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Related Articles: The Outdoor Garden Pond: Tips, Tricks and Reminders for Ease of Care and Beauty by Anthony Calfo, Water Feature Design, Siting, Pond Construction: Block, Liners, Concrete and Pond LinersRepairPlumbing, ElectricalPumps, Example Ponds/Water Features

/Aquatic Gardens, Design, Construction & Maintenance

 Aquatic Gardens: Size and Shape

by Robert Fenner

Ponds need not be large to "do their job" in a garden setting

Aquatic Gardens

Ponds, Streams, Waterfalls & Fountains:
Volume 1. Design & Construction
Volume 2. Maintenance, Stocking, Examples

V. 1 Print and eBook on Amazon
V. 2 Print and eBook on Amazon

by Robert (Bob) Fenner

In previous articles you were introduced to considerations of water feature design philosophy and site selection. In this, our third piece on design, I'll share my ideas concerning the concepts of size and shape.

Both along the lines of function and aesthetic, water-and landscaping are artistic and engineering endeavors. Both require creativity and planning. There are several techniques and paths to generating a finished habitat. My preference is a systematic approach involving consideration of the ultimate desired effect(s). Next, I figure backwards from what I want to achieve, to how to realize these sights and/or sounds.

These planning ends are met from design, construction and maintenance considerations.

Size and Shape Designs:

Can be determined in several ways: I encourage you to make a brief sketch to scale of the area in mind. The simplest approach involves a piece of graph/quadrille paper for you to mark off the boundaries of what exists now (e.g. property lines) and what is probably going to remain (e.g. the patio).

Next comes the fun part. Items to be added can be made approximately to scale out of paper and moved around on your two-dimensional "plot plan". Trees, walkways et. al. are easier to visualize in this manner; especially if there's more than just you deciding on the design. A piece of string to represent the perimeter for a free form basin works nicely.

Some companies provide scaled layouts. Duncan Water Gardens has such a set-up for their modular, sectional fiberglass ponds. Other layout planning aids involve "paste-up systems"; or if you really want to get fancy, you can use a computer.

Often you can get ideas of the features to be constructed at the site with the use of a garden hose to mark the boundaries. Once there is agreement with the parties concerned, the edge may be marked with stakes, flags, flour or chalk. (See the Excavation article).


Just how big your water feature should be depends on one's taste, pocketbook and functional desire. Is the feature to be a center-point, a focus? Is it to merely complement, blend in with the rest of the environment?


1) In general, water features should be as large as practical. This makes them more stable and easier to control.

2) Their sides should be as vertical as possible. Limiting sunlight striking the sides, and spooked koi jump easily out of shallow-sloped basins.

Dial in those walls as vertical as you can... using a pick ax, or squared off shovel if you can... or better still, a skilled operator and back hoe!

3) They should be as deep as allowed (your local building codes department will tell you), and is safe (keep small children in mind). Greater depth means sunlight reaching the bottom.

You don't want the size of the system to overpower the setting, neither should it be insignificant or un-serviceable. Systems under a hundred gallons, a few inches deep with sloping sides are maintenance nightmares. They are so unstable it is difficult to keep living things in them, or if they are intentionally without life, to balance them chemically.


Shaping your system is very important. If it comes pre-made as with a pre-cast fountain or formed pond, the spatial arrangement will require less decision-making; other than where to place it.

Formal and informal basins should not be too odd shaped by themselves or for their setting. Informal, natural ponds sides should not make sharp or sudden turns. These will promote stagnation and may cause livestock losses due to jumping, scratching.

All water features should have bottoms that slope to one or more definitely deeper areas. If a depression or sump can be made there, all the better. At best a drain line can be connected to facilitate cleaning and dumping (See Plumbing ).

Leave adequate area around perimeter for access, plantings and the addition of rock and other materials over and behind the basin's edge.

Lastly, in designing the shape of your system, you may want to provide some steps to facilitate getting in and out for periodic cleaning. Biological systems are notoriously slippery.

Weather Matters:

Check with your neighbors and the local weather office; the "make the walls as vertical as you can rule, needs to be modified for geographic locations where surface water freezes.

For areas where there is a possibility or known freezing of the ground, special provision needs to be made for either preventing the feature's water from freezing solid. We'll get to this on Over-wintering Water Features, but you'd do well to configure your basins to prevent damage should they freeze.

You know one of the ways that water is "strange stuff" is that it decreases in density, expands and "floats" on freezing. This can cause your basins trouble regardless of what they're made of, if they start icing up and the solid water has no place to expand to. The simplest plans call for gradually sloping (15-20%) the sides of all basins to the greatest depth of freezing; when/where in doubt, all the way to their bottoms.

Please don't rely on just emptying the pond, heaters, "crush-box" mechanisms to prevent damage to your aquatic garden in freezing weather. These fail-safe approaches can fail (with rain, electrical outage, warming spells...) and refreezing/expanding water damage the feature's walls.

Costs; Obvious & Real:

Chief consideration should be given when determining size and shape as to long-term maintenance costs. Design and construction costs may be minor in ultimate comparison. Size your feature to fit your budget in terms of on-going time, materials and energy costs.

Larger features with more exposure mean more cost as detailed in the size rules of thumb. If the water is to be recirculated, give consideration to the size of the pump, it's application and operation and maintenance costs. (See Sections on Plumbing, Pumps, Circulation) The costs of running pumps can be

high and is only going to get higher. Biological ponds where the pump is to run continuously can be especially expensive. Look into the best available, most appropriate technology for the long-haul in selecting equipment.


I suggest you consult with as much local talent as you can stand before accepting any one design: magazines and books, fish clubs, hobbyist gardening organizations, retail fish and nursery businesses, landscape and waterscape contractors, maybe even knowledgeable, experienced neighbors can be a wealth of information.

With adequate help you will be able to determine the size and shape of your water feature and the monthly, annual costs to maintain it.

Bibliography/Further Reading:

Allison, Millie. 1984. Our bonsai koi pond. Koi USA 1,2/84.

James, Barry. 1987. Shapes & sizes; we don't all have the luxury of space, but there are few gardens without room for a water feature. Practical Fishkeeping 3/87.

Lamont-Brown, Raymond. 1991. Sweet streams; as the Japanese have known for thousands of years, a stream adds beauty and new perspectives to a garden. Aquarium Fish Magazine 1/91.

Aquatic Gardens

Ponds, Streams, Waterfalls & Fountains:
Volume 1. Design & Construction
Volume 2. Maintenance, Stocking, Examples

V. 1 Print and eBook on Amazon
V. 2 Print and eBook on Amazon

by Robert (Bob) Fenner
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