When my husband and I moved to Johnson County in 1978 we bought a few acres of arable land at Grandview.

We moved into a repossessed mobile home and went to work making it our home place.

We put in a well in 1978. The well has been giving me problems recently, so I decided to have a stock tank dug.

I have allowed cattle to graze with the only water source being the well.

I contacted Stan Ellison at the USDA Natural Resources Conservation Service for his expertise on putting in this tank. Here’s what I discovered.

Use care in selecting a pond site. Construction costs, fish production, usefulness and length of life of the pond are all affected by its location.

A good pond site should have soil containing enough clay to hold water, land lying so as to permit the most economical construction, a drainage area of the right size to assure a good water supply, and a location suited to the purpose the pond is intended to serve.

Avoid sites that receive drainage from feed lots, barn lots, or septic tanks.

Ponds that are one acre or more in area are better for fish production than those of smaller size. For a fish pond it is best to have 15 acres of watershed area for each surface acre of water.

Larger ponds also provide more stable sources of water for livestock. I probably will not put in fish.

If you are in doubt about the soil of a particular site, sample the subsoil by using a soil auger or posthole digger in several locations along the proposed dam site.

A simple test for suitable clay content is to squeeze a handful of fairly moist soil into a firm ball. If the ball doesn’t crumble with a little handling, the soil contains enough clay for use in the dam core. If the ball crumbles easily, the soil is not suitable.

You should consider several aspects of the topography of a pond site.

Construction cost is less if the dam can be located where the banks of the proposed pond basin come close together.

The area to be flooded should be as flat and wide as possible to obtain the most water volume in relation to dam height but have sufficient depth to prevent excessive growth of water weeds in the shallower areas.

The banks of the proposed water line should be fairly steep to avoid shallow water in which these weeds may become a problem.

If the ground below the dam slopes gently, you can use a sod spillway. If it is steep, you may have to make a more expensive concrete spillway.

Avoid sites requiring dams more than 20 feet high; construction costs will be high.

It is unwise to build ponds by damming creeks. Usually creek watersheds are too large and the runoff too great to control except by large, expensive dams and spillways.

The runoff also is likely to be muddy, and the pond soon would become silted. This kind of pond is a poor producer of fish.

The watershed should be proportionately larger if the pond is intended for irrigation or for watering large herds of livestock.

If you find a good dam site where the watershed is too large or too small, you may be able to get the proper proportion by building a terrace to divert water either from the pond or into it to control the water level.

The watershed must be protected from erosion. Permanent grass cover or unburned woodland free from erosion is best.

All gullies and bare soil in the watershed should be revegetated.

Locate ponds so they do not receive barnyard, feed lot or septic tank drainage that may stimulate the growth of undesirable filamentous algae — moss or “pond scum.”

Avoid sites that permit drainage from roads. Road drainage adds greatly to the watershed area and is a source of contamination, especially silt, that keeps the water muddy.

Locate the pond where it will serve the most uses, bearing in mind that soil and drainage areas must be suitable.

You may be able to locate ponds so they furnish water to livestock, the barn, house or truck garden. This are also a good reason for building a larger pond.

A diversion terrace may solve the problem of a deficient pond site.

If the watershed is too large, part of the runoff can be diverted with a terrace.

If it is too small, the watershed could be increased by terracing in more area.

Terraces often can be operated to suit different weather conditions.

In times of drought, the entire runoff from a large watershed can be diverted into the pond. In wet years runoff can be bypassed after the water reaches spillway level.

Ponds located on good sites may fail because of faulty construction.

Securing a good pond requires special attention during construction.

I hired a contractor recommended by the USDA to dig the tank. He did an excellent job.

We hope that when we get a few good rains the tank will fill up and be a good source of water for some time to come.

Vicki Gilpin is a Johnson County Master Gardener Wildbunch Writer from Grandview.