Agriculture and Irrigation in Alberta
Alberta's Irrigation System
The distribution of the irrigation area in Alberta primarily involves the 13 irrigation districts in southern Alberta (approximately 525,000 hectares), but also includes the "private irrigation" of more than 100,000 hectares of irrigated land as far north as the Peace River country.
Although agricultural production under intensive irrigation is not unique to Alberta, the irrigated area within the province represents 65% of all of the total irrigation area across Canada. With more than 8,000 kilometres of conveyance works and more than 50 water storage reservoirs devoted to managing a finite water resource, based around irrigated agriculture, Alberta is the capital of irrigation in Canada.
Across the more than 625,000 hectares of irrigated land in the province, irrigation producers are able to grow a great diversity of crops, many of which can only be successfully produced under the longer and warmer growing season of the irrigated area, but a region where naturally-available moisture for crop growth is generally less than half that required and very erratic in its distribution. With more than 40 different types of crops being grown, irrigation water users can have the flexibility needed to sustain viable farm enterprises, even during times with market swings in commodity prices. However, having that market flexibility does not come to the producer without a significant investment in irrigation equipment and other agricultural production systems.
Irrigation in Alberta is unquestionably a significant part of the agricultural landscape, occurring on less than 6% of the cultivated land base in the province, but contributing more than 19% of the gross primary agricultural production.
In Alberta, irrigation (district and private) accounts for 96% of total water allocations for the agricultural sector, while allocations for stockwatering, feedlots and registration together make up the remaining 4%. As of 2005, registrations and licences allow withdrawals of up to 4,307,429 dam3, and this accounts for 45.3% of total water allocations in Alberta. However, irrigation licences in the SSRB account for 75% of the total volume of all South Sask. River Basin (SSRB) allocations.
Water Used for Irrigation
Irrigation for agriculture is the largest user of water in Alberta, accounting for 60 to 65% of all water consumed on average. In 2007, irrigation - including small, private irrigators - accounted for nearly 43% of allocated surface water, or more than 4.1 billion m3. It represents almost 73% of all water allocated in the South Saskatchewan River Basin. Thirteen organized irrigation districts collectively represent the largest amount of water allocated for a specific purpose in Alberta at over 3.5 billion m3. The four largest districts account for 83% of total diversions, with two more accounting for an additional 12%. Seven remaining small districts account for the other 5%.
Nearly all uses of water result in some water that is not returned back to the ecosystem from which it was derived. With irrigation, the majority of water applied to crops is taken up by plants for growth, or evaporates into the atmosphere. Additionally, a small amount of water is never used for irrigation itself; however, it is required to maintain the minimum depth of water in canals and reservoirs in order to transport irrigation water through the system. Therefore, some of this water ends up as return flow back into other creeks and/or rivers, though seepage and evaporation losses in canals and reservoirs can occur.
In much of southern Alberta, there is not enough rainfall and moisture to naturally sustain agricultural crops. However, there is abundant sunshine and heat that can contribute to growing many different crops if water were not a limiting factor. Early in the settlement of Alberta, it was recognized that agriculture would not be successful in the southern region without an abundant and assured supply of water to irrigate fields. Irrigation Districts were organized and granted water licenses to divert large quantities of water from the tributaries of the South Saskatchewan River, primarily the Oldman (St. Mary, Waterton and Belly) and Bow Rivers.
What does the indicator show?
Water requirements for irrigation vary from year to year. In general, the greatest factor driving demand for water is the weather, although the type of crops grown also influences demand.
This indicator depicts the reported amount of water diverted over time by Irrigation Districts.
Irrigation diversions are driven by the relationship between supply and demand during wetter and drier years. For example, demand for irrigation water will be highest when it is a relatively hot and dry year. However, these years are typically when the available supply of water tends to be less. In wetter years, more water is generally available to divert, but crops may not need as much irrigation. The balance between supply and demand can be partially addressed by planning what crops to plant according to wetter or drier years. Growing fewer water-intensive crops in drier years will help conserve water and reduce the need for increased irrigation diversions.
Note that total allocations permitted are higher than amounts historically diverted. Allocations do not guarantee water supply; rather, they guarantee the right to take water if sufficient water is available.
Here are some additional insights on irrigation in Alberta
- Irrigation development in Alberta totals in excess of 1.6 million acres and represents two-thirds of all irrigation development in Canada. About 1.3 million acres are located in the 13 organized irrigation districts and about 300,000 acres in private irrigation developments.
- Irrigation contributes almost 20% of the province’s gross agricultural production on about 5% of Alberta’s cultivated land. It is estimated that the direct and indirect impact of irrigation is worth about $5 billion to the Alberta economy.
- The irrigation water distribution and management infrastructure supports the water needs of about 42,000 people in 50 municipalities, and 12 major industrial users.
- More than 87,000 acres of wetland habitat have been created or enhanced by irrigation development in southern Alberta.
- Irrigation district infrastructure has a 2003 replacement value of $2.5 billion dollars. Within the irrigation districts, there are 38 individual off-stream reservoirs, with live storage capacity ranging from a few hundred to 260,000 acre-feet. Combined, the live storage capacity of these reservoirs is nearly 1 million acre-feet.
- The Irrigation Rehabilitation Program, initiated in 1968 has improved over 50% of the more than 7,600 kilometres of irrigation district conveyance works. To date, the combined rehabilitation contribution of the Alberta Government and Irrigation District water users totals approximately $665 million.