National Institute of Hydrology (NIH)

The study attempts to carry out field testing of the weighing raingauge for measurement of rainfall, which is at the core of all hydrological measurements. The tipping bucket rain gauges are generally used for automated recording of rainfall data. It has been reported that the tipping bucket mechanism of such raingauges frequently malfunctions and gives erroneous data, especially during high intensity rainstorms.

The Systems Hydrologique European – European Hydrological System (SHE) is a physically based distributed model and it provides a useful setup for understanding the importance of evaporation data and soil parameters. 

In this study, single column hydrologic simulations have been carried out for examining the sensitivity of this model to pan evaporation data of the various stations as well as the increase in conductivity of the unsaturated zone. Furthermore, the reduction in the value of exponent appearing in the Averjanov’s formula and reduction in the values of moisture content at wilting point and residual water content has been studied for a single grid of 2 km X 2 km size of the Narmada river.

In this study, unsteady flow towards a fully penetrating well screened in both the aquifers of a two-aquifer system separated by an aquitard has been analyzed using numerical approach. Existence of multi-aquifer systems is common in a sedimentary basin.

This report presents the various methodologies for correct assessment of irrigation return flow, which is one of the most significant components  in the water balance of irrigation command areas. A part of the water applied to the irrigation fields percolates deep to recharge the groundwater and is known as  irrigation return flow. In this report methodologies have been presented for assessment of irrigation return flow through soil moisture modeling, water balance approach, experimental determination and groundwater modeling. 

The study attempts to explain flood wave propagation in natural and artificial channels within the perspective of site-specific rating curve. The study looks at the impacts of channel characteristics – bed slope, flood plains, channel shape, expansion-contraction combination, inactive storage, Manning’s roughness, expansion and contraction on flood wave propagation.

The study looks at the various processes and mechanisms of wind erosion as well as the factors that contribute to the increase or decrease of wind erosion in desert areas in the particular context of the Great Indian Desert. The method of estimation of soil loss in a desert area due to wind as suggested by Woodruff and Siddoway on the lines of Universal Soil Loss Equation (USLE) is explained.

The report develops rainfall-runoff modeling for simulating and forecasting the flow from a catchment, and in determining the inflow series for the ungauged catchments on the basis of records of gauged catchments.

Because of the scarcity of data, mostly lumped models have been used to model the rainfall-runoff process in a catchment. However distributed models are more accurate and need to be adopted for modeling the complex processes at the scale of basins.

The study attempts to develop a mathematical model for transport of a solute in groundwater by taking the mass balance of the dissolved pollutant over a static elementary volume in three cartesian coordinates.

The management of groundwater resources is becoming a complicated task due to the overwhelming pressure on groundwater and the changing scenario of groundwater quality (physical, chemical and biological). 

The hydraulics of groundwater is governed by many bounded and un-bounded factors. The mixing of constituents in groundwater is an important factor that shapes the occurrence of constituents in any precise location at any given time.

The study presents automated mapping of snow cover using a new spectral channel of Indian Remote Sensing (IRS-IC) data for the Spiti sub-basin of the Satluj river basin. Snow is an important phase of the hydrological cycle and the estimation of snowmelt runoff in the Himalayan rivers, either seasonal or daily, is of immense use in proper management and use of water resources in the basins.

The report presents a methodology to assess the probability distribution of Dissolved Oxygen (DO) based on the Streeter-Phelp’s equation. The methodology involves the use of first order analysis and Monte Carlo simulation to analyze the uncertainty associated with DO. The mean and standard deviation of the parameters have been assumed as same for the study’s probability distributions.