Define the service to be delivered
State water volume, quality, reliability and any ecological or spatial objectives. Keep essential requirements separate from desirable benefits. A nature-based and an engineered option cannot be compared fairly if one includes polishing, storage and maintenance while the other does not.
Make the interfaces visible
For a hybrid concept, show the upstream unit, nature-based component and downstream barrier as connected functions. Identify which unit protects the next and how bypass, abnormal loading and maintenance are handled. Name the owner of each interface.
Compare lifecycle commitments
Bring land, establishment time, energy, residuals, monitoring and maintenance into the same comparison. Include climate and seasonal conditions. Avoid treating either a low-energy description or a small footprint as a complete environmental assessment.
Test the preference against uncertainty
Ask whether the preferred option changes when land, load, climate or maintenance assumptions change. Record the decisive trade-offs and information gaps. The output should explain why an option fits this project, not claim that one technology family is always preferable.
Sources & context
- US EPA · Constructed wetlands: technical resources ↗
- IPCC AR6 WGII · Chapter 17: Decision-making options for managing risk (2022) ↗
Background reading checked 9 October 2026. The review questions and structures above are BGF editorial guidance; the references are not BGF project evidence or endorsements. Apply them to the relevant site, data and agreed scope.