Irrigation

Much of Utah’s agriculture would not be possible if were not for irrigation. Utah’s arid climate provides limited and frequently unreliable annual rainfalls. However, the combined climatic and geographic conditions of the state have historically resulted in conditions that produce vast quantities of stored precipitation in the form of snow at high elevations. The snowpacks melt as spring temperatures rise, and as water courses down from higher elevations, the water joins with other waters, increasing in volume, and concentrating in streams and rivers. The topographic boundary from which each stream receives its concentration of water is called a “watershed.” Early Mormon settlers seized upon the opportunity to utilize waters stored in mountain snowpacks to supplement croplands by distributing water via networks of canals; and by storing spring runoff in dams to extend water availability throughout the dry seasons. The network of dams and canals has allowed expansion of crop variety and yielded increased production. Although many agricultural lands in the west rely exclusively on rain-fed or “dry farm” cultivation, variability in precipitation patterns can greatly affect agricultural productivity.

Dams, canals, and pipelines are constructed to take advantage of the topography of each watershed. With this infrastructure, water managers are able to distribute the concentrated streams outward to lower elevation lands that are suitable for crop production. The Canal data and Flowline data show the location of canals and ditches.

Within each watershed, various entities (or individuals) have legal claims (i.e., water rights) to use the water for “beneficial use” and are permitted to divert waters from the streams into the storage dams, canals, and pipelines. The distribution of water is governed by state law and is based largely on geographic proximity, available supply, and ownership of the water rights. The WRPOD data shows water points of diversion. The county can use this data to see where water is being diverted from its natural flow.

• Provide public safety by limiting access to dangerous structures, as well as  training and encouraging operators and the public to be practice safety and identify safety concerns.
• Preserve access and system efficiency with regular maintenance of right-of-ways and easements. When possible, coordinate efforts between canal operators and municipalities as a means of encouraging cooperative relationships between organizations while facilitating public interests.
• Establish a long-term plans for:
  • Transitioning of land and water resources with shifting community needs
  • Preservation of historical significance and public access where desirable
  • Modernization of shared operations and equipment that facilitate the use of appropriate irrigation technologies
• Encourage agricultural irrigators to:
  • Modernize and provide resources to assist with upgrades such as pressurized pipe systems that reduce traditional flood irrigation and favor transitioning to sprinkle and drip application
  • Practice sound irrigation strategy such as: “Deficit Irrigation” which balances water cost with the crop yield to achieve ideal economic outcomes; limit irrigation runoff and control pollution from that runoff
• Coordinated irrigation scheduling between water users—cooperate with crop irrigators’ operational needs when systems are shared with secondary irrigation users.
• Encourage residential and commercial landscape irrigation efficiency and water quality protection practices that emphasize native plant choices, xeriscaping techniques, reduction of impermeable surfaces, reduction in chemical use, proper stormwater handling, etc.
• Utilize stormwater treatment methods that prevent stormwater runoff from entering canals and ditches.

There are different irrigation methods that may work better in different scenarios, depending on spatial or temporal factors like location, elevation, season, etc.

Utah State University Extension provides information and expertise about irrigation.

Irrigation best management practices focus on efficient water use and nonpoint water pollution. Irrigation efficiency is calculated as the ratio of the amount of water needed by a crop and the amount of water diverted for irrigation. The Water-Related Landuse data can be used to locate areas of the county that use irrigation and areas that are not irrigated.

In Utah irrigation systems are an integral element for agricultural viability.[1] Therefore, irrigation best management practices and conservation efforts are important to make sure that water use is sustainable. Some economic facts related to irrigation are:

• Utah’s crop income for 2014 was $532,111,000.[2]
• As much as 82% of Utah’s developed water is used for agriculture.[3]
• In 2008, small farms (annual sales under $250,000) made up 62% of the total irrigated farmland in Utah.[4]

Some useful links to the Utah Division of Water Rights include:

• An online list of Utah Canal Companies by county.
• An online list of Water Companies by county.

Flood irrigation is generally associated with the largest potential for erosion, followed by sprinkler, and then drip irrigation.[5]

The science and practice of irrigation is intrinsically connected to agriculture in Utah and is dependent on the extensive networks of canals, pipes, and ditches that make the usage of water rights possible. Irrigation also plays a significant role in affecting downstream water quality and hydrology available for subsequent users, whether the user is human, animal, or vegetation.

It is often the case that those who manage the agricultural conveyance networks are the same individuals that are the irrigation managers; however, this is not always the case. This overlap between irrigation supply managers and irrigation water users regularly creates confusion as to whether one is speaking about conveyance (water delivery via ditches and canals) or irrigation (water use). It is beneficial to understand the distinction between conveyance managers and irrigation managers. Farmers and ranchers are the water users, or the irrigators. They may be involved with managing the diversion from which they receive their water, or they may simply be shareholders that are more comparable to customers subscribed to a service, much like residential water users connected to a municipal water line. Irrigation or canal company officials may never actually irrigate any farmland; their job may simply be to manage the conveyance system’s water rights, diversions, canals, gates, etc. This distinction is critical to understanding how to achieve water savings and how to protect watersheds from runoff. Some water savings are achievable by addressing conveyance, and others by addressing irrigation application. So, when talking about water saving application techniques, typically one is speaking about irrigators, and when talking about controlling water losses in canals because of seepage, one is discussing issues within the purview of conveyance managers. Additionally, application options the irrigators may have depend largely on how the irrigation company is willing to deliver the water. The irrigator’s allotted flow of water, and the given time frame within which the water must be taken, may dictate the types of irrigation available to the irrigator. For example, irrigation companies changing from open canal to gravity pressurized pipe may open new opportunities to irrigators.

Improved efficiency of the application of irrigation water is often perceived to mean that the “saved” water is subsequently available for an expansion of irrigated acreage. This notion is incorrect. The expansion of irrigated agricultural application increases consumption, thus removing additional water available to downstream users. For example, a farmer saves 50% of the water previously applied to a 100-acre field (Field A) by switching from flood to sprinkler irrigation. Although they have saved 50% of the applied water, applying the leftover 50% of the water to an identical and newly expanded 100-acre field (Field B) essentially doubles the consumptive losses, and actually uses more water than would have been used had the farmer never tried to save any water on Field A. This paradox creates a disincentive for water savings in the agricultural community and slows the application of modernized irrigation methods.