The Small Streams Network (SSN) is a statistically designed national monitoring network consisting of an unbiased and representative set of monitoring sites across English streams. It will give a clear picture of stream health across England by monitoring a wide range of parameters, supporting long-term measurement and detection of change. SSN monitoring follows a five-year panel design that balances temporal and spatial coverage. Each year, 300 sites are monitored.
This Analysis Ready Dataset contains details of the network design and sampling locations, alongside water quality samples and ecology samples carried out at SSN sites since 01 April 2023. When fully implemented, the SSN will provide a nationally representative dataset to support robust national insights. This release of the data reflects a network that is still in development, so users should be aware of current limitations related to representativeness, sampling balance, data variability, and exclusions.
The Small Streams Network is a project funded by the UK Government through Defra's Natural Capital and Ecosystem Assessment (NCEA) programme. The NCEA is Defra's largest research and development (R&D) programme. It will produce a baseline of our natural assets by 2029; enabling a natural capital approach to policy and decision-making.
Users should ensure they have read the NCEA Analysis Ready Data Limitations Statement and dataset specific limitations/caveats outlined in the Data Dictionary Attribution statement: © Environment Agency copyright and/or database right 2025. All rights reserved.
