36. Reintroduction of Heptageniidae to the River Mimram

Themes: Water Quality, Habitats and Wildlife; Status and monitoring


  • That whatever the flow level, the river and its associated habitats, including banks and floodplains, are managed to support chalk stream species
  • That water quality, temperature and river bed quality are such that they support chalk stream ecology

Project description

To return Heptagenids to the Mimram, following their disappearance, possibly due to pollution incidents in the early 90s, and river restoration and Chalk stream replication at Panshanger and better monitoring of the Riverfly populations to assist protection of the river from pollution.


Heptageniidae are a group of mayfly believed to at one time been present in the River Mimram, though they are no longer found likely due to historic pollution events. This project will examine historical records on the Mimram, and other local rivers, and current records on the Lea to identify species of Heptageniidae that were once present on the Mimram.


The project will also seek to identify Heptageniidae found on the River Chess and Bulbourne during ARMI monitoring to species level.

A feasibility study of reintroductions, from previous projects (if any) and chances of success, taking account of current hydro-ecological conditions, pollution levels, macrophyte populations, prospect of reduction of abstraction on the Mimram ( imminent), and restoration projects carried out on Mimram, will be conducted with the ultimate aim of reintroduction of Heptageniidae from a suitable local donor river or breeding /hatching in suitable premise.

Project lead: TBC
Project partners: TBC
Funding source: TBC
Project start: TBC
Project end: TBC
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