This project will remove fish migration barriers and significantly improve stream flow in Lemhi Little Spring Creek that will be important for functionally reconnecting this tributary with the Lemhi River. Actions necessary to complete this project include; (1) abandon  L-52, an upper Lemhi River irrigation canal that co-mingles with and captures water from Lemhi Little Springs before transporting this water approximately 6 miles, (2) install a new irrigation system that converts from flood to sprinkler irrigation and conserves water, (3) upgrade Idaho Power Co.'s transmission lines to 3-phase power, (4) remove all fish passage barriers on Little Springs, Mill Creek and a channel of the Lemhi River, (5) backfill L-52 at Mill Creek, Little Springs and a channel of the Lemhi River, (6) contour L-52 at points where ephemeral draws bisect L-52 to allow natural water flow during run-off events, (7) transfer water rights and develop an agreement not to divert between IDWR and the ranch.

Currently, L-52 withdraws 4-16 cfs from the Lemhi River, but also captures significant flow from Little Springs and Mill creeks. All three watersheds can be flow limited at critical periods for ESA listed Chinook salmon and steelhead.  This flow is transported 6 miles along a very inefficient water delivery system that results in high conveyance loss. L-52 is also a catchment for water runoff causing regular breaching of ditch banks leading to excessive erosion problems and sedimentation in the Lemhi River. With a new pivot system, only 2 cfs are needed to irrigate the same acreage more efficiently. Thus, instream flow will increase significantly in a segment of the Lemhi R, in lower Mill Creek, and in most of Little Springs Creek. Fish passage barriers at the interception of L52 with Little Springs and Mill creeks will also be removed. Lastly, stream habitat will be improved in upper Little Springs Creek because warm, turbid water previously injected by L-52 will no longer occur.

The removal of barriers and improved flow and stream habitat will benefit abundance, productivity, spatial structure, and genetic integrity of ESA listed Chinook salmon and steelhead in the Lemhi River sub-basin. These species will have greater access to good quality spawning and rearing habitat in Little Springs and Mill creeks. Specific benefits to the habitat include: (1) increased flows from 2-13 cfs for more than 6 miles of upper Lemhi River and/or Little Springs, (2) increased connectivity of lower Mill Creek with Little Springs, (3) improved connectivity of Little Springs with the Lemhi River (4) elimination of fish passage barriers in Little Springs, Mill Creek and a channel of the upper Lemhi River, (5) elimination of fish entrainment at L-52 and Little Springs as well as L-52 and Mill Creek, and (6) reduction of sediment and water temperatures in Little Springs.

The IDFG will complete compliance and effectiveness monitoring activities under the Lemhi Conservation Program. Implementation will occur under the Integrated Status and Effectiveness Monitoring Project. An effectiveness monitoring design will be developed to establish how these projects increase the quantity and improve the quality of existing habitat. Habitat response measures include adequate passage flows, the amount of wetted area provided by the target flow, the response of the riparian community, and changes in stream temperature.  Fish response will be measured in this reach at several intervals throughout the watershed. These include expanded distribution of anadromous fish, changes in survival, changes in size and age distribution of stream resident/fluvial trout, and changes in abundance. Monitoring strategies will include use of PIT tags and arrays to interrogate tags, electrofishing, snorkeling, and trapping.

Approximately 3.5 miles of Little Springs Creek will be monitored for project effectiveness, 0.5 miles of lower Mill Creek, and 0.25 miles of the Lemhi River.

The project incorporates numerous points of restoration (approximately 12 points) along a 7 mile reach of  L-52.

Project activities include:

(1) Survey utility easements and complete permitting requirements. (2) Upgrade electrical lines to 3-phase. (3) Complete on-farm sprinkler design.
(4) Obtain bids and construct on-farm irrigation system. (5) Restore numerous (approximately 12) points along L-52 including removal of barriers, back-filling portions of L-52 at diversion points, contouring points along ephemeral draws to natural grade. (6) Contour irrigated lands on Cottom Ranch to divert irrigation tail-water from entering Little Springs.