Elk Creek History
Elk Creek is a small (4,735 acres) urban coastal watershed located on the southern end of Crescent City in Del Norte County, California. Most of the watershed has been touched by urban, residential, and industrial development. The watershed includes the Elk Creek Wetland Wildlife Area and stretches into Jedediah Smith Redwoods State Park.
The majority of the Elk Creek basin is in private ownership with only 14% public. Approximately 40 percent of the basin has been developed, primarily focused in the lower (western) portion of the watershed. Development includes road building, removal of riparian vegetation, reduced connection to the floodplain, loss of wetland habitat, and increased urban runoff.
The Lower Basin
Above the estuary, the main channel of Elk Creek flows through a broad floodplain valley containing an extensive freshwater marsh. The main channel in this wetland complex has been historically modified through channelization, channel straightening, and rerouting in several locations through secondary connecting channels. There are also several examples of historic channels currently severed from the modern stream channel at the lower portion of the valley.
A portion of the lower basin was also historically developed into a lumber mill where a large log pond (~8 acres) was constructed. The upper portion of the valley appears to be largely unaltered having little evidence of historic channel modifications. Based on a lack of development encroachment, the lower two kilometers of Elk Creek represents one of the most substantial and intact relic coastal marshes in California. This is especially unique given its proximity to Crescent City, the most populated area in Del Norte County.
The main channel throughout the valley is approximately 4 kilometers in length and flows through a large open wetland complex with multiple channels and ponded areas. The channels through this section are flanked by a wide floodplain (150 – 300 meters) lacking both conifer forest and deciduous riparian tree cover. This wide valley lacking conifers indicates the lower watershed has substantial wetlands associated with the stream. This same area also has thick patches of reed canary grass (Phalaris arundinacea) which could be limiting native wetland plants and reducing water quality through oxygen demands from decaying biomass. Outside of this wide mesic floodplain, the entire inner watershed is flanked by thick stands of conifers dominated by Sitka spruce (Picea sitchensis) and Coast Redwood (Sequoia sempervirens). These forests currently provide a thick buffer between Elk Creek and the more developed portions of the outer watershed. Overall, the lower basin has very little gradient or elevation gain and has been modified by multiple large tsunami events depositing sand sheets throughout the lower watershed (Peterson et al. 2013).
The Upper Basin and Tributaries
The headwater forests of the eastern portion of the watershed are dominated by old growth coast redwood in Jedediah Smith Redwoods State Park. Northern basin headwaters drain upper Elk Valley containing a mix forested rural residential properties and pasture. Western headwaters are composed of numerous forested low-elevation finger gullies in the coastal plain surrounded by a mix of urban and rural residential areas of Crescent City. The eastern flank of the watershed contains a mix of commercial, rural residential, pasture, and forested lands. Although little work has been done describing spawning habitat distribution in Elk Creek (see results section), the only likely spawning habitat of any value occurs in headwater tributaries having higher gradients and sorted gravel.
The watershed has a history of alterations from timber harvest and grazing, which have reduced the quantity and quality of habitat for fish and wildlife. Timber harvest began in the early 1900’s and continued into the 1950s. However, there are intact stands of old-growth redwood that remain in the upper basin within Jedediah Smith Redwoods State Park (NMFS 2014). The remaining harvestable tracts are less than 100 acres. Likely the largest remaining negative impact from timber harvest occurs in the lower basin and main channel, which were dredged, channelized and/or filled around and upstream of the historical mill sites.
Given the many historical modifications, and present and increasing development pressure, restoration efforts are needed to increase water infiltration, restore salmonid access to habitats, and improve hydrologic function while accounting for the area’s vulnerability to climate change and sea level rise. The collection of essential data on the current conditions of the main channel and key tributaries that flow through Crescent City will allow us to map different restoration options that will improve fish passage, water quality, wetland habitat, and urban greening.