WHAT IS GROUNDWATER AND WHERE IS IT? Nebraska is blessed with abundant water underground, called groundwater. It fills the openings or pore spaces in sand, gravel and rock formations below the ground. The formation is said to be saturated when the pores are completely filled with water. A formation containing a usable amount of water is called an aquifer. Most aquifers in Nebraska are a mix of sand and gravel, but porous consolidated rocks and some fractured rocks are also aquifers in some parts of the state. An aquifer may be a single mass, a layer or a series of layers. Groundwater is the major source of water supply in Nebraska. It is relatively plentiful and of good quality in most of the state and is used extensively as a supply for irrigation. It is also a vital and attractive resource for other uses, particularly for most municipal and industrial uses and virtually all private supplies. Private wells serve more than 350,000 Nebraskans. Groundwater, like surface water, is a renewable resource that makes up part of the total cycle of water on the planet, which is a constant quantity changing forms and locations. This endless movement and use of water is called the hydrologic cycle. Groundwater is replenished mostly by precipitation and in some areas by infiltration from streams, lakes, ponds and irrigation canals. Precipitation, as rain, snow or ices, either runs off the land to streams or other surface water bodies or infiltrates into the soil. The majority of the precipitation enters the soil, but most of that water is evaporated form the soil surface or transpired by plants; the combination of the processes is called evapotranspiration. The remaining water in the soil can move slowly downward-a process called percolation-until it reaches the top of the saturated zone, know as the water table, where it adds to groundwater in storage. In areas of heavy use or during dry years, groundwater use can exceed aquifer recharge. HOW DOES ONE DRILL AND CONSTRUCT A WELL? The drilling equipment most commonly used in Nebraska is a hydraulic rotary machine. A drill bit cuts the hole, and the cuttings are removed by the drilling fluid. Most drill holes for domestic wells are 9-10 inches in diameter. After drilling, the water well contractor will put a watertight casing in the hole to prevent contaminants at or near the surface from entering the well. State regulations specify the casing that can be used. Plastic casing is most often used. After grading the quality and size of the water bearing formation, the water well contractor selects the well screen that will give your well the best pumping efficiency and the longest life. The well screen is joined to the casing at one or more intervals in the water bearing sections. When the casing and screen have been installed in the well, several methods are used to develop the water producing capabilities of the well. The well is developed by pumping with compressed air, the contractor’s pump or by bailing. To ensure a sanitary well, regulations also require chlorination of the drilling mud and the sand or gravel pack. Chlorination eliminates both harmful bacteria and harmless, but problem causing, iron bacteria. The final step in preparing a well for the pump is disinfection, after which the disinfectant is flushed from the well. HOW MUCH WATER WILL YOU NEED? Planned and constructed wisely, a good, dependable water well can supply you with all the water you need now and in the future. A rule of thumb is to allow for between 75 and 150 gallons per person per day. You need to take into account the peak demand, for example when there may be extra guests. The amount of water expected for domestic supply is usually 4-10 gallons per minute. However, with an adequate storage tank, a well producing as little as one gallon per minute can be sufficient for domestic needs. In many wells, several hundred gallons of water are already stored in the well column. For every foot of a 4 inch diameter well below water level, there is about 1 gallon of water. Outside use of water can pose much greater demands. You need to calculate the required well yield if your well is needed for additional water uses such as: swimming pool and lawn and garden irrigation. SOME FACTS TO REMEMBER: Studies show that most Americans would prefer their own private water well. You can decide how to treat your well water if you so desire. You may not ever have to worry about water restrictions. A good, properly constructed water well will be an asset to your property. After the initial cost of installing a well and pump system, your water is virtually free. Even with budgeting for future service, it will more than likely be much less expensive than commercially available water. This information was obtained in from the Nebraska Well Drillers Association and the American Ground Water Trust.