While it may look like a simple hole in the ground, it’s very easy to design a bad dugout, says Shawn Elgert, a Red Deer-based professional engineer with more than 12 years experience in agricultural water systems.
Elgert spoke to producers on a recent county tour near here.
Elgert advises producers to start with good water quality when designing a dugout.
“One of the best ways to start out with the best water quality is to do things like construct grass waterways. A nice gentle slope on a grass waterway will help filter out sediment and nutrients which can later on lead to algae growth,” he said.
He suggests installing a gated culvert so that during runoff periods, the culvert can be closed to prevent poor-quality water from entering the dugout. Good dugouts also have a properly constructed ditch or a bypass ditch.
Elgert advises keeping dugouts away from animal bedding or feeding areas. They should be situated away from trees, as leaves, brush and sticks can fall into the dugout and leave organic matter, which is a source for weed and algae growth. Croplands which are overfertilized can also provide excessive nutrients which can lead to algae growth.
Aerating a dugout can improve water quality, said Elgert. Oxygen spread by aeration helps keep many nutrients such as phosphates and nitrates out of circulation and locks them down on the bottom of the dugout.
Elgert says that when planning the site, it’s very important to have a sufficient runoff area for the dugout. “You can build a big dugout but if you don’t have enough runoff area, it’s not going to fill and you won’t have fresh water flushing out the old water, which then can lead to water quality problems.”
It’s important to have a waterway that supplies the dugout consistently every year.
“We generally design a dugout by looking at runoff maps for the area,” explained Elgert. Municipal ditches may be good water sources, but they often have their own problems. “There are chemicals, nutrients and fertilizer that can get into the municipal ditches. Getting a culvert might help in some of these cases, so you can shut the water off when it’s not good quality,” he said.
Intake should occur about four feet from the top of the dugout so that the water drained out is not full of sludge or nutrients from the bottom. Water from the bottom of a dugout contains less oxygen. Intake should not be too close to the top of the dugout as algae and cynobacteria can be drawn into the watering system.
Sloped walls are recommended, but should not be so steep as to create slumping, said Elgert. Sloped walls provide weed control and reduce temperature, which cuts down on weed and algae growth.
“We probably recommend more than 13 feet deep to help provide cool temperatures and prevent weed and algae growth. Sediments come into your dugout year after year and we do want your dugout to last a long time. As sediments come up and fill up the bottom of the dugout, you won’t lose a lot of depth over the years,” he said.
Elgert told producers they should always dig a test hole before digging a dugout to make to make sure there are no sand lenses where water can seep out. Dugouts should be designed to store enough in the event of a two-year drough, so that if there is no runoff for two years, the producer will still have water. This should take into evaporation loss and ice at the end of the second year.
Producers who wish to build a dugout must often obtain a licence if they build dugouts of a certain size or near a creek. Elgert recommends that producers contact Alberta Environment if they had questions regarding licensing.