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This program covers various topics related to watersheds, biodiversity, the water cycle, the river continuum concept, and stormwater runoff. It also includes information on water chemistry certification for Alabama Water Watch.
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Today’s Outline: • Review: what is a watershed? • Alabama Biodiversity • The Water Cycle • River Continuum Concept • Stormwater Runoff 6. Water Chemistry Certification for Alabama Water Watch
Review: What are Watersheds?
1. Watersheds • Major Alabama Watersheds • Watersheds = an area within which all surface water drains to a common waterway
2. Watersheds • Watersheds can be nested: smaller ones within larger ones
3. Watersheds • Basin: A collection of watersheds draining to the coast at a single point. • E.g., Mobile Basin
4. Watersheds • Birmingham straddles 2 major watersheds: • Cahaba and Black Warrior • Watersheds and Basins: great concept for teaching • Social sciences/studies • Natural sciences Themes: Everybody Lives in a Watershed. We are all connected through our watershed.
5. Biodiversity • The more diversity of watersheds, the more species an area will have. Extensive Watershed diversity in Alabama: • 2 major river basins • 13 major watersheds • Vast network of rivers
The Big Picture: The Water Cycle
6. The Water Cycle Our’ Blue Planet Water Distribution on Earth • 97.2% in oceans • 2.8% on land • 2.2 % is ice • 0.6 % is groundwater • <0.01 % is lakes • <0.001 % is rivers
The Water Cycle (Aka: The Water cycle)
Linking the Water Cycle to Watersheds, to Biodiversity: The River Continuum Concept
7. River Continuum Concept • Rivers change as the progress from the headwaters to the coast • Size • Speed • Habitat types • Biodiversity
8. River Continuum Concept • Headwaters: • Small creeks and streams • Rocky substrate (bottom material) • Narrow streams, often steep hillsides • Forested margins, well-shaded
9. River Continuum Concept Midreaches • Wider channel • Much direct sunlight • More nutrients than headwaters • More plants than headwaters • Substrate: smaller materials: smaller rocks and sand
10. River Continuum Concept Lower Reaches • Slower current • deeper channel • “Muddy water” • High nutrient levels • Substrate: shifting sands and silts • Few plants • Swamps
11. River Continuum Concept • Estuary: interface of freshwater rivers and oceanic waters.
12. River Continuum Concept • The different zones of a river (headwaters to lower reaches) provides different habitats for different species. • But even within a small area, different habitats support different species. The more diversity of natural habitats and conditions, the more species will be supported.
Threats to Rivers: Focus on urban runoff
13. Threats: Urban Runoff The Major Threats to Rivers: • Dams • Sedimentation • Pollution • Over-extraction of water • Invasive species • Stream channelization • Urban Runoff – a place to start teaching about watersheds
14. Threats: Urban Runoff • Runoff: Water from precipitation that flows across the surface to the nearest drainage • Stormwater: runoff from developed areas
15. Threats: Urban Runoff Effect of Impervious Surfaces • What causes runoff? • Impervious surfaces block the absorption of rainwater into the ground. • Impervious surfaces: pavement, streets, roofs, sidewalks
16. Threats: Urban Runoff • Effects of increased Runoff • More and higher floods • Low flows during dry season • Sometimes: discharge of raw sewage into rivers • Increased pollutants • Fine sediments • Hazardous chemicals • Nasty bacteria • Nutrients
17. Threats: Urban Runoff Flooding: • Because rainwater doesn’t percolate into the soil, stormwater gets rapidly ‘dumped’ into creeks, streams and rivers. Trussville, May 2003
18. Threats: Urban Runoff • With floods, stream habitats altered and destroyed • High volumes scour stream substrates • Secondary bank erosion • Loss of habitat
19. Threats: Urban Runoff Low flows • Because groundwater isn’t recharged, there is little in reserve to keep streams flowing when rains are infrequent.
20. Threats: Urban Runoff • Sewage Discharge • Stormwater system • Collects rainwater and directs it away from developed areas. • In some cities, including B’ham, stormwater was linked to sewage system. • When it rains…
21. Threats: Urban Runoff …Sewage treatment plants can’t handle the large volume of water. • Stormwater and sewage dumped into streams and rivers • Yuck.
22. Threats: Urban Runoff • Runoff and Pollution • Runoff contains toxins: Runoff contains contaminants: oil, gas, other car drippings, fertilizers, herbicides, pesticides, detergents, etc.
23. Threats: Urban Runoff • Runoff containssediments: sand and silt • From construction • From developed areas
Threats: Urban Runoff • Sediments fill and cover habitats in river. • Esp Sand and silt • Crevices between rocks needed for fish, insects, mussels, etc.
Threats: Urban Runoff • All this impacts our drinking water
24. Threats: Urban Runoff • Why use Urban Runoff as a starting point for teaching about watersheds? • It is an urban problem • Urban students will be familiar with stormwater systems and problems • It is wherever you are • Easily observed in or near your school • Impacts are far-reaching, involving social and environmental issues
25. Threats: Urban Runoff Community–building themes • Everyone lives in a watershed • Anywhere you stand, you are in the watershed • We share the watershed with each other, and with the ecosystem Questions to stimulate thought • Where does the water go from any location? • What is the nearest creek or stream, and where does it go? • Where does stormwater from our school and our homes flow? • Who lives downstream from us, and how are we affecting them? • Who lives upstream from us, and how are they affecting us? • What can we do to be better watershed citizens?!