Running a farm takes a lot of water. When it comes to watering crops through irrigation, giving thirsty animals a drink, or washing away their waste, there’s a lot of wastewater to deal with at the end of the day. There are a lot of chemicals within leftover irrigation water, also known as tailwater. Fertilizers, pesticides, and all the excess nutrients and chemicals used to grow plants and keep them healthy, can be toxic to wildlife and humans alike if it’s allowed to flow into surface water. Livestock wastewater is full of ammonia, decaying organic matter, and other dangerous toxins. These require treatment of some kind before being released into surface or groundwater.
Eutrophication occurs in the wild when there’s a severe lack of oxygen within an ecosystem and can be caused directly by over fertilization of an environment. When massive amounts of fertilizer, waste, or oxygen-hungry algae is introduced to a system, oxygen levels plummet. High levels of fertilizer and ammonia found in agricultural waste can easily lead to eutrophication in ecosystems where the water is released. Eutrophication is toxic to aquatic organisms, and can cause sudden death in fish, bacteria and shellfish alike. They also promote excessive flora, which reduces available oxygen, which is a major concern for ecosystems where both microorganisms and bigger organisms are heavily reliant on dissolved oxygen to survive.
Oftentimes, in agricultural or construction sites where sediment or toxins in runoff is a concern, a sediment basin is used in order to allow suspended particles to settle. This is often an excavated basin at a lower elevation than the irrigated fields so that gravity assists in water flowing downwards. Here, water is held for an extended period of time. If water moves too fast, or doesn’t spend enough time within the basin, sediments won’t have a chance to settle. HRT is critical here and is achieved by creating snakelike paths for the water to follow. Baffles placed within a sediment basin trap sediment itself, force a longer path for water to flow through, and ensure proper sedimentation before water is released into the wild.
