Construction sites, or areas cleared for agricultural purposes, are especially vulnerable to increased sediment and pollutant run-off. In agricultural ventures, flattening fields for irrigation or clearing out vegetation for a new orchard can cause major disruptions to the natural drainage of the watershed around its area. Nutrients and pesticides used on crops for human consumption may render the water non-potable and allowing these toxins to flow into the groundwater or further downstream can be both unsafe and costly.
Oftentimes, farmers will utilize leftover water at the end of an irrigation cycle, known as tailwater. This water can be pumped back into irrigation systems to be applied to crops again or can be saved in a variety of different storage reservoirs to be used for different purposes. The water that’s stored either prior to or in preparation for irrigation will be stored in an irrigation or tailwater reservoir. These can be in-ground basins where a previous depression in the ground has been widened or come in the form of large standing tanks.
For a farmer struggling with water-shortages, providing a reliable form of year-round water-storage can make all the difference. Not only will capturing and reusing tailwater reduce a farmer’s overall water needs and improve their efficiency, but it will also protect their soil health and the health of the surrounding water table from dangerous nutrients and chemicals found in agricultural runoff.
Irrigation reservoirs
Farmers have relied on public water infrastructure for years in order to store and provide irrigation water. However, increasing demand and falling supply have led to severe water-shortages. In some parts of the San Joaquin Valley in California, farmers received a 0% water allocation. In Arizona, farmers relying on water allowances from the Colorado river will soon be given no water allowances at all and will be forced to depend entirely on ground water.
Ponds constructed with a waterproof liner can store precipitation and prevent seepage, allowing for semi-permanent storage when the dry season returns. These can also provide flood control for heavy rains, which are intensified by long periods of drought, by slowing and retaining water before it flows further into the watershed.
The size of an irrigation reservoir will depend on the crops being watered, the local precipitation and snowmelt, the method of irrigation, and expected losses due to seepage, runoff, or evaporation.
Field Spraying
These ponds can provide water needed for spraying insecticides, fertilizers, or other treatments to fields and orchards. Each acre of field crops will typically require around 100 gallons, while some orchards may require up to 1,000 gallons of water to cover an acre at a time.
Tailwater storage/treatment
Agricultural tailwater is dangerous for the environment if allowed to soak into the groundwater or flow into the local watershed. Full of nutrients, pesticides, and chemicals, this water is best re-used in irrigation, where it can help farmers maximize their water efficiency, and reduce the amount of new water that they need to pump for each irrigation cycle.
A tailwater retention pond will serve to capture sediment in a trap or via dredging, while holding water in a primary storage pond. Water will then be pumped from the retention pond back into the irrigation system, either to be used on the same field, or transported downhill to irrigate the next plot.
Livestock ponds
Adequate and clean water is incredibly important for healthy livestock. Not only does this directly contribute to the health of the animals, but it also affects the pastureland and available forage for grazing.
The size of the pond will need to meet the needs of livestock, which varies by the kind of animal and the local environment. Beef cattle and horses will typically require up to 15 gallons of water per day, while Sheep and Hogs will need between 2 and 4 gallons. Guides are widely available for various regions and various species’ individual needs.
Typically, watering holes should be small enough to encourage livestock to eventually seek new water sources, but not so far apart that they must travel long distances to do so. Constant or over-drinking from a particular water-source will encourage over-grazing in nearby pastureland or harm the pond’s ability to filter itself and control sediment. A good rule of thumb is to space livestock basins no more than a quarter mile apart in difficult terrain, and no more than a mile apart in level areas that are easier to traverse.
Aquaculture
Both freshwater and saltwater animals and plants can be grown in impounded water reservoirs. The size of the pond will depend on what is being grown, the type and quality of the water supply, and accessibility considerations.
An acre of water surface can yield up to 300 pounds of fish a year. These impoundments can range from 1 or 2 acres up to a 114-acre pool.
Shallow water will encourage weed and mosquito growth, making harvesting and management difficult. Deepening edges around the pond or a steeper slope will help reduce these factors.
