PO4 - Improving chemical status and priority substances

A polder is a low-lying tract of land enclosed by embankments (known as dikes) whose altitude is usually below sea level. It forms an artificial hydrological entity, meaning it has no connection with outside water other than through manually operated devices. The re-naturalisation, or depoldering, of polders involves enhancing their sub-natural characteristics to allow better water storage in watercourses inside the polder and increase...

Sediment capture ponds are engineered ponds placed in networks of forest ditches to slow the velocity of water and cause the deposition of suspended materials. Sediment capture ponds are most useful for managing the effects of ditch construction and maintenance, road work and final feeling. While used primarily in forests, sediment capture ponds may be a useful temporary measure for preserving water quality in and around construction sites or...

Forests act as natural sponges, absorbing excess rainwater to prevent flooding and retaining moisture for gradual release during dry periods. By increasing soil infiltration and storage, forests provide a consistent water supply, buffering against the extremes of climate change and increasing the resilience of ecosystems.

Forest access roads and other roads in rural areas often cross streams and other small watercourses. The design and material used in forest road building may have strong impact on erosion risk and water quality in streams. Bridges or culverts used at stream crossings must be properly designed to...

Headwater catchments are the source areas of rivers and streams and are critical for maintaining the structure, function, productivity and complexity of downstream ecosystems. They are vital to hydrologic cycle as they are one of the main areas where precipitation contributes to surface and groundwater. Headwaters are typically...

Continuous cover forestry is a forest management approach that maintains a continuous canopy during the regeneration phase, avoiding clearcutting in favour of selective harvesting or small-scale clearing. The main idea behind continuous cover forestry is a reduction in the number or size of clear-cuts. Some definitions of continuous cover forestry state that no clear-cuts shall be larger than 0.25...

Trees in urban areas deliver multiple benefits, including improved aesthetics, microclimate regulation, and enhanced urban hydrology. They also serve as crucial biodiversity refuges and contribute significantly to reducing particulate air pollution. Trees intercept precipitation, reducing the volumeof rainfall that needs to be processed by sewers systems and other...

Streambed (or riverbed) represents the bottom of the river, including each bank. In the past, riverbeds have been artificially modified with concrete or big boulders, altering flows and reducing habitat for wildlife and vegetation diversity. The changes were aimed at preventing flood or supporting changes of agricultural practices for example. This has led to more...

Filter strips are uniformly graded, gently sloping, vegetated strips of land that provide opportunities for slow conveyance and (commonly) infiltration. They are designed to accept runoff as overland sheet flow from upstream development and often lie between a hard-surfaced area and a receiving stream, surface water collection, treatment or disposal system. 

Filter strips are generally planted with grass or other dense vegetation...

Dams and other transversal barriers are obstacles crossing the river section and causing discontinuities for sediment and fauna. Removing them consists in destroying all the obstacles, restoring the slope and the longitudinal profile of the river, therefore allowing re-establishment of fluvial dynamics, as well as sedimentary and ecological...