Surface Water

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 develops the wavelet element method for hydrological application purposes in general and modeling of flow in a canal due to breach of bank in particular. Due to high seasonal variability of rainfall and cyclones in coastal India, flood discharges cause frequent breaching of canals.

Canal breach modeling is of great significance in open channel hydraulics. The study of breach of a canal is a relatively new one as compared to dam breach, which is a well researched field. The analysis of the problem is complicated due to dynamics of flow within the canal. The limitations of the above model due to the one-dimensional model analysis of the problem is hoped to be overcome in two or three dimensional analysis.

The study applies a hydraulic simulation model, Hydrologic Engineering Centre (HEC-1) to Baitarni river for modeling hourly flows of the river at Anandapur gauging site. HEC-1 model had been developed by US Army Corps of Engineers, for rainfall-runoff modeling. It provides a powerful automatic optimization technique for estimation of some of the parameters. The optimization technique of the model has been utilized in the present study and model parameters have been calibrated and validated for the study area.

The report presents a detailed review of mathematical modeling of flows in alluvial streams. Various computer codes for this are presented and a model for simple-island case is prepared. Branched flows in open channels with alluvial conditions occur in natural and man-made systems. Analysis of such flows by mathematical modeling is important considering its applications in water resources and environmental engineering.

The report describes the software, which has been developed for flood control regulation of a system of reservoirs. The reservoirs can be gated or ungated, and the system can have any combination including weirs and diversions. For operation of reservoirs, the scenario has been divided into two categories depending on the reservoir level and inflows - normal operation and emergency operation.

The input data requirements of the software are modest. This software along with previously developed software for conservation operation would provide a complete set of tools to analyze any system configuration for the range of purposes for which reservoirs are commonly built in India.

The report deals with the procedures to estimate dispersion coefficient from exit concentration observed due to a step change in the concentration input. A simple method as well as an optimization method has been evolved and the application of the methods on published datasets discussed.

Dispersion occurs in many problems of groundwater flow, such as pollution from concentrated and distributed source, sea water intrusion, seepage of polluted surface water through rivers or lakes and changes in water quality due to artificial recharge. Application of the solution of advection-dispersion equation in soil media for prediction and forecasting of solute concentrations requires the estimate of coefficient of hydrodynamic dispersion, commonly known as ‘dispersion coefficient’.

The report uses the Soil Conservation Services (SCS, 1956), Curve Number (SCS-CN) method, a widely used event based rainfall-runoff method for simulating daily rainfall-runoff data of three catchments, viz., Ramganga and Hemavathi catchments of the sub-humid regions and Sabarmati catchment of the arid region of India.

In the model formulation, the daily variation of parameter, potential maximum retention is governed by the known antecedent moisture condition. Hydrologic simulation studies provide a useful and important input to water resources planning and watershed management practices.

W  E  D  O              F1 ‘ Whispering  Height ’, 132 St. Mary’s Road, Chennai 600 018, Tamilnadu, India.

  wedo@wedo2050.org, wedo2050@yahoo.co.in

  91-44-24985023, 24953339, 99401-36388, 94440-10339, 42030921

Water and food Equitable Distribution Organization

The report discusses the water availability computations under different data availability scenarios. Water availability generally refers to the volume of water available from the basin or stream at a particular point over a specified period of time. Volumetric relationship is reflected between rainfall and runoff. Many factors like climatic and basin characteristics affect the water availability of a basin. Time and space distribution of rainfall, its intensity and duration, surface vegetation, soil moisture, soil characteristics, topography and drainage network are some of the important factors.

The study attempts to apply Geomorphological Instantaneous Unit Hydrograph (GIUH) and Geographical Information Systems (GIS) based approach for flood estimation. The design storm data of four catchments along with morphological characteristics have been considered. The geomorphological parameters and time area diagrams for each of the dam catchments were generated using the GIS package, Integrated Land and Water Information Systems (ILWIS).

The geomorphological parameters together with the time-area diagram forms an important input for the GIUH based Clark model. This model has been applied for deriving the instantaneous unit hydrograph and thereby to estimate the design flood in four dam catchments located in Luni and Chambal basins in Rajasthan viz. Jawai, Sei, Gamabhiri and Alnia. A review of the previous studies carried out using GIUH approach has been presented. Furthermore, a review of studies carried out using GIS techniques is also provided.