Before Covid's one-year anniversary burns up all the candles, here's another event to commemorate: the 2020 drought. Starting last spring, here in the east and branching west, the weather started to dry up, and by summer there was a full-blown drought in progress. Those with ponds will likely remember water levels dropping, water temperatures rising, and algae blooms blooming. Unless your pond has generous water supplies, and perhaps super leak resistance (membrane liner, thick native clay, bentonite, or another sealant) you may have lost fish and quit swimming due to discolored water, gobs of algae, and weeds.
For pond owners with concerns about basins that may not be great at water retention, fears of another drought, or both, here are some ideas about maintaining a good water level.
1) Fix Leaks. All-natural earthen ponds "leak" to some degree. Whatever the supply source, some percent of it seeps away, gradually or fast, depending on pond basin material. Porous soil and ledge rock can cause significant seepage. Same for stony, shaley basin material. To reduce seepage in leaky ponds, natural (local, native) clay is sometimes added to the basin to slow down seepage. This often requires savvy contracting work involving dewatering the pond, adding clay in properly moistened and compacted layers, and sometimes covering with a protective layer of small stone. In extreme cases, leaks are stopped by lining the pond with a PVC or other material membrane. This requires considerable contracting work, including dewatering, proper basin prep, and liner protection under and over.
Find structural and construction leaks or basin leaks, and repair. This includes faulty piping and embankment deterioration. The less your pond leaks the less your need for supply water especially when drought hits. Some pond owners/builders express concern about hot weather evaporation. I think there is less loss to evaporation than to seepage and leaks, and to lack of supply.
2) Supplementary Water. Many ponds, leaky or simply drought-afflicted, carry on thanks to supplementary water supplies. These extra water sources include well water, spring water, water from a nearby brook or other water entities, roof runoff piped to the pond, even water trucked to the pond from a commercial supplier or perhaps your local fire department. Watershed runoff to the pond may be improved with drainage ditching or piping (French drain type).
3) Aeration. Adding oxygen and water circulation through aeration won't increase your pond water supply or stop leaks, but it can improve water quality that drought spoils. Algae (filamentous, planktonic, etc.) is the most common result of drought spoiled water, and aeration can add oxygen to enhance the decomposition of nutrients that feed algae. Aeration can improve water circulation which in turn reduces stratification and algae triggering warming, as well as fish kills due to oxygen depletion. Pond bed diffusion is often the best type of aeration for general pond water quality improvement.
4) Critter Control. Some pond critters can cause leaks. Crayfish, mostly the large species in the south, can tunnel into pond basins and dams and cause leaks. Muskrats may dig burrows in basins and dams and cause leaks. Beavers can dam up pond spillways and cause flooding that leads to dam failure. Keep an eye out for critter leaks or embankment damage when trying to locate or anticipate sources of water loss.
5) Reduce Water Wicking. Vegetation in the watershed feeding your pond needs water to live. Trees can be a big source of water use before runoff or springs can get to your pond. Consider reducing surrounding plants to improve your water supply. When I cut an acre of trees in the watershed above my pond and turned the land into a field, the water supply to the pond increased. When cutting, avoid damaging ground cover and triggering erosion runoff into the pond.
6) Pond Planning. When planning a new pond, do your water homework. Dig test pits to analyze groundwater levels especially in dry weather, check soil types and bedrock. Calculate the volume of watershed runoff to the pond to help estimate pond size, and supply required, which will vary depending on locale/zone, geography, cover, location, etc. Locate available supplementary water in the event it's needed.
7) Miscellany. Already our best Vermont weather forecaster is expressing concern about low groundwater tables and low precipitation this winter. If the drought does occur, or your pond experiences low water for whatever reason, one plus is that it can be a good time for repairs and improvement. Exposed edges can be dug out and freed of unwanted plants, and shoreline angles steepened to create deeper cooler water, less friendly to plant and algae growth. "You want to work with nature, and not against it," a friend once counseled me.
For more about droughts in the October 2020 Pondology, click here.
And from a couple of other sources, here's more good information on contending with drought and low water ponds.
Topics vary from month to month and provide great information when researching where you want to build a pond, or how to keep it clean. Other areas of interest are pond use for more than swimming, and how to keep fish happy in your pond.