containment curtain. top of page