SmartRivers results

SmartRivers on the Hamble brook 

This year we conducted the first SmartRivers surveys of the Hamble, to both assess the current health of the brook and as part of baseline monitoring for planned restoration schemes. SmartRivers is a citizen science monitoring method run by Wild Fish, it involves kick-sampling to collect aquatic invertebrates with the sample sent off for laboratory analysis.  

  

Organisms are identified to species level, and this highlighted the Hamble’s significance as a winterbourne chalk stream, with over 6300 individuals from 30 species identified at just one site. This included rare winterbourne specialists such as the Scarce Purple Dun mayfly, Paraleptophlebia werneri which has only 156 recorded sightings in the UK. 

  

The sensitivity of different species is then used to calculate the impacts from different stressors such as chemical, organic or sediment pollution. However, since drying is a natural part of the winterbourne cycle the indicators can be distorted so this is less reliable. Wildfish are aware of this limitation of SmartRivers and will use data such as those provided by the Chilterns Chalk Streams Project to improve the interpretation.  

The ground water that feeds the Hamble brook has been dropping for much of the year, and the stretch in which p. werneri was detected in Spring was dry by the Autumn surveys. Other sites were showing signs of pooling and shortly after the samples were taken the entire river entered its first full dry phase since 2021. The specialist species need these periods of drying to be able to compete against more vigorous species that would dominate in perennial rivers. 

  

The health of ephemeral and winterbourne streams can be hard to monitor due to this flow intermittence and the impact it has on the ecology, and this means there is both a lack of historical records and current understanding. But the Chilterns Chalk Streams Project, by working with organisations such as WildFish, are determined to continue furthering the understanding of these rare and threatened water courses. 

 

 

Check the Chilterns Smarter Water Catchment website for the Chess results.