Long-lasting rehabilitation and restoration of bodies of water:  
Helping to preserve natural and cultural landscapes.

In Germany, standing bodies of water cover a total area of 4161 km2* – roughly as much as the federal states of Hamburg, Berlin and Saarland combined. In addition to pure size, however, the diversity of these lakes and ponds and their functions are vitally important. Bodies of water shape landscapes and towns. They are valuable; sometimes as protected habitats for animals and plants, as well as being places for recreation and leisure. Many also have a functional purpose, such as for flood protection, fish farming or water storage. .

However, maintaining this wide variety of waters and keeping them healthy and beautiful is often a major challenge for the states, municipalities, associations and private owners who manage them. Problems occur under the surface of the water and can go undetected for many years. This makes it important to familiarise yourself with the typical symptoms. Once a problem has been identified, lack of expertise on its actual causes or insufficient financial resources can make it difficult to resolve the issue quickly.

The experts at OASE WATER TECHNOLOGY provide a wide range of services for long-lasting, effective and cost-effective support for all those who manage bodies of water.

*Statista, March 2020

Water is not just water:
The challenges that different bodies of water pose. 

In principle, every body of water has its own "DNA". It is characterised by its location and geology, any tributaries, former or current uses, and pollution from industry and agriculture. All of these create special conditions that require bespoke solutions. We can respond to these requirements with our systematic water therapy and address a wide range of problems in any type of lake or pond.


1. Bathing lakes in line with the EU directive

From a tourism perspective, it is highly desirable for a large lake to be classified as an official EU bathing water with excellent water quality. However, the EU directive stipulates that the water quality must be monitored continuously and meticulous reports filed if anomalies occur or bathing bans are imposed. If problems last too long or occur too frequently, the body of water may have its certification withdrawn.  

Our products for long-lasting water therapy are cost-effective solutions that can be used, for example, to reduce organic sludge in order to effectively prevent algal blooms and restore the volume of open water that has been lost. They comply with EU directives, are eligible for EU funding when used as a maintenance measure and – naturally – are safe for humans and animals.

2. Natural bathing lakes/woodland pools

Natural bathing sites are particularly important during hot summers as they provide a place for people to cool off, relax and experience nature. They are also of great ecological importance as species-rich biotopes. If a lake's natural balance is disturbed and the water quality deteriorates, however, the number of naturally occurring organisms there can decline. Swimming may also be restricted by bathing bans.  

Our products restore the self-healing powers of bodies of water in a natural way and help to keep them stable. This allows lakes and ponds to be continuously used as bathing sites while still preserving their natural biodiversity.

3. Small local bodies of water

Village ponds, park ponds and urban pools often have long histories and, consequently, struggle with problems in the present day. Waste, leaves and dead plants accumulate over the years. Resident animals are often fed, which is well intentioned but ultimately detrimental and leads to more and more organic matter being deposited on the bottom. In turn, all of this promotes algal growth and depletes the oxygen content of the water. This can turn the water smelly and kill fish, which draws public attention to the unhealthy condition of the pond.  

We offer easy-to-use, cost-effective water restoration solutions that get to work immediately and are based on substances that occur naturally in the water. This means that both the citizens' interests and water protection requirements are addressed.

4. Bodies of water in nature reserves/Special Areas of Conservation (SAC)/Natura 2000 sites

Nature reserves are highly sensitive areas in which flora and fauna are left to develop undisturbed. But even bodies of water in these areas are not safe from deteriorating water quality, sludge build-up and algal blooms. This poses quite a challenge for the authorities responsible for maintaining them: On the one hand, the "no deterioration" rule obliges conservators to take action; on the other, nature conservation requirements set strict limits, for example regarding the use of machines and the emissions they produce. Many treatments contain active substances and are therefore banned in areas protected by the EU Habitats Directive, because there is a strict prohibition on introducing foreign substances in these special areas.

In cases such as these, we recommend using our product SchlixX Plus, an effective solution that complies with nature conservation guidelines and has won the German Award for Sustainability. A successful example of SchlixX Plus in action is at an SAC in Georgsmarienhütte, Germany, where it was applied to a mill pond measuring approximately one hectare in size.

5. Fisheries

Fish farms should ideally be productive waters with high yields and high feed conversion rates. Undetected sludge accumulation can lead to oxygen depletion in the water and reduce the water volume. In addition to insufficient water hygiene or unstable water quality, this can make fish unhealthy or, in the worst-case scenario, even kill them.  

Our solutions for stabilising bodies of water and raising their oxygen content are optimised for efficiency, being 100% environmentally friendly and leaving no residues in animal organisms. This allows the water volume to be reclaimed safely by reducing sludge levels and without the usual expensive dredging process. This protects both the fish – and the owners – from the stress of mechanical sludge removal. You can see how our method was used cost-effectively and successfully in a fishery by reading our reference report on the Rödental fish farm.

6. Storm water retention reservoirs

As heavy rain is becoming ever more common, storm water retention reservoirs are playing an increasingly important role in built-up areas. They manage rainwater to relieve storm drains and prevent flooding in populated areas. If a retention reservoir silts up, its intake capacity decreases – and the likelihood of flooding and costly damage to homes and infrastructure increases.  

Effective sludge reduction using microbial and mineral mechanisms can restore the original water capacity quickly, straightforwardly and without expensive dredging. This is a sustainable solution, as restoring the full function of an existing retention system can eliminate the need to invest in new reservoirs.

7. Water reservoirs/storm water sedimentation reservoirs

The same applies to these facilities: Restoring and maintaining existing capacity is an effective method for protecting against flooding in the long term. And it is significantly cheaper than building new reservoirs, which have a poor carbon footprint due to the large amount of concrete required.

Use our Water Technology Partner Network to find a local certified OASE Water Technology Partner to perform the treatment quickly and easily on-site.

8. Ponds and lakes on golf courses

Golf is not only a sporting challenge; it also gets you out into nature. But water obstacles affected by blooms of blue algae or that smell bad due to sludge formation would spoil anyone's game. 

In this context, rehabilitating bodies of water is not just about restoring the aesthetic appearance of the golf course – it also makes them more sustainable. Reclaiming water volume means that more pond water is available for irrigating the putting greens, which reduces or even eliminates the need to use precious drinking water.

9. Bodies of water near the coast

These are usually large inland lakes near the coast that often contain brackish water. However, it's not their salinity that is the problem – rather, it's their location at the far end of river systems. Everything that has entered the rivers along their way to the sea is deposited in these lakes. As a result, many problems can occur at once – accelerated algal growth and sludge formation, oxygen deficiency, poor water quality – and lead to a loss of biodiversity.

These lakes can be remediated to preserve a piece of nature and restore biodiversity by carefully analysing the water and applying systematic water therapy.

10. Bodies of water with delicate deposits or finds

It is not always the nature conservation that poses challenges to municipalities or states. Man-made phenomena can make water restoration using conventional dredging methods equally problematic or even dangerous. For instance, some lakes or dams still contain unexploded bombs or the remains of ammunition that were dumped there at the end of the war. Suspected historical or archaeological finds in a body of water are a further complication.  

In situations such as these, sludge reduction by means of water therapy is likewise an ideal way to restore water volume, expose possible finds in the water and clarify their condition.

11. Quarry lakes

The former operators of quarry lakes and gravel pit lakes are obliged to take care of them once excavation has ended. However, they often do not fully comply with these requirements, to the detriment of fishing clubs who lease such waters in many places, as well as other users. If sludge develops in deeper areas, oxygen-free zones can form that threaten the species present at the respective water depth and can even kill the fish there. Especially in warm summers, these zones that are hostile to life can be observed spreading to the surface of the water.  

Our cost-effective sludge-reduction products are remedies that do not affect fish stocks or any other animal species that commonly find refuge at these sites. Our sustainable treatment method uses only substances that are naturally present in water, meaning that contact with the groundwater is fully taken into account in quarry lakes too.

12. Post-mining lakes

These bodies of water have an influence on groundwater and usually pose multiple serious problems that require long-term and expensive management. In many cases, high iron content leads to the formation of iron oxide, which produces sulphuric acid. Water in post-mining lakes typically has an extremely low pH. This means that lifeforms cannot survive in it and results in "dead" bodies of water. The parties responsible for such waters are obliged to stabilise their pH value. However, the usual measures, such applying lime or lime milk, do not solve the problem in the long term. Another problem common in post-mining lakes is toxic ammonia. The official plan of action stipulates that the body of water must be oxygenated for centuries to achieve complete detoxification.

We offer sustainable alternatives that can permanently neutralise the lake. Our solution is based on an environmentally sound method that can reduce the detoxification process to only ten years. This saves an immense amount of money and effort, and plays an essential role in restoring the body of water as a natural habitat.

Identifying problems at an early stage:
The first step towards long-term solutions.

When it comes to bodies of water, the sooner a problem is identified and addressed, the better – in terms of both water quality and cost. Even laypeople can determine whether a pond or lake is at risk or already affected if they know the tell-tale signs. If you notice that a body of water has any of the symptoms below, it is advisable to commission a professional to analyse the water quality.

Visual properties:

  • Decreasing visibility
  • Iridescent film on the water's surface
  • Green streaks in the water
  • Conspicuously increasing number of gas bubbles
  • Silting
  • Sedimentation

Sensory properties:

  • Putrid smell in the air
  • Extremely unpleasant smell when you rub water in your hand
  • Fish caught in the water taste musty/bad

Changes in flora and fauna:

  • Fish gasping for air
  • Fish dying
  • Algal growth, blue algae bloom
  • Loss of aquatic vegetation

Changes in the relevant water parameters:

  • pH value exceeded
  • High nitrate levels
  • High phosphate levels
  • Oxygen depletion

If a body of water in your area of responsibility has one or more of these symptoms, our local OASE partners provide professional assessment and water analysis services to determine the type, extent and the causes of the problem. Find your OASE contact partner using our Contact page.