Theme-IV-4-Isotopic characteristics of water in Bist-Doab and their hydrological significance.

Abstract

A study was conducted to characterize various water resources in the Bist- Doab region, Punjab using stable isotopes. Characterizing the water resources in a region like Bist- Doab, which has varied geomorphology, intensive cultivation of crops and a long network of canal system, is most critical and important factor. Taking into account all these factors, the use of stable isotopic technique could be suitable to characterize the waters of Bist- Doab region. To accomplish the study, the surface water samples from the rivers Sutlej and Beas and shallow groundwater, and rainfall samples from the Bist- Doab region were collected randomly to get representativeness of the entire study region. The isotopic composition d'80 of rainfall, Rivers (Saltluj and Beas) and shallow groundwater is -16.3%o to 1.1%o, -11.4%o to -6.6%0 (Satluj) -7.3%o to -6.6%0 (Beas), and -7%o to -4.9%o (shallow groundwater) respectively. The slope of LMWL derived for the study area is similar to that of GMWL and IMWL (north). Whereas, the intercept of the same differs varies from IMWL (north) and GMWL indicating difference in source of precipitation. Among the rivers, Satluj show depleted isotopic composition than that of the Beas. The isotopic composition of the R. Satluj shows enriched character near the confluence with R. Beas indicating a probable mixing of R. Beas or influence of groundwater as base-flow. The groundwater composition shows similar isotopic character to that of precipitation near Kandi belt and at the central part of the study area. The high depleted isotopic concentration of groundwater surrounding Garhshankar might be due to the influence of canal draining from R. Satluj. The best- fit lines of precipitation, groundwater and rivers derived from the 180 and D plot shows that the groundwater behaves similar to that of precipitation with a minor influence from the rivers.