BIOTIC INDEX METHODS USED FOR WATER QUALITY ASSESSMENT

Abstract

ABSTRACT As water quality assessment is the prime concern of a Water Resources engineer for multiple purposes, chiefly for supply of drinking water, treatment of drinking water and for sewage treatment. Therefore some most reliable, inexpensive, at the site and easy methods are sort after. Whereas water quality assessment kits are portable and used at the site, they too have certain limitations of accuracy and the laboratory tests are more laborious, time consuming as well as prone to miscalculations due to time gaps and mismanagement. Therefore in developed world some natural parameters are now used as indices of water quality. These are the macro-invertebrates which are living at the bed of a water body and they are filter feeders. These species mainly depend on the type of water quality in that particular stream. They are different for fresh waters and different for polluted waters. And accordingly there population per unit square area differs. They are termed as biotic indices and currently there are quite a few such methods available for particular regions in the European countries. But developing countries have yet to practice those methods and check their validity as well as apply correction factors for their parts of the world, except for a few south American countries. This paper contains a brief description of those methods, besides the findings, results and conclusions of an attempt made for the first time to identify such Taxa-macro-invertebrates-, vis-à-vis the water quality tests done with the help of portable kits and standard lab tests, of a main fresh water stream-Dachigam Nallah-in Srinagar the summer capital of Jammu and Kashmir, India. This stream supplies drinking water to major portion of the Srinagar city. Dachigam Nallah is coming directly from glaciers, flowing through the hilly terrain and ravines for a long run from the origin of the channel having almost no polluting interventions of humans. Satellite picture (Fig. 2) of the stream shows green colour of water which supports pristine condition of water. The type of Taxa found is tabulated in Table 1. The physical and chemical tests for 17 parameters were conducted and the test results are tabulated in Table 2. The relationship of Taxa to water quality was tried by the use of four different biotic index methods. Those results are presented under the heading, “RESULTS”. It was concluded that use of such methods could prove quite beneficial for developing world and agencies UNEP, OSDA, WHO etc. are ready to help such projects.