Branch Creek enters North Fork Toppenish Creek at river mile 3.2, and drains a 23-square-mile watershed. Mid-Columbia River steelhead use the stream for spawning and rearing. Two locations on Branch Creek were identified as suitable for culvert removal and replacement by armored stream fords. One is located at RM 1.1 and the other at RM 1.4. The project is located in the NW1/4, NE1/4, Township 9 North, Range 14 East, Section 1, on tribal trust land in the closed area of the Yakama Reservation.
Agency Creek enters Simcoe Creek at river mile 9.5, and drains a 23-square-mile watershed. Middle Columbia River steelhead use the creek for spawning and rearing. Steelhead redd counts in Agency Creek have ranged from 4 to 20 since 1999, and the creek is recognized as a spawning aggregation for steelhead recovery purposes. Juvenile steelhead rear through the summer in the creek near its confluence with Simcoe Creek.
Yakama Reservation Watershed Project (YRWP) proposed to remove a culvert on North Fork Simcoe Creek just above its confluence with Diamond Dick Creek within the closed area of the Yakama Nation Reservation. The culvert was undersized and a seasonal barrier to ESA listed Middle Columbia River Steelhead (MCRS). At high flow, the culvert became clogged and temporarily re-routed water down the adjacent road stranding fish and damaging the road surface.