Pond for using precipitation
Precipitation can also be retained in a pond and used from there. The drawback, however, is that the quality of the water is less easy to control, as a result of factors such as falling leaves, vermin and temperature fluctuations. As a consequence, the quality of the water might on occasion be less acceptable in summer. Small ponds are particularly susceptible to this phenomenon. Larger ponds have a more stable climate and more ways for keeping the water clean and treating it using helophyte banks and similar features.
The pond’s design should allow for water level fluctuations. The pond should preferably have a depth of 1 metre or greater: the temperature will remain relatively low in summer, diminishing the risk of algae and other problems with the quality of the water. This situation can be improved by adding elements to make the water circulate, to aerate the water and to ensure a properly functioning ecosystem in the pond.
In winter, the greater depth prevents the pond from freezing solid. Water will remain available for use. In addition, any fish in the pond can survive the winter.
Rainwater ponds that serve as reservoirs are subject to substantial fluctuations in water level, as a result of changes in rainfall and usage. As such, it is often more advisable to use a structural and closed reservoir for retaining rainwater and for topping up the visible part in order to limit differences in water level.