Adopted

History and objectives

The town of Douai, the SIADO ( Intercommunity association of Cleansing of the area of Douai ), the SED ( Company of Water of Douai ) and of the Town of Douai, were particularly interested by the alternatives, because at the same time located in zone of mining Affaissement, and industrial Séquelle S (polluted sites, grounds and sediments), where any flood can take catastrophic proportions. These entities when they wanted to create association ADOPTED obtained a strong support of the Area and the Agency of water, also interested by the safeguarding of the food of the tablecloths, because the not polluted tablecloths start to miss in this area which depends to 96% on the tablecloths for the drinking water supply. This area in addition one of is urbanized Europe and the periurbanisation continues contributes to develop the proofing which is at the same time source of floods, drynesses, water pollution and erosion of the grounds.

Association is opened with building owners, public or deprived project superintendents, developers, architects, companies of public works and buildings, suppliers, etc which it associates at commissions of work and reflection and with the publication of documents of assistance and council.

Alternative techniques

They are based on triple principle:

to store rain water temporarily, upstream, for by a effect-plug slowing down and controlling the flows towards the downstream.
To infiltrate the water not polluted in the ground, as long as possible, to reduce volumes running out towards the downstream
To distinguish and treat separately polluted water of rain water and Streaming and among these last to take care that those which streamed on polluted substrates (roads, courses of factories, grounds polluted, etc) are treated according to their characteristics (load in microbes, deterging, heavy metals, pesticides, pollutants road, etc)

What implies;

to manage water closest to is not fall, with passive solutions (not depending on pumps, valves, winnowings and pipes which are likely to be stopped, etc), as of the roof for example with the vegetalized terraces, or close to the house, with systems of Noue S and restoration of Wetlands functional (such as natural lagunages which also purify water, which is not the case of the sewer S collecting rain water)
Eviter or to limit the streaming, which is a powerful factor of pollution water and of fast transfers of pollutants towards the downstream and the sea (the Turbidité of water became one of the most critical parameters for the rivers of the North of France).

Advantages:

Fight against the floods and the drynesses
Restocking of the underground layers
Cost reduced compared to the traditional solutions (pipes, pumps)
Less pollutant emissions in the natural environment
Reliability (by developing passive systems and solutions most self-sustained possible éco-techniques, by the ecosystemic processes natural.

Examples of techniques " alternate "

They associate various solutions such as;

fitted - tank , whose very porous material is designed to store rainwater temporarily, with relarguage slow to chop the risings. Water is purified there - to a certain extent - while percolant there, thanks to the bacteria installed in the substrat.
Des buried equivalent structures can receive the water of the roadways, injected by Avaloir S judiciously laid out if the coating is étanche.
Après storage, if there is position risk, water can be evacuated towards a discharge system intended for its purification (purification plant or natural Lagunage according to the type of Risque…)
Well of absorption ; they are wells of injection in the tablecloth. They require of which that water is very clean, this is why the wells of infiltration theirs are preferred, water being purified while percolant in the ground and/or a purifying substrate prepared before reaching the tablecloth.
ditches and/or valleys : They allowing a storage the free air before infiltration det/ou evapotranspiration by the plants which purify the water of the Nitrate S, Phosphate S and of part of its pollutants;
Trench drainage ; linear, surface structures offering a buffer volume allowing a provisional storage of the water which can then be treated, lagunée or infiltrated in the ground.
Basins of infiltration ; vegetalized (it can even be a question of a easily flooded garden , conceived so that there is no small island where children would be likely to be surprised by the rise of water). They of a size more important than the preceding solutions, and are positioned to collect surface the massive water surges, before purifying them and slowly infiltrating in the ground after storage temporary.

Conditions of success

They are a good transversality of the highways departments, cleansing, green areas, which must work upstream and can usefully join the services of a Paysagiste and a ecologist to develop an ecological management and thus differentiated favorable to a better management and purification of water. Adopted showed that these solutions if they are based on a relevant diagnosis, that they take into account the climatic risk growing, the constraints and appropriatenesses of the sites concerned, and if they are integrated in a coherent way and as of the upstream of the projects and on a scale the basin slopes allow very important economies.

Association also showed the importance of the legal tools which allow the communes and agglomerations to impose many these solutions. An additional appreciation écopaysagère can be brought, with for example in this area the integration of the sites of management of water in the green and Blue Trame of the District council.

The rain water can also be the subject of recovery starting from the roofs for one or more successive valorizations.

See too

Flood
Dryness
Master development plan and management of water (WISE)
DCE (Parent directive on water)
green Screen
natural Lagunage

External bonds

Adopa (Site of association ADOPTED)

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