Determination of plant characteristics used in discharge capacity assessment of Turkey Creek watershed on South Carolina coastal plain, USA
Riparian vegetation type, composition, structure, and its abundance on floodplains exert a strong influence on riparian surface and subsurface hydrology and discharges of rivers and streams. The conditions of flood waters flow in such valley types are shaped by the existing vegetation cover. In this study, on the basis of vegetation inventory in four selected and representative basins, the substitute geometrical parameters of the medium and tall vegetation were determined and friction coefficients for low vegetation. These parameters were determined for 72 km2 forested watershed draining a 3rd order stream as affected by floodplain riparian vegetation on the Atlantic Coastal Plain in South Carolina, USA. The vegetation parameters, determined directly from the measurements, were verified against the rating curve, that was achieved from discharge measurements as well as from discharge capacity calculations of the valley cross-section. In discharge capacity calculation, the Pasche method was used to calculate the total Darcy-Weisbach friction factor for each cross section according to the type of vegetation and flow interaction between the main channel and vegetated areas. In this approach friction caused by interaction between the main channel and vegetated areas are taken into account. The calculations performed on the basis of determined geometrical parameters of tall vegetation, show good agreement between the model and the measurements.