Algal control and prevention technologies for Lake Diefenbaker irrigation canals

Abstract

The Lake Diefenbaker irrigation project makes up an extensive 500 km of canals that officially began in July 2020. These canals contain pumps for increased and enhanced irrigation throughout southern and central Saskatchewan. However, the efficiency of the canals is hindered by the growth of filamentous algae. The filamentous algae are a nuisance and block pumps, making it difficult for water to be distributed to all the desired locations within the province. Currently, a synthetic chemical, Magnacide H, is utilized to control the growth of the algae at the cost of approximately $1 million per year, which is high cost. This study, as such, seeks to review, evaluate, compare, and develop algal prevention and control technologies as well as propose a suitable canal design option that would minimize algae growth. Five field trips to Lake Diefenbaker Irrigation Canals were conducted in June, July, August, September, and October to ascertain the factors contributing to the canal's algal blooms. Tests were also conducted to determine the canal's suitability for irrigation to check whether the key parameters were within the optimal range. According to the test results, all the parameters were within the recommended Saskatchewan irrigation guideline. This study considers three algal prevention and treatment options: 1) Non-toxic dyes and colorants, 2) microbubbles and nanobubbles, and 3) Ultrasound technology. The use of microbubbles and nanobubbles technology was selected as the most suitable option. Although highly efficient, the other options failed because of their high costs and low location suitability. Furthermore, the study recommends that the modified canal design be deeper, narrower, sloped, or trapezoidal. Such a design is recommended because it can limit the amount of sunlight entering the water. In addition, deepening the canal's edges with an inclination ratio of 2:1 can help control the growth of algae by minimizing the number of shallow areas that receive sunlight penetration. As research and testing for algal control and prevention methods are still relatively new, further research is required to understand the effectiveness of algal control and prevention technologies fully.