The Department of Irrigation in partnership with the National Water Supply and Drainage Board (NWSDB) officially commissioned a computerized Supervisory Control and Data Acquisition (SCADA) telemetry system across the Nilwala River Salt-Water Exclusion Barrier in Matara today, October 2, 2026.

During dry weather intervals and high ocean tides, dense marine salt wedges frequently push upstream along the lower reaches of the Nilwala River, predisposing the municipal drinking water intake pump stations at Nadugala to dangerous salinity spikes and threatening over 12,000 acres of low-lying paddy fields in the Nilwala flood plain. The newly upgraded automated barrier features motorized stainless-steel radial gates fitted with real-time electrolytic conductivity sensors that measure water salinity concentrations continuously.

When river sensors detect incoming salt wedges reaching the critical 0.5 parts-per-thousand potable limit, the automated control system instantly lowers the barrage gates within 90 seconds, sealing off tidal intrusion while allowing upstream freshwater to pool behind the barrier for municipal extraction. As river levels rise, automated sensors recalibrate gate heights to maintain safe upstream discharge and prevent localized flooding.

Irrigation engineers affirmed that the automated SCADA installation guarantees uninterrupted, safe drinking water distribution for over 250,000 residents across the Matara Municipal Council and surrounding rural water supply schemes. Local farmer federations in Thihagoda and Malimbada celebrated the technological milestone, emphasizing that dependable salinity exclusion protects productive low-country paddy crops from permanent soil salinization.