Erosion and Turbidity Monitoring in Lost Man Creek, Redwood National and State Parks, Water Years 2003-2011

Klein, Randy

Redwood National and State Parks (RNSP) conducts an erosion control and prevention program to reduce long-term sediment yield from lands in the Redwood Creek basin, northern California. The extensive network of abandoned and failing logging roads in the basin poses risks to water quality of streams and dependent, federally listed threatened species. RNSP initiated a watershed restoration program in 1978, following expansion of the park (PL 95-250). The goal of the program is to reduce erosion and sedimentation of streams, and to restore the natural ecosystems to conditions similar to what would have existed without the logging disturbance. The program addresses roads both within the park as well as those outside the park through cooperative agreements with landowners. Typically, road removal in RNSP consists of excavating stream crossing fill material, restoring channels close to their original configuration, and placing excavated fill in stable locations to best mimic pre-disturbance topography and drainage patterns. Although completely preventing erosion following road removal is physically impossible, minimizing erosion and the resultant effects on downstream turbidity and suspended sediment concentrations (SSC) is an important goal of the program that reduces detrimental effects of excessive and chronic turbidity on federally listed threatened salmonid species (Sigler and others, 1984; Newcombe and MacDonald, 1991; Henley and others, 2000; Klein and others, 2003). Studies of erosional responses to road removal work (Klein, 1984; Weaver and Sonnevil, 1984; Weaver et al, 1987; Madej, 2001), and over 25 years of observations of road removal work in RNSP indicate that: 1) erosional responses are skewed, i.e., most sites will likely experience modest erosion with a few experiencing relatively large volumes of erosion, 2) the greatest erosional responses occur within the first several years following road removal, and greatly diminish with time as vegetation grows on excavation sideslopes and channels find stable grades and armor themselves with rock and woody debris, and 3) that causative factors cannot always be anticipated or mitigated. Since the inception of the program in 1978, the parks have employed adaptive management to modify restoration treatments to best meet National Park Service management policies and minimize post-treatment erosional responses. Road removal began in Lost Man Creek in 2000 and was completed in 2009. Before work began, RNSP developed a Biological Assessment (BA) in consultation with NOAA Fisheries to evaluate the possible effects of road removal on listed salmonids in Lost Man Creek, a tributary to Prairie Creek, and ultimately Redwood Creek. The BA included a proposal to undertake a post-restoration monitoring program which began in 2003. The objectives of the monitoring program were: 1) to assess the effects of the road removal program on downstream turbidity and suspended sediment concentrations; and 2) to provide adaptive management feedback for refining erosion control methods and application criteria aimed at minimizing downstream effects and maximizing cost-effectiveness. In response, NOAA Fisheries issued a Biological Opinion (BO) supporting the restoration work with terms and conditions requiring (among other things) the proposed monitoring program. The monitoring program was concluded in 2011, one year after road removal work was completed. This final report presents results for the entire monitoring period: WY2003-2011.

Erosion and Turbidity Monitoring in Lost Man Creek, Redwood National and State Parks, Water Years 2003-2011

See also

Collections