October water quality summary
Friends of the Dart — October Water Quality Summary
During October, Friends of the Dart carried out four rounds of water quality monitoring across the River Dart catchment, supported by the Wild Dart Fund and the Devon Environment Foundation. Sampling covered both dry and wet conditions and included key sites such as Steamer Quay, Stoke Gabriel, Dittisham, Warfleet Creek, and key tributaries including the Mardle, Ashburn, Hems, Ambrook, and Harbourne.
Early October (dry weather):
The first October samples, taken under dry conditions, showed elevated E. coli levels upstream of Totnes Weir and at Steamer Quay, with all upstream sites on the main River exceeding the threshold for poor water quality. In contrast, smaller tributaries such as the Staverton Village stream recorded excellent results, while the Harbourne River narrowly fell below the “excellent” threshold (500 cfu/100 ml) and was classified as good. Sites on the main River downstream of Steamer Quay showed lower E. coli levels, with Stoke Gabriel and Dittisham recording excellent results, and Warfleet Creek recording a good result.
Mid-October (dry weather):
Testing focused on Holne Weir, the Ashburn and Mardle rivers near Buckfastleigh, streams along the old Totnes–Buckfastleigh road, and the River Hems with its Ambrook tributary.
Very low E. coli levels were recorded at Holne Weir (0 cfu/100 ml) and along the old road (0–300 cfu/100 ml).
The Ashburn and Mardle both showed elevated concentrations (900–1300 cfu/100 ml).
On the Hems, results suggested pollution inputs upstream of Broadhempston STW (700 cfu/100 ml upstream vs 300 cfu/100 ml downstream).
The Ambrook tributary continued to show high bacterial levels (1500–2000 cfu/100 ml), particularly at Tripe’s Copse and Torbryan.
A sample from Staverton Bridge (Old Mill Leat) showed low levels (200 cfu/100 ml).
Late October (after rainfall and storm spills):
Following 5 mm of rain and four combined sewer overflow (CSO) spills, sampling on the Mardle, Ashburn, Old Mill Leat, Ambrook, Hems, Harbourne, and Bow Creek showed mixed results.
The Mardle recorded very high E. coli levels (4600 cfu/100 ml), while Tripe’s Copse and Torbryan remained elevated (3500 cfu/100 ml and 2100 cfu/100 ml respectively).
The Hems downstream recorded its lowest concentrations since March (as low as 300 cfu/100 ml at Ambrook Downstream).
The Harbourne showed very low levels (200 cfu/100 ml), but Bow Creek rose again to 1200 cfu/100 ml.
Late October (wet weather, no CSO activity):
During the final week of October, samples were collected from the remaining four sites under wet weather conditions, completing this month’s monitoring round. A small amount of rain (1.7 mm) fell in the 48 hours prior to sampling, and no combined sewer overflow (CSO) spills were recorded on WaterFit Live.
Results from Still Pool, Dartington Beach, Dartington Pontoon, and Steamer Quay showed a clear gradient in E. coli concentrations, increasing downstream towards Totnes:
Still Pool (Staverton): 700 cfu/100 ml
Dartington Beach: 800 cfu/100 ml
Dartington Pontoon: 1,200 cfu/100 ml
Steamer Quay: 4,100 cfu/100 ml
Based on bathing water thresholds, Still Pool and Dartington Beach were classified as good, while water quality at Dartington Pontoon and Steamer Quay was poor.
Friends of the Dart will continue regular off-season monitoring at the four designated bathing sites and, in partnership with the Environment Agency, conduct a walkover of the River Hems to investigate sources of persistent bacterial pollution.