Planning concept
The terrain was modeled in the northern and eastern boundaries by soil layering. The overall result is a spacious lawn with a good view, as well as retreats and niches in the peripheral areas. Visibility from the outside, especially from the street and the railroad side was limited by the terrain modeling and a new perimeter planting.
The Neptune filter was elevated and integrated into the embankment. The curved side towards the sunbathing lawn was terraced and is used as a spectator stand for the beach volleyball court. The northeastern embankment was equipped with wooden platforms, creating attractive sunny berths. On the eastern side, a new water attraction was built in the form of a meandering flow channel with flow velocities that vary due to the incorporation of bumps. Adjacent to the sanitary area and catering facilities, a new toddler area was built that traces the outer contour of a whale. In the southeastern area of the site, a street ball area for youths has been planned.
From the entrance area with seating terrace, a narrow paved path leads through the spacious beach area of the non-swimmer pool. The water-facing side of the walkway was constructed using fine gravel, so that the material movement in the water would be as low as possible. The opposite side was made in sand.
Water treatment
The water treatment for the natural swimming pool Zeven is carried out by two separate filter systems; a sprinkled soil filter, the so-called Neptune filter and a wet filter.
The wet filter is fed directly via the overflow edges and is dammed up with a water overhang of approx. 30cm. Parts of the filter are planted with marsh plants. The water flows vertically through the filter and is collected in pumping shafts. During its passage through the filter material, the water is purified as a result of microorganisms and is transported back to the areas of use by pumps.
At the same time, the Neptune filter is fed with raw water from the overflow channels. The pores of this filter are not completely blocked, ensuring an optimal oxygen supply and germ elimination. Here, too, the water flows vertically through the filter and is collected via drainage pipes and then transported back to the basins.
The filling water is fed from another well. The filling water is first passed through a phosphate adsorber before being fed into the application area, so that excessively high P concentrations can be reduced. This adsorber is also switched on when the number of bathers is high, because of the fact that nutrients are also brought in by the bathers. Excessive algae growth can thus be counteracted.
The dimensioning and design of the water treatment is carried out according to the recommendations of the FLL, Forschungsgesellschaft für Landschaftsbau und Landschaftsentwicklung e.V. (Research Society for Landscaping and Landscape Development).
Characteristics
Outdoor pool area: 21,500 m²
Usable Water area: 3,480m²
Total Volume of Water: 4,415m³
Water treatment: Neptune filter (700m²), wet filter (300m²)
Nominal number of visitors: 1,600 visitors/day
