The effects of rainfall and catchment characteristics on runoff yield in semi-arid areas of Tanzania
Loading...
Date
1996
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Sokoine University of Agriculture
Abstract
A complete randomised block design three replications (viz :at 6%,experiment with (CRDB) and 15% 18% slope) was conducted in Kisangara, Tanzania from November, 1994 to May,1995. The experiment consisted of catchment length (viz: 6 m and soil surface cover treatments and 12 m)
(viz:natural vegetation and bare-and-compacted) . The study period covered two rainy seasons, short rainy season (locally known as Vuli) and rainy long of objectives season the study Masika).
(locallyknown wereinvestigate to as The effects of rainfall and catchment characteristics on runoff yield and to use the data obtained to develop and test an empirical model for semi-arid conditions of Tanzania.Runoff yield from 60 m2 (10 m x 6 m) and 120 m2 (10 m x 12 m) catchments was measured using a runoff collecting system.Rainfall, soil particle size distribution, soil moisture,
infiltration rate and soil bulk density for the catchments were also monitored throughout the two rainy seasons. The results generated a showed that catchments at 18 percent slope significantly higher mean runoff yield than the catchments at 6 percent slope equal to or more than 6 mm.
(p< 0.05) at rainfall amount similarly catchments at 15 percent slope generated a significantly higher mean runoff yield than catchments of 6 percent slope (p< 0.05) at a rainfall amount equal to or more than 6 mm. However, the mean runoff yield generated from catchments at both 15 and 18
percent was not significantly different (p< 0.05). The mean runoff yield per unit area of catchment was not significantly different from the 6 m and 12 m length catchments. However, the total mean runoff yield generated from the 6 m length catchments was 9 percent- more than the total mean runoff yield generated from the 12 m length catchments for the two rainy seasons studied. The mean runoff yield from bare and compacted catchments was significantly different from the mean runoff yield generated from natural vegetated catchments (p< 0.01).The mean runoff yield from bare and compacted catchments at 18 percent slope was highly correlated with the rainfall characteristics (r> 0.95).Overall correlation coefficient between mean observed and mean predicted runoff of the empirical model developed was high (0.84) indicating that the model is suitable for semiĀ arid
conditions of Tanzania and can reliably be used to predict runoff in areas where no such measurements are made to design harvesting. The optimal micro-catchments for rain water.
Description
Dissertation
Keywords
Rain water harvesting, Rainfall, Natural vegetation, Evaporation