Tenmile Creek historically was suitable habitat for Chinook salmon, coho salmon and steelhead trout throughout the year, but now many reaches and tributaries become too warm to be supportive and in some years lose surface flow all together.  Since 2021, the SWRCB 319h grant has funded deployment of automated temperature probes that are tied to a weight and placed in flowing water to measure the streams ambient temperature.  Temperatures have varied widely depending on the flow year, and probes are exposed to the air when streams go dry.  For a full report on water temperatures and flow conditions, see reports developed for this project:  Tenmile Creek Aquatic and Riparian Condition Reports for WY 2022 and WY 2023.  Below are maps showing stream reach conditions in Water Years 2018 - 2023. ERRP collected data for a previous State Coastal Conservancy grant since 2018 and data and analysis are available in previous reports for WY 2018-2019 and WY 2020-2021. 

The riparian zone of a stream extends back from the water’s edge for different distances, depending on the slope of the adjacent hillside.  There are many water loving tree species that live in these areas including alder, willow, maple, cottonwood, and ash trees, but riparian zones can also be comprised of conifers and oaks.  Benefits of a healthy riparian zone are shade, cover over the stream, moderated stream temperatures, reduced bank erosion, accretion of sediment, and production of insects for fish food.  To learn more about riparian zones, see http://www.krisweb.com/stream/riparian.htm

In addition to the bioengineering project that will produce willow thickets that extend out over the stream, non-native Himalaya berry will be removed from Cahto Creek sites on the opposite bank and native tree gallery forests will be created in their place (see Hogan and Mueller plans).  Riparian zones can have substantial influence on water temperatures and ERRP is conducting a study on Cahto Creek at ten nine different sites to determine air temperature variability related to stand conditions.  For a complete summary of data and analysis of air temperature data, see the Tenmile Creek Aquatic and Riparian Condition Report for WY 2023.

Open sites, such as the Hogan property on Cahto Creek, where there is currently only Himalaya berry, and along the power line at the Cahto Creek Ranch, had the highest and lowest air temperatures.  Sites with multi-tiered canopies had lower peak temperatures and less severe cold in winter as they create a microclimate that can also buffer water temperatures.  The baseline data collected at the Hogan site will allow long term assessment of changes with seral stages.

Effects of excess sediment in streams may be subtle, where fines fill spaces between gravel on the bed, or they may be dramatic where pools are filled.  A method know as V-Star can be used to measuring fine sediment in pools in order to quantify sediment levels.  Excess sediment transport reduces aquatic insect production, decreases salmon and steelhead egg and alevin survival, fills pools and can widen the stream course making it more subject to warming. In the most extreme cases, streams can be so deeply buried that they may lose surface flow.  Learn more at: www.krisweb.com/stream/sediment.htmi