The hydraulics of overland flow on hillslopes

._________________________________________ Acknowledgments__ _ ______________________________ Introduction.______________________________________ Description, of the problem_______________________ Review of the literature._--_-----_______________ Scope of the investigation________________________ Laboratory apparatus and techniques of measurement-__ Laboratory equipment.__________________________ The laboratory flume__________________________ Simulation of rainfall__________________________ Discharge measurements.________________________ Depth measurements.___________________________ Surf ace-velocity measurements. __________________ Other measurements.___________________________ Field sites and description of measurements.___________ General location.._______________________________ Geology and soils.______________________________ Vegetation.,_ __________________________________ Topography__ --__-----_______________________ Artificial rainfall__--------_____-______________ Runoff measurements,__________________________ Sediment samples_______________________________ Surface-velocity measurements__________________ Flow pattern of overland flow-_-_--____-_________ Depth measurements.___________________________ Page Al 1 1 1 2 3 4 4 4 5 6 6 6 6 7 7 8 9 10 10 12 12 12 13 13 Page Analysis of results and discussion. ______-_____--____-_ A14 General__ _ _________________---__-------__--14 Laboratory tests with uniform flow.______________ 15 Laboratory tests with artificial rain _______________ 19 Field investigation of overland flow.______________ 25 Comparison of field results to laboratory data______ 28 Probabilistic approach to overland flow and the shape of hillslopes. _________-_-_-___-_-_--_-__-__-----_--31 Hydraulic changes downslope___-_______-_-____-31 Application to the shape of hillslope profiles_______34 Erosion and sediment transport___________-__-__---36 Rills and dynamic equilibrium________-______--36 Erosion and laminar flow--___------------------42 Summary of findings.____-_______-__-__-----------_44 References. __________-_--__-_------__-___---------45 Summary of data: A, Vegetation type and relative density of cover at field sites..___________._ _____ _48 B, Example of data from measurements of surface velocity, Pole Creek Site 3________-___ 50 C, Example of data from depth measurements, Pole Creek Site 3__________._____ 51 D, Summary of laboratory data for uniform flow 52 E, Summary of laboratory data for artificial rainfall 53 F, Summary of field data for overland flow sites.___ 66

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