Dearest Gluggums,
“Help PonDoc I have a leak!” I ask, how big of leak? “Oh, I know it is going down.” You don’t. You must calculate and find out. It is relatively simple. All bodies of water evaporate into the atmosphere at about 660 gallons (2,500 liters) of water per day per quarter acre and this can be over 1,000 gallons (3,800 liters) on a hot windy day. Summer brings such days.
To manage water you need a gauge. This is simply a board painted white with black marks every inch. Drive this into the lake and read it over a period of time. Now for the boring part…
To calculate how much water is being lost over time, you must know the surface area of the pond. A quarter acre is 10,890 square feet. If the water drops 1 inch, that is 1/12 cubic feet or 1/12 times a quarter acre (907.5 cubic feet). There is 7.48 gallons per cubic feet or an inch drop represents 6788.1 gallons of water. If this happened over a day (1,440 min) then the “leak” is 4.7 gallons per minute. This is just significant and it is possible to make-up this volume using a well. Volumes exceeding 10 gallons per minute are considered serious. Often a pond will drain to a level and stop; this indicates the leak is above the water level.
Being aware of the temperature and weather, you can make very good estimates of how your pond is behaving. You can mitigate a lot of water loss in how and where you plant. For instance, if you put plants upwind, you will create turbulence reducing evaporation. A wind break for a pond in addition cools the water reducing evaporation. If you require additional water, do it at night and slowly so as not to tax a well.
Froggie, your greenness, I hate it when your puddle dries up. All that is required is a log of how much water is being lost. Then you can start to control this and budget for the cost of fixing it. In sedimentary places, clay can be used; and in fractured terrain a liner should be considered. Glug, I really hate leaks. I cannot see underground…
Sincerestly,
PonDoc from the pond