Simulation of the Runoff in a Short-Term Scale and Assessing the Hydrologic Effects of Climate Change in the Zarinerood Basin (As Part of the Orumyeh Lake Great Basin)

Abstract

Snowmelt has a significant effect on rivers outflow in Western Iran. Occasionally, in some areas about 90% of runoff result from melting snow. Access to accurate and timely information for measuring the volume of available water resources is necessary. It is important to plan and design programs for drought-resistance and flood prevention as fundamental issues in Iran. The water balance (WB) model was used to estimate daily runoff produced by melting snow, without reliance to satellite images, from October to February (2005-2006) in the Zarinerood basin. This model uses available data and information in the basin to provide the possibility of estimating daily runoff in the short-term. For this purpose, the watershed was divided into three elevation zones and in each zone, an index station was determined. Using the water balance model, runoff was estimated from each station producing the outlet runoff in the basin. To calculate model accuracy, the correlation coefficient (R2) and root mean square error (RMSE) were estimated as 0.62 and 0.003, respectively. These results showed that the accuracy of the model to estimate daily runoff was acceptable. Therefore, the calibration of this model endorses its use in similar basins. It has been shown that increasing temperature has affected on snow-melt period as shifting it from spring and early summer to winter in North-west Iran. It results to increasing runoff rates in the snow-melt season and therefore this region encounters intensive drought and flood.