Fairfield Osborn Preserve - Hydrology

Hydrology

Copeland Creek and its tributaries drain this property; moreover, all of these streams rise on Sonoma Mountain and eventually discharge to the Laguna de Santa Rosa, which discharges to the Russian River. The Copeland Creek watershed is the southernmost drainage in the Russian River drainage basin. All creeks south of Copeland, beginning with Lichau Creek, are part of the San Francisco Bay watershed. Precipitation within the Copeland Creek watershed is considered moderate within the state of California; in fact, the maximum intensity for an historic one hour rainfall is classified as below average (at about 1.90 inches (48 millimeters) per hour). Since many of these upper reaches of Copeland Creek involve steep slopes, often above 50 percent, the momentum of streamflow in winter months is high. Even though soils in the watershed are moderately erosive, the extensive basaltic armoring of Copeland Creek minimizes sedimentation and produces an outcome of stream waters lacking in significant turbidity.