River Condition Assessment

RIVER CONDITION ASSESSMENT
What’s an RCA?
A River Condition Assessment (RCA) evaluates the condition of rivers, streams, canals, and other natural (or semi-natural) linear features containing running water. The original MoRPh Rivers field survey was designed so that not-for-profit organisations could give their citizen scientist surveyors a standardised and easy to follow methodology. The RCA is like an expanded version, where the field survey is combined with a comprehensive desk study and analysis using dedicated software to get the final score.
It’s usually done because the watercourse needs to be entered into the Biodiversity Net Gain (BNG) Statutory Metric, but it’s also useful in guiding restoration and conservation works.
When do I need one?
If you’re doing BNG and have a watercourse within 10m of your site boundary, you almost certainly need one. Even if it’s dry for a lot of the year. Your ecologist will let you know if this is required in the initial stages of site work, but you can also get a good idea of whether an RCA will be needed by having a look at the Environment Agency’s Statutory Main River Map.
What’s involved?
Desk Study
The first step of the assessment is a desk-based study of the reach (i.e. 1-5km rather than just the area around your site) to determine the overall river type, the exact extent of the subreach to be surveyed, and then calculate how many individual survey points need to be completed in the field to cover 20%.
Site Visit
After this, the surveyor walks the entire length of the subreach to get an overview of watercourse character, and then selects “representative” locations for each module. Each module has 5-10 individual datapoints, each with around 400 individual observations covering vegetation structure, geology, morphology, deadwood features, hydraulic function, encroachment, and many other aspects of the watercourse at that specific location.
Indicator Analysis
The results from the field survey are entered into the same dedicated software where we did the desk study.
When the desk- and field-based elements are combined, a baseline condition is generated. This can then be entered into the BNG Statutory Metric, along with the encroachment scores.
That’s only half of the job though! Once the baseline has been determined, we then need to work out what enhancements are needed to get the required BNG uplift. Thankfully, the software deals with that too…
Who can do it?
Whilst the MoRPh Rivers is designed to be used by (almost) anybody, the RCA can only be conducted by a qualified surveyor. Cartographer have a searchable register… or you can just get in touch with us!

What’s an RCA?

When do I need one?

What’s involved?

Desk Study

Site Visit

Indicator Analysis

Who can do it?