PO2 - Improving status of physico-chemical quality elements

Retention ponds are ponds or pools designed with additional storage capacity to attenuate surface runoff during rainfall events.  They consist of a permanent pond area with landscaped banks and surroundings to provide additional storage capacity during rainfall events.  They are created by using an existing natural depression, by excavating a new depression, or by constructing embankments.  Existing natural...

Riverbank represents both natural and man-made features following the river flow. In the past, lots ofmany artificial banks were built with concrete or other types of retaining walls, thus restricting the natural movements of rivers, leading to river degradation, increased water flow, increased erosion and reduced biodiversity. 

Infiltration trenches are defined as shallow excavations filled with rubble or stone. Their function is to facilitate the natural process of infiltration into the surrounding soils from the bottom and sides of the trench, thereby enhancing the soil's inherent capacity for drainage. Ideally, they should receive lateral inflow...

Swales are broad, shallow, linear vegetated channels which can store or convey surface water (reducing the rate and volume of runoff) and remove pollutants. They can be used as conveyance features to pass the runoff to the next stage of the SuDS treatment train and can be designed to promote infiltration where soil and groundwater conditions...

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...

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...

Green roofs are multi-layered systems that cover the roof of a building with vegetation and/or green landscaping over a drainage layer. There are two types of green roof: 

• Extensive green roofs cover...

A riverbank protection is an inert or living construction providing bank fixation but also an obstacle for the lateral connection of the river. Eliminating it consists in removing some parts of the bank protection, especially the inert one, in order to enhance lateral connections of the river, diversify flows (depth, substrate, and speed) and habitats, but also cap floods in the mainstream. It is a prerequisite for many other measures like re...

A river meander is a U-form taken by the river, allowing it to decrease water velocity. In the past, rivers have been straightened by cutting off meanders. Many rivers in northern and Western Europe have been straightened and channelized to, for example, facilitate log floating and/or speed up the drainage of water and control/limit the river bed movements. Channelizing was also a way to gain land for cultivation. River re-meandering consists...

A floodplain is the area bordering a river that naturally provides space for the retention of flood and rainwater.  Because of regular flooding, floodplain soils are generally very fertile and they have often been dried-out to be used as agricultural land. Floodplains in many places have also been separated from the river by dikes, berms or other structures designed to control the flow of the...