The Upper Feather River watershed (UFRW), in California's northern Sierra Nevada, includes approximately 60,000 acres of upper-watershed irrigated rangelands. Three years (2005-07) of ambient water quality monitoring (Phase 1) in the UFRW demonstrate limited water quality impacts in the form of increased temperatures, decreased dissolved oxygen, and increased E. coli concentrations. In summer of 2007, we began more detailed monitoring within the watershed to pinpoint sources of E. coli and identify management practices which contribute to high in-stream water quality.

We hypothesize an improvement of in-stream water quality with the employment of more water-conservative irrigation management in the UFRW. However, changes in irrigation management must demonstrate a direct benefit to the land manager to be adopted on the watershed scale. Thus, simultaneously in summer 2007, data collection commenced on a study of the correlation between soil moisture characteristics and forage quality in Sierra Valley, the largest valley in the UFRW.

Our hypotheses are:

1.) Depth to water table will correlate with forage quality (nutrition and palatability) and abundance, such that with increasing depth to water table, forage quality will improve to a certain point, beyond which forage quality will decrease.

2.) Soil moisture will correlate with forage quality such that with increasing soil moisture, forage quality will improve to a certain point, beyond which forage quality will decrease.

3.) Plant species community composition will vary with soil and hydrologic regime.

We aim to identify optimal soil moisture conditions for maximal forage production to be used as a guideline for irrigation management in the UFRW.