How to Control Algae in Water Impoundments, Reservoirs and Dams

Water Management  a perennial problem| water impoundments | reservoirs | dams

The management of large volumes of water in reservoirs, dams and water impoundments is a perennial problem for water managers. Frequently these water impoundments are subject to run- off of fertilizers and other nutrients from agricultural land, or from storm water and other sources. These excess nutrients combined with relatively high water temperatures experienced in Australia are the perfect breeding ground for algae. Algal blooms are frequently experienced. Algal blooms often degrade stored water in reservoirs, dams and other water impoundments.

Offensive smells, low dissolved oxygen and blue green algae | cyanobacteria | fish | smell

Some species of algae release toxins (cyanobacteria). All blooms decrease dissolved oxygen in the water which in turn effects fish within the impoundment. The visual amenity frequently declines and there is often an offensive smell associated with the blooms. Constant monitoring is essential and attacking the algae before it turns into a major bloom is essential. Coptrol is ideal for this task.
Recommended dose rate
If algae is a problem in your drip irrigation or in your water source follow this 5 step method to keep your water clear and bright.

1.  First identify the algae present. Please use our guide here for more information. This page explains common algae within Australia.

2.  Now calculate the volume of water to treat. Ignore depths below 1 metre. Please refer to our “Quantities” page to calculate the amount of water to treat.

3. Next calculate the amount of Coptrol needed. An easy way to calculate is:

  • If the algae is fine and free floating use 2 mL of Coptrol per 1000 Litres (1 cubic metre) of water. That is equivalent to 2 Litres of Coptrol per 1000 square metres of surface area.
  • If the algae is long and stringy use 5 mL  per 1000 litres of water (1 cubic metre) or 5 Litres per 1000 square metres of surface area.

4. Dilute the required amount of Coptrol using a 1:10 or even a 1:20 Coptrol water dilution.

5. The best application method is by spraying. Apply on a sunlit wind free day when algae first appear. If this is impractical, please refer to our “Application” page on how to apply Coptrol.