The District has begun the planning process for the Upper Trinity River Wateshed. To date, we have compiled a summary of reports with information about the watershed, met with several landowners, spoken with land managers, visited properties with specific issues of concern, put out a Request For Qualifications for a consultant to assist in the development and evaluation of a watershed monitoring plan, and completed the data collection for a road inventory on private lands in the upper portion of this watershed.

Summary of Reports

Although this watershed has not been a high priority for watershed planning, there were still several studies that looked at the Upper Trinity River, probably the most thorough analysis is the Sediment Source Analysis for the Mainstem Trinity River completed by the EPA in 2001. This study developed estimates of sediment production and delivery by process for the entire Trinity River watershed (including the Upper Trinity River) using a combination of field measurements and indirect techniques, involving aerial photo and GIS-based analyses. Sources were stratified by time period, land use type, and dominant process, in order to assess management and non-management related sediment sources and their relative contributions. The purpose of this report was to compile, summarize, and analyze sediment production data for the Trinity River Watershed that could be used for TMDL development. The sediment production data are then integrated with other geomorphic information to develop a preliminary sediment budget for portions of the Trinity River watershed. This study combined office-based analyses of aerial photographs and GIS coverages with extensive field data collection and inventories, including considerable streamflow and sediment transport data collection. The report concluded that significant construction of new roads has led to increasing sediment yields from road surface erosion, despite improved practices.

Road Inventory Data Collection Completed

Road inventory and watershed assessment surveys are tools used by resource managers to identify sources of active sediment delivery to streams that can be detrimental to the local fisheries. Funding for most of these surveys tends to be tied to watersheds that feed into anadromous rivers, such as the Trinity or the South Fork of the Trinity, since the impact to salmon and steelhead can have such a broad economic effect. This year, however, the RCD received funding from the U.S. Fish and Wildlife Service to conduct an inventory in the Upper Trinity River Watershed (UTRW), which is an area that has been closed to anadromous fish since the construction of the Trinity Dam in 1964.

Working with assistance of the Natural Resource Conservation Service, the RCD has completed the survey of 114 miles of mostly gravel and native-surfaced roads on property owned by Timber Products Company, based out of Yreka. Timber Products owns 44% (17,650 acres) and manages 114 of the estimated 179 road miles of the area surveyed within the UTRW. For those of you who are familiar with the north part of the county, the surveyed area ends at HWY 3 at the base of Scott Mountain and starts at Mt Eddy near the Dead Fall Lakes area. If you have ever driven up the Parks Creek Road (also known as the IP road) then you have driven up, and through, the center part of the watershed covered by this survey.

To conduct the survey, RCD crews slowly drove the roads while using hand held GPS units and various measuring instruments, to identify and map active sources of sediment, such as landslides and road failures, as well as potential problems like undersized or plugged culverts and severe gully erosion in the road surface. Measurements were taken at stream crossings to calculate the amount of road fill over the culverts and to record the size, length and angle of the culvert. The main objectives of the survey were to:

• Identify all active sources of sediment delivery to streams
• Collect data necessary to evaluate adequacy of stream crossing culverts
• Identify stream crossings with potential to divert the stream down the road, if the culvert were to fail
• Locate, number and map all culverts

This winter, when the field season is over and the crew is office-bound, the information collected in the field will be entered into a data base and the GPS data will be entered into a Geographical Information System (GIS) program. With these two powerful tools, the data will be analyzed and the various features will be mapped out. The end result will be a resource that can be accessed by planners to prioritize sediment reducing watershed restoration activities that will lead to the improvement of stream habitats and the reduction in the amount of sediment that is delivered into the Upper Trinity River and Trinity Lake.