Two sub-basins in a catchment have been earmarked for settling displaced persons. The rainfall characteristics typical of the watershed is presented as follows: Typical Rainstorm Time from start (mins) 0-15 15-30 Rainfall depth (mm) 2.5 3.5 4.0 30-45 45-60 3.2 60-75 5.0 75-90 3.5 Sub-basin characteristics Sub-basin characteristics Flow length Average slope (%) % Silt % Clay Soil Structure Permeability Land-use Organic Matter Content Very fine sand P-Factor Sub basin A Sub-basin B 300 m 200 m 3 4 60 50 20 30 Coarse granular Fine granular moderate Arable 2% 10 0.1 Fine granular Established grass 3% 5 0.15 Catchment A is arable with C-factor of 0.2. The rainfall erosivity index is computed as R = El 30/100. Determine the following; (i) (ii) Compute the Weischmeier index using the Weischemeier equation. KE 11.87+8.73 Which of the two catchments are at risk of degradation by erosion if it were to be used to settle the displaced persons if the C-factor for settlement is 0.3? The permissible soil loss is 10 tons/acre-year (Hint: use the USLE). (iii) Using the Erosion Hazard Classification for lowlands of Lesotho technique, Assess the erosion hazard for each catchment resulting from the proposed change in land use to settlement i.e before and after the change in land use.