Sulphur Creek Watershed Analysis

The Sacramento Watersheds Action Group received a grant from the Cantara Trustee Council to conduct an assessment of the Sulphur Creek watershed, document the findings of the assessment, and make recommendations for watershed restoration projects. SWAG also initiated the formation of a Coordinated Resource Management Planning group (CRMP), which is now referred to as the Sulphur Creek CRMP.

SWAG conducted the analysis from the fall 1997-through fall 1998. The analysis includes documentation of major land uses, both past and present, an inventory of erosion and sediment sources, a stream habitat inventory, an analysis of riparian conditions, and a preliminary hydrologic analysis.

The Sulphur Creek watershed offers much potential for restoration, which will benefit fisheries, wildlife, community education and awareness, and recreation. Sulphur Creek, especially the lower reach, can provide excellent winter spawning and rearing habitat for native anadromous fish. Sulphur Creek, which is located within the City of Redding also offers tremendous potential for community and recreation use. The mouth of Sulphur Creek is located across the Sacramento River from the Turtle Bay Museum complex. The newly completed Sundial pedestrian bridge, which crosses the Sacramento River, provides access from the museum complex to the Sulphur Creek watershed.

Sulphur Creek watershed encompasses almost 3000 acres with 7 miles of intermittent stream and 2 miles of ephemeral stream, all located within a protected greenway. It is conceivable that a future extension of the trail system around the Turtle Bay Museum and Arboretum will connect with the upper watershed and Keswick Dam, providing over seven miles of continuous green space. These beneficial uses depend on restoration of the disturbed lands.

The lower and middle portions of the watershed exhibited the most evidence of disturbance from mining where the entire stream was dredged. The extensive mining, road building and railroad construction within the watershed resulted in severe deterioration of fisheries and wildlife habitat, alteration of the natural hydrology, and stream channel degradation.

In addition to dredger mining, the lower reach of Sulphur Creek, through the Arboretum, was also severely impacted by the installation of the Market Street culvert (1930s) and the construction of the Casa Blanca Motel (now demolished). The channel in this reach was dredged and the channel was filled with large deposits of boulders and cobbles. There is evidence that later gravel mining further concentrated large sediment deposits in the channel. The Market Street culvert then altered the natural flow and directed that flow through an area with high concentrations of dredger tailings. In the 1940s, the Casa Blanca Motel was built which permanently redirected the stream out of its original channel through large deposits of cobbles and boulders. In 1975, the City of Redding constructed a sewer line, with associated ridges of cover material, through the arboretum, which was known at that time as Benton Ranch. These continuous berms of sewer line acted as levees, which directed the stream out into the oak savanna and away from the location of the pre-1940 channel.

Sulphur Creek has tried to move through the dredger tailings and move the cobble as bedload for over five decades. The resulting abnormally high bedload in this reach has caused aggradation which in turn has caused lateral migration of the stream causing extreme bank erosion, loss of riparian vegetation, and an increase in the width to depth ratio. The lower reach is classified as a D3 stream type and lacks fisheries habitat features (e.g., pools, and vegetative cover).

As a result of this analysis and participating in the CRMP for two years, the following five restoration goals and their corresponding objectives have been established for Sulphur Creek. They are not listed in any particular order.

Goal 1: Increase habitat for Salmon, steelhead and other wildlife

• Establish and enhance a permanent managed riparian buffer zone on both sides of the stream for its entire length through all reaches
• Provide spawning gravel
• Build fish habitat structures in the lower and middle reaches
• Stabilize the streambank in the lower and middle reaches using natural materials and vegetation.
• Enhance aquatic habitat for invertebrates and amphibians
• Supply carbon materials to stream (leaf litter, woody debris)

Goal 2: Increase recreational and educational opportunities

• Build a multiple use trail along Sulphur Creek which would connect the arboretum to Quartz Hill Road
• Provide recreation and wildlife access over or under Market Street.
• Maintain and enhance recreation access through the Union Pacific tunnel
• Develop a trailhead and restroom facility in the middle reach.
• Install benches along the trail
• Develop a watershed-wide fire hazard reduction program.
• Establish interpretive vista points
• Establish salmon spawning view points

Goal 3: Decrease flood potential

• Build storm water detention ponds in the upper watershed
• New developments and urbanization should minimize impermeable surfaces as much as possible
• Replace the undersized culvert under Market Street
• Consider setback levees in the lower reach to protect existing developments

Goal 4: Improve water quality

• Repair upland erosion and sediment sources
• Provide the shade and canopy cover necessary to reduce thermal pollution and lower water temperatures
• Stabilize and protect the sewer lines
• Preserve the dredger ponds, establish wetlands and riparian buffer zones in all reaches
• Connect storm sewers to recharge basins
• Connect storm drains to down drains which will safely carry the storm water down slope without eroding the slopes
• Redirect storm drains to detention ponds

Goal 5: Restore the natural channel morphology

• Construct occasional deep pools and scour holes
• Develop a functional floodplain
• Encourage and prolong seasonal flows with stable low flow channels
• Remove excess dredger tailings from the stream
• Restore a stable sinuosity and gradient with the appropriate corresponding substrate; boulders, cobbles and gravel
• Establish a with to depth ratio which is typical for a stream of this type
• Treat identified large sediment sources which have the potential to negatively impact the sediment budget (e.g., Beltline road fill (Secret Canyon), Old Highway 99)

To conduct the assessment, SWAG formed an interdisciplinary team (ID Team) made up primarily of professionals who were members of the Sulphur Creek CRMP, or who workedfor an agency or group that was a member of the Sulphur Creek CRMP. The only members of the ID team who were not members of the SCCRMP were Sue Maurer, Russ Weatherbee, and John Hedges. Sue Maurer wais a fish habitat specialist from the Scott River CRMP. Ms. Maurer conducted the stream habitat inventory with the recommendation of Carl Harral, CDF&G Fishery Specialist. Russ Weatherbee was a GIS specialist with Whiskeytown National Recreation Area. John Hedges, from Hedges Aerial Surveys, provided the 1997 air photo. (This air photo may be viewed at the SWAG office.)