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Assessment of Stream Habitat Conditions, and Recommendations for Improvement, in the Noyo River
This restoration planning assessment provides guidance to habitat restoration efforts in the Noyo River Hydrologic Sub-Area (HSA) in Mendocino County (Figure 1). It appraises habitat conditions, recommends measures to improve habitat, and identifies streams having particularly good habitat conditions.
The Noyo River HSA is about 106,260 acres, or 166 square miles, in size; it has about 150 miles of perennial streams potentially usable by salmonids. The main anadromous salmonid species in the HSA are steelhead trout (Oncorhynchus mykiss) and coho salmon (O. kisutch).
Habitat conditions for 51 streams were summarized from 52 stream habitat field surveys conducted from 1994 through 2004. Improvement recommendations for each stream were prioritized from the relative suitabilities of the habitat conditions, and also from habitat survey field notes and other available information. Additionally, a list of “priority” streams having good overall habitat conditions was developed from the aggregate habitat condition ratings for the streams, and consultation with local fishery biologists.
The habitat variables generally having the least suitability over the HSA are length in pools and pool shelter. Suitability of pool depth is generally high. Suitability of pool dominant fines is generally high. Suitabilities of riparian bank vegetation and shade canopy are generally high. The habitat condition ratings indicate that, of the conditions examined, length in pools and pool shelter are the conditions having the greatest limiting effects on coho salmon in Noyo HSA streams.
Water temperature monitoring data indicate that water temperatures are generally suitable for coho in the Pacific Ocean tributaries sub basin, including Pudding Creek and Hare Creek, and also in the South Fork Noyo River and tributaries. Water temperatures are less suitable in the mainstem Noyo River and in several tributaries to the upper mainstem Noyo.
The most common improvement recommendation for HSA streams is addition of large woody debris, which directly addresses poor pool shelter conditions widespread in the HSA. The improvement recommendations can be used as a starting point to develop restoration projects. The following are identified as priority streams, with relatively high quality overall habitat conditions:
- Pudding Creek
- Hare Creek
- Little North Fork Noyo River
- South Fork Noyo River
- Kass Creek
- North Fork South Fork Noyo River
- Parlin Creek
- North Fork Noyo River
- Hayworth Creek