Rivers & Watersheds

1. Rivers & Watersheds

2. Rivers, streams, and Creeks http://ga.water.usgs.gov/edu/earthrivers.html • Water flowing over the earths surface from higher altitude to lower • Most water in theses comes from precipitation runoff • Runoff is lapped up, evaporates, diverted by people, sinks into the ground as groundwater recharging aquifers • Aquifers: The saturated zone beneath the water table and are huge storehouses of water. • Rivers flow through valleys and are part of that valleys watershed: where all water flows destined to be part of the drainage basin

4. Drainage Basin: water of all forms converges from the area watershed to a single point or basin

5. Largest drainage basin in US

6. Watershed A watershedand a drainage basin includes all of the land that drains into a river or bay either directly or through its tributaries. As it collects below high land forms it becomes a lake. It is called Reservoir if it is a dammed river.

7. Watershed The high land that separates one river valley or watershed from the next, is called the divide.

8. Upper Chattahoochee Water Shed • C:\Documents and Settings\PullenS\My Documents\Watershed Quality Assessment Report WATERS US EPA.mht

9. Summary of the flow of water • Creeks flow and merge into larger streams which flow and merge into even larger rivers which may find their end at a lake which is surrounded by high land forms ,or flow into an ocean or sea. • If people have built a Dam a river will become a reservoir: Lake Lanier is a reservoir

10. Rivers as Movers

11. Rivers as movers: They move a great deal of material. The faster the water moves, the larger material that can be carried down stream.

12. Fast moving upstream portions can often move rocks and boulders. Downstream portions usually only transport small silts and clays.

13. This process tends to sort materials by size. Larger heavier materials are left behind while smaller siltier materials flow with the river

14. A stream or river cannot cut its bed any lower than the body of water into which it flows. As the stream approaches this base level, the slope and speed of the stream decrease.

15. The river channel becomes wider, deeper, and the volume is bigger as there are more tributaries or smaller springs contributing to the volume.

16. The river valley also changes at this point. It becomes more open, more of a U shape with a wider river floor.

17. The lower or downstream portion of the river is at its deepest, widest and slowest speed. It also has the largest volume and a very gentle gradient.

18. The river valley tends to be broad, flat and bounded by bluffs. These bottom lands are often areas that flood.

19. Lower portions of rivers often start to meander or form a s-shape river pattern.

20. Erosion is greater on the outside of the bend, deposition more on the inside.

21. Rivers deposit the sediment they have carried as they slow down. This sediment load will often form deltas as the river flows into the quiet waters of a bay or gulf.

22. Stream Health in Georgia • Under Pressure - going change • Population growth • Sources of drinking water • Home for plants and animals • Flood control

23. What Makes a Stream Healthy? • Natural flows • Diverse Habitats • Pollution Free • Sources of food • Habitat • Chemistry…all contribute to Biological Integrity of a sustainable aquatic ecosystem

25. Biological Indicators • The presence, condition, and numbers of the types of fish, insects, algae, plants and other aquatic life provide accurate information about the health of freshwater, coastal and marine waters.

26. Biological assessments • evaluate the condition of a water body using direct measurements of the resident biota in surface waters and integrate the cumulative impacts of chemical, physical, and biological stressors on aquatic life

27. Biological Indicators and the EPA • Tell us the health of a system • The objective of the Clean Water Act is to restore and maintain the chemical, physical, and biological integrity of the Nation's waters. – Sec. 101 (a) • It is the national goal, that wherever attainable, an interim goal of water quality which provides for the protection and propagation of fish, shellfish, and wildlife and provides for recreation in and on the water be achieved by 1981. – Sec. 101 (a)(2)

28. Freshwater Threats • two-thirds of the nation’s freshwater mussels are at risk of extinction; almost 1 in 10 may already have vanished forever. • half of all crayfish species are in jeopardy • over 40% stoneflies are at risk • freshwater fishes and amphibians are doing little better, with about 40 percent of the species in these groups at risk • dragonfly and damselfy species have about 18% at risk.

29. Freshwater Ecosystems and Humans freshwater ecosystems are being severely damaged by human activities. The major threats to freshwater biodiversity include runoff from agricultural and urban areas, the invasion of exotic species, and the creation of dams and water diversion. Overexploitation and pollution also threaten groundwater supplies. These kinds of threats and others have already significantly impacted the biodiversity within these ecosystems.

30. How is Georgia’s Biodiversity Faring?

31. Macroinvertebrae or steams and wetlands • Organisms that lack an internal skeleton • Can be seen with naked eye • Mayflies, stoneflies,dragonflies, larvae • 97% of all animal species

32. Water Quality Indicators

33. Stressors of Macroinvertebrae • Urban and agricultural runoff: pollution point and non point • Thermal pollution: raises temperature depleting dissolved oxygen by addition of pollutants or removal of trees that cool the waters. Oraganisms rely on temperature changes for life functions. • Sewage and fertilizers: induce algae growth which then dies inviting bacteria which uses oxygen up – dissolved oxygen (DO)depletion caused by Eutrophication

34. Construction takes natural land forms away Poorly protected cropland adds sediment to the water causing turbidity. Destroys habitat –smothering organisms Introduction of alien species compete for resources and do not have natural predators

35. Environmental Degradation • Decreases diversity of streams by eliminating intolerant species leaving more tolerant ones. • If maggots, snails, and dragon fly nymphs exist the water quality is of low . • Diversity means good water quality • Summary of good water quality for a stream: variety of food sources, adequate dissolved oxygen levels, and temperature conducive to growth all indicated by water color, plant covergae, erosion, and stressors.

36. Lake Water Quality • Chemical Quality • Dissolved Oxygen • Nutrients: phopsphorus, nitrogen • Nutrient rich can cause eutrophication • Turbidity: solids in water such as dust, dirt algael. Water clarity allows for sunlight to reach photosynthetic organims which make oxygen for the water. Also warms water. • Ph: all organsims have preference

37. Water Quality Continued • Biological Quality • Water Clarity or Turbudity: algael, zooplankton,plant material indicated by a secchi disk • TDS: total dissolved solids • Phytoplankton • Zooplankton • Microbes and protists