Conserve water from wells in drought
By Heath Herje
Oklahoma Cooperative Extension Agriculture Educator
Drought has been a big part of our state since we became one. With the ongoing drought I have been receiving calls regarding water wells for drinking and irrigation. Residents have been asking how fluctuating water tables and low or dry creeks, rivers and lakes, will affect water quantity in their wells.
The concern over water is fairly new to most people because during the last 30 wet years it was rarely a topic of discussion. When people overused water, their view was never that they were "wasting" since after all, it was so abundant at the time. 2011 and 2012 changed all that and now it's not just farmers and ranchers concerned about conserving water.
While residents on the city water system are forced to use less water, rural residents, farmers and ranchers who use water wells for drinking, irrigation, and livestock water do not typically fall under these mandates. Does this mean they should continue with business as usual and waste water? No. In fact, during times when water supplies are dangerously low, everyone should take initiative and do their part to conserve. This exceptional drought has impacted groundwater levels in many areas of our state and some residents who use water wells are concerned.
Groundwater, which is found in aquifers below the ground, is one of our most important natural resources. In fact, according to the U.S. Geological Survey, groundwater is the source of about 38 percent of the water that county and city water departments supply to households and businesses (public supply). It also provides drinking water for more than 97 percent of rural populations who cannot access water from a county/city water department or rural water district. With so many people relying on groundwater for drinking and irrigation, you can imagine what a strain this can place on supplies during droughts.
More than 15.9 million water wells for all purposes serve the United States and approximately 500,000 new residential wells are constructed annually, according to National Ground Water Association estimates. In addition, the United States uses approximately 79.6 billion gallons per day of fresh groundwater for public supply, private supply, irrigation, livestock, manufacturing, mining, thermoelectric power, and other purposes.
According to the NGWA, more than 90 percent of the groundwater pumped from wells in the Ogallala, the nation's largest aquifer stretching from Texas to South Dakota, is used for agricultural irrigation. Representing about one-third of all U.S. irrigated agriculture it creates about $20 billion annually in food and fiber. The trouble is we are using more than is being replenished at an alarming rate and on crops like corn not equipped to handle heat and drought. In fact, some officials are wondering how much longer we can use this aquifer before irrigation is no longer an option.
While we do not have the exact answers to this and many other water-related questions, this trend has state and federal officials in the Great Plains concerned. $20 billion looks good, for now, but then what? Will irrigation wells in this area even be an option in 50 years? The water level in an aquifer like the Ogallala that supplies irrigation wells does not always stay the same. Droughts, seasonal variations in rainfall, and overpumping affect the height of the underground water levels. If a well is pumped at a faster rate than the aquifer around it is recharged by precipitation or underground flow, water levels can be lowered.
Some residents wonder what would cause their well to run dry. A well is said to have gone dry when water levels drop below a pump. This does not mean that a dry well will never have water in it again, as the water may return as recharge increases. But the timing on that is anyone's guess. The water level in a well depends on well depth, the type (confined or unconfined) of aquifer the well taps, the amount of pumping occurring in that aquifer and the amount of recharge occurring. 2011 and 2012 were examples of years where recharging of some aquifers was dramatically less in some areas compared to wet years.
A deep well in a confined aquifer in an area with minimal pumping is less likely to go dry than a shallow, water-table well. However, this does not mean wells in a confined aquifer will not go dry, as they are also influenced by pumping rates and lack of recharge. Since aquifers can be quite extensive the usage of a well can influence other people miles away. Groundwater that supplies a well also feeds streams and rivers during periods of low flow, so pumping from that well may also cause water levels in streams to lower. This can happen during drought and if other wells near it are withdrawing too much water.
When it comes to smart water usage in our wells, we should plant drought-tolerant plants, lawns, pastures, and crops that do more with less. We should also step away from tradition and instead of crutching our pastures and lawns up in late summer with seemingly mindless watering, let them go dormant. Farmers can do their part by switching from conventional tillage to no-till and by planting crop varieties with drought-tolerant genetics that require less or no irrigation. Many progressive farmers are stepping completely out of the box and planting corn and soybean alternatives like mungbean, grain sorghum or guar that take the heat and stand up to dry conditions.