HYDROLOGICAL MODELING OF URBAN AREA BY CONSIDERING LAND USE AND CLIMATE CHANGE

Abstract

The effects of urbanization on hydrological processes and water resources have been quantified and predicted by detailed characterization and modeling of affected urban area. SWAT hydrological model has been selected to test its applicability in ungauged urban watershed of Vadodara city, Gujarat India. The main objective of this work is to study the SWAT model and its applicability i.e. test and assess the capabilities, and performance of SWAT model for Vadodara city watershed, which is ungauged urban area by simulating the water balance components in order to understand the status of hydrological process and water resources in that area. The Vadodara city watershed is ungauged. Therefore, a regionalization approach has been used to predict the river discharge at the outlet of the watershed. SUFI-2 algorism using SWAT-CUP2012 used for calibration and validation of runoff process that has been done on monthly basis. Likewise, the trend of temperature and rainfall for 35 year has done using the MK trend test and land use land cover change of the area is analyzed. The model was calibrated and validated based on the comparison of simulated and observed flow rates at the basin outlet for the periods 1979-2001 and 2002-2013 respectively. Therefore, for the monthly time step, the application of the NSE values was 0.53 and 0.61, the determining coefficient (R2) was 0.69 and 0.51, while the value of PBIAS was 5.3% and 10.4%, and RSR values were registered as 0.71 and 0.63 for the periods of the calibration and validation process, correspondingly. The result suggests that there has been a good match between simulated and observed flow. Therefore, the model performance is applicable and strong predictive ability for the ungauged watershed of Vadodara city. Depending on the Mann Kendall trend test result both average annual maximum and minimum temperature substantial increasing trend was observed in the study area. Likewise, trend analysis of rainfall is done on seasonal and annual scale. Annual scale trend test result shows us it an increasing in the Vadodara city watershed. An attempt has been made in this research paper to see to the land use and land cover changes of Vadodara city watershed of India during the period of 1990-2017. Four Landsat image were taken for this analysis. The result revealed that agricultural land use decrease by 30% in 2017. Whereas the urban area of the watershed show an increasing trend. The result suggests that there has been a good match between simulated and observed flow. Therefore, the model performance is applicable and strong predictive ability for the ungauged watershed of Vadodara city