Manipal Institute of Technology researchers led by Dr K Balakrishna, Professor at the department of Civil Engineering is actively working on monitoring the health of the coastal rivers of Karnataka. His group is studying on five important west flowing rivers of southwestern India namely, Payaswini, Nethravati, Seetha-Swarna, Sharavati and Kali rivers, which are also the primary source of drinking water and source of food to over four million population living in the districts of Dakshina Kannada, Udupi and Uttara Kannada districts. The group has investigated the presence of major ions (Na, K, Ca, Mg, bicarbonates, chlorides, sulphides), heavy metals (Pb, Zn, Cd, Cu, Fe, Ni etc) and organic contaminants (antibiotics, personal care products etc) in the rivers and sediments of this region (Figs 1, 2, 3). The primary sources of major ions and heavy metals are natural, from the weathering of the catchment rocks in the Western Ghats. The organic contaminants though minor and currently not threatening the biota in the rivers, are primarily sourced from the wastewaters that are discharged into the rivers from the villages and towns adjoining the rivers and the agricultural effluents. His group is also studying the presence of diatoms, a variety of algae in Kali river to monitor the health of the river. Specific species of diatoms are an indicator of pollution, whose studies are underway (Fig. 4)

Groundwater discharge into the coastal oceans help promote fishery in the coast. Dr Balakrishna’s team are actively identifying potential submarine groundwater zones across coastal Karnataka. The groundwater discharged into the coastal oceans bring in nutrients to the sea, that results in increase in the phytoplankton growth and fish catch in the region (Figs 5, 6, 7, 8). The findings of Dr Balakrishna’s research group are reported in over 20 peer-reviewed publications.