2. 225 square miles 20 inches/yr rainfall

7. From the Main Street Bridge, Ventura River: Feb. 2, 2005 (above), Oct. 2, 2004 (below) looking downstream looking upstream

8. December 2005 top, November 2006 bottom – VR01

9. From the Foster Park Bridge, Ventura River: Feb. 2, 2005 (above), Oct. 2, 2004 (below) looking downstream looking upstream

10. The Ventura River upstream from Shell Bridge in July 2001, August 2002 and July 2003 (from left to right).

11. The river downstream of Shell Bridge in (clockwise from the upper left) June 2001, June 2002, June 2003 and February 2003.

12. From the Shell Bridge, Ventura River: Feb. 2, 2005 (above), Oct. 2, 2004 (below) looking upstream looking downstream

13. (left to right) VR02 in October 2002 & March 2003 May and June 2003 September & November 2003

14. December 2005 top, November 2006 bottom – VR02 left, VR03 right

15. Conductivity  The ability of dissolved ions to carry an electrical current  Most rivers range from 50 to 1500 µS/cm  Also a measure of total dissolved solids (TDS)  Drinking Water: < 1600 µS/cm or 600 mg/L TDS

22. VR01

26. land-use differences produce order-of- magnitude variations in nutrient concentrations