Value of water retention
Economic value of water retention consists mainly of avoided costs. If the natural water retention mechanisms have been damaged the artificial flood mitigation is necessary in some places. It means extensive costs for society.
Flood damages may cause large expenses as well. Floods damage buildings, roads, bridges and other infrastructure. Also commercial forests and agricultural lands suffer from the excessive water volumes. Loss of nutrients and organic compounds is especially great on agricultural lands because the soil is usually barren during spring floods and erosion is substantial.
Floods induce many health risks both directly and indirectly. Direct risks are for example injures of many kind in accidents. Indirect risks arise from, for example, contaminated water and mould damage. Contaminated water is a risk in cities when the sewer network does not have sufficient capacity and the sewage water rises into the streets and buildings. Mould damage may occur in buildings that have been under water. Exposure to mould may cause amongst other things continuous colds, dyspnoea and exanthema.
Fundamentally, the intrinsic value of water retention arises from the existence of intact natural areas that enable the functioning of important ecosystem mechanisms such as water retention.
It is crucial to remember that floods are natural and for some species vital phenomenon. Flood mitigation costs are lower if infrastructure is not built, in the first place, on flood sensitive areas. Nevertheless, it is probable that climate warming increases floods also in Finland which may result in increasing flooding.
- Updated (20.01.2015)