Water as habitat: how to create ecological value without turning the garden into a problem

Water can create habitat, cool the space and increase diversity, but it can also bring a risk of drowning, mosquitoes, poor quality, leaks and heavy maintenance. Its ecological value depends on shape, depth, margins, circulation, planting and the connection to the rest of the garden.

A small drinking dish, a shallow sheet of water, an ornamental pond and a rainwater retention area are not equivalent. Each has different aims and demands. Before selecting plants, you need to define the source of the water, the variation in level, the overflow and the quality.

In rain-fed systems, the design must allow for dry spells and intense events.

A margin with gentle slopes and varied depths offers more conditions than a tank with vertical walls. Emergent, floating and marginal plants perform different functions.

There should also be exit points for wildlife, and protection where there are children. Ecological value does not justify lapses in safety.

Mosquitoes take advantage of small pockets of standing water, especially in containers with no predators and no circulation. A well-designed system reduces dead spots and maintains suitable conditions.

Blanket chemical treatments can affect other organisms. Management should act on the cause: circulation, excess nutrients, accumulated matter or poor design.

Water with excess nutrients encourages algae and lowers oxygen. Leaves, fertilisers and run-off from paving should be controlled at source. In planted ponds, the relationship between volume, depth, shade and planting influences stability and should not be resolved with equipment alone.

During dry spells, topping up can concentrate salts or alter the temperature. During heavy rain, the overflow needs to carry water away without sweeping plants or wildlife to dangerous spots.

The most common mistakes are creating depressions with no overflow; using vertical edges around the whole perimeter; making no provision for maintaining pumps and filters; and introducing wildlife or plants without assessing the risk.

At Diaplant, the type of water feature is chosen by function and by the capacity for maintenance. An ornamental pond, a water point and a natural swimming pool have different demands and different ecological value.

Water becomes habitat when it is treated as a system. Shape, safety, quality and maintenance have to be resolved before the visual effect.

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• How do nature-based solutions contribute to biodiversity in cities? (2025).
• Comparative analysis of bioretention design strategies for urban runoff infiltration: a critical overview. (2024).
• European Commission. Pollinators and EU Pollinator Monitoring Scheme. (2025).