Conductivity

Conductivity of the water samples varied from 270 to 630 uS with few variations as it was doubled between Bhilawadi and Sangli. The conductivity of the water increased with the increase in distance from the origin of the river.

Chlorides

Chloride content of the water varied from 25.7 mg/1 to 100.3 mg/1. The chloride content did not show any discernible trend till Bhilawadi (170 km from the source) but was found to increase 3.5 times between Bhilawadi and Sangli and declined thereafter.

Bicarbonates

The concentration of bicarbonates increased with increase in the distance downstream. It varied between 91.5 mg/1 and 381.2 mg/1.

Total Alkalinity

It ranged between 25.5 mg/1 and 83.0 mg/1. Initially, it decreased with increase in distance from the source, again increased significantly decline after Takari.

Sodium

The concentration of sodium ranged between 2.5 mg/1 and 13 mg/1. It increased with the downstream distance. It was five times higher at Sangli as compared with that at Dhom and declined after Sangli.

Potassium

Contrary to all other parameters studied, potassium content of the water registered least fluctuations. It varied within a narrow range of 0.5 mg/1 to 1.5 mg/1. Its lower values suggest the insignificant contribution of potassium salts towards the salt buildup in the river water.

Calcium

Calcium content varied between 2.0 mg/1 and 10 mg/1. There was increasing trend in the calcium content with the increase from the source; however, higher values were recorded at Takari and Sangli.

Sulphates

The total sulphate content increased with the downstream distance. It was 1.8 mg/1 at Dhom (30 km from the source) and increased four times at Ghalwad but again decreased at Narsinhawadi. The study revealed that there is a considerable salt buildup in the Krishna river which could be one of the major factors causing damage to the soils in this region due to salt accumulation as a result of improper irrigation practices in agriculture. The concentrations of sodium, calcium, alkalinity and sulphate were considerably higher in the downstream sampling sites. There were few important hikes in chlorides and conductivity near Sangli which could be attributed to the dischrage of sewage from this city. The decline in the concentrations of most of the parameters after Sangli can be ascribed to the dilution of the river water as the Warna and the Panchganga rivers join the Krishna just after Sangli and moreover these rivers flow comparatively for shorter distances with few diversions and hence, may be low in salt content.

The alarming salt buildup in the river, which could emerge as a problem of complex nature for agriculture and other uses of water, the begining of which has already been made, needs immediate attention. As industrialization, irrigation and use of pesticides and inorganic fertilizers are bound to increase in future, there is a threat to the resource and calls for major study of the river taking into consideration physico-chemical, geological, and biological aspects.

ACKNOWLEDGEMENTS

We are thankful to University Grants Commission, New Delhi, for funds to the College for implementation of a Restructured Course in Pollution. Encouragement from Professor R. M. Raverkar and Professor B.G. Dhavale is also gratefully acknowledged.

REFERENCES

• APHA-AWWA-WPCF. 1975. Standard Methods for the Examination of Water and Waste Water. 14th Ed. American Public Health Association, New York.
• ELBERT, C.H. 1971. Irrigation and salt problems in Denmark.'South Australia. Geogr. Rev. 61 (2): 355-369.
• I.S.I. 1974. Indian Standard Methods of Sampling and Test (Physical and Chemical) for Water Used in Industry (I.S : 3025-1964). Indian Standards Institution, New Delhi.
• MASTERS, G.M. 1974. Introduction to Environmental Science and Technology. John Wiley, New York.
• MOORR, C.V., J.H. SNYDER and D.A. PETERSON. 1974. Effects of Colorado river water quality and supply on irrigated agriculture. Water Resources 10 (2): 137-144.
• NAIK, G.R. 1975. Salinity problems along Krishna river, p. 14-21, in: S.P. Gurjek (Ed.) Discovering Krishna. Report of the Krishna Expedition. River Valley Expedition and Research Society of India, Sangli.
• PALIWAL, K.V. 1971. Quality of irrigation waters and their effects on soil properties in Rajasthan: a review. Ann. Arid Zone 18 (4): 266-278.
• PRINGLE, W.L., R.R..CAIRNS, A.M.F. HINNINE and B. SIEMENS. 1975. Salt status of some soils of the Slave river lowlands in Canada's Northwest Territories. Can. J. Soil Sci. 55 (4): 399-406.
• SKOGERBOE, G.V. and J.P. Law, Jr. 1971. Research needs for irrigation return flow quality control. US—EPA Project Report No. 13030.