Building Project - Filtration Technology
Visibility is most important for an excellent diving experience.
Except for a few mountain lakes, inland waters will never reach the visibilities of tropical coral reefs. There, a huge volume of water has nearly no influx of nutrients from the shore. Also, the ground is nearly completely free of sediments, because everything sinks into the depths and is thus eliminated from circulation.
The intense blue of clear water in the sea exists only in free water or the exterior reefs where waves don't clash against the reef crests.
In inland water visibilities of 15m are considered first class. Too many things live in fresh water as a cause of nutrient influx. (Photo: Temple area in July).
Inland waters, especially in the plains, are connected to streams of ground water that invisibly introduce nutrients and iron/manganese compounds. Iron flocculates in contact with oxygen and causes a brown tint. Nutrients such as nitrate and phosphate accelerate algae growth.
Where ground water leaks onto sandy grounds, iron compounds will usually flocculate.
Turbidity of the water is usually caused by a mixture of iron, brown-green sediment and green algae.
By sealing with liner the problem of nutrients being introduced through ground water is mostly solved. The 'only' task left now is to bind and extract from the system those nutrients that are introduced by wind and rain. This is nearly impossible to do directly. Rather, they are nearly always first used by animals and plants, preferably minute algae, that cause an emerald green colour.
The effect caused by algae: The left two gaps in the wall are still above water, while the one on the right is submerged.
Many algae feed many water fleas. The Consequence: Bad visibility in the bio-sludge.
To this end NaturaGart developed the filtering trench technology. Water is conducted through a shallow trench where nutrients are used for plants. This technology allows for good visibilities up to 10m if the influx of nutrients is small.
The filtering trench has proven itself for thousands of customers. In the Park there are several types.
Inconspicuous: An approximately 5'3
One problem, however, is that for example in spring nutrients abound in high concentrations but the plants are not ready yet to absorb them.
This is why in April there is usually a proliferation of algae.
The dead algae sink to the ground and are 'vacuumed' by the NaturaGart Target Suction Technology.
During construction extensive pipe systems were already installed.
Conduits were also incorporated into many places in the reef walls.
The pipes lead from the deepest suction points in the lake to the dams. Above they end in several filtering trenches. Several techniques allow to regulate the strength of suction applied at each point.
Additionally, NaturaGart fine filters were installed.
More information about the NaturaGart filtration technology.
Part of the suction system in the Underwater Park.
Pipes transit into the filtering trenches (construction phase).
Large bundles of pipes reach the surface at four points. With a special NaturaGart technique the single pipes are led through the dam.
The bunch of pipes in the middle of the eastern shore...
...is distributed to a large dam conduit.
The filtering trenches lie to the sides of the scuba diving park. At the end of the trench is a well with a pump. These areas will not be accessible to the general public except during guided tours.
The northern end of the trench next to the eastern cave...
...and the southern end with the aluminium construction for the piers.

The importance of the filtration technology could be appreciated during a test run in 2005: Because the financial bureaucrats kept hassling us, we had to start up sooner and delay the planed cleaning or the lake until the next winter.
We started out with 15m visibility and had about 3-5m toward the end.During the second year visibility was normally around 8-10m; only on Sundays did it go down to 5-6m.

Sinking the boat caused a cloud of mud that took 5 hours to reach the other end of the lake.
500 scuba divers per day reduce visibility to 3-5m. Sedimentation of the stirred up particles takes between 1 and 3 days.