What Ponds Do
Read about Earth Pond
series author Tim Matson.
Photo by Josph Mehling
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
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,
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!