Adlul Islam

Streamflow Response to Climate Change in the Brahmani River Basin, India

Climate change can significantly affect the water resources availability by resulting changes in hydrological cycle. Hydrologic models are usually used to predict the impacts of landuse and climate changes and to evaluate the management strategies. In this study, impacts of climate change on streamflow of the Brahmani River basin were assessed using Precipitation Runoff Modeling System (PRMS) run under the platform of Modular Modeling System (MMS). The plausible hypothetical scenarios of rainfall and temperature changes were used to assess the sensitivity of streamflow to changed climatic condition. The PRMS model was calibrated and validated for the study area. Model performance was evaluated by using joint plots of daily and monthly observed and simulated runoff hydrographs and different statistical indicators. Daily observed and simulated hydrographs showed a reasonable agreement for calibration as well as validation periods. The modeling efficiency (E) varied in the range of 0.69 to 0.93 and 0.85 to 0.95 for the calibration and validation periods, respectively. Simulation studies with temperature rise of 2 and 4°C indicated 6 and 11% decrease in annual streamflow, respectively. However, there is about 62% increase in annual streamflow under the combined effect of 4°C temperature rise and 30% rainfall increase (T4P30). The results of the scenario analysis showed that the basin is more sensitive to changes in rainfall as compared to changes in temperature.

Simulation of Water Temperature in a Small Pond Using Parametric Statistical Models: Implications of Climate Warming

AbstractChanges in temperature and precipitation patterns due to global warming are likely to affect the quantity and quality of water in different water bodies. Water temperature modeling techniques are usually employed to study the effects of global climate change on stream and river ecosystems. This study aims to identify a suitable air–water temperature relationship for a small aquatic pond in a semiarid region of India and examine the effects of increased water temperature on the small pond’s attributes. The performance of two parametric statistical models—simple linear regression (SLR) and four-parameter nonlinear logistic regression (NLR) models—was evaluated. The developed models were field tested for mean, minimum, and maximum air–water temperatures on daily, weekly, and monthly timescales. The model parameters were estimated from the measured air–water temperature time-series data using the least-squares optimization method. Model performance was evaluated using three statistical indicators—the ...

Technological Interventions for Managing Ravine Lands for Livelihood and Environmental Security

Rehabilitation of degraded ravine lands is immensely important to conserve land and water resources for sustaining and improving production and productivity and to counter impacts of climate change. There is a need to effectively implement improved package of practices along with soil and water conservation measures in marginal lands around the ravines. It is estimated that these practices may result in 9–28% improvement in cropping intensity and 20–66% increase in current yield levels with an overall improvement of 118–280% increase in net returns through increased crop production. If the shallow ravine lands are brought under scientific cultivation of high-value as well as low-value fruit trees, it may augment the supply of fruits in the daily diet of people in India. These horticulture-based systems are cost-effective with high benefit-cost ratio. In deep ravines, silvopastoral systems are viable technology for stabilization and productive utilization. Ravine area development will not only contribute to bridging the growing demand and supply gap for food, fodder, and fuel but also help restore livelihood security for resource constraint communities and mitigate climate change impacts, besides providing improved ecosystems services. Apart from scientific and technological interventions for reclamation and productive use of ravine land, the support and involvement of the local farmers and local community in planning, project formulation, and implementation of different government programs and reform of local land tenure and social arrangements are equally important for the success of ravine reclamation programs.

Solution to Green–Ampt infiltration model using a two-step curve-fitting approach

Infiltration is an important hydrological process affecting the runoff, groundwater recharge and solute transport process. The Green–Ampt (GA) model, describing one-dimensional infiltration process, yields an implicit equation for estimation of cumulative infiltration with time. In this paper, an explicit approximation to the GA model is derived using two-step curve-fitting technique. The Marquardt’s algorithm is employed for least-squares estimation of nonlinear parameters. Performance of the proposed model is compared with the implicit GA model using numerical and published field experimental data. The quantitative statistical indicators namely, percent relative error (RE), maximum absolute percent relative error (MARE), percent bias (PB), and Nash–Sutcliffe modeling efficiency (E), are used to assess the performance of the proposed model. The solution of the proposed model matched very well with that of the implicit GA model with MARE ≤ 0.146%, PB ≤ 0.070%, and E value approximately equal to 1 for both the dimensionless numerical and dimensional field experimental infiltration estimates. Simulation results of the proposed model demonstrated the capability of the derived model in estimating infiltration rate and cumulative infiltration accurately and can be applied to solve variety of real-life hydrological problems.