HYDROLOGY

The boundaries of BOR completely enclose four watersheds (three
tributaries of Arroyo Aguague and one tributary of Arroyo Hondo), facilitating ecological, biogeochemical, and hydrological research at the whole-watershed scale. Approximately two-thirds of the 1,320-hectare (3,300-acre) Blue Oak Ranch is drained by tributaries of Arroyo Aguague, itself a tributary of Coyote Creek (via Penitencia Creek), which flows into the southern San Francisco Bay. The remainder of the ranch is drained by Smith Creek in the Arroyo Hondo and its tributaries. The four perennial streams and their many intermittent tributaries are lined with bay-laurel (Umbellularia californica), white alder (Alnus rhombifolia), sycamore (Platanus racemosa), big-leaf maple (Acer macrophylum), and coffeeberry (Rhamnus purshiana).

Seventeen livestock ponds are well distributed around the property; most are man-made reservoirs fed by spring seeps or runoff. Many of the smaller, shallow ponds are ephemeral in years of average rainfall. The deepest reservoirs are Big Lake (21 feet deep), Rope Swing Pond, Cabin Pond, and Gramps’ Pond. These deep ponds normally contain water year-round, and serve as reliable habitat for a host of wildlife as well as a source of emergency water for wildfire suppression.

The streams and the seventeen ponds on the ranch represent the Sensitive Aquatic Resources Areas, and harbor concentrations of many species of aquatic and semi-aquatic species.

Posted on March 7, 2014 06:40 AM by infomgr