Covering letter to the EA, sent September 2025

Dear [——]

We enclose a report into low flows and drying of the River Tarrant in Dorset. The report was prepared by John Lawson, who has researched and published many other respected and influential reports on abstraction impacts in chalk streams. John is on the CaBA chalk stream restoration group's expert panel for water resources. 

The report makes a compelling case that groundwater abstraction in the Tarrant, Stour and Pimperne catchments is severely impacting flows and causing almost annual, unnatural drying in the River Tarrant, an important salmon spawning tributary of the River Stour.

We can all accept that the upper part of the Tarrant is a natural winterbourne, as are other neighbouring, slope-face chalk streams. There is also evidence that the lower part of the stream does very occasionally dry under natural conditions. However, the severity and duration of extreme low flows and the frequency of drying, especially in the lower river, has markedly and quite obviously increased as the abstraction at Black Lane has increased in the adjacent Pimperne valley. Whereas historically the lower river Tarrant dried naturally no more frequently than once in every twenty-five years, in the recent decade it has dried every single year, in spite of the high winter recharge in some of those years. Conversely, the one year it didn't dry - 2017 - the Black Lane abstraction was switched off for an extended period of time, and rainfall was actually lower than average. 

This, backed up by other evidence included in the report, provides a very strong case for investigating and re-evaluating the abstraction impacts in the River Tarrant and the Pimperne Brook. The need for this is made urgent by the fact that the Tarrant is such an important spawning and nursery stream for Atlantic salmon, a species now listed by IUCN as endangered in England, arguably critically endangered in the chalk streams, and doubly so in the chalk streams of the Stour catchment. The Stour salmon must be on the very edge of extinction.

Under these circumstances it is of extreme concern that the River Tarrant and Pimperne Brook are wrongly assessed as "supports good" for WFD flow classification, when they are so obviously adversely impacted, and as a result are excluded from AMP8 investigations. The report proposes that the flows of the Tarrant and Pimperne Brook sources are re-classified to “does not support good”. The sources should then be added to the list of Middle Stour sources for which AMP8 over-abstraction investigations are planned for completion by the end of 2026.

To underline that we are conscious of the need to identify solutions as well as urgent problems, the report also includes some very practicable suggestions for realigning abstraction in the area, so as to protect flows in the Tarrant without loss to public supply. The report proposes that the feasibility and effectiveness of the suggested realignment of abstractions should form part of the AMP8 investigations scheduled for completion in 2026. If the outcome of these investigations is positive, trialling of the realignment could start in 2027.

Could we please request, as soon as possible, a meeting to discuss what to do about all of the this. 

Best wishes

Ben Bayer

Chairman, River Tarrant Preservation Society