NFM Flow Gauging, Performance & Efficcacy Testing
NFM Flow Gauging
Natural Flood Measures (NFM) refers to using natural processes to slow, store, filter water in a catchment to reduce flood risk, improve water quality, and enhance biodiversity. It’s a green low-cost alternative or complement to traditional “hard” civil engineering methods like creating dams.
Core principles behind NFMs are slowing the flow, runoff e.g., through leaky dams, earth bunds, or hedgerows. Storing water by using wetlands, floodplain reconnection, or temporary ponding areas. Increasing infiltration by restoring soils, planting trees, and improving ground structure. Managing sediment and nutrients by intercepting flow paths to prevent erosion and pollution.
The effectiveness of a NFM can be modelled however models can only be considered approximations and many additional parameters can come into play way beyond those the catchment topology.
Pre-Construction NFM, Flow, Level, Groundwater and Rainfall Monitoring
The team at Radio Data Networks can provide a range of retrofit flow/level gauges, flow structured, groundwater monitoring stations and rain gauges to enable models to be calibrated enabling the design of the NFMs to be optimised prior to construction.
These gauges as per the illustrations on this page can be made lightweight, transportable enabling them to be retrofitted to existing bridges, culverts, pipes and weirs that flow into and out of the catchment.
Where there are no structures, retrofit temporary V-notch dam walls or flumes can be manufactured complete with gauges housed in stilling tubes.
Post-Construction, Flow Reduction Efficacy Testing .
After a NFM is constructed the “as built” performance can be verified using gauges, for given levels of rainfall and where applicable groundwater levels. Post construction gauging can be also used to identify any leakage or bypassing in structures and to assess the ROC invested as a £/m3 storage or £/l/s ROC figure.
Finally the same gauges can be used to assess the long-term degradation of the NFM enabling the optimisation of maintenance such as for example the need for dredging or the degradation, or failure of leaky dams constructed from trees.
