A Perfect Pond

By Marvin Boyer | February 2, 2010
From Missouri Conservationist: Feb 2010

The countless ponds that dot farms, woods and suburban properties have provided immeasurable delights, including fishing thrills and tender family moments, such as when a child catches his or her first fish. However, many Missouri ponds are no longer helping knit families together or providing endless recreation. They’ve grown old as they’ve collected silt and soil from runoff and erosion. Many of them have become so shallow—less than 8 feet deep—that they experience fish kills.

What can you do when the pond you love is no longer capable of producing good fishing? The least expensive option is to let the aging process continue to the benefit of wildlife other than fish. Waterfowl, muskrats, salamanders and frogs are just a few animals that thrive in shallow, fishless ponds.

Another relatively inexpensive option is to stock a small pond with adult hybrid sunfish in the spring to provide some fishing for the kids. Depending on the weather, these fish may die in a fish kill if not harvested annually.

It’s also possible to make an old pond young again, returning it to its good old days, when the fishing was great. The Conservation Department recently renovated a 4.8-acre pond at August A. Busch Memorial Conservation Area. Our goal was to create “a perfect pond” from a silted-in unproductive pond. What we learned in the process should help private landowners who may be considering rejuvenating a pond on their property.

Can You Fix Your Pond?

You first have to discover whether the project is feasible. It’s a good idea to consult with an experienced contractor (one with a bulldozer, track hoe and dump truck at a minimum) to discuss the renovation. This will help give you an idea of the time and labor involved and problems that the contractor might face with your pond. It will also give you a sense of how much it will cost. Regional Conservation offices can provide you with a list of local conservation contractors.

Plan for an excavation schedule that allows adequate time for cutting the dam, allowing the pond basin to dry, moving the accumulated sediment (or “spoil”) to an appropriate location, and mulching and seeding the basin. Our 4.8- acre renovation took two months to complete and required us to haul, dry and spread 1.2 million cubic feet of spoil.

A perfect pond provides a variety of fishing opportunities. The best way to achieve this is to carefully plan the placement of materials, soil and cover while maximizing shoreline length. Catfishers and bank anglers are likely to prefer areas with a clean, hard bottom that slopes fairly quickly to deeper water, so those areas are excavated down to clay. This clean or relatively featureless area typically is located near the dam.

In other areas, we leave a 1- to 3-foot-deep layer of rich organic soils for aquatic vegetation. The soil may be pushed into humps or divided by trenches or channels. These areas become the production zones of the pond where aquatic plants, bugs and fish live and grow in large numbers.

The bottom of the pond away from the dam should be contoured to a more gradual slope. These large areas of shallow water (less than 4 feet deep) can be planted with several species of native aquatic vegetation. Spawning beds of pea gravel should be placed nearby.

In our lake project, for example, half the lake bottom has a gentle slope, creating shallow water habitat, and about 40 percent of the shoreline harbors aquatic vegetation. We built spawning beds from 2 to 5 feet deep to provide spawning habitat at different depths. This encourages the hatching and rearing of sport fish to take place near shallow cover where a buffet of aquatic invertebrates helps boost their growth.

Another important benefit of leaving a layer of rich soil in the pond is providing nutrients for planktonic algae and zooplankton growth. This is the base of the food chain in your pond and directly relates to the pounds of sport fish your pond can grow without supplemental feeding or fertilizing.

Think of Fishing

Designing your pond so that deep water is close to open and easy-to-reach areas near the dam and shallow fertile water is more difficult to fish provides anglers with choices. Energetic anglers looking for big fish and quality habitat can walk or boat to distant cover while anglers who wish to avoid snags or who like to bottom fish can stay near the dam. Weed-free areas can be easily maintained with limited herbicides or a light stocking of grass carp after beneficial vegetation is established throughout the pond.

Covering parts of the shoreline and dam with rock, although expensive, adds a great deal of longevity to pond improvements because the rock reduces wave erosion and muskrat burrows. Rock can also be combined with excess clay and soil from the basin excavation to create jetties—20- to 80-yard peninsulas that reach toward the center of the lake. Cover the top 4 feet of jetties with a 2-foot blanket of rip-rap to keep them from eroding.

Jetties not only provide easy access to good fishing areas but also increase shoreline length and provide rocky cover, which produces more fish and invertebrates, especially crayfish. In our lake project, the shoreline measured 1,785 feet. Adding jetties and a small island increased the shoreline to 2,861 feet—a 38 percent increase in available shoreline and habitat for fish, invertebrates and anglers.

Woody habitat is also helpful. Use cedar trees and hardwood collected near the pond to build brush piles of various sizes for fish structure after earth moving is complete. We put at least two sizeable (25- to 40-foot diameter) brush piles per acre and placed them in water 2 to 8 feet deep. A variety of woody materials, combined with earth moving equipment, can be used to create many different kinds of fish habitat. A good rule of thumb is that the more cover you install the more fish the pond can support.

A perfect pond will stay productive for a long time. That’s because you will have made provisions for keeping as much soil as possible from the pond. Installing a silt basin directly upstream of the pond’s main stream channel or drainage area can be considered preventative maintenance. And it’s a relatively simple matter to clean out the silt basin every 10 to 15 years to keep it protecting your pond.

Fertilizing, straw mulching and seeding land around the pond—especially on the slopes draining toward the pond—helps soil from pouring in every time it rains. Fescue is the perfect grass for erosion control.

When the final grade is near completion, plug the dam with pure clay from the deepest part of the pond. Spread quality topsoil over the back of the dam repair, and complete any repairs or touch-up work on the front or back of the dam.

The fun part is about to begin. If the weather cooperates, it will soon be time for fish stocking. Typically the pond fills with water in a normal year without a problem, and in three to four years, the pond will be perfect, just as it was in the good old days.

Fishy Cover

Be creative when creating fishy cover for your pond. Many people use recycled Christmas trees, cut cedar trees, hardwood trees and wooden pallets for fish habitat, but almost anything will work as long as you keep it from floating around the pond. If you install fish habitat when the pond is dry, you can anchor it into the bottom with stakes or cable. If heavy equipment is available, you can arrange cedar trees into a dozer pile and cover the root mass with dirt to anchor the pile.

Once the pond is full, use cinder blocks or concrete anchors for brush piles. Many people build their brush piles, including anchors, on top of ice covered ponds so that the piles sink to the bottom when the ice melts. Another option is to use a johnboat to deliver brush pile components.

Cinder blocks and Christmas trees work well together. Simply put the trimmed tree trunk through the hole in the block and screw a piece of scrap lumber or plywood to the base of the tree to keep the block from slipping off. The bottom-weighted tree will stand vertically underwater and provide cover over a range of depths, depending on the size of the tree.

On ponds and lakes with fishing docks, a low-cost method of providing fish cover is to tie unweighted trees to the dock for a few months. When the trees become waterlogged and sink, simply cut or untie the rope and attach more trees. Eventually, you’ll build up a pretty good brush pile right where you like to fish.

This Issue's Staff

Editor In Chief - Ara Clark
Managing Editor - Nichole LeClair Terrill
Art Director - Cliff White
Writer/Editor - Tom Cwynar
Staff Writer - Bonnie Chasteen
Staff Writer - Jim Low
Photographer - Noppadol Paothong
Photographer - David Stonner
Designer - Stephanie Thurber
Artist - Dave Besenger
Artist - Mark Raithel
Circulation - Laura Scheuler