L50 Habitat Restoration & LSC-3 Diversion Removal

Previously a 1.8 cfs water right was delivered via the Lemhi River L-50 diversion for 0.3 miles to be comingled into Lemhi Little Springs Creek (LLSC). The comingled water conveyed another 1.2 miles in LLSC, then was re-diverted from LLSC at the LSC-3 diversion into an unscreened open ditch for 2.8 miles to the point of use, traveling a total of 4.3 miles.
As part of this project, the landowner exchanged the point of diversion (POD) from L-50 and LSC-3 to an existing screened diversion, L46a, effectively closing L-50 and LSC-3. This improved Lemhi River stream flow by 0.9 cfs (652 acre-feet/year). The L-50 POD was not a fish passage barrier, but was removed as part of improving flow. A total of approximately 1.08 miles of stream is protected for sufficient flow for spawning and rearing habitat.
The open ditch irrigation system was converted to a pressurized pivot sprinkler system. The existing 49.2 acre irrigation footprint remains the same. A pump station, pivot and 960 feet (0.18182 miles) of irrigation pipeline were installed. The new irrigation system improved water conveyance and distribution efficiency.
The fish passage barrier at the LSC-3 (diversion) was removed by the landowner thereby preventing fish entrainment in the unscreened diversion. A total of 2.7 miles of stream was made accessible by removing this fish passage barrier.
The objective of this project was to close and remove both the L-50 diversion from the Lemhi River LSC3 diversion (fish passage barrier) on LLSC. This project was another step in the reconnection of LLSC with the Lemhi River.

The actions from this project will improve fish migration and remove the possibility of entrainment for ESA-listed species.