How many Nebraskans know the source of their drinking water?
The general public's accuracy in being able to answer this question is of concern to both agricultural producers and Nebraska municipal water supply operators and managers. While both groups represent diverse interests, an adequate and safe water supply is fundamental for a strong economy and for public health and safety. Water quality and quantity do hold much in common for agricultural and for drinking water and municipal supply systems.
Water, energy, nutrients and economics are central themes for both agriculture and municipalities. The same issues for Nebraska agricultural and municipal water interests are seen to exist globally. Worldwide interest and priorities are evolving for water policy and technology. As seen elsewhere, Nebraskans benefit when agriculture and municipal water interests work together on quality and quantity.
The Nebraska Section of the American Water Works Association has traditionally focused upon the needs, trends and technology relating to municipal public water supply systems. In 2014, the Nebraska Section formed the Total Water Solutions subcommittee. A primary goal of TWS is building understanding and positive collaborative working relationships with all Nebraska water stakeholders, especially agriculture.
This article seeks to further describe a number of practices in which municipalities manage water. Most Nebraska municipal systems derive their source of supply from groundwater. Regardless of size, communities' land uses within an individual watershed have a direct effect on quality and quantity of supply.
Nebraska's economy relies directly upon agricultural land uses and the farm economy. A healthy agricultural economy benefits municipal business, industry and government. For example, commercial and residential construction within larger Nebraska municipalities was robust in 2016. In contrast, farm producer commodity prices were severely reduced in the same year. With reduced farm income, the state of Nebraska experienced a tax revenue shortfall of $2 billion.
As a point of interest, irrigated agriculture measures quantities of water use in acre-feet, while municipal use is typically tracked in gallons. As an example, in a dry year the city of Lincoln delivers 14 billion gallons of water to its customers, which is about 8.7 inches (annually) for the area served by the municipal water system; 14 billion gallons is equivalent to 43,000 acre-feet. In addition, about 80% of the water use in Lincoln is returned through the wastewater system as treated effluent. Some of this water is a direct return of the potable water supply, and some portion is extraneous water from infiltration.
Relatively small individual household water savings can represent significant conservation for municipal systems, given the number of customers. Examples of reduced residential water usage in municipal systems include flow restriction devices on water fixtures, shower heads, sinks and toilets. Nationally, these practices have produced major reductions in water used for municipal systems. Lincoln has decreased per capita water use by 25% since the early 1980s.
Significant reductions have also occurred as a result of increased water efficiencies in manufacturing and industry, municipal water rate structures to discourage wasteful use and target summer turf irrigation, and an overall emphasis and awareness on the value of water from organizations such as AWWA and the Nebraska Water Balance Alliance (NEWBA).
A large portion of peak summer water uses for agricultural producers and municipalities goes to plant and landscape production. Water conservation for agriculture and municipal users requires making use of drought-tolerant plants and metering of water use. Significant improvements in agricultural irrigation efficiencies on crops have also been made as a result of producer awareness and technology. Examples of agricultural water efficiency include a producer's use of soil moisture probes and weather station information in making decisions as to when to irrigate.
Electrical costs in operating a center pivot may typically fall in the $1,500 to $2,000 range per revolution in irrigating a quarter section. Saving that application benefits water levels and costs. Not overwatering may actually enhance crop production and water quality. Nebraska nurseries and the University continue working together in developing water conserving plant materials and options.
A fundamental tool for municipal water conservation is having rate-based delivery of water to customers. Moreover, rate plans where the per unit cost of water increases with increased use have an even higher impact on reducing water use. These rate plans not only recognize that a customer should pay for the amount of water they use, but also for the incremental cost associated with having a supply, treatment and distribution system to deliver water during the high summer demand period as a result of turf and landscape irrigation. The two largest municipalities in Nebraska use this type of increasing water rate structure.
Water quality has and will continue to be an important and ever emerging issue for water utilities. While water supply quality has been strictly regulated in the states, people will continue to have impact on water supply quality. Customers’ expectations and awareness are ever increasing, especially with events like Flint, Mich., and Des Moines, Iowa. In Nebraska, water supply quality can be influenced by both municipal and agricultural activities.
Municipalities are meeting increasingly stringent water treatment quality requirements for wastewater treatment facilities. Increasingly treated effluent is evaluated as a useful commodity or resource. Examples of the resource nature of treated effluent include landscape irrigation, wastewater plant internal water demands and as a heating-and-cooling source. Also, processed solids from treatment plants may be used to produce methane gas that is converted to electricity. These solids may also be used as an agronomic source of nutrients on farmland.
Rainwater that falls within communities must have adequate drainage systems and may require monitoring. Land development and construction projects must plan sedimentation and erosion, ensuring that soils are not eroded away from the project site.
Residential development of crop land results in considerably more runoff for a given rain event. The increased hard surface with streets, driveways and roofs may result in as much as 75% more rainwater leaving a development. A common practice is to require developers to provide storage of stormwater as part of their land development plan. Therefore, water quality is better ensured, waterway erosion is minimized and downstream flooding is reduced. To the extent to which this extra water could be considered as an opportunity in a potentially water-short area might change how it is managed.
Nebraska municipalities are working with local natural resource districts in developing integrated management plans. These plans examine agricultural and municipal water quantity and quality conditions for the district.
How can we better connect in building collaboration on water quality and quantity across all users within Nebraska? The Total Water Solutions looks for opportunities to work with the Nebraska Farmer and interested groups and individuals to further build an understanding and collaboration within our drainage basins.
This article was written by the Total Water Solutions Committee of the Nebraska American Water Works Association. For more information, contact Steve Owen with the TWS at [email protected].