Understanding Rivers and Streams: The Hydrologic Cycle and Drainage Basins

1. Rivers and Streams The Hydrologic Cycle

2. Rivers and Streams Drainage basinorwatershed

3. A River Drainage Basin Mill Creek Drainage Basin

4. Walla Walla River Drainage Basin Mill Creek Drainage Basin

7. Flow

8. Flow

9. Equilibrium and the longitudinal profile Gradient Velocity Discharge Q = V x A ft3/sec (cfs) or m3/sec (cms) V = velocity A = Cross-sectional area = Width x mean depth Base level (ultimate and local)Gradient Load

10. Velocity Variation

11. Variations with Discharge

12. Load

13. Load: • Bed load (rolling, saltation) • Suspended load: silt and clay carried in suspension • Dissolved load: ions in solution HCO3- SO42- Ca2+ Na+ Mg2+ typically  90% of dissolved Competence: the amount of load that a particular stream can carry

14. Load: Suspended Load

15. Load: Bed-load

25. 2000 Hydrograph for Mill Creek at Walla Walla 1800 Averages for 1942-1990 1600 1400 1200 1000 800 600 400 Maximum 200 Mean Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Discharge (cfs)

26. The Graded StreamThe Longitudinal Profile

31. Braided/Meandering

32. Braided/Meandering

33. Velocity Variation

34. Meandering and Floodplains

35. Point Bar – Cut Bank

36. Point Bar – Cut Bank

37. Point Bar – Cut Bank

38. Point Bar – Cut Bank

40. Meandering and Floodplains

41. Meandering and Floodplains

42. Meandering and Floodplains

43. Meandering and Floodplains

44. Meandering and Floodplains

45. Meandering and Floodplains

46. Meandering and Floodplains

47. Deltas

48. Deltas

49. Deltas

50. Deltas