1. Fluvial Geomorphology GRG 338-C Streamflow (Discharge)

2. Importance geomorphic significance (performs “work”)! hydrology water resources ecological

3. Big Thompson River, CO

4. Rio Pánuco, San Luis Potosi

5. Rio Tamuin, San Luis Potosi

6. Mississippi River bank erosion, upstream of New Orleans

7. Rio Moctezuma, San Luis Potosi

8. Importance geomorphic significance (performs “work”)! hydrology water resources ecological

9. Lower Rio Panuco @ Panuco, Veracruz

11. Importance geomorphic significance (performs “work”)! hydrology water resources ecological

15. Importance geomorphic significance (performs “work”)! hydrology water resources ecological

16. Channel bar / aquatic habitat Oxbow lake / riparian wetlands Delta / coastal wetlands

19. Flow Paths to Stream Channel

20. Runoff Ground water (base flow) Sources of streamflow (discharge) have different travel times Runoff (throughflow) Ground water

21. Hydrographs express the relationship between discharge and time single event hydrograph

22. Discharge (m 3 /s) Time (hours, days, weeks) Single event hydrograph shape a function of runoff and base flow 2 1 3 4 5 6

23. Runoff Ground water (base flow) Source of streamflow determines the hydrograph shape

24. Discharge (m 3 /s) Rising Limb Base flow Runoff Falling limb Peak Time (hours, days, weeks) Elements of a single event hydrograph

25. Depth (D) Width (W) Velocity (V) Continuity equation for discharge (Q): Q (m 3 /s) = V (m) * A (m 2 )

26. q i = w i (d i 1 + d i 2 ) (v i 0.2 + v i 0.8 ) 2 2 Q =  q i w d d v 0.2 v 0.8

28. v = velocity (m/sec) d = depth (m) w = width (m) Q, q = discharge (m 3 /sec) v i 0.2 v i 0.8 q i = w i (d i 1 + d i 2 ) (v i 0.2 + v i 0.8 ) 2 2 5.0 m 6.5 m 3.0 m 1.7 m 0.0 m 5.0 m 0.9 0.1 0.2 0.5 0.8 0.7 1.9 2.3 0.9 0.2 q 1 = 0.64 m 3 /sec : (5.0 * 0.85 * 0.15) q 2 = 7.64 m 3 /sec : (5.0 * 2.35 * 0.65) q 3 = 30.9 m 3 /sec : (5.0 * 4.75 * 1.3) q 4 = 46.0 m 3 /sec : (5.0 * 5.75 * 1.6) q 5 = 6.88 m 3 /sec : (5.0 * 2.5 * 0.55) Q = 92.1 m 3 /sec

30. Q (cms) Q – stage rating curve standard procedure for estimating Q Stage (m) 48 46 44 755025

31. Q (cms) Q – stage rating curve uniform x-sec. geometry Q bf Stage (m) 48 46 44 75 5025 Q bf floodplain

32. Discharge (m 3 /s) Ground water Runoff Time a. b. c. a.b. c. Channel scour and deposition during a single event

33. Q – stage rating curve non-uniform x-sec. low – high channel Q (cms) Stage (m) 48 46 44 755025 Low flow High flow

35. Q – stage rating curve non-uniform x-sec. low floodplain Q (cms) Stage (m) 48 46 44 755025 Low floodplain High (older) floodplain

36. Guadalupe Valley at Cuero, TX

38. Guadalupe River @ Cuero, TX (06/27/02 - 07/31/02) 0 5 10 15 20 25 30 35 40 020000400006000080000 Discharge (cfs) Gage Height (ft)

43. Guadalupe valley at Cuero

44. Q – stage rating curve single line assumes scour = deposition during flood event Q (cms) Stage (m) 48 46 44 755025 Q (cms) Stage (m) 48 46 44 755025

45. Channel scour (erosion) and deposition (infilling) during Q event influences rating curve Max. scour

46. Discharge (m 3 /s) Base-flow Runoff Time a.a. b.b. c.c. a.a. b.b. c.c. Scour = deposition Q (cms) Stage (m) 48 46 44 755025 b.b. a.a. c.c.

47. Scour < deposition c.c. b.b. a.a.

48. Q (cms) Stage (m) 48 46 45 755025 Scour < deposition c.c. b.b. a.a. b.b. a.a. c.c.

49. Guadalupe River @ Cuero, TX (06/27/02 - 07/31/02) 0 5 10 15 20 25 30 35 40 020000400006000080000 Discharge (cfs) Gage Height (ft)

50. Rising stage Falling stage

51. Factors influencing the shape of hydrographs a.Precipitation characteristics b.Surface characteristics c.Basin characteristics

52. Factors influencing the shape of hydrographs a.Precipitation characteristics distribution intensity duration seasonality

53. distribution

54. Factors influencing the shape of hydrographs a.Precipitation characteristics distribution intensity duration seasonality

55. Factors influencing the shape of hydrographs a.Precipitation characteristics b.Surface characteristics influence on runoff and baseflow!! c.Basin characteristics

56. b. Surface coverage Consider how influences infiltration and runoff!!! land use soils vegetation

57. Urbanization results in higher rates of runoff due to a reduction in infiltration influence on hydrograph?? influence on hydrograph?? Impervious cover 2.5 cm/hr

58. Runoff… high rates! Ground water… much lower! Urban hydrology…

59. Rising Limb Base flow Falling limb Peak Discharge (m 3 /s) Time (hours, days, weeks) Runoff New Hydrograph… due to increased impervious cover higher highs… and lower lows steeper rising limb higher peak discharge steeper falling limb low base flow Ground water

60. Infiltration capacity (cm/hr) Time after onset of rainfall (hours) 3 2 1 321 Coarse-textured (gravel, sand) Fine-textured (high clay content) soils

61. clay soil/geology Discharge (m 3 /s) Time (hours, days, weeks) Sandy/gravel

62. Infiltration capacity (cm/hr) Time after onset of rainfall (hours) 3 2 1 321 Forest (original vegetation) Corn field land use

63. agricultural (corn field) Discharge (m 3 /s) Time (hours, days, weeks) forest

64. Factors influencing the shape of hydrographs a.Precipitation characteristics b.Surface characteristics c.Basin characteristics

65. area shape slope drainage density c. Influence of basin characteristics on streamflow * Assumes all other factors are constant Smooth vs. Flashy

66. Streamflow Regimes discharge conditions over a year water year in U.S. (Oct 1. - Sept. 30th)Dec. Oct. Feb. Apr. June Aug. Discharge (m 3 /s)

67. 1. Perennial streamflow regime humid regions… flow all year long humid regions… flow all year long streamflow sustained by base flow between rainfall events streamflow sustained by base flow between rainfall events

68. Streamflow Regimes 1. Perennial Supplied by base flow Supplied by precip. events Dec. Oct. Feb. Apr. June Aug. Discharge (m 3 /s)

69. 2. Intermittent streamflow regime semi-arid… seasonal flow base flow sustains streamflow during wet season Canadian River, TX Panhandle

70. 2. Intermittent Discharge (m 3 /s) Supplied by precip. events Supplied by base flow Dry season… no base flow Dec. Oct. Feb. Apr. June Aug.

71. 3. Ephemeral arid… flow only after a rainfall event arid… flow only after a rainfall event Monterrey, NL

72. Streamflow Regimes 3. Ephemeral Discharge (m 3 /s) No base flow! Individual precip. events Dec. Oct. Feb. Apr. June Aug.

76. Flood Recurrence Interval (RI) Avg. # years between floods of equal or greater magnitude Annual peak Q: RI = (n + 1 / N) n = # years of record N = rank of a particular flood event

78. Flood Recurrence Interval (RI) Avg. # years between floods of equal or greater magnitude Annual peak Q: RI = (n + 1 / N) n = # years of record N = rank of a particular flood event

79. Guadalupe River floodplain @ Cuero July 3 rd … July 7 th

83. 2002… 1998 flood

84. 2002

85. 2002 1998