River Taf Water Quality Report: October 2026

Monthly Assessment and Comparative Analysis.

This report provides an analysis of the water quality data collected across the River Taf in October 2026 at Llandowror, Whitland Church, Login, and Glogue, with comparisons to results from September2026 and earlier months. Sampling was conducted across four locations this month, with no data recorded for the Water monitoring station.

Water temperatures continued their seasonal decline across the catchment in October, reflecting typical mid-autumn cooling. Downstream temperatures along the lower stretch were recorded at 14.7°C at Llandowror and 14.4°C at Whitland Church, representing a further reduction of approximately 1.2°C to1.8°C from September. Upstream locations also showed lower temperatures, with Login measuring14.3°C and Glogue remaining constant at 13.7°C.

Dissolved oxygen concentrations remained stable, high, and healthy across all sampled sites. Downstream readings along the lower stretch were measured at 9.5 mg/L at Llandowror and 9.2 mg/L at Whitland Church. Upstream readings were similarly high, measuring 9.8 mg/L at Login and 9.8 mg/L at Glogue, ensuring ample oxygenation for aquatic life.

pH measurements increased slightly across all sampled sites in October, moving into an alkaline range between 8.3 and 8.5. Downstream, values were recorded at 8.3 at Llandowror and 8.3 at Whitland Church. Upstream, pH values were measured at 8.5 at Login and 8.5 at Glogue. All recorded values sit

comfortably within the standard ecological guidance range of 6.0 to 9.0.

Nutrient parameters exhibited minor variations across the river system during October. Phosphate levels along the lower stretch were recorded at 0.50 mg/L at Llandowror and 0.22 mg/L at Whitland Church. Upstream phosphate levels measured 0.33 mg/L at Login and 0.20 mg/L at Glogue.

Nitrate levels along the downstream stretch moved to 2.0 mg/L at Llandowror and 1.5 mg/L at Whitland Church, returning towards levels observed during early spring. Upstream nitrate values remained steady at 0.8 mg/L at Login and 1.0 mg/L at Glogue. All nitrate concentrations remain well below the excessive

threshold of 5.0 mg/L.

Ammonia concentrations remained low across the catchment. Llandowror recorded a reduction to 0.02 mg/L (down from 0.22 mg/L in September), while Whitland Church measured 0.04 mg/L, Login measured 0.01 mg/L, and Glogue measured 0.07 mg/L. All readings remain comfortably within the

target threshold of less than 0.3 mg/L.