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Great Plains Region
Billings, Mont.
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Todd Dixon
(406) 247-7303
Mark Andersen
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Released On: August 27, 2004

Bureau of Reclamation Eastern Montana Reservoir Information
Drought conditions will continue to affect irrigation, power, and recreational water users throughout eastern Montana, according to Dan Jewell, recently named Area Manager for the Bureau of Reclamation's Montana Area Office.

The federal water resource management agency released updated water supply information to help recreationists prepare for the upcoming September 4-6 Labor Day weekend. "Although we continue to experience record-low inflows to most of our reservoirs, generally favorable weather conditions have enabled us to meet most of our water needs," Jewell said.

In spite of low inflows and low water levels, boat ramps should be usable at most locations during the Labor Day weekend, Jewell said. "We urge recreationists to check for the most up-to-date information on boat ramp status at Reclamation's website http://www.usbr.gov/gp/", he added.

Current conditions at Bureau of Reclamation facilities:

Clark Canyon Reservoir - The Beaverhead watershed in southwestern Montana continues to be one of the most severely drought-impacted areas in the State. Monthly inflows to Clark Canyon have been below normal for 53 consecutive months and the cumulative inflow since April of this year is the lowest on record since construction of the dam in 1965. Inflows to the reservoir are currently averaging 18 percent of what they would normally be at this time of year.

Clark Canyon Reservoir has not filled to the top of the conservation pool since 1998 and storage within the reservoir has steadily declined since then. Storage reached a peak of 55,371 acre-feet this year, which is about 17,500 acre-feet less than in 2003 and the lowest peak storage ever reached in Clark Canyon Reservoir. As a result, no water has been delivered to water users in the East Bench Irrigation District this year.

Weather conditions have, however, improved over the summer. Timely precipitation throughout the watershed has reduced irrigation demands on storage out of Clark Canyon Reservoir.

The reservoir water level is currently at elevation 5498.6, which is approximately 8.5 feet lower than this time last year. Lake recreation has been severely impacted this year due to the extremely low water levels in the reservoir. The boat ramp at Beaverhead Camp is currently open with a water level three feet above the end of the ramp. Concrete plank extensions are also in place.

Canyon Ferry Reservoir - Similar to Clark Canyon, monthly inflows to Canyon Ferry have been below normal for 53 consecutive months. Cumulative inflow since April is the third lowest on record since construction of the dam in 1955. Current inflows to Canyon Ferry Reservoir are approximately 45 percent of normal for this time of year.

In response to near record low inflows, and to conserve storage in the reservoir, releases from Canyon Ferry to the Missouri River are being maintained at 2,800 cubic feet per second (cfs). While this flow is less than the desired flow for maintaining a healthy river fishery downstream, it is higher than current inflows to the reservoir. As a result, reservoir storage continues to decrease.

Canyon Ferry Reservoir is currently at elevation 3782.4 with a storage content of 1,429,716 acre-feet, which is 82 percent of normal for this time of year and approximately seven feet lower than last year at this time.

While recreationists should be able to safely launch boats at most locations around Canyon Ferry during the Labor Day weekend, boaters are encouraged to log onto Reclamation's website at http://www.usbr.gov/gp/ for up-to-date information on specific boat ramp conditions.

Gibson Reservoir - Inflow to Gibson Reservoir is currently about 70 percent of average, although Gibson Reservoir did fill to the top of the conservation pool this spring. Timely precipitation throughout the summer helped reduce irrigation demands. As a result, storage in Gibson Reservoir is currently 15,000 acre-feet higher than at this same time last year. Releases from Gibson Reservoir to the Sun River are currently being maintained at 200 cfs to satisfy downstream demands. Due to favorable hydrologic conditions, project water users have not experienced water shortages this year.

Lake Elwell (Tiber Reservoir) - Inflow to Lake Elwell is currently about 50 percent of average for this time of year. Storage in Lake Elwell is about 91 percent of normal, but nearly 75,000 acre-feet (or 4.6 feet in elevation) less than last year at this time. Releases to the Marias River are being maintained at 500 cfs, which is the optimal level to support a healthy downstream river fishery. The Marias River Basin downstream of Tiber Dam is the only area in the State where minimum fishery flows are being maintained. No significant impacts to lake recreation activities or to downstream river fisheries are anticipated this year.

Milk River Project (Fresno & Nelson) - Timely and locally abundant precipitation across northern Montana has decreased irrigation demands within the basin. Fresno Reservoir is currently at elevation 2558.6 with a storage content of 38,071 acre-feet, which is 98 percent of normal for this time of year. Runoff into Fresno Reservoir since April of this year has been approximately 76 percent of normal, due mainly to diversions from the St. Mary River Basin.

Due to generally favorable hydrologic conditions throughout the basin, water users have experienced only minor shortages this year. Based on the latest water supply forecast, water users in the Milk River Basin increased irrigation allotments to near the normal allotment of 2.0-2.5 acre-feet per acre. Irrigation deliveries are expected to continue through mid-September. Storage in Fresno and Nelson Reservoirs is expected to drop to no lower than 20,000 acre-feet in each reservoir to protect the minimum winter storage supply in the Milk River Basin. Moderate impacts to lake-based recreation are anticipated at both reservoirs.

Bighorn Lake (Yellowtail Dam) - Monthly inflows to Bighorn Lake have been below normal for 58 consecutive months. The cumulative inflow since April is the second lowest on record since construction of the dam in 1967 and the current inflow is only 36 percent of average for this time of year. A general lack of early precipitation created unusually early and heavy irrigation demands, which severely depleted stream flows into Bighorn Lake.

In close coordination with Montana Fish, Wildlife and Parks, releases from Bighorn Lake to the Bighorn River have been maintained at 1,300 cfs, which is significantly lower than the desired flow for maintaining a healthy fishery in the Bighorn River. According to MFWP reports, fishery population estimates have declined from an average of about 5,000-7000 fish per mile to less than 500-700 fish per mile during this drought. While overall population numbers have declined significantly, the quality of the remaining fishery appears to be excellent despite the low flows.

Timely precipitation has improved the runoff into Bighorn Lake. Storage in Bighorn Lake continues to slowly decline, but at a slower rate than earlier forecast. Bighorn Lake is currently at elevation 3585.4 with a storage content of 668,414 acre-feet, which is about 66 percent of normal. The lake elevation is currently about 18.75 feet lower than at this same time last year.

The minimum lake level to safely launch boats at Bighorn Lake is elevation 3580. Based upon the latest outlook, the level of Bighorn Lake should be adequate to safely launch boats during the Labor Day weekend. Boaters are encouraged to log onto Reclamation's website at http://www.usbr.gov/gp/ to check for up-to-date information prior to planning their weekend.

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Reclamation is the largest wholesale water supplier and the second largest producer of hydroelectric power in the United States, with operations and facilities in the 17 Western States. Its facilities also provide substantial flood control, recreation, and fish and wildlife benefits. Visit our website at www.usbr.gov.