Following is the June 23 update on Painted Rocks from Larry Schock.
The reservoir is currently spilling, however the inflows are dropping off pretty fast. The reservoir inflows today (269 cfs) were roughly 58% of what they were last week (460 cfs).
With the inflows to the reservoir dropping off daily, we will be down into the base flow range of 75-100 cfs before we know it. Unfortunately, these lower flows we are experiencing this year are about 3-4 weeks ahead of schedule.
In preparation for the upcoming contract delivery season, we continue to make gate adjustments on a weekly basis in order to gradually switch the flows from the spillway to the low-level outlet. One such adjustment was made today.
Currently about 65% of the outflows are coming out of the low-level outlet and 35% over the spillway. As the inflows continue to recede the percentage of flows from the low-level outlet will continue to increase. The dam will be operated in a manner to ensure that the outflows match the inflows, and a small amount of water will always be flowing over the spillway. However, the bulk of the water will always be coming out of the low-level outlet.
This status will remain in effect until contract water deliveries are called for by the MT Fish Wildlife and Parks (FWP), or the Painted Rocks Water Users Association (PRWUA).
I want to take time to remind everyone how Painted Rocks Reservoir is managed, and how releases are made.
1. The DNRC does not determine when contract water is delivered. The DNRC ensures that the reservoir is filled in a timely fashion and kept full until water is requested by the contract holders. Release adjustments will generally be made in 50-75 cfs increments. Whenever possible, gate adjustments will be made mid-week, however this is conditions/contract delivery dependent.
2. Decisions regarding the timing and size of the contract water releases are made by:
If you have not already done so, please read the announcement below regarding bridge construction activities in the area immediately below the dam. The bidding process has been completed and the contractor for the Painted Rocks Dam Toe Access Road Improvement and Bridge Project has been selected, it is Price Contracting, Inc. from Stevensville, MT.
Larry A. Schock, CFM
Civil Engineering Specialist
MT DNRC WRD MRO
(406) 542-5885
PUBLIC ANNOUNCEMENT
Montana Dept. Natural Resources and Conservation
PAINTED ROCKS DAM CONSTRUCTION PROJECT
MODIFIED RESERVOIR OPERATIONS, RIVER FLOW REDUCTIONS, AND FISHING ACCESS CLOSURES
Project Overview
On August 1, 2021, the Montana Department of Natural Resources and Conservation (DNRC) will begin a construction project below Painted Rocks Dam. The purpose of this project is to develop access for future maintenance, repairs, and safety improvements to the lower spillway and outlet area of the dam.
Planned activities include the construction of a bridge and improvements to the existing primitive road. Approximately one-half mile of the road will be improved to a 16-foot width with gravel surfacing. A single-lane bridge will be constructed immediately downstream of the uppermost boat launch site on the West Fork Bitterroot River.
Construction activities will begin on August 1, 2021, and continue through the winter months. The project is expected to be completed in spring of 2022. Once completed, the public will have vehicular access to the improved road on the east side of the river, and foot access across the new bridge to public lands on the west side of the river.
Access Advisories
Effective August 1, 2021, the uppermost boat launch downstream of the dam, along with the primitive road which passes near the USGS gaging station, will be closed to public use. Recreationists will find alternative river access at a developed fishing access site located about 3 miles downstream at Bonnie Blue Bridge, on Mud Creek Road.
The school bus turnaround area on West Fork Road (Hwy 473) will also be closed to general public use, though it will be opened at limited times to allow for the drop-off and pick-up of students.
Modified River Flows
To help facilitate construction activities, contract water deliveries and stream flows in the West Fork Bitterroot River will be reduced two (2) weeks earlier than normal.
- Reductions in dam outflows will begin on September 1, 2021.
- Flow reductions of approximately 50 CFS will be made every 3-4 days until September 20, 2021.
- Releases from September 20 through December 31, 2021, will be held at 60 CFS.
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- Additional short-term stream flow reductions to 40 CFS may occur 3 to 4 days per week to accommodate construction activity. These reductions will last less than 4 hours.
- From January 1 through March 31, 2022, stream flows will be held as low as possible but may reach 90 CFS or higher to manage reservoir levels in advance of spring runoff.
River flows and public access to the river will be fully restored following completion of this project prior to the 2022 runoff cycle. DNRC appreciates your understanding as we work to ensure Painted Rocks Dam remains safe and efficient into the future.
For more information, please contact DNRC at (406) 444-0465. Thank you!