5. Summary

From the above-mentioned suggestions, it can be concluded that the management of agricultural practices is required to adapt to the whole catchment region. The essential features of nutrient runoff from croplands should be taken into consideration for the protection of the lake water quality. Pollution abatement methods, continuous monitoring of point sources pollution, and laying demonstrations to enlighten the public perception towards lake degradation would be beneficial.
This paper serves as an initial discussion of the diffuse pollution in the Kolleru Lake catchment. The results of SWAT modeling showed that 28% of the highest NO3-N load contributed from the Ramileru basin, and 32% of TP load from the Thammileru basin, which make them to the critical river basins of diffuse pollution. Among them, the average load of individual sub-basins is estimated. This study indicated that diffuse pollutions are mainly governed by agricultural runoff. Apart from that, HRU priority level critical sources of NO3-N and TP were identified against the village communities. Besides, the first and second priority levels of BMPs of diffuse sources were highlighted. These results improve the understanding of pollution levels and targeting control measures of critical priority areas in the Kolleru Lake catchment. The communication between the stakeholders and water quality managers are required for knowledge exchange. This is a basis for a profound understanding of the ecological crisis of lake degradation levels, and a prerequisite for the development of further implementation measures.
Data availability statement: The authors would like to share the data based on request.