1. Watersheds and Hydrology
What’s Water Got to Do with It?
More water moves through ecosystems than any other material
The materials that it carries and deposits and the energy that it expends are major drivers in shaping the contour of the land and the habitat availability/suitability for organisms.
A resource that humans cannot live without
Slide discussing water and ecosystems

2. Watersheds and Hydrology Learning Objectives
Where do we find water?
What is the hydrologic cycle?
How many dimensions does a stream have?
4 How do we characterize stream water?
5 What do we want to know about stream flow?

3. Where do we find water? Question 1
Slide listing objectives for session 9, river as habitat

4. Global distribution of water

5. Global distribution of freshwater
Water Storage
Reservoir
Percent (%)
of total
Percent (%) freshwater
Oceans
96.5
Ice and Permanent Snow
1.74
68.7
Groundwater
1.7
30.1
Lakes
0.013
0.91
Soil Moisture including permafrost
0.023
0.26
Atmosphere
0.001
0.04
Streams, Rivers, Swamps
0.036
Biosphere
0.0001
0.003
Igor Shikomanov “world fresh water resources in Gleick 1993 Water Crisis (Oxford Press)

6. Watersheds and Hydrology
Where do we find water?
What is the hydrologic cycle?
How many dimensions does a stream have?
4 How do we characterize stream water?
5 What do we want to know about stream flow?

7. Question 2 What is the hydrologic cycle?
Precipitation
Interception
Infiltration
Evaporation
Transpiration
Runoff
Ground water

8. Watersheds and Hydrology
Where do we find water?
What is the hydrologic cycle?
How many dimensions does a stream have?
4 How do we characterize stream water?
5 What do we want to know about stream flow?

9. How many dimensions does a stream have?
Question 3
How many dimensions does a stream have?

10. Question 3 How many dimensions does a stream have?
Longitudinal (upstream to downstream)
Lateral (bank to bank and valley wall to valley wall)
Vertical (water surface to bed to hyporheic to ground water)
Temporal (time: seconds to millennia)

11. Longitudinal Changes in Streams
Certain characteristics of streams change ‘predictably’ from upstream to downsteam
Channels become wider
Channels become deeper
Flow becomes slower, but greater in volume

12. Longitudinal Changes – Reach Scale
Longitudinal changes are also observed at shorter scales than the entire river length
We call this shorter scale the “reach” scale
One example of reach scale changes is the pool-riffle pattern found in many streams draining areas with medium gradients
Riffle is an area of rapid flow over coarse substrate (sediment) whereas the pool is a slower flowing stretch with finer substrate

13. Lateral Patterns There are also some predictable changes laterally
The stream has its low flow channel, the low point of which is the thalweg
The stream has banks which define its frequent flow limit
The stream has a floodplain which defines its flow limit on less frequent events, annual or lesser frequency
Thalweg

14. Lateral Patterns
Some streams and rivers will have a single dominant channel while others have a network of interwoven channels

15. Lateral Features
As rivers increase in size they will develop a complex floodplain system

16. Vertical dimensions Velocity changes with depth in stream channel
Diagram by:Eric G. Paterson
Department of Mechanical and Nuclear Engineering
The Pennsylvania State University

17. Vertical Features Hyporheic (below stream) inter-actions
Exchanges occur with groundwater just below the stream

18. Lateral and Vertical Patterns
In many large alluvial valleys, creatures that live in ground water and hyporheic water can be found in the subsurface water kilometers from the stream.
In other words the stream extends well beyond its visible channel.

19. Temporal dimension Stream flow changes Second by second
Hourly
Daily
Monthly
Seasonally
Annually
Millenniumly
Channels migrate
Riparian areas go through disturbance and succession
Seasonal changes in inputs

20. Watersheds and Hydrology
Where do we find water?
What is the hydrologic cycle?
How many dimensions does a stream have?
4 How do we characterize stream water?
5 What do we want to know about stream flow?

21. What are the major physical, chemical,
and biological components used to
characterize water quality?
Slide outlines the objectives for session 10

22. Selected Important Habitat Factors
Light
Substrate
Temperature
Oxygen levels
Flow velocity
Food availability pH
Hydrologic, nutrient and sediment regimes
Organic input and transport
Toxics and other pollutants
Biological communities

23. Influence of temperature on growth rates
1.0
Midges
Daily Growth Rate (mg/day)
0.5
Blackflies
Daily growth rates as a function of temperature for three aquatic insects in Georgia. Modified from Benke 1993.
Mayflies 8 16 24 32
Temperature C
Modified from Benke 1993

24. Watersheds and Hydrology
Where do we find water?
What is the hydrologic cycle?
How many dimensions does a stream have?
4 How do we characterize stream water?
5 What do we want to know about stream flow?

25. What do we want to know about stream flow?
Question 5
What do we want to know about stream flow?
Magnitude - how much?
Frequency - how often?
Timing when?
Duration how long?
Rate of change – how fast?
Slide of ways to characterize flow, emphasis on magnitude.

26. 1982

27. Mean daily flow (cfs) Juanita Creek Water Year 2010
Oct
May

28. Mean Monthly Flows Juanita Creek Water Years 2005-2009

29. Oct 13 midnight
Oct 12 midnight

30. Mean Daily Flow Juanita Creek (cfs)

31. 15 minute flows Juanita Creek May 27-29, 2004

32. Unregulated
Regulated

33. How much water is enough?
Depends on who or what is using the water
Historically managed for minimum flows (what is the minimum flow that keeps fish alive)
Legal issue of water rights complicates situation

34. Examples of where to locate national data for watersheds and streams
Watershed data
EPA Surf your watershed
Climate data (national and international)
Climate data (Washington)

35. Examples of where to locate national data for watersheds and streams
Stream data- quantity and quality
USGS Water Resources Data
Soils data
Aquatic biologic indicators

36. 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
Summary slide of land use change and ecological effects.