Information from and email by Larry A. Schock, CFM DNRC Water Resources Division
The DNRC has received several inquires lately concerning the outflows at Painted Rocks Reservoir and how the reservoir is operated. Therefore, the following email will provide a brief explanation of reservoir operations.
The operation of Painted Rocks Reservoir involves three main parties. The DNRC, the Painted Rocks Water Users Association (PRWUA), and the MT FWP. Painted Rocks Reservoir holds approximately 32,656 acre-feet (af) of water, with 25,000 af of that stored water marketed to the MT FWP and the PRWUA. Additionally, there is the Bitterroot River Water Commissioner who manages the river in a manner that insures the apportionment and diversion of decreed and contract waters.
The DNRC is owner of the dam and the reservoir area. It is our responsibility to insure that the reservoir is filled and operated safely and that water is available for delivery to the contract holders. Once the reservoir is full the amount of water that flows into the reservoir equals the reservoir outflows. The reservoir is held in this state of equilibrium until the contract water is requested. The DNRC is under contractual obligation to deliver the contract water a the dam to the contract holders when it is called for.
The 10,000 af (or 2/5ths) of shares that has been marketed to the PRWUA is primarily used for agriculture purposes. Releases to the PRWUA usually occurs in mid July, but it is delayed this year due to higher than normal flows on the East Fork and the Mainstem of the Bitterroot River.
The other 15,000 af (or 3/5ths) of shares has been marketed to the MT FWP for in-stream uses . The local FWP contact in the Bitterroot Valley is Chris Clancy at 363-7169. The FWP contract water is released for instream flows in the mainstem of the Bitterroot River, based upon the conditions at Bell Crossing. According to the FWP current guidelines, they determine their desired releases based upon a minimum targeted flow rate of approximately 450 cfs at the Bell Crossing gage. As of today the flow rate at the Bell Crossing gage is approximately 737 cfs. The current FWP guidelines do not discuss the release of water from the reservoir for the augmentation of flows in the West Fork of the Bitterroot River, only the mainstem of the Bitterroot River.
Recently inquires have been made to the DNRC about the following issues; low water levels effecting raft access to the river; low water levels effecting quality of fishing; low water levels effecting water temperatures; and bad access road into the shuttle parking area upstream of the USGS gage below the dam.
Low Water Levels
The low flow conditions in the West Fork of the Bitterroot River are simply a reflection of the low inflows into the reservoir. As inflows to the reservoir drop, the DNRC adjusts outflows to match. The DNRC is passing all of the inflows through the reservoir, either over the spillway or out of the low level outlet. Flows below the dam will raise, pending a call for contract water from either the PRWUA of the MT FWP. The DNRC has recently made several gate adjustments on July 23rd, 24th, and 28th in order to insure that the reservoir outflows matched the inflows. These adjustments are also needed in order to transition the flows from the spillway to the low level outlet in preparation for the anticipated contract water deliveries. An additional adjustment is anticipated on July 31st. Requests for the release of contract waters for in-stream purposes on the West Fork of the Bitterroot River should be directed to the FWP.
The dirt road that goes upstream past the USGS gage to the pioneer launch site below Painted Rocks Dam, is not a DNRC road and it is located on US Forest Service (USFS) property. Any concerns about this pioneer road, launch, and camping site should be directed to the USFS West Fork District Ranger Office.
Larry A. Schock, CFM
DNRC Water Resources Division
Missoula Regional Office
Click here to go to the Montana Fish, Wildlife, and Parks (MT FWP) site for the West Fork of the Bitterroot.
Click here to go to the MT FWP site for Painted Rocks Reservoir, Tributary of the West Fork of the Bitterroot. They have an interactive map link.
Click here for contact information for US Forest Service, West Fork Ranger District.