Notice of Availability of a Final Environmental Impact Statement for Renovation of Crow Creek Dam on Crow Creek Indian Reservation, South Dakota

DEPARTMENT OF THE INTERIOR

Bureau of Indian Affairs

Notice of Availability of a Final Environmental Impact Statement

for Renovation of Crow Creek Dam on Crow Creek Indian Reservation,

South Dakota

AGENCY: Bureau of Indian Affairs, Interior.

ACTION: Notice.

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SUMMARY: The Spillway at Crow Creek Dam is on the verge of failure.

Failure of the spillway could lead to the catastrophic failure of the

dam, endangering lives and property in the floodplain between the dam

and Lake Francis Case on the Missouri River. During its 55-year life,

the reservoir has trapped approximately 5,000 acre-feet of sediment

which has reduced its water-storage capacity from 7,000 to 2,000 acre-

feet. An Environmental Impact Statement (EIS) was necessary to address

the impact of controlled or catastrophic release of the sediment. Six

alternatives for renovation are considered in the document.

This Notice is published in accordance with the National

Environmental Policy Act (NEPA) regulations found in Parts 1500-1508 of

40 CFR.

DATES: The Notice of Intent to prepare an EIS was published in the

Federal Register on September 21, 1992. Two scoping meetings were held

on September 30, 1992. The draft EIS was released on December 31, 1993.

A public hearing was held on April 13, 1994; and a tribal council

informational meeting was held on April 14, 1994.

ADDRESSES: Comments should be addressed to Mr. Don Whitener, Acting

Area Director, Bureau of Indian Affairs, 115 4th Avenue, S.W.,

Aberdeen, South Dakota 57401.

FOR FURTHER INFORMATION CONTACT: Mr. Leonard Alberts, Safety of Dams

Coordinator, Bureau of Indian Affairs, Branch of Natural Resources, 115

4th Avenue, S.W., Aberdeen, South Dakota 57401. Telephone (605) 226-

7621.

SUPPLEMENTARY INFORMATION: The Crow Creek Sioux Tribe has a contract

with the Bureau of Indian Affairs (BIA) to perform Safety of Dams

activities at Crow Creek Dam. The Tribe contracted the EIS work to

Morrison-Maierle/CSSA of Helena, MT; a private engineering consultant.

Six alternatives were considered, including No Action. The BIA has

chosen Alternative 6 as a preferred alternative. Alternative 6 will

breach the dam, drain the reservoir, naturally stabilize the reservoir

sediments, and eventually return the reservoir area to a naturally

vegetated condition. The existing concrete spillway will be removed and

the reservoir will be lowered by excavation of the underlying material.

A period of 5 years will be used to stage the breaching of the dam so

that the amount of sediment released downstream will be minimized.

The Crow Creek Sioux Tribe favors Alternative 6 as an interim

remedy to relieve the existing safety hazard since funding for other

alternatives is not available. The tribe prefers, as a permanent

rehabilitation, Alternative 2 which involves rehabilitation of the dam

with a design flood capacity of 55,000 cfs and operation to flush

sediment. The five-year phased breaching of the dam will be performed

in a manner that will allow pursuit of Alternative 2 if funds become

available. Alternative 2 would include the construction of a new

spillway, a new outlet works, and possibly installation of roller-

compacted concrete overtopping protection for the dam embankment. The

outlet works would have a greater capacity for flushing of sediment.

While sediment flushing would prolong the life of the reservoir, it

would make establishment of fish populations very difficult. Eventually

the reservoir would fill with sediment and become wetlands and riparian

habitat.

The BIA has committed to monitoring sediment losses from the

reservoir during the implementation period of Alternative 6.

Appropriate mitigation will be developed if significant impacts occur

during the staged breach.

Dated: August 12, 1994.

Ada E. Deer,

Assistant Secretary--Indian Affairs.

[FR Doc. 94-20378 Filed 8-18-94; 8:45 am]

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