River Processes. Drainage Basin Morphometry

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Nathaniel Wilkerson
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1 Drainage Basin Morphometry River Processes Morphometry - the measurement and mathematical analysis of the configuration of the earth s surface and of the shape and dimensions of its landforms. Horton (1945) - drainage composition 1

2 Drainage Basin Morphometry Shreve (1967) River Processes 2

3 Drainage Basin Morphometry River Processes Linear morphometric relationships 3

4 Drainage Basin Morphometry River Processes Length ratio 4

5 Drainage Basin Morphometry River Processes Areal morphometric relationships 5

6 Drainage Basin Morphometry River Processes Drainage density 6

7 Drainage Basin Morphometry River Processes Drainage density 7

8 DRAINAGE BASINS Basin Morphometry relief morphometric relationships Relief ratio 8

9 Drainage Basin Morphometry River Processes Relief ratio Stream Profiles 4000 Rupal Elevation (m) Buldar Raikot Distance (m) 9

10 Drainage Basin Morphometry River Processes Hypsometric analysis 10

11 YEAR MO DAY NF ED sta River Processes Drainage Basin Morphometry River flow (discharge) conditions also exhibit (under appropriate conditions) some degree of morphometry peak discharge event (15800 cfs (11/15-11/27)) Mbar sta NF CC sta CC sta R = R 2 = NF ED day mean Mbar NF CC R 2 = CC

12 Drainage Basin Morphometry River Processes discharge season ( to ) R 2 = R 2 = R 2 =

13 Drainage Basin Morphometry River Processes low flow season ( to ) R 2 = R 2 = R 2 =

14 River Processes Drainage Basin Evolution - denudation 14

15 Drainage Basin Evolution - denudation A number of interrelated geologic, hydrologic, and topographic factors cause the magnitude of sediment yield to vary widely from region to region. The most important of these are precipitation and vegetation, basin size, elevation and relief, rock type, and human activity. River Processes 15

16 Drainage Basin Evolution - denudation Precipitation and vegetation River Processes 16

17 Drainage Basin Evolution - denudation Basin size River Processes 17

18 River Processes Drainage Basin Evolution - denudation Elevation and relief 18

19 River Processes Drainage Basin Evolution - denudation Rock type 19

20 River Processes Drainage Basin Evolution - denudation Human factor 20

21 River Processes Drainage Basin Evolution - denudation Rates of denudation - difficult to do, because quantifying human impact is vague. A valid estimate can be made only if the volume of sediment derived by erosive processes can be accurately determined, the boundaries of the source area are definable, and the time interval of sediment accumulation can be ascertained within reasonable limits. 21

22 River Processes Drainage Basin Evolution - denudation 22

23 River Processes Drainage Basin Evolution - denudation 23

24 River Processes Drainage Basin Evolution - denudation 24

25 River Processes Drainage Basin Evolution - denudation Sediment budgets To make a complete sediment budget analysis one must identify and quantify: sediment mobilization (processes that initiate motion and move sediments any distance), sediment production (sediment reaching or given access to a channel), and sediment yield (sediment actually discharged from the basin). 25

26 River Processes Drainage Basin Evolution - denudation 26

27 River Processes Drainage Basin groundwater hydrology 27

28 River Processes Drainage Basin groundwater hydrology The groundwater profile: 1. Zone of moisture 2. Vadose zone 3. Capillary fringe. 4. Saturated zone 5. Water table 28

29 River Processes Drainage Basin groundwater hydrology movement of groundwater Equipotential surfaces 29

30 Aquifers 1. unconfined aquifers 2. aquitards 3. confined aquifers 4. piezometric surface River Processes Drainage Basin groundwater hydrology movement of groundwater 30

31 River Processes Drainage Basin groundwater hydrology movement of groundwater Aquifers 5. artesian flow 31

32 Aquifers River Processes Drainage Basin groundwater hydrology movement of groundwater 32

33 The Ogallala aquifer largest freshwater aquifer in the western hemisphere. River Processes Drainage Basin groundwater hydrology movement of groundwater The Ogallala aquifer largest freshwater aquifer in the western hemisphere. 33

34 River Processes Drainage Basin groundwater hydrology porosity and permeability Permeability ability of a material to transmit water Darcy s Law: Porosity (n) - volume of voids relative to the volume of total. The Ogallala aquifer largest freshwater aquifer in the western hemisphere. n = Vv/Vt where: Vv refers to the volume of the voids (liquid and gas phases), and Vt refers to the total volume of a representative volume of rock. 34

35 River Processes Drainage Basin groundwater hydrology porosity and permeability The Ogallala aquifer largest freshwater aquifer in the western hemisphere. 35

36 River Processes Drainage Basin groundwater hydrology movement of groundwater Aquifers Groundwater/surface water interactions Water tables and pumping 36

37 links 37

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Surface Processes Focus on Mass Wasting (Chapter 10)

Surface Processes Focus on Mass Wasting (Chapter 10) 1. What is the distinction between weathering, mass wasting, and erosion? 2. What is the controlling force in mass wasting? What force provides resistance?