What do we measure besides water in streams?

1. What do we measure besides water in streams? USGS Water quality, e.g. temperature, pH, nutrients, sediment Wood Fish Insects EPA EPA

2. Engineering view of a stream 1 5 V = 2 m/s A = 3 m2 n = 0.04 t = 120 N/m2 Ecological view of a stream B-IBI = 23 pH = 7.2 TDS = 110 mg/l DO = 8.3 mg/l D50 = 10 cm Adapted from Gordon et al. 1992

3. Landscape controls Land use/cover and vegetation Physiography Climate Gross reach morphology Habitat Forming Processes Solar energy and Organic input Regime Nutrient Inputs Sediment and Hydrologic Regime Stream Morphology and Conditions Habitat complexes and conditions e.g., pools, riffles, temperature, etc. Biodiversity Species assemblages Modified from Roni et al. 2002.

4. Effects of human disturbances on rivers and floodplains Session 11

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

6. Developed Natural Rapid flow limited storage Slow flow Pollutant wash off Natural cleaning Large storage in soil, channel and valley floor Limited recharge Recharge Adapted from Booth

7. 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

8. FORESTRY

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

10. URBANIZATION

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

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

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

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

15. Why do we care if human disturbances lead to changes in streamflow?

16. Streamflow functions • Medium where aquatic organisms live and propagate • Provide the forces that create and maintain in-channel and off-channel habitat, riparian patch communities, etc. • Rejuvenate floodplain soils and vegetation and recharge groundwater

17. River Transect floodplain Ward and Tockner 2001

18. Streamflow functions • Provide the forces that create and maintain in-channel and off-channel habitat, riparian patch communities, etc. • New channel formation • Wood recruitment and distribution • Sediment recruitment and transport • Removal of fines

19. Streamflow functions • Rejuvenate floodplain soils and vegetation and recharge groundwater • Maintain connectivity with hyporheic zones • Redistribute soil and nutrients to floodplain forest • Distribute seeds and prepare seed beds

20. Local processes --------------------------------------Catchment processes Meandering reach Glacial floodplain Lowland floodplain Landscape diversity Low ----------------------- Water Level -------------------------------- High Ward and Tockner 2001

21. Which characteristics of streamflow are important to assess?

22. Flow characterization • Magnitude - how much? • Frequency - how often? • Timing - when? • Duration - how long? • Rate of change – how fast?

23. 3 7 30 90 1 3 7 30 90 • Day minimums Day maximums 1

24. MAGNITUDE • TREE REMOVAL TENDS TO INCREASE • ANNUAL WATER YIELDS • TENDS TO INCREASE PEAK FLOWS

25. Flow characterization • Magnitude - how much? • Frequency - how often? • Timing - when? • Duration - how long? • Rate of change – how fast?

26. FREQUENCY • INCREASED DRAINAGE DENSITIES AND • DECREASED STORAGE MAY • INCREASE THE MAGNITUDE OF • COMMON RUNOFF EVENTS

27. Unregulated Regulated

28. Flow characterization • Magnitude - how much? • Frequency - how often? • Timing - when? • Duration - how long? • Rate of change – how fast?

29. TIMING • A SWITCH FROM SUBSURFACE TO SURFACE • FLOW PATHS DELIVERS EVENT • WATER TO CHANNELS FASTER • CHANGES IN STORAGE IN THE WATERSHED • CAN ALTER SEASON OF PEAK RUNOFF

31. Flow characterization • Magnitude - how much? • Frequency - how often? • Timing - when? • Duration - how long? • Rate of change – how fast?

32. RATE OF CHANGE • CHANGES IN HYDRAULICS FROM CHANGES • IN SEDIMENT SUPPLY OR WOOD • SUPPLY AFFECTS THE RISE AND FALL • OF PEAK FLOWS

33. Channelization, dams and diversions change many features of stream ecology

34. Take – home messages • Flow regimes play a major role in habitat • Land-use alters flow paths and storage components and hence, flow regimes • Effects vary with spatial and temporal scales • Research on which aspects of flow are most critical to various biotic responses are in progress • Don’t forget the basic processes involved