Effect of Covers and Rainfall on Soil and Water Conservation Using a Tilting Flume Model

The effect of stone and vegetative covers was evaluated for soil and water conservation in a waterway on salty soils in the Northeast of Thailand. Experiments were conducted on a hydraulic tilting flume under simulated unit flow (120 and 45 cm²s^-1), rainfall (120 mm/hr) and slope (0, 1.2,1.4,1.6,1.8,2.0, 2.2, 2.4, 2.6, 2.8 and 3.0%) conditions. The depth of soil was maintained at 0.20 m. over a perforated bed to facilitate deep drainage. A comparative study of bare soil, stone cover (50%) and vegetative cover (50%) is made to evaluate soil loss, deep drainage, Manning's roughness coefficient. The study has revealed that stone cover is more effective than vegetative cover at lower discharge in reducing the flow velocity and thereby soil erosion. Deep drainage has been reduced from lower discharge to higher discharge for all the slopes with cover measures, including bare soil. It is also found that cover measures are necessary beyond 2.6% bed slope in order to prevent rill erosion in salty soils.