Colgan Creek Watershed Tour
Wherever you are, you’re in a watershed—a bowl-like function of landscape catching rainwater—where rainwater flows into a creek or river. The Colgan Creek watershed is almost 5,000 acres of drainage, and 9 miles of stream—one of many watersheds encompassed by the Russian River watershed. Colgan Creek’s headwaters are on Taylor Mountain, the County’s newest regional park. From here, water travels southwest across Santa Rosa and pours into the 30,000-acre Laguna de Santa Rosa, which joins Mark West Creek to enter the Russian River at Mirabel, and flows into the sea at Jenner.
Taylor Mountain Headwaters Hike
We begin our tour on Taylor Mountain early spring, when the rains have coaxed lush green grass from the mountain. We pay our park-use fee and approach the trail. Right away we are in the shadows of two tanks, six stories high and impounded by fencing topped with barbed wire. These Kawana water tanks hold 20 million gallons of Russian River water, including water from the Colgan Creek that flowed to the Russian River and was pumped back to the tanks.
Near the water tanks is the entrance gate where a sign instructs us to share this park with cattle. These gentle animals, if not managed properly, can harm the watershed, each one drinking up to 30 gallons a day, depositing waste on land and in the waterways, and trampling delicate habitat areas. Boldly, we enter the park and climb the mountain to explore the place where Colgan Creek begins.
Mt. Taylor is a healthy, oak woodland habitat. As we climb it, we find native wildflowers and plants that were useful to California Indians, and plants such as Indian lettuce, which still is gathered and eaten by modern-day foragers. We also find soap plant—named for one of its uses—and the California mugwort, which Pomos used for purposes including pain relief and religious rituals. In the damp earth we also notice small animal prints and the deep hoof prints of cattle.
Rainwater has also cut into the mountainside. Shallow cuts run into deeper cuts that release sediment into the creek. This sediment loss on Taylor Mountain has impacts that begin here and build up all the way to the ocean.
Excessive sediment releases degrade the water clarity needed by migratory fish, for spawning. The erosion we can see on a small scale here joins sediment erosion from other places, traveling to mouth of the Russian River at Jenner where, after a storm, it appears as a large brown plume stretching out to sea.
Sediment not reaching Jenner builds up in flat stream reaches, filling in gravel beds needed by spawning salmon and aquatic insects.
Above: Eroding head-cut on Mt. Taylor.
Right: Oak tree in eroding head cut, losing stability as soils are washed away.
Cows in the Watershed
Over time, these cuts become gullies that continue to erode and deepen, presenting danger to the cows. Cuts and gullies can trip and injure a heavy bovine, and steep ravines can trap and kill one. Riparian fencing and rotational grazing techniques can be used to mitigate destructive impacts from cows and prevent over grazing in the watershed.