In Minnesota water has always played a central role not only for recreation but also industry. Not only is Minnesota home to more than 11,800 lakes but also huge rivers like the Mississippi, the Minnesota River and the Saint Croix River. This allows Minnesota to be the fifth largest producer of agricultural goods in the United States. But this part of the economy also accounts for a significant share of the water used in Minnesota. In total, 34 percent (87.9 billion gallons in absolute numbers) of the state´s water is just used for irrigation purposes. This is unsustainable!
Relying too much on groundwater
Since the end of World War II, Minnesota has shifted its water supply from surface water sources like the Mississippi River to groundwater pumping. Especially over the last 25 years, there has been a steep increase of 35 percent in the usage of groundwater. Although not solely responsible for this increase (an increasing population as well), farming is regarded as one of the key areas to tackle an unsustainable use of water, groundwater in particular. According to Professor Deb Swackhamer, former director of the University of Minnesota Water Resources Center, groundwater can be compared to a saving´s account for times of droughts. In contrast to surface water, which can be refilled through rain, groundwater, is replenished on a geological time scale that might take up to 10,000 years. Thus, it is clearly not sustainable to mostly rely on groundwater. If the groundwater reservoirs decline, it might take generations until they can be used again. In parts of South-West and Central-Minnesota, people have already witnessed a lowering of the groundwater level, which can cause serious water supply problems for communities, industries, and wildlife. Low groundwater in Little Rock Creek in Central-Minnesota has led to decreasing oxygen and increasing water temperatures that harm the brown trout population there. Though a regional issue, the Little Rock Creek case amplifies the importance of a more sustainable use of groundwater.
Cleaning up surface water sources
But why is it not possible to just switch back to surface water sources, which were used in the past? Today, more than 40 percent (more than 4100) lakes and streams in the state of Minnesota do not meet the federal quality standards for water, often caused by the side-effects of agriculture like nitrate and phosphorous contamination from fertilizers and animal manure. By infiltrating the ground or running into rivers, streams and lakes, these substances can negatively impact the overall water quality and foster the growth of toxic blue-green algae. Hence, it is not possible to use the contaminated water for irrigation or even drinking. Drinking contaminated water can cause serious illnesses such as the Blue Baby Syndrome, which is a blood disorder that can even be even be fatal in infants.
Proximity to pollution sources can negatively impact the quality of water.
Thus the state, companies, as well as advocacy groups have taken steps to tackle the problems of future groundwater shortages and water contamination in the state. To reduce water consumption in industries and agriculture (together accounting for about 42 percent of the freshwater used in Minnesota), businesses are encouraged to use more conservation-based processes and equipment. A common problem in this context are leaky water pipes and other related equipment. Even a very small leak of one drop of water per minute accounts for more than 10 gallons of lost water per year. Multiplied with the remaining leaks from a farm or plant this already accounts for significant amount of water loss. In fact, both companies and nature can benefit from simple steps like fixing leaking pipes since people save money and nature suffers less from an unsustainable usage of its precious natural resource.
Leaky water pipes account for a significant amount of water loss.
Modernizing water supply and treatment
Modern efficient irrigation technology in agriculture also saves water such as low-pressure irrigation. In general, extracting water from streams, lakes or the ground is a highly energy intensive process. Today, still most irrigation systems rely on high-pressure impact sprinklers that release a large amount of water at high pressure to water fields. Thus, these systems require pumps that push large amounts of water through pipes at a very high velocity. But low-pressure systems reduce the pumping demands significantly since pumps extract less water to create the pressure necessary to supply the sprinklers. Moreover, these systems also save water by using larger droplets that are more resistant to wind and evaporation. In contrast, high-pressure rely on small fine droplets, which can spread and be carried away by wind or evaporate in dry atmospheric conditions. Consequently, these systems have to run longer every day in order to achieve the same level of irrigation as the low-pressure systems. Moreover, the short intervals of “light rain” by the low-pressure system are also not disruptive to the soil and help to maintain its infiltration capabilities.
Low pressure irrigation system
How do we tackle not only water waste but water pollution caused by industries and farming? An effective way to diminish the effect of runoff water is the creation of a living cover around ditches, rivers, streams and lakes. This living barrier holds water on the landscape, filters contaminants like nitrate, and allows water to reach aquifers while simultaneously reducing runoff. Living cover can consist off perennial crops, cover crops, prairie and grasses, wetlands as well as forests. The plants´ root systems hold the soil in place, build organic matter and keep the water clean. In 2015, Minnesota enacted a buffer law which designated about 110,000 acres of land to living cover along its rivers, streams and ditches. From now on, the law requires perennial vegetation of up to 50 feet along public waters and 16.5 feet along public ditches.
All in all these ideas area just small steps. But with the help of such efforts to reduce water consumption and enhance the quality of water, people can protect the world´s most precious resource.
Tobias Luthe is a student in North American Studies focusing on politics and economics at the John-F.-Kennedy-Institut of the Freie Universität Berlin. He is spending the fall and spring semester 2016/17 at the University of Minnesota in the Twin Cities Minneapolis-Saint Paul.