Is declining groundwater levels linked with the discontinuity of traditional water harvesting systems (tank irrigation)? Empirical evidence from West Bengal, India

Abstract

The present study aims to identify and analyze factors responsible for the discontinuity of irrigation tanks and the declining groundwater levels in the Indian state of West Bengal, and attempts to establish the link between age-old water-harvesting structures such as tanks (surface water) and groundwater recharge. Using district-level secondary data from 1992 to 2011, a fixed effect and dynamic panel regression models have been estimated in order to identify the determinants of the performance of irrigation tanks and the decline of groundwater levels, respectively. The results indicate that, while the average annual rainfall positively influences the performance of irrigation tanks, the mechanization of the farms, the density of the wells, increased rural population and per capita income adversely affect the performance of tanks. The results of the determinants of the decline of groundwater levels show that, while the average annual rainfall, density of tanks and forest cover are likely to influence groundwater levels positively, the density of wells is found to be adversely affecting the groundwater levels in the state. The interaction between tank irrigation (surface water) and groundwater levels is found to be strong. Hence, both tank irrigation and well irrigation should be used as complementary methods. rather than substitutes in order to maintain a hydrological balance, and use and manage water resources sustainably in the long run.