OBJECTIVES

The objectives of the study were:

• To explore the physicochemical status of aquatic ecosystem in the Sharavathi river basin by investigation of the water, soil and sediment and
• To suggest the suitable implementable management options.

Study Area

Sharavathi river, flowing northwest, originates in the Western Ghats near Ambutirtha in Tirthahalli taluk of Shimoga district. With a length of about 128 km and total drainage of 2771 sq. km., the river with its tributaries flows along the rugged terrain of western ghats of southwest Shimoga and southwest Uttar Kannada districts. The river drops to a vertical fall of about 253 m near Jog and joins the Arabian Sea at Honnavar in Uttar Kannada (Karnataka State Gazetteer Part-I, 1982). This region supports a rich diversity of flora and fauna. Karnataka Power Corporation Limited constructed a dam across the river in 1964 near Linganamakki, which is at present one of the oldest hydroelectric projects in India. The dam has its catchment area of nearly 1991 sq. km. receiving water mainly from rainfall and Chakra and Savahaklu reservoirs, which are linked to dam through a canal. The Linganamakki dam construction has resulted in the submersion of 6,800 acres of land of 62 villages along with loss of biodiversity. The aquatic and soil ecosystems are the major resources under threat. Although different checklists are used to assess the cumulative impact of water related project on the ecosystem, in the present study, water, soil and sediment were characterized to assess the impact. For this purpose continuous monitoring of the Sharavathi and its primary and secondary feeders along with the catchment soil and sediment were carried out for four months. The water soil and sediment sampling sites with their corresponding latitude and longitude are given below in Tables 1 and 2.

Sediment Sampling Sites

The sediment sampling sites are (1) Sharavathi (Nagara),(2) Sharavathi-1, (3) Sharmanavathi, (4) Haridravathi, (5) Muppanae, (6) Reservoir, (7) Hurlihole, (8) Yennahole (9) Valagere, (10) Nittur and (11) Sampakai with corresponding longitude and latitude as given for water sampling sites.