Impacts of temperature-rainfall and land use/land cover changes on the hydrological regime in the Muhuri River basin, Northeast India

The present study aims to assess the impact of temperature-rainfall (TR) and land use/land cover (LULC) on the hydrological regime of a forested watershed. The authors consulted meteorological, hydrological, and remote sensing data in this research work. The study applied statistical techniques like regression and analysis of variation (ANOVA), which have been used to analyze the variability of TR and LULC and their impact on the hydrological regime of the river. To analyze the variability, the whole study period (1986-2016) was divided into two phases, i.e., 1986-2000 (Phase I) and 2001-2016 (Phase II). The statistical analyses proved that within the study period, water discharge, water level, hydraulic radius, and flow velocity experienced variation significantly (p value < 0.05) except for wetted perimeter (p value > 0.05). All the variables have decreased considerably in the second phase of the study period, i.e., in the 2001-2016 periods. Moreover, phase-wise seasonal analysis proved that the variations during monsoon and non-monsoon are lacking and prominent, respectively. The response of hydraulic variables to temperature-rainfall proved that the hydraulic variables had an insignificant correlation (R = 0.15 to 0.41) with the annual and the monsoon rainfall, while significant relation (R = - 0.26 to 0.78) was observed with the non-monsoon rainfall and temperature (maximum and minimum). There was a significant variation (p value 0.00) of LULC change in both phases. Statistical analyses proved that among the two phases of the study, the mean value of the forest class decreased significantly (from 550.37 to 425.67 km(2)). In contrast, rubber plantations increased extensively (from 21.36 to 128.36 km(2)) in comparison to the other LULC classes. Statistical analysis proved that the LULC change is very much responsible for the hydrological modifications rather than the rainfall.