Introduction

A hydro-metreological network is an organized system for collection of information of specific kinds such as precipitation, run off, water quality, sedimentation and other climate parameters. The accurance in the estimation of both quality and quantity of water resources and thus for making the ielisions for integrated water resources development and management depends on how much information are available for the region concerned. Data on temporal and spatial characteristics of water resources of a region are obtained by a network of observational stations. Setting up a station requires investment for infrastructure equipment, logistics, and for operation and maintenance. Scientific planning is necessary for network design so that the desired results could be achieved with minimum cost.

Having enough relevant and accurate hydrologic information reduces the chances of under-design or over design and thus minimizes the economic losses, which leads to the overall increase in the benefit/ cost ratio. It has not, so far, been possible to define the optimum level of hydrologic information required for planning, design and development of a specific project in a region, due to difficulties in developing a benefit cost function of hydrologic information. Further more the requirement of water resources data depends on their end use therefore, it is difficult to formulate general rules on network design. While designing hydro-meteorological networks, the decisions to be taken are:

• the variables to be measured and the frequencies and duration of observations;
• the location of gauging stations;
• the instruments to be installed and methods of observation; and
• data observations and transmission system.

Since the hydro-meteorological data networks are operated by a number of independent agencies, a good coordination among them is important. This will reduce the expenditure and improve data quality. Of particular importance is the coordination between hydromet, water quantity and quality data networks.