How to Construct a Concrete Pond
>Estmating the materils
Excavating
To drain or not to drain
Placing the forms
Working with Concrete
Pouring the Floor
Setting
Fountains and Spouts
If you plan to mix and pour the concrete yourself, first figure the cubic feet of fill required for your forms, and then divide by 27 to see how many cubic yards you need. A cubic yard of concrete consists of seven sacks (7 cubic feet) of cement, 14 cubic feet (0.52 cubic yard) of sand, and 21 cubic feet (0.78 cubic yard) of gravel. Allow some margin. It isn't too expensive a proposition to have some sand and gravel left over, and you can get a full refund for every unbroken bag of cement you don't use.
Before ordering lumber, consider your many needs for wooden planking, over and above that required for the concrete forms. You may have to build your own platform for mixing concrete. You will need a number of pieces for bracing, and probably you will want to lay out a plank track for the wheelbarrow to protect the lawn
You will need cinders, and they are awfully hard to find in these days of diesel and electric power. Any industrial plant that burns coal for power probably will have a load it will sell you reasonably enough. In estimating the needed amount of cinders, plan to cover the entire pond floor with a foot of them, and then tamp them down to a 6-inch thickness.
If you can't get cinders, then crushed limestone or gravel-which are somewhat more expensive-will have to do. With these, allow a 7- or 8-inch thickness on the pond floor, before tamping.
Once I would have told you the most practical time to build a pond was the fall of the year. The soil is easy to work then. A man's lawn, flower, and vegetable gardens make few demands upon his spare time, and the weather is cool enough for him to do heavy work in comparative comfort. These advantages still hold.
My principal reason for recommending pond building as an autumn job would have been in the interests of curing the pond. A tremendous amount of free calcium in newly formed concrete dissolves in the water when the pond is first filled, making it fit for neither flowers nor fish. We used to wash away this free calcium by filling the pond with water, allowing it to set for two or three days, draining it, and then repeating the process up to a dozen times. When a piece of litmus paper dipped into the water finally told us it was no longer alkaline, the pond was at last considered cured. You were lucky if you finished the business in six weeks.
A simpler system was to build the pond in the fall, leave it uncovered, and let the winter weathering take care of the curing-which it did very well.
A few years ago, however, we worked out a system for curing a pond, quickly and surely, within a few days. This system reduces the work of pond preparation to a fraction of what it once was and enables a man to start building a pond in midsummer and bring it into bloom for a good part of the remaining season. In the section on curing concrete ponds, this matter of curing is discussed fully.