TR-134 : Low flow forecasting using statistical approach

Abstract

The availability of water resources is highly variable both in space and time in India. Assessment of river fibw during non-monsoon months along with its time distribution is essential for planning and development of water resources and related schemes for meeting the growing requirements of our developing society. Low flow modelling is also necessary far dealing with problems of stream pollution. The analysis of low flows is equally important for municipal and industrial water supply schemes, both from view points of quantity and quality.

The quantum of flows in the river in the lean season is generally very low - varying from about 15% in l*rder snow fed rivers to less than 1% in some of the smaller river systems in coastal areas. Although the availability of water during non-monsoon season is very low, it plays a vital role on the dk,velopment and activities of the region. Reasonably accurate estimation of the water resources available during lean period and also its possible forecast will go a long way in systematic developmental planning and utilization of the water resources.

The importance of low flow forecasting is being increasingly felt for efficient management of the existing water resources projects as well as for optimal planning of the future projects. A number of models have been suggested by various authors in the recent times for the flow flow forecasting but the statistical approach is still relevant and unavoidable under specific circumstances. In this report, a suitable statistical model for the low flow forecasting has been described.

This report is a part of work programme of Hydrologic Design Division and the study has been carried out by Shri M.E. Hague and Rakesh Kumar, Scientists of the Institute.