National Institute of Hydrology (NIH)

The report presents the status of the sediment studies carried out in the lower as well as higher altitude region of the Garhwal Himalayas. The processes associated with sediment production in the mountainous region have been described with an emphasis on the glaciarized region. Suspended sediment concentration and load observed in the Dokraini glacier melt stream near its snout has been computed.

In this study, regional flood frequency relationships have been developed using L-moments for South Bihar, in the alluvial plains of Indo-Gangetic basin and Kaimur-Chhotanagpur Santhal Pargana plateau. The annual maximum peak flood data of twenty-two gauging sites whose catchment areas vary from 11.7 to 3171 sqkm have been used. The mean annual peak floods of these sites vary from 29.15 cumec to 1293.2 cumec. Comparative regional flood frequency analysis studies have been carried out using some of the commonly used frequency distributions viz Extreme Value (EV1), General Extreme Value (GEV), Normal, Log Pareto (GPA) and Wakeby based on L-moments approach.

In this study, the mathematical model developed at the National Institute of Hydrology for estimation of the Clark model parameters using the geomorphological characteristics of an ungauged basin has been applied for simulation of the direct surface runoff (DSRO) hydrographs of the Ajay basin up to the Sarath gauging site of South Bihar.

In this study, a two dimensional numerical model in the vertical plane for simulating miscible transport of saltwater in a coastal aquifer has been developed. In order to simulate the variable density flow, the governing partial differential equation of flow and solute transport has been written in terms of pressure and concentration respectively.

The Soil Conservation Services Curve Number (SCS-CN) method presented in this report has been applied to two large catchments in sub-humid regions of India and its performance evaluated. The variation of the curve number is examined and discussed and a critical evaluation of the employment of the single linear reservoir routing technique and linear regression technique presented.

This report is a compilation of the status of natural resources as well as of the hydrological problems & constraints being faced in the Kandi belt of Jammu region of Jammu & Kashmir. Suitable actions and methods are recommended to tackle these problems in the study area.

This status report on "Hydrology of Arid Regions in India" compiles the scattered information on the subject. It is divided into nearly fourteen categories, covering sections like geology, rainfall, desertification of arid lands, position of groundwater in arid & semi-arid regions and dune landforms. 

The report attempts to provide solutions to the twin problems of waterlogging and salinity in the irrigated command area through various drainage or traditional reclamation measures viz controlling the intensity of irrigation, providing drainage system, lining, improving natural drainage, preventing seepage or adopting modern technology for application of water.

The report, a part of the regular work programme of the Flood Studies Division of the National Institute of Hydrology presents a literature review on modeling debris flow. Occurrence of debris flows is a common natural phenomenon and denotes the rapid flow of debris with sufficient water to disperse grains uniformly throughout the entire depth. Dam break flows, landslides and flows in a mountainous terrain are some of the examples.

In this study, an attempt has been made to develop a regional flood formula using L-moments for the north Brahmaputra river system. The annual maximum peak flood data of twelve gauging sites of the north bank tributaries of the river have been considered. The screening of the data has been carried out for assessing the suitability of the data for regional flood frequency analysis by computing the Discordancy Measure (Di) in terms of L-moments. Also, homogeneity of the region has been tested using the L-moment based heterogeneity measure, H.