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RESERVOIR CAPACITY AND PHOSPHORUS CONCENTRATION ASSESSMENT IN A SOUTH INDIAN RESERVOIR USING REMOTE SENSING TECHNIQUES

Periodic assessment of the reservoirs is essential to evaluate the changes in storage capacity due to sedimentation and also its quality which reduces the usefulness of water. The conventional methods are time consuming, laborious and costly in comparison to the remote sensing techniques. The water spread area of the reservoir reduces with the sedimentation at a given level and this fact is utilized in estimation of reservoir capacity. Satellite imaging is based on the scientific principle that chemical and biological constituents have a unique spectral reflectance signature derived from molecular vibration that can be detected with sophisticated algorithms. An attempt has been made in one of the reservoirs of south India to assess the capacity of the reservoir using temporal images from IRS LISS III sensors. Both per pixel and sub pixel approaches were made to derive the capacity of the reservoir. In addition phosphorus concentrations were measured in the reservoir and a relationship was derived between total phosphorus concentrations and reflectance in the imagery. This paper demonstrates the use of satellite imagery to determine the storage capacity and to quantify the concentrations of phosphorus in the reservoir.