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Water playgrounds, urban climate and more - Water playgrounds as an important element of climate adaptation
Are we still allowed to plan with water in public spaces in times of heat and drought, in times when rivers have dried up and when there is even a shortage of drinking water in some places? Especially during this year's hot summer, this question has been asked frequently, particularly in connection with public water features. However, only at first glance this question appears justified. It is indeed true that drinking water must be used economically. Per capita consumption is currently 127 litres a day or 46 m³ a year. On average, a water feature consumes between 100 and 2,000 m³ per year, whereby this depends strongly on the size and the amount of water circulated. Typical playground water pumps consume between 50 and 200 m³ of water over the year. When people discuss water wastage in connection with water playgrounds or fountains in public spaces, they ignore the fact that there are almost 2.2 million pools in Germany, both permanently installed and so-called pop-up pools, the vast majority of which are filled with drinking water. The annual water consumption of a large pool is estimated at 200 m³, that of a small pool at 30 m³. They are each used by only few people. Public pools are available to many people, often those who cannot afford a pool in their own garden because they do not have a garden and often live in cramped housing conditions. So before public water features are switched off, we would have to discuss about water consumption in private spaces, otherwise we will hit those who have only few alternatives anyway.
In addition, there are urban climatic reasons why water in public spaces is important even when there is a general lack of water. It is getting hotter and hotter in cities. High sealing rates and heat storage capacities of the built materials, low levels of shading and low proportions of greenery have long led to heating, which is being exacerbated by climate change-induced warming. In addition to functioning urban greenery, which indirectly provides cooling effects through its evaporation capacity, water elements are available that allow direct cooling of the skin and indirect cooling through air temperature reduction in small-scale surroundings. Cooling is particularly important for children and the elderly. They are among the most vulnerable groups. And in general, if we still want to spend time outdoors in the future, more cooling will be needed.
In addition to the important direct and indirect cooling function, water features as public and thus communal elements have a social significance that should not be neglected and additionally make a contribution to social justice. Moreover, there is hardly any other element which stimulates human levels of perception as much as water does. Hearing, smelling, seeing, feeling and emotionally experiencing water is not only relevant for child development, but also provides adults with pleasure, relaxation and recreation. All these are very important reasons for maintaining and expanding water features in public urban spaces.
Options for water features and water playgrounds
Now that drinking fountains are already part of the urban infrastructure in many European cities, they are also being brought back into use over here. Various cities are currently experimenting with fountains to cool down the hot air. On city squares, fountain fields have always been a popular attraction, not only for children. Water sprays, for example - both on their own or in combination with mist nozzles - work just as well on the ground as they do vertically as a column, which is technically not too complicated. Water pumps are almost standard for playgrounds and can be combined almost endlessly with sand play areas, floor-level watercourses, water tables and movable elements such as flaps or weirs. Floor-level watercourses become more varied with different surfaces that change the water movements. So entire water worlds with a variety of effects can be realised by combining the elements described above. In terms of design, almost anything is possible from near-natural to technically formal shapes. Near-natural design approaches attempt to create a natural-looking water landscape. Wood, natural stone, gravel and sand are used, and plants are planted around the edges. Water tables are available in wood and metal; the appearance of the latter is somewhat more formal, but they are easier to maintain. In urban contexts, there are often brick watercourses or water channels formed from natural stone paving. They are easy to maintain, but in terms of design and play value, care must be taken to ensure that the channels do not appear too lifeless or formal.
Temporary water features are a good option because they do not require a lot of installation work. Perforated tubes and lawn sprinklers with timers, temporary water basins made of foil or watercourses made of plastic pipes are also interesting and work well especially if the installations are supervised, which is usually the case at events or promotions.
Water games are interesting whenever interaction and variations are possible, through changing amounts of water, fountains of different heights that are controlled by time or by motion detectors and sudden splashes of water. Particularly important are variable situations that children can create and change themselves, for example through elements that change flow directions or accumulate water, that make water spring and bubble through their own actions or move it to another level, such as step pumps, water mushrooms or Archimedean screws. A connection with pedals or even trampolines should also be taken into consideration. This would encourage creativity and togetherness. Play situations that can be actively influenced are therefore always better than those that can be controlled by others.
Both free nature and also designed urban nature offer a variety of options in water quantities, flowing movements, materials and spatial situations. Of course, it would be best if all children could find exactly such danger-free play offerings in their immediate living environment. Nevertheless, direct integration of water playgrounds next to streams or ponds is not advisable. Nature and water protection concerns, but also issues such as water depth or water quality and generally the question of traffic safety can hardly be clarified, if at all. In all this, the question arises whether stream or pond banks should really be designated as legally secured playgrounds, which does not mean that these water offerings are not suitable for play.
Types of water features
If sufficient space is available, it is easy to install pumps. The direct outflow area should be paved to avoid washouts or permanently standing water. Pumps are often combined with sand areas. These should be designed in a way that allows water to drain away (even underground). A pump or a fixed water outlet can be combined with stone watercourses. A special way of creating watercourses is with water tables, which are available as prefabricated elements and are easy to play on due to their elevated position.
Especially interesting for older children are pools in which movable rafts or other large parts such as Archimedean screws, islands, bridges or footbridges and stepping stones can be integrated. These installations are very similar to the water landscapes described above. They offer a wide range of possibilities for appropriation. Here, special attention must be paid to water quality. Water consumption and maintenance costs are high and intensive use is only possible in really warm weather. Pools should therefore always be combined with other elements outside the pools - as a "bad weather alternative" and for smaller children.
Water playgrounds should symbolise the free play of streams and ponds and thus stimulate imagination. On the basis of these considerations, it must be decided whether to choose a design that is close to nature or more formal. The decision, however should not only be based on design aspects but also on the required type of sealing and the expected pressure of use. If water is to flow over longer distances or stands in a kind of basin, solid seals made of concrete, waterproof mortared stone inserts or glass-fibre reinforced plastics are recommended. In the past few years, plastic and fall protection surfaces have been very popular. They offer a wide range of colours, but have a very specific design that is not suitable everywhere. In addition, they can be slippery. Clay or loam seals are usually unsuitable for water playgrounds because they soften when people walk on them. Foil seals are also rather unsuitable due to the rather complicated integration and their susceptibility to destruction. Robustness and durability, protection against the entry of dirt from adjacent areas, prevention of softening of the sealing or good maintainability are essentially determined by the frequency of use. A sand surface can work if there is sufficient time for it to dry, and no water is permanently in the surface, thus allowing bacteria to breed. The combination of sand and water is one of the most popular in all water playgrounds. However, it is a fact that sand is poison for fine nozzles or pumps. Therefore, robust water outlets are the clear preference in the play area
Wood and metal are the most popular materials for the water elements, the latter especially for the movable elements. Occasionally, there are suppliers who use composite materials, but these can swell after longer usage and are then only usable to a limited extent.
Traffic safety must be taken into account as early as the design phase starts. Drop heights of max. 60 cm and pool depths of max. 40 cm, in a few exceptional cases also 60 cm, shallow entry and exit areas in pools and non-slip surfaces are thus important planning issues. The requirements for water quality, in turn, must be solved in terms of planning and maintenance. Water outlets must be operated with drinking water or water of drinking quality for faecal parameters. Pools, watercourses, puddles should be of bathing water quality. Meeting these requirements demands clear maintenance management. The question of water quality also arises for fountain fields and other fountains or water features in public spaces. Nevertheless, groundwater, spring water and, to a limited extent, even rainwater are potential alternatives, although the necessary official agreements are usually not entirely straightforward. State hygiene plans, originally created for day-care centres, are sometimes transferred to water playgrounds without further critical examination.
With regard to the advancing climate change, as many playgrounds as possible should at least have pumps - if only for direct cooling. In addition, installations with as much water movement as possible or high evaporation rates through sandy areas or plantings, for example, are very useful. If the run-off water can be used for planting or marsh beds or a small stream, an additional cooling effect can be achieved and, moreover, the water quantities necessary for the playground operation can be used in a responsible way. In completely stony environments, circulation systems with the relevant treatment could also be a good choice.
At the strategic level, heat adaptation plans are recommended that either address all relevant heat adaptation issues in an urban society or just focus on a specific sub-area, such as water in urban spaces. It should, however, be clear to all of us: Water is essential when it comes to heat issues and the relevant field of action. In this regard water playgrounds provide many possibilities. However, more important than water consumption, at least in terms of costs, is often the maintenance effort, which is also an essential resource. Doing without water should not be an option.
Katrin Korth: Mikroklimatische Anforderungen an Stadträume. In: Neue Landschaft, Ausgabe 3/2022
Katrin Korth: Wasserspiele – Normen und Kosten. In: playground@landscape, 07/2020
Katrin Korth: Wasserelemente für Kinder – Herausforderung oder Vergnügen? In: Tagungsband der FLL-Verkehrssicherheitstage 2019, Falkensee/Bonn
Kommunalhandbuch Spielflächen, 1. Auflage 2017, Beckmann Verlag Lehrte