Rain overflow basin for collecting and storing water

A rain overflow basin for collecting and storing water, comprising:

• an inflow;
• an outflow;
• wherein water flows from the inflow toward the outflow;
• a basin chamber;
• separated from the inflow and the outflow by a wall section, the wall section having a through hole fluidly connecting the inflow to the basin chamber;
• a basin spillway, which is equipped with a weir threshold, and is connected downstream of the basin chamber;
• a first drain in fluid communication with the basin spillway and which discharges the basin spillway;
• a clear water spillway having a second drain, which is connected downstream of the basin chamber and separately from the basin spillway, the clear water spillway including an opening to the basin chamber;
• a retention element is provided inside the basin chamber, which extends into the basin chamber;
• wherein water draining from the basin chamber through the opening into the clear water spillway flows through the retention element.

A method for renovating a rain overflow basin, the rain overflow basin comprising an inflow;

• an outflow, wherein water flows from the inflow toward the outflow;
• a basin chamber separated from the inflow and the outflow by a wall section, the wall section having a through hole fluidly connecting the inflow to the basin chamber;
• a basin spillway, which is connected downstream of the basin chamber;
• and a drain in fluid communication with the basin spillway, which discharges the basin spillway;
• the method comprising the following steps:
• providing a partition device in a region of the basin chamber, which forms a storage space, which is connected downstream of the basin chamber and upstream of the basin spillway;
• providing a passage between the inflow and the basin chamber by at least partially opening the partition device or by introducing a connecting device between the inflow and the basin chamber;
• creating at least one passage opening in the region of the partition device, which is used for water to pass from the basin chamber to the storage space;
• and
• installing at least one retention element, which extends into the basin chamber, in a region of a passage opening, or installing an inflow element, which extends into the basin chamber, in a region of the passage opening, wherein a plurality of retention elements extend into the basin chamber from the inflow element;
• providing a weir threshold between the storage space and the basin spillway to create a gradient of water inside the storage space, which drops from the weir threshold toward the partition device, the gradient creating a reverse flow of water from the storage space toward the basin chamber with dropping water level in the rain overflow basin.