Pond Management Frequently Asked Questions
Below are common questions received at the Extension office. Some of the questions and answers are referenced though the publication, Indiana Ponds Q & A, Purdue Extension.
What is a good source of information on building a farm pond?
One of the best sources of information is: "Ponds - Planning, Design, Construction." The USDA Natural Resources Conservation Service (NRCS)- Agriculture Handbook 590. It contains detailed information on design surveys, site selection, drainage area, pond layouts, soil analysis and spillway construction. A copy of the publication is available here: http://www.in.nrcs.usda.gov/pdf%20files/PONDS.PDF
Where can I purchase fish for stocking my pond?
Fish may be purchased from a number of commercial producers.
How many grass carp should I stock in my lake?
The amount of grass carp needed for control of submerged vegetation depends on the infestation of aquatic plants. Grass carp at the rate of 20 fish per acre are needed if at least half of the area is normally covered by vegetation. For vegetation in only a narrow belt around the edge, five to 10 fish per acre are sufficient.
How do excess nutrients affect the pond?
The concentration of nutrients affects the health of a pond. When plant nutrients enter a pond, plant growth increases. For example, high phosphorus levels result in algal growth, excess floating vegetation (duck weed and water meal), and excess submerged vegetation. As algae grow beyond the pond's ability to support it, large amounts die and decompose. The decaying plant material uses up available oxygen, sometimes causing death of fish and other aquatic life.
My pond has a lot of plant growth and algae on the water surface. Why does this happen?
Factors that contribute to excess algae and plant growth include:
- A high nutrient level (usually phosphates): the result of nutrient-loaded runoff from crop fields, pastures, geese droppings, lawn fertilizer, or excessive amounts of leaves (in ponds surrounded by woody cover).
- Stagnant water: lack of wave action or water flow from the watershed that encourages growth, especially if nutrient levels are high.
- Small pond size or shallow depth: conditions more apt to promote excessive plant growth than a large size or greater depth.
- A low water level in the pond: a condition which limits wave action and agitation from the wind.
The best long-term solution is to reduce the amount of plant nutrients entering the pond. Adding an aerator can help but only treats the symptom; not the cause of the problem. A significant amount of algae in the pond should be removed or the decaying vegetation will lower the oxygen level and could kill fish.
Does adding blue dye to ponds help reduce plant and algae growth?
Blue dye blocks some sunlight, reducing plant vegetation in the pond. However, blue dye treats the symptoms, not the cause. It is a temporary fix that must be repeated periodically to control algae.
- Apply early, by April 15, to prevent germination.
Do livestock or horses around a pond impact the water quality?
If animals have physical access to the pond, they can add nutrients into the pond (through manure). Their hooves can also break down the shoreline as they enter and leave the pond. Runoff from heavily used pasture can even cause problems. Water should be diverted or go through a filter strip before entering the pond.
How can I tell when the oxygen level in the pond is low?
Fish will gulp for air at the surface of the pond. Ponds are most likely to be deficient in oxygen:
When ponds have warm water temperatures - because warm water holds less dissolved oxygen than cooler water.
At dawn — because plant photosynthesis does not occur at night so oxygen is not added during evening hours.
During cloudy days — because photosynthesis depends on sunlight.
Four to ten days after ponds are treated with a herbicide for aquatic vegetation control.
Who is responsible for my Homeowners Association pond maintenance?
You will need to check legal documents to know for sure, but the most likely scenario is that the Developer has transferred ownership of the pond to the association. In this case, the association would be responsible for maintaining the pond and any surrounding area owned by the association. If you have questions or safety concerns, contact your city hall at Johnson County Stormwater Management Program.