Let me describe my pond a bit, because it reflects my theory on sustainable pond design. As I see it, a pond should be a joy, not backbreaking work. Most will agree. There are exceptions, such as ponds for growing out fish, propagating plants, etc., but this is not my topic. I live in a mild temperate zone, which influences pond design to a degree, but all ponds have certain items in common such as: 1) sufficient depth to prevent a full freeze in winter; 2) a shallow zone to allow water to quickly adjust temperature (among other things); 3) a shelf area(s) to set potted plants. For me, these are the basics. More can be added, but this is personal preference. Water circulation is paramount and I have always tried to incorporate a watercourse to bring character to the pond as well as provide a silting system.

There is much discussion about using rocks in ponds and I do use them. The most important area for them is the shallow zone, where many plants flourish in summer along with teaming insect life. This area is approximately 40cm (18") deep, reflects 20-30% of the total pond surface and is completely covered with rocks ranging from large gravel (big toe size) to standard fist size. No special mix. This is how they were graded in the delivery. Sediment builds up, but is flushed mainly by koi grubbing, as this is their forage table.

From this plateau, my pond drops, first slowly in plateaus, then rapidly, to a depth of 120cm (50"). Here is my main Nymphaea planting area and the winter home for the fishes. Only the plateaus have a few rocks. The deep area may have accumulated a few, but they are hidden under the lily pads.

My watercourse is also laid out with rocks, largely for the aesthetic effect, but many plants root themselves against the light current and thrive. The watercourse is designed as three joined basins to break the flow and create interest, with the added effect of allowing sediment to settle out of the water. String alga grow here and are regularly harvested (excellent compost/mulch), the water flows back via a small waterfall, which the fish seem to positively enjoy!

Maintenance is minimal. I remove sediment once a year with my pump, but always leave a layer of a few centimeters. Also, which is a factor often under rated, I never make a massive cleaning! I do a bit here, a bit there, never so much that the system's balance will be put in danger of collapse. Any cleaning regime will release toxic material into the system. Every time I play in the pond, removing yellowed pads, harvesting overgrown Myropyllum, etc., a bit of mulm is disturbed and removed via the watercourse.

This year (2003) I had the worst algae bloom I've ever experienced and it lasted all of two weeks this spring. Its cause was clear. The temperatures went from 10°C (42°F) to 28°C (82°F) overnight. We had a very strange spring! The pond is in its fifth summer and I've never had a problem. No green water, no disease outbreaks. I am happy with the result, which is the main point of the exercise. Admittedly, it is a small pond in comparison to many, the smallest I've ever created, but it is the most wonderful thing in the garden!

You'll notice, in the background, there are stepping stones through the shallow zone, where many plants are given free reign in the early season. I then pull them to remove their contained organics and let new ones grow. This year I had tons of Nymphoides and added a few Nelumbo cultivars in pots. There were dragonflies galore and myriad baby fishes. This is my favourite corner. There's always something happening!