March 15, 2012 - Pond levels are on the rise thanks to recent rains, but with another hot, dry summer predicted, some pond owners may need to consider pond aeration systems to keep fish alive.
According to Dr. Billy Higginbotham, with Texas AgriLife Extension, most recreational ponds don't usually require aeration systems, but following the kind of year Texas experienced in 2011, more landowners are installing them.
"Warmer water does not hold as much oxygen as cooler water does, so typically if aeration is used, it is during the warm months of let's say, June through September," Higginbotham said. "It is not necessary for ponds to normally be aerated, depending on what the goals of the land are. Given the year that we had in 2011, with the low water levels, we experienced oxygen depletions in many ponds across the state. Therefore, there were a number of landowners that became more interested in either aeration or drilling wells to supplement the water levels because of the lack of rain."
The ponds that are most in need of supplemental aeration are those ponds that are being managed intensively for high densities of fish. A prime example of this would be in ponds being utilized for catfish production. Owners are particularly interested in aeration systems when they are supplementing their fish with floating fish food.
"The typical farm pond without aeration and somewhat normal water levels should be able to support a neighborhood of 1,000 pounds of fish per surface acre during the hot months," Higginbotham explained. "When you start going beyond that or if you have a desire to raise a higher density of fish than that, or if you pond starts dropping, like we had in the drought of 2011, and your fish are crowded up in less water, then aeration becomes something that a landowner may want to look at. Or, if a landowner has had oxygen depletions in the past and they want to do all they can to prevent that, supplemental aeration can kind of serve as an insurance against future oxygen depletions if it is used properly."
But when owners start driving their system beyond 1,000 pounds of fish per surface acre, supplemental aeration may need to be considered.
"People don't want to go through another repeat of losing their fish because of low oxygen levels -- it is something to consider," Higginbotham said.
Like with any investment, there are considerations to be made before making substantial purchases or changes to an operation. When it comes to an aeration system, there are several to choose from and each has different operational requirements.
"Obviously, if that pond is in a pasture where there is no electricity available to run a motorized system, then that is not going to be an option, and they may need to look at a design that incorporates a windmill," Higginbotham explained. "Now, if that pond is in a real protected area where wind action is limited, then even a windmill may not be functional. Most of the systems casino online greece are going to require access to electricity. So, that is just going to depend on where that pond is located as to whether or not that is feasible."
Some commonly used systems have a fountain. Many people prefer these for the aesthetics.
"In addition to the casino online aesthetics of having that fountain, it is moving water and bringing water in contact with the air which helps improve the oxygen levels," Higginbotham explained. "That would be one type, the second type would be pond aerators that are not necessarily a fountain type, but they are surface units that typically use vertical lift pumps and they are moving a lot of water at the surface. They may be taking water from several feet below the water and exposing it to the air. It is a little different aussie pokie from a fountain... it is online casino bonus no deposit just more efficient in terms of just bringing more water in contact with the surface to again increase oxygen levels.
"The third type, and we are beginning to see a number of these used in parts of the state, are called the diffuser systems," he continued. "Basically, these system set on or near the bottom and they emit a fine stream of air bubbles from a variety of heads, online casino pokies depending on the unit model."
What a diffuser systems can do is prevent a body of water from stratifying, if the pond owner is using the appropriate size per number of the units, and keep the oxygen level more uniform than just the surface unit option is capable of. Stratification occurs when a warm light layer on the surface heats up because of the sun beating down on it during the summer months and further down at some depth where light transmission stops, there is a cooler layer of water that is denser, so it layers near the bottom. Where there is less sunlight availability in that deeper layer, the pond doesn't have oxygen production through photosynthesis. So, the ponds get a warmer, lighter layer during the summer riding on top of a cooler, denser layer and that is called stratification.
If the pond is not real deep, a surface unit can do the same thing (as a diffuser system) but you get into some of these extremely deep ponds and a surface unit is only going to work for a certain depth, depending on the size motor they have got on it," Higginbotham said. "These bubble diffusers start at the bottom and emit bubbles from the bottom and this can then help keep a pond from stratifying, again if you use the right size based on the pond size and depth, and make more of that pond available to the fish during the summer months when ponds tend to heat up and stratify."
Stratification typically occurs in many ponds in the state. It renders part of that water column unusable for fish during those hot, summer months. Aeration systems, again depending on which one, can help prevent stratification if they are started in late spring before stratification occurs, and make more of that habitat available for fish.
"It depends on the goal of the landowner as to whether they even need aeration," Higginbotham explained. "It depends on where that pond is located and what they have access to in terms of electricity, or in case of a windmill-driven system, enough wind action in the summer to drive that aeration system to where it can ad oxygen to the water. Then you can go from there. Not all ponds need an aeration system, and we hope that 2011 is an extreme example of what can happen.
"Fortunately, now with the rains that we have had in November through February, a lot of our small to mid-sized ponds have been able to recover and will be off to much better start in 2012," said Higginbotham.
While some pond levels are rising, with summer weather predictions mirroring the 2001 forecast, now might be an ideal time for pond owners to plan ahead and consider an aeration system.
