- Do irrigation ponds damage the environment?
Far from damaging the environment, irrigation ponds offer a method to capture and store both stormwater and irrigation runoff, reducing the pressure on vulnerable aquifers. Eliminating excessive withdrawals allows groundwater levels to recover, which supply water to lakes, ponds, rivers, and streams and the vital ecosystems they support. Capturing irrigation runoff protects both surface and groundwaters from contamination that comes with excess fertilizers, pesticides, herbicides, and excessive salt and mineral levels. Water stored in irrigation ponds remains part of the natural water cycle and their use helps the environment.
- What are the negative effects of farm ponds?
Poorly built and inadequately managed farm and irrigation ponds can develop serious problems that can damage both the local ecosystems that depend on them and any downstream ecosystems, even though they may be thousands of miles away. Water quality needs to be monitored and managed in irrigation ponds to ensure that nutrients don’t build up to the point where algae blooms become a problem. A bloom of cyanobacteria, or blue-green algae, generates toxins that can be harmful and even deadly to humans, wildlife, fish, and other aquatic creatures. An algae bloom of less harmful varieties signals that eutrophication in the pond is well underway. Eutrophication is a process describing the deterioration of an aging or dying pond. There are high levels of turbidity, or cloudiness, in the water from suspended silt and organic particles. As those particles settle, the pond is gradually filled in. As organic matter decays, nutrients are released which feed algae blooms and reinforce the cycle.
An out-of-control cycle of bloom-anoxia-death-decay results in a pond permanently starved of oxygen that is unable to support any life aside from surface scum (algae) and anaerobic bacteria. A well-maintained and managed pond will not experience these symptoms. Instead, it plays a valuable role in a healthy and active ecosystem.
- How can I make my irrigation pond a valuable part of the ecosystem?
That’s a great question. You’re obviously interested in contributing to the support of healthy and robust natural environments and preservation of the Earth’s delicate balance of renewal. Fortunately, there are some easy steps to take to integrate your farm pond into the local environment. If you’re interested in allowing wildlife to access your ponds for drinking water, build it with gently sloping shorelines so that creatures can safely approach without danger of falling in. In the interest of reducing evaporative loss, limit the width of these shallow edges, but be sure to install a few wildlife ramps that give wayward deer or racoons a way to escape if they take an inadvertent dip.
Plant native grasses and wildflowers in a wide buffer strip around your pond. This will not only help minimize the risk of erosion, but it will reduce the amount of sediment carried into your pond and provide important habitat for pollinators and for dragonflies, which help keep mosquitoes and other pests at bay. You can add brush piles, trees, shrubs, and logs to the far side of buffer strips to provide additional wildlife habitats. Adding a few nest boxes will encourage cavity-nesting birds to settle in the area.
Be sure to keep embankment dams free of shrubs and burrowing animals, since they can damage the structure to the point of collapse. Regular mowing will prevent woody shrubs from getting established, and the use of chicken wire across the embankment face will discourage burrowers. If you intend to water livestock from your stormwater pond, invest in a pump and fill a stock tank instead of allowing them access to the pond itself. This will prevent damage to the edges of the pond and eliminate contamination from animal feces.
- Do I need a permit to use an existing pond on my property for irrigation?
As sources for clean, fresh water continue to diminish and the world at large becomes increasingly aware of the importance of healthy natural ecosystems, the practice of drawing from existing surface and groundwater is coming under control of local, state, and even federal authorities. Even if a pond is located entirely within the boundary lines of your property, your county or state may require a water use permit, depending on how access rights are defined in your area. Even building a brand new pond may require permits due to zoning restrictions and laws designed to protect vulnerable wetlands.
- What should I test for in my irrigation water?
Irrigation water should be tested for pH, mineral content, and common contaminants like herbicides, pesticides, and petroleum residue. The water should also be evaluated for conditions like high turbidity, or cloudiness. Cloudy water signals a high level of suspended particles in the water column, which may indicate excessive levels of planktonic algae, silt, soil or sand. Problems like these that persist over time indicate poor water quality and can damage your pumps and clog irrigation equipment.
- Should I use an aerator in my irrigation pond?
The value of an aerator in your irrigation pond depends on several factors. Aerated water tends to lower levels of contaminants and harmful bacteria that could be inadvertently applied to edible crops. Aeration also introduces oxygen into the water column and subsurface aeration mixes the oxygen throughout the water column. Plentiful oxygen below the surface levels supports a healthy population of beneficial bacteria and other microbes that help purify and increase the quality of stored water.
If your pond is in constant use during the warm months, the associated water movement and replacement may be high enough to keep oxygen at high levels, but very deep ponds may still benefit. If you’re seeking to keep oxygen levels high at depth, a submerged aerator will be more effective. If you’re constantly fighting algae and pond scum on the surface of your pond, a surface aerator will be more effective. In this case, the goal is less oxygenation and more surface water disturbance, since algae prefers still or even stagnant water conditions.
- How do I keep weeds from growing in my pond?
A pond built with a relatively steep slope (3:1) will ensure that water around the perimeter quickly becomes deep enough that sunlight cannot penetrate, and plants won’t grow. Keep the shoreline mowed to discourage marginal plants from stretching into the water. This also helps you keep an eye on the shoreline to make sure there are no signs of erosion or other problems.
- Can I raise fish in my irrigation pond?
While it's theoretically possible to combine uses of a farm pond to include both irrigation and sport fishing, there are several reasons that may not be a good idea. During irrigation season, you may need to draw down water levels significantly, which could be harmful to fish, who will find fewer opportunities to cool off in the depths. Lower volume means fewer places to hide, and a more concentrated fish density can cause stress, poor growth, and fish kills. Other issues include water quality questions, particularly if you're storing irrigation tailwater or collecting stormwater runoff. Contaminants like high levels of nutrients or herbicides can kill your fish or make them unsafe to consume.
- Are there resources available to help cover costs of installing an irrigation pond?
The Environmental Quality Improvement Program (EQIP) operated by the National Resources Conservation Service (NRCS) offers technical and monetary assistance for agricultural and specialty crop growers who use or are considering installing an irrigation reservoir as a primary or supplemental water source for their operations. Contact your local NCRS for more information. NRCS also offers numerous additional programs that offer financial support to assist in building irrigation ponds. The programs typically have limited funding and therefore limited application periods, and are usually confined to specific states, counties, or water districts. It's a good idea to bookmark the NRCS website and check frequently for announcements of new initiatives.
- What other resources may be available?
Projects and initiatives funded by state legislatures and administered through agencies dedicated to soil and water conservation, natural resource protection, or agricultural operations are worth looking into. Your county's cooperative extension service may be able to direct you to a variety of current or upcoming programs. It never hurts to network with local farmers and listen for news through the grapevine!
