TN-111: Data acquisition systems (DAS) for hydrological measurements

Abstract

The amount of water in different phases of the hydrologic cycle and its movement from one phase to another forms the basis cc hydrological measurements. Data on various hydro-meteorological variable, e.g. precipitation, discharge, soil moisture, etc. are required for hydrological forecasting and efficient water management. Some hydrological variables, e.g. rainfall, stream flow and ground water have been measured for many years, albeit mostly for specific purposes.

With the availability of cheap reliable micro-electronic devices, such as microprocessors, solid state devices, sensors based on new technologies and communication systems, measuring instruments have become much more capable and intelligent for use in many fields, including operational hydrology. The characteristics of these devices, such as low cost, low power consumption, high reliability, and toleration of a wide range of environmental conditions make them particularly suited to applications in operational hydrology. These instruments are capable of working unattended for long periods, usually in remote sites, far from mains electrical supply. In addition to the direct use of microprocessor technology in measuring instrumentation and data transmission systems, on-site data processing and analysis is also being carried out using state-of-art intelligent instruments.

Data Acquisition Systems (DAS) are increasingly being used for hydrological data collection and processing. These systems provide an accurate, real-time (if required) analyses along with data collection and transmission for applications in various hydro-meteorological studies Basically, any DAS comprises of three components sensors, cat: collection system, and data transmission system. A comprehensive literature survey various DAS has been completed. The report compiles the relevant information about various DAS and hydro-meteorological sensors.