Latest revision as of 15:33, 5 January 2016

Water flow quantity improvement

General description

Water quantity is often dramatically reduced by water abstraction and diversion, especially in Mediterranean countries. With the exception of water abstraction at large dams, reduced water quantity is usually the result of cumulative impacts to the watershed. Therefore, restoration of water quantity generally requires a watershed-scale land restoration and management strategy.

Something in common for all the measures to increase water quantity is that water demand should be reduced, or alternative mechanisms for water regeneration should be implemented (water renewal and recycling, improve water retention and storage). Reductions on surface or groundwater extractions are specific ways to reduce water consumption.

In contrast to water abstraction and diversion, there are several other pressures which do not mainly affect overall water quantity but timing, i.e. the flow regime (e.g. changes in land cover, soil structure and compacting, loss of floodplains and wetlands, and stormwater runoff from urban areas). The loss of water retention combined with accelerated runoff typically increases the frequency and magnitude of flood peaks but also reduces the availability of water to streams during the prevailing low flow (base flow) periods. Therefore, the respective measures are also covered here (improve water retention, water storage, and increase minimum flows) but mainly fall in Category 03: Flow dynamics improvement.