Read about Earth Pond
series author Tim Matson.
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Photo by Josph Mehling

What Ponds Do
and How They Benefit You

by Tim Matson - Click images to enlarge

In my pond design and restoration business, I find that a highly interesting aspect of the work is the wide spectrum of objectives that people express when they explain what it is they want their ponds to "do."

Recently I was running a seminar. One of my students was developing his own independent study program that focused on building small ponds. His objective was to raise native fish organically in suburban and urban areas in New England. The ponds were planned to range from earthen basins to artificial tanks, depending on location. The fish would feed on earthworms raised on composted kitchen scraps.

I'd had experience researching so-called "aqua domes" in the 1980s. I gave him pertinent input and research leads on tank design, filtration, geodesic domes, etc. Then for the fun of it, we visited a neighbor just down the road who harvests an entirely different crop from his pond: electricity.
His one-acre pond is sited at an elevation over 100 feet (30.5 meters) higher than the house. It releases sufficient runoff to drive a small hydroelectric turbine near the home. Living entirely without the municipal grid, his family relies for electricity on a combination of solar power (mostly in summer) and hydropower in winter, when the Vermont sun doesn't much shine.  

These ponds represent two entirely different objectives. They use radically different pond designs, yet they are essentially based on the same concept: impounding water. 
  People familiar with large (1/4 acre [0.1 hectare] or more) earth ponds probably recognize some of their most familiar uses. These include fire protection, garden and livestock irrigation, fish production, ornamental plant growing, and waterfowl culture. Two of the most popular objectives people have when building or restoring a pond include beauty (a landscaping asset) and recreation. A remarkable attribute of a pond is that it typically yields a variety of these assets simultaneously.

In many ways, pond construction is still based on traditional, even ancient, methods. Locate water, evaluate soils, excavate the basin (often using "waste" material to build an embankment to impound the water), create spillways, and finally, landscape.

In addition to these, I use several newer techniques and revive older ones when useful for my pond projects. These include various types of membrane liners in ponds used with highly pervious soil, and/or where water supply is limited. Sometimes these liners require under drains and water recapture systems to prevent displacement of the liner and loss of ground water. Household roof catchement systems also help the water supply situation where natural ground water and watershed runoff prove inadequate.

Where water quality poses a problem, various types of aeration help to remedy pollution, low oxygen, and nuisance plants and algae. Interestingly, I also notice that more pond owners employ biological "cures" to help improve water quality. Pond owners often stock crayfish because of their ability to keep the pond bottom free of organic detritus and small plants, as well as leeches. Placing barley straw around a pond edge can be helpful at reducing algae. And where permitted, owners stock certain fish species, such as sterile carp, that help control algae and invasive plants. 

Where do ponds go from here? Growing concerns about energy costs, greenhouse emissions, and food quality, cost, and availability may place a significant role answering this question. People worry about water quality and supply.

Ponds often offer solutions to these problems, sometimes
one at a time, but more often with overlapping assets.

Meanwhile, I'm off to the pond for some ice-skating. It's fun, and it's good exercise. More of that good old pond-benefit overlap! 

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