Cottom Little Springs Creek

Project Narrative

An undersized culvert at a road crossing was replaced with a 5 x 24 squash culvert eliminating one fish passage barrier. This opened up 1.21 miles of anadromous salmonid bearing stream. After the culvert was replaced a new inlet and outlet channel was established, the creek was rerouted and a stream meander was established by the realignment.Approximately .38 miles of the Little Springs stream channel was narrowed from 12 feet wide to 4 feet wide and sinuosity was increased with the placement of native sod and willow cuttings were planted on both sides of the channel. An additional .07 miles of Little Springs Creek streambank was stabilized using anchored coir log revetments and re-contouring of slope to 3:1. Originally the project proposed to create pools through the above mentioned channel reconfiguration and connectivity as well as placement of instream structures. The creation of pools was dropped after a site visit by the USBWP/OSC/IDFG technical team (tech team). The tech team advised the project sponsor that the pools would be created naturally created through the channel reconfiguration treatment and therefore the creation of pools was unnecessary. Two rock sediment barriers constructed of washed angular rock (136 cubic yards) were placed to reduce sediment transport into the project area from an adjacent flood irrigated pasture. These structures were placed across an existing down cut gully and will also help reduce additional down cutting and bank instability by concentrating cattle traffic over the sediment barriers. Native willow cuttings (1200) were planted on the stream bank and adjacent riparian areas (1.5 acres). Upland grass seeding and straw mulch was applied on adjacent upland soils to rehabilitate where re-contouring and ground disturbance from machinery had taken place. Walters Creek (a perennial tributary to Little Springs Creek) was reconnected to Little Springs Creek by plugging an unused irrigation ditch that intercepted and diverted the entire flow channel and dewatered the natural channel. The natural channel (.58 miles) was rewetted by this action and an additional 1.85 cfs of base flow will now reach Little Springs Creek.