About 98% of Alberta’s irrigation is in Southern Alberta, where more than fifty different irrigated crops are grown. Water is diverted from three rivers (Oldman, Bow, and St. Mary) and delivered to about 6,000 irrigation districts through an interconnected system of about 50 storage reservoirs, and 7,900 km of canals and pipelines. Groundwater is not used for irrigation in Alberta. About 7,600 km of the canals and pipelines are owned and operated by the irrigation districts, and about 300 km by the Government of Alberta (GoA). Irrigation in Alberta was about 708,000 ha in 2016 and amounted to almost 70% of Canada’s irrigated area.

Development and implementation of technologies related to rehabilitation of water supply infrastructure and on-farm irrigation within the irrigation districts have resulted in significant water savings through reduction of distribution losses (seepage, evaporation) and improvements in on-farm water use efficiency and productivity. Salinity and waterlogging, which affected about 20% of the irrigated area throughout the irrigation districts in the 1970s, were essentially eliminated because of the irrigation rehabilitation program and improvements in on-farm irrigation technologies.

Rehabilitation measures adopted were as follows:

1. Replacing Surface Canals with the Underground pipeline - Surface canals were replaced with buried polyvinyl chloride (PVC). It was carried out in about 4,100 km (54%) of the 7,600 km of irrigation district-owned water distribution systems. These pipelines eliminated seepage, evaporation, and operational spills; reduced soil salinity and waterlogging on adjacent lands; improved water distribution efficiency and water delivery effectiveness for irrigation producers; and freed valuable land for irrigation development.
2. Surface Canal Rehabilitation - The rehabilitation of surface canals was focused on the larger canals, which cannot be replaced with underground pipelines. Priority was given to canals where seepage was a problem. Rehabilitated canals were designed to optimize water delivery effectiveness, and incorporate armor on the canal banks to protect against erosion. A buried plastic membrane was installed in the canal bottom and banks to prevent seepage losses. Automation and remote flow control of water in the canals continued to be an integral part of the irrigation rehabilitation program. This included pump control, reservoir control, upstream level control, downstream flow control, and water ordering by irrigation producers.
3. On-Farm Irrigation Technology Improvements - Newer irrigation technologies, such as low-pressure drop-tube pivot systems, and the production of higher-value specialty irrigation crops were introduced. About 76% of the on-farm irrigation in the districts were carried out using low-pressure, drop-tube pivot irrigation systems which had an efficiency rating of about 84%.
4. Irrigation Demand Model - The Irrigation Demand Model (IDM), developed in 2002, enabled irrigation districts to assess long-term water supplies relative to expected irrigation demand more accurately. This informed water allocation and expansion decision-making ensured equitable water sharing for all the irrigation producers and other water users. The IDM determines the on-farm water demand for each irrigated parcel of land within each irrigation district, using historic and current weather data and annually updated cropping and on-farm irrigation system data. The model links this data with the irrigation district water distribution Network Management Module, which is then used to estimate conveyance losses (return flow, evaporation, and seepage). The IDM was updated in 2017 which enabled an even more accurate assessment of ongoing water demand within the irrigation districts.
5. Alberta Irrigation Management Model (AIMM) - This decision support software package helped in informed irrigation scheduling. The software acquires the necessary climate parameters required to calculate evapotranspiration and irrigation recommendations from a comprehensive network of automated weather stations located throughout the irrigation districts. Producers can choose the closest weather station for their information requirements.

Until 2012, improvements to the irrigation conveyance infrastructure resulted in annual water-savings of about 50 MCM. In addition, advances in sprinkler irrigation technology resulted in significant improvements in on-farm irrigation efficiency, which increased from about 35% in 1965 to about 78% in 2012. This reduced the mean on-farm irrigation demand, based on a 10% chance of exceedance, from about 474 mm in 1999 to about 419 mm in 2012. On-farm irrigation efficiency is expected to increase to 85% by 2025. By 2012, changes in irrigation systems and water conveyance infrastructure reduced the gross demand by 74 mm, which included a 55 mm reduction in on-farm demand and a 19 mm decrease in conveyance losses, at a 10% chance of exceedance. During this period, rehabilitation of the canal distribution infrastructure, combined with improvements in the on-farm irrigation systems, reduced annual gross irrigation demand by 170 to 200 MCM, even including about 30,300 ha of irrigation districts’ expansion during that time.

Implementation of a cost-shared funding program, specifically for the rehabilitation and upgrading of existing irrigation water supply infrastructure, was initiated in 1969. With the introduction of PVC pipe technology in the early 1980s, the focus of the program shifted to the replacement of surface canals with underground pipelines. Total pipeline installation within the 13 irrigation districts averaged about 105 km/year from 1999 to 2012 and represented almost 90% of the total annual rehabilitation work carried out by the irrigation districts.

Irrigation districts authorized a further expansion of about 0.612 Mha because of improved water savings from the newly developed water supply infrastructure; and automated water conveyance systems. This expansion represents an increase in the irrigated area by about 57,000 ha from 2012 levels and about 34,000 ha from 2016 levels. Furthermore, Irrigation producers were expected to upgrade to more efficient irrigation systems on an additional 160,000 ha of land to reduce energy and labour costs, increase water use efficiency, and improve management of available irrigation water for higher value crop production. Increasing use of higher efficiency sprinkler nozzles and variable-rate irrigation technologies by irrigation producers on low-pressure centre pivot irrigation systems also enhanced on-farm efficiency gains. Irrigation districts are continuing the replacement of surface canals with underground pipelines wherever possible, and rehabilitation of an additional 1,600 km of un-rehabilitated surface water conveyance infrastructure.

Keywords: Fertigation; drainage water of fish farms; yield production; SALTMED

Presented at: 69th IEC Meeting 2018, Saskatoon, Canada

Keywords: ANFIS; groundwater level; salinity; SVM; waterlogging

Presented at: 69th IEC Meeting 2018, Saskatoon, Canada