1. Lecture 12 - 1 ERS 482/682 (Fall 2002) Why watersheds? ERS 482/682 Small Watershed Hydrology

2. Lecture 12 - 2 ERS 482/682 (Fall 2002) Definition –ridge or stretch of high land dividing the areas drained by different rivers or river systems (e.g., Continental Divide) –the area drained by a river or river system –an area of land where all of the water that is under it or drains off of it goes into the same place

3. Lecture 12 - 3 ERS 482/682 (Fall 2002) http://www.cwp.org

4. Lecture 12 - 4 ERS 482/682 (Fall 2002)

5. Lecture 12 - 5 ERS 482/682 (Fall 2002) Figure P1 (NRC 1999)

6. Lecture 12 - 6 ERS 482/682 (Fall 2002) Why are watersheds important? We all live in a watershed

7. Lecture 12 - 7 ERS 482/682 (Fall 2002) Why are watersheds important? We all live in a watershed We all affect watersheds –Increased impervious surface Runoff Infiltration

8. Lecture 12 - 8 ERS 482/682 (Fall 2002) Why are watersheds important? We all live in a watershed We all affect watersheds –Increased impervious surface Runoff Infiltration –Waste discharges

9. Lecture 12 - 9 ERS 482/682 (Fall 2002) Why are watersheds important? Source: Center for Watershed Protection http://www.cwp.org

10. Lecture 12 - 10 ERS 482/682 (Fall 2002) Why are watersheds important? We all live in a watershed We all affect watersheds –Increased impervious surface Runoff Infiltration –Waste discharges We all use watersheds

11. Lecture 12 - 11 ERS 482/682 (Fall 2002) Watershed issues Runoff processes Hydrologic modeling Erosion Sediments Floods Urbanization Forest management Fire Grazing TMDL assessment