1. How do humans affect watersheds and the hydrologic cycle ?

2. Human caused disturbances Agriculture Timber harvest Mining Urbanization Introduction of exotic species Harvesting of fish and wildlife

3. Land use/cover and vegetation PhysiographyClimate Landscape controls Nutrient Inputs Solar energy and Organic input Regime Habitat Forming Processes Species assemblages Stream Morphology and Conditions Biodiversity Habitat characteristics & conditions e.g., pools, riffles, temperature, etc. Sediment and Streamflow Regime Modified from Roni et al. 2002.

4. Land Use and Vegetation The landscape control factor on which humans have the most influence –Mining: extent of vegetation alteration depends on type of mining –Forestry: tree removal and replacement over time –Urbanization: tree removal and replacement with grass and impervious surfaces –Agriculture: tree removal and replacement with pasture or crops

5. Effects of vegetation removal on hydrology and streams Precipitation ?

6. Effects of vegetation removal on hydrology and streams Precipitation ? Evapotranspiration ?

7. Effects of vegetation removal on hydrology and streams Precipitation ? Evapotranspiration Infiltration ?

8. Effects of vegetation removal on hydrology and streams Precipitation ? Evapotranspiration Infiltration Surface runoff ? Subsurface runoff ?

9. Effects of vegetation removal on hydrology and streams Evapotranspiration Infiltration Surface runoff Subsurface runoff Frequency and magnitude of peak flows ?

10. Effects of vegetation removal on hydrology and streams Evapotranspiration Infiltration Surface runoff Subsurface runoff Frequency, magnitude and timing of peak flows Materials transported to stream ?

11. Effects of vegetation removal on hydrology and streams Evapotranspiration Infiltration Surface runoff Subsurface runoff Frequency and magnitude of peak flows Materials transported to stream

12. Aggregate Mining In-channel mining In-channel and floodplain mining Photos by M. Kondolf

13. Effects of instream aggregate mining Continuity of sediment transport interrupted Produces local sediment deficit Can lead to increase accumulation of fines and blocking of sediment

14. Effects of instream aggregate mining Incision can lower the water table This can lead to loss of groundwater storage Can affect hyporheic zone Reduce summer base flow

15. Effects of floodplain and terrace mining Pumping to dewater pits –can lower base flows in the channel and increase evaporation from the waste pits – may increase saltwater intrusion near coasts If channel migration captures the pits, in-channel storage ponds will alter flow travel times Old pits may be altered to serve as off-channel winter habitat for salmon

16. FORESTRY

17. Photos by R.S. Lindsay Photo by Carrie Inman Agriculture

18. URBANIZATION

19. Forestry, agriculture and urbanization All of these human activities alter the watershed What alterations do they have in common?

20. Forestry, agriculture and urbanization Remove trees and other vegetation Soil compaction – increased runoff Reduce organic matter delivery Build roads

21. Large storage in soil, channel and valley floor Recharge Natural cleaning Pollutant wash off No recharge Rapid flow limited storage Slow flow NaturalDeveloped Reduced soil storage Limited infiltration Precipitation

22. Floods and Urbanization surface runoff vs. infiltration natural land cover vs. urban area

23. TREE REMOVAL INTERCEPTION EVAPOTRANSPIRATION SOIL MOISTURE SATURATED SUBSURFACE/ SURFACE FLOW RATE OF TIME IT TAKES WATER TO TRAVEL TO CHANNELS FROM STORM RUNOFF

24. CHANGES TO WOOD/ORGANIC REGIME CHANNEL ROUGHNESS AND STORAGE RATE OF WATER TRAVEL TIME THROUGH CHANNEL FLOW PEAKS EARLIER AND HIGHER DOWNSTREAM

25. Drainage Density time Q Q Low peak, gradual rise and fall Higher peak, quicker rise and fall Roads, Ditches, Drains Channels P P Lower drainage density Higher drainage density

26. Roads and Soil Modification Compacted Soil Soil removal/ Cut banks Ditches, culverts, drains Infiltration Soil water Storage space Surface runoff Subsurface flow interception Drainage density and water delivery to streams Soil saturation

27. How do we manage watersheds? Dept of Natural Resources Regulations U.S. Forest Service Regulations Clean water act Endangered Species Act Total Maximum Daily Loads (TMDLs) City and County Regulations

31. Washington Water Types Type S –Shorelines and large rivers Type F –Rivers and associated wetlands, lakes, ponds, etc. > 0.5 acres at seasonal low level and have FISH Type Np –Perennial streams without fish Type Ns –All other streams not included above- seasonally dry streams without fish

32. Regulations a function of water type and forest site class Core: No harvest or construction except for permitted road activities Inner Zone: Harvest allowed but must meet future desired conditions standards (140 yrs) Outer Zone: Must leave 20 conifer trees per acre > 12 inched dbh

34. Lab reminders Remember Q (discharge) = Area X velocity –Q units are volume/time –Area units are ft or meters squared –Velocity units are ft or m per second

35. Lab reminders Velocity meter method: –Do NOT take the average velocity of your flow meter measurements and multiply by cross-sectional area to get discharge Q. The velocity meter method involves summing the delta Qs to get the total Q. –That is, as your diagrams indicate, each place you took a velocity measurement is the center of a small area of the stream cross-section. As with the float method, Q=VA. As the spreadsheet indicates, compute Q for each small area and then sum all the Qs to get the total Discharge for the stream.

36. Take Home Messages Understand the interactions between land use/land cover and components of the hydrologic cycle Be able to describe what is typically measured in watersheds and why Be aware of Washington stream types and how they are used in management