Abstract:
Water is the most indispensable natural resources for the survival of all
living beings. On the other hand, water availability is declining and the demand is
increasing, making the gap between these two wider day by day.Scientific water
management is a must to sustain the domestic and irrigation water needs.
Quantifying the elements of hydrologic processes at micro watershed scale and at
weekly or monthly temporal scale is the most important prerequisite for water
resources development of a locality. For understanding the watershed
characteristics and behavior, models play an important role which are also useful
for extrapolating the current conditions to potential future conditions.
Hydrological modeling is considered as a powerful technique in planning water
resources. In this study, the hydrology of Valanchery watershed, a small sub
watershed of Bharathapuzha, was modeled using SWAT, a physically based
distributed watershed model. The study aims to calibrate the model, simulate the
hydrologic elements and stream flow and to suggest remedies to combat the water
scarcity in the study area.
Using ArcGIS 10.2.2, the datasets required for the ArcSWAT was
prepared. As the watershed selected for the study was ungauged, the model was
calibrated for Kunthipuzha basin which lies in the immediate neighbourhood and
having similar characteristics with the study area. For this, the model was initially
set up and ran for Kunthipuzha basin and using the daily observed stream flow at
Pulamanthole gauging station, the model was calibrated and validated. The
calibration and validation periods were respectively, 2000 to 2006 and 2007 to
2009. An NSE = 0.81 and R 2 = 0.82 was obtained for calibration, an NSE = 0.73
and R 2 = 0.88 was received for validation. With these calibrated parameters, the
model was set up and ran for the Valanchery watershed using regionalization
technique. The whole watershed characteristics and behavior and that of sub
watersheds and of different reaches of the mainstream were determined and
predicted. It was found that the characteristics and hydrologic process elements
such as surface runoff, lateral flow, deep percolation, base flow and ET of the
99various sub watersheds were varying considerably. Using these vital information,
water resources conservation and utilization can be planned scientifically at micro
spatial levels to mitigate the water scarcity scenario.
