The environmental services provided by beaver have substantial economic value, which can be quantified.
Five key aspects are involved:
- Flood mitigation. Through reduction of velocity, retention and evening out of peak flow discharges, beaver habitat can help alleviate downstream flooding – likely to be a growing consequence of climate change. The insurance and water utility sectors have a financial stake here.
- Water purification. By oxygenating water and retention and cleansing of silt containing pollutants. In Latvia the water purification impact of the beaver dams has been calculated as worth at least £40 million (Balodis 1994). For obvious reasons such calculations have yet to be undertaken for Wales or the British Isles, but simple extrapolation suggests benefits in diminution of pollution and reduction in treatment costs downstream which could attract sponsorship interest from water utilities.
- Water retention. Damming changes the shape of local water tables, enabling greater storage for subsequent release during drier periods – again a likely feature of longer, hotter summers resulting from climate change. This could again be of interest to water utility companies.
- Reduced siltation. This can be useful in reducing turbidity, and infilling of water courses, reservoirs, lakes or dams. Beaver are currently being used in Tatarstan to reduce the sedimentation of Lake Raifa caused by upstream erosion [Reference Gorshkov 2003].
- Wetland creation. Adding up the above wetland benefits and quantifying the results can achieves startlingly high figures. In effect beaver are creating valuable wetlands “free of charge” that would be extremely costly to restore by artificial means.
In Bavaria, as elsewhere in Europe, substantial flooding caused by torrential rain in 2004 resulted in hundreds of millions of euros of damage to residential housing and the local economy.
The need for reinstatement of natural vegetation in upland watersheds and creation of wetland areas to capture, hold and delay the throughput of flood water is now widely recognized, as is the role of the beaver in helping to create such habitat naturally and at minimal cost.
“The disastrous flooding this year has shown that the reduction in wetlands during the last 100 years has exacerbated flooding. The re-creation of natural retention areas serves for flooding protection and species conservation at the same time” Edmund Stoiber -Prime Minister of Bavaria 2004