|Monday, Aug 19, 2013|
The removal of the dams on the Elwha River was put on hold last October while the National Park Service addressed issues associated with the water intake structure at the Elwha water facilities. Throughout the Elwha River Valley, though, park scientists continue to be busy with restoration and monitoring projects.
In early August, the interagency sediment team was out surveying the Elwha River. The team collected sediment samples to evaluate grain size distribution and surveyed floodplain deposits and longitudinal profiles of the river from Rica Canyon to the mouth.
Revegetation staff continues to monitor and assess planted and unplanted areas in the two drained reservoirs. Based on data collected at the end of last year, the mortality rate of six of the planted native species was 3%, which equates to a 97% survival rate.
Of the six species studied, the mortality rate for Douglas fir seedlings was the highest at 36%. The species with the highest rate of survival, despite being heavily browsed by deer, was black cottonwood, with less than 1% mortality. Ongoing research and plant trials are evaluating how to lower the rate of Douglas fir mortality and are expanding to look at the performance of other planted species.
This month, crews are revisiting 27 plots established in former Lake Mills in 2012 and installing 41 additional plots in former Lake Mills and former Lake Aldwell. At each plot, they are collecting data on ground cover, species richness, species abundance, and species performance in both planted and unplanted areas. Project managers will use this data to determine how well the area is revegetating and progressing towards forest development.
The Washington Department of Fish and Wildlife is in the process of installing a fish weir on the Elwha River. The weir, located downstream of the former Elwha Dam site, will be used by the state to count and collect fish. The weir is part of a multi-agency effort to monitor the influence of removing the Elwha and Glines Canyon dams on salmon and steelhead returns to the Elwha River ecosystem and minimize harm to steelhead and Chinook, both federally listed threatened species, during dam removal.
Each fish that passes through the weir is weighed, measured, and counted for the purpose of monitoring the fish populations. Depending on the species, the fish will either pass through and continue on its journey upstream or downstream or be collected and relocated to the clear waters of Little River, the state's rearing channel, or the tribal facility. Each August, the weir is installed on the Elwha River at the start of the Chinook and pink salmon run.
Park fisheries biologists have also resumed weekly fish surveys in the Elwha River and its tributaries. The fisheries crew will survey for adult fish and redds (nests) through the end of the run in the fall. Chinook and pink runs peak from late August though early September.
Click on the link below for more information about the Elwha River restoration project or go to the Elwha River restoration Facebook page.