Meacham Creek - Bonifer Reach Floodplain Connectivity II

The PCSRF funds were used specifically for the excavation of the new side channel habitat which resulted in the creation of .18 miles of off-channel stream creation and for 25 acres of off-channel area to be connected. Using non-PCSRF funding sources, 13.4 acres were planted and .1 acres of wetland was treated and .04 acres of wetland was created. Work was completed outside of the work window and within the ordinary high water during the fall of 2017 so the project was completed sooner than expected.

Over the last 150 years, much of the Meacham Creek watershed has been negatively impacted by road construction, agriculture and livestock grazing, the Union Pacific Railroad and other human activities. Direct channelization and the construction of levees and spur dikes also occurred in Meacham Creek following the 1964 flood, which have altered natural hydrologic and geomorphic processes that shape the form and function of Meacham Creek. Channel sinuosity has greatly decreased from historic conditions from 1916 to present. The decrease in sinuosity corresponds with the construction of levees and spurs dikes and a loss of valley floor width from the railroad encroachment. As a result of extensive levees, spur dikes, cattle grazing, and other impacts, Meacham Creek is subject to problems associated with decreased floodplain connectivity, degraded channel structure, limited large wood and sources, altered hydrology and sediment transport, poor riparian cover and conditions, and elevated water temperatures and rate of heating. Key in limiting salmonid fish production, these watershed impacts led to high stream temperatures, lack of summer flow, limited floodplain connectivity, lack of overall habitat complexity and side-channel habitat, and limited in-stream shade and cover. Specifically identified primary limiting factors for the Meacham Creek watershed include in-channel characteristics, floodplain/riparian, sediment, and water quality – temperature. Each of these factors limiting fish production has contributed toward Middle Columbia River steelhead and Columbia River Basin bull trout that are present in the Meacham Creek watershed being federally listed as threatened under the ESA of 1973, as modified.

Habitat enhancement in the upper Umatilla focus area, and specifically in Meacham Creek, is expected to reduce summer stream temperatures, improve overall channel and floodplain stability, and ultimately improve aquatic habitat conditions. The CTUIR natural resource staff expects measurable response in key characteristics of hydrology, geomorphology, and connectivity resulting in improved riparian vegetation conditions and improved conditions for important aquatic species. Specifically, proposed actions are expected to improve connectivity between surface flow and shallow groundwater in the channel and floodplain, and the riparian forest. This will result in cooler in-stream water due to the influence of increased hyporheic interaction. We expect to observe increases in the incidence of cold water refuge areas for salmonids (e.g. pools and reaches downstream of meander bends or islands). Adverse impacts associated with the implementation actions are expected to be temporary and insignificant when compared to the expected long-term benefits to the upper Umatilla focus area ecosystem.

The future management of these project areas will remain the same as they are currently. The CTUIR owns most of the project areas with some individual allotments interspersed. Since the purchase of the property, the only livestock grazing that has been permitted is the use of goats to control invasive plant species. Furthermore, there is a fence running the full length of the railroad right-of-way to prevent trespass cattle grazing.