Estimation of Annual Runoff in Indravati Sub Basin of Godavari River using Statistical Approach

Prediction
of runoff from known rainfall is one of the major problems confronted by hydrologists.
There is lack of availability of long period runoff records in large number of
catchments in India. Investigators have proposed many empirical relationships
for runoff estimation in different catchments based on limited data of
parameters affecting runoff. These regional relationships are useful in
planning of water resource projects. This study was carried out to obtain
simple yet effective relationship for estimation of annual runoff in Indravati
sub basin of Godavari river. Regression analysis was carried out using annual
rainfall, annual runoff and average annual temperature data to develop
empirical models for annual runoff estimation. GIS software was used for
preparing maps for the study area and to extract the precipitation and temperature
data available in grid format from IMD. The best suited empirical model is then
selected as per statistical criteria with lower values of standard error,
standard deviation, mean absolute deviation (MAD), root mean square error
(RMSE) and higher values of R square and correlation coefficient.  Statistical significance of selected empirical
model was evaluated by paired t test, F test and P value at 95 % confidence
level. The developed relationship is then compared with the existing Khosla and
Inglis and DeSouza relationships. Outcome of this comparison produces
encouraging inferences to suggest an effective regional relationship for annual
runoff estimation in the Indravati sub basin of Godavari river in India.