Chapter 02 / BUILDING YOUR POND
Watch the site in sun, shade and rain.
At a glance
The best position is not always the lowest point in the garden. Low ground may collect muddy runoff, fertiliser and road or terrace drainage. A slightly higher location with a planned overflow can be easier to manage. Before digging, watch where rainwater actually travels and where standing water remains.
Light is equally important. Water lilies and many flowering marginal plants need a suitable sunny position, while partial shade can make the garden more comfortable and limit overheating. The aim is to match the plants and the pond's use to the real light pattern, rather than choosing a fixed amount of shade for every pond.
Look beyond the water outline. Consider tree roots, buried services, access for excavation, space for soil storage and the route for equipment maintenance. Stand at the house and at the seating area to check the view. A pond that feels connected to the garden is often more satisfying than one placed only where digging seems convenient.
The main idea: A simple site sketch should show sun, rainwater routes, trees, services and working space.
In practice
- Photograph the proposed area in the morning, around midday and later in the afternoon. Repeat at a different season if the shade from buildings or deciduous trees could change the decision.
- After rain, mark incoming water paths and the eventual overflow route. Keep enriched surface runoff separate from the pond wherever practical.
- Lay a hose or rope on the ground to represent the rim. Walk around it with a wheelbarrow and imagine reaching each planting shelf. Move the outline until both the view and access work.
Going deeper · the science behind this chapter
A site receives and loses water through several pathways. The water balance is change in storage = rainfall + deliberate supply + incoming flow − evaporation − overflow − other losses. A falling level can therefore have several explanations before a liner leak is considered. Keep top-ups visible and measurable so that they do not conceal a persistent loss.
For a 20 m² water surface, 10 mm of rain contributes about 200 litres directly. That is area multiplied by rainfall depth: 20 × 0.010 = 0.20 m³. Runoff from surrounding hard surfaces can add much more, but it also carries whatever is on those surfaces. This is a volume example, not a recommendation to connect a driveway or roof without assessing water quality.
Light availability changes with depth as well as shade. Suspended particles, coloured dissolved material and algae all reduce underwater light. A site with plenty of sun may still support poor submerged growth if the water is turbid. Conversely, a sheltered pond may develop temporary temperature layers because wind mixes it less effectively.
Surveying these processes together improves the choice of site. The relevant question is not simply 'How many hours of sun?' but 'What combination of light, heat, water supply and unwanted input will this location create?' [R1, R2, S23]
Observe → map → mark the outline → test access → settle the position.
Related guides
Watercolour scenes are AI-generated illustrations. Diagrams and teaching models are identified in their captions.