Why water features are worth getting right

A pond, a rill, a pebble pool or even a simple birdbath can turn an ordinary garden into somewhere that hums with life. Garden ponds have become genuinely important for amphibians, dragonflies and bathing birds, so a well-placed water feature is one of the most generous things you can do for wildlife. The catch is that water evaporates, splashes and quietly disappears — and in a dry summer, topping up from the mains tap can feel like fighting a losing battle. The good news is that with a little forward planning, most features can run almost entirely on rainfall.

Capture rainwater before it leaves the garden

Every roof, shed and greenhouse is a potential reservoir, and the maths is rather motivating: 1 mm of rain falling on 1 square metre of roof yields 1 litre of water. A modest 3 m × 3 m shed roof therefore collects 9 litres for every millimetre of rain, so a wet week delivering 25 mm will fill a 220-litre water butt several times over. Link two or three butts together and divert the overflow from the last one into a bog garden or planted soakaway rather than down the drain.

Fit a downpipe diverter so the butt tops itself up, and raise it on a sturdy stand so a watering can fits underneath. Keep butts dark or shaded to limit algae, and cover the top with a lid or fine mesh to keep out leaves and mosquitoes.

• Add guttering to sheds, garages and greenhouses that currently have none.
• Use an overflow pipe or rain chain to lead surplus water to thirsty planting.
• Keep one butt plumbed with a tap close to the pond for easy summer top-ups.

Design a feature that barely needs topping up

Evaporation is driven by surface area, sun and wind, so shape matters more than you might expect. A deep pond with a modest surface loses far less water than a wide, shallow one, and it stays cooler, which suits frogs and newts. A few extra centimetres of depth is worth more than an expensive liner upgrade.

• Keep open water in partial shade, ideally sheltered from afternoon sun by a hedge or large shrub.
• Avoid splashing fountains and open sprays, which lose water to the air remarkably quickly. A gentle bubbler or a small waterfall that returns its splash to the pond is far more frugal.
• Consider a pebble pool or buried-reservoir feature, where gravel or slate hides a sump beneath. The exposed surface is tiny, so topping up may be needed only a few times a season.
• Check the water level regularly and inspect the liner edges; a slow leak at a fold can waste more water than evaporation ever does.

When you do top up, use rainwater in preference to tap water. Mains water is treated, often hard, and carries nutrients that feed blanket weed and algae.

Plant the water's edge as well as the water

Marginal and floating plants shade the surface, reducing evaporation and keeping the water cooler. They also take up dissolved nutrients, leaving less for algae, and give cover to tadpoles, water boatmen and emerging dragonfly nymphs. Choose natives and long-established garden plants that suit still water.

• Marsh marigold for early nectar, purple loosestrife for midsummer colour, water mint and water forget-me-not for shelter along the edge.
• Yellow flag iris and ragged robin for taller structure; both cope well with fluctuating levels.
• Submerged oxygenators such as hornwort keep water clear, while a small water lily or frogbit shades open water.

Surround the pond with dense, low planting and mulch bare soil around the margins. That slows evaporation from the surrounding ground and keeps the whole area noticeably damper.

Small habits that add up in a dry spell

• Top up in the evening or early morning rather than at midday, and use a can instead of a hose so you can see exactly where the water is going.
• Let the level fall a little in high summer. Most wildlife copes with several centimetres of loss, and a lower level means a smaller surface losing water.
• Switch the pump off on hot, windy days if it sprays or splashes.
• Clean filters in a bucket of pond water, never under the tap.
• Net or rake leaves out in autumn instead of draining and refilling the pond.
• Never add grey water, soapy water or water from a softener to a wildlife pond.

A feature that looks after itself

Put the three pieces together — rainfall captured from every roof you have, a shape that limits evaporation, and a generous fringe of native planting — and you have a water feature that mostly runs itself. You will still need to check levels in a long dry spell and top up from the butt, but the mains tap becomes a last resort rather than a weekly chore. That is better for your water bill, better for the creatures that rely on the pond, and quietly satisfying in a summer that turns out hotter than expected.