How to Prevent Algal Blooms in Dams

If preventive strategies aren’t considered, fighting algal blooms can be expensive and ineffective. Dense blooms can quickly spiral out of control and greatly impact the environment, sometimes to the extent that recovery is long and water quality is affected for years. 

Unfortunately, dams are prime locations for harmful algal blooms due to various characteristics, including stagnant water and agricultural runoff. Learning to prevent dense blooms is vital for maintaining water quality and protecting aquatic life.

What is an Algal Bloom?

Algal blooms are thick green or blue-green algae on the water’s surface. While seemingly harmless in appearance, they can be a risk to human and animal health. They grow rapidly and distress aquatic ecosystems by depleting oxygen and blocking sunlight, among other harmful effects. 

Typical algal blooms found in dams include the following: 

  • Blue-green (cyanobacteria) algae
  • Planktonic algae
  • Filamentous algae

The Importance of Preventing Algal Blooms in Dams

Algal blooms quickly destabilise water quality and can lead to biological, environmental, and economic complications. Harmful algal blooms (HABs) deplete oxygen to the extent to which dead zones are created–areas where fish, plants and other organisms struggle to survive.

As marine ecosystems suffer, water quality decreases and the treatment process becomes more expensive and complicated. However, as their impact is severe, there is no other choice but to mitigate algal blooms.

  • Toxin Production: Certain species produce toxins that can cause human and animal illnesses.
  • Respiratory Irritation: Blooms may release airborne toxins, which can cause respiratory issues and worsen conditions like asthma. Algal toxins can kill if inhaled or ingested.
  • Aquatic Organisms Mortality: Dam conditions without enough oxygen, sunlight, or warmth can kill fish and plants.
  • Food Chain Disruption: Algal blooms weaken ecosystems and interrupt natural food webs, impacting biodiversity.
  • Drinking Water Contamination: Toxic species make drinking water difficult to consume, leading to health issues and expensive treatment processes.

This is just a sample of what algal blooms can do to a dam and its environment. We can reduce algal blooms and their consequences by addressing the underlying issues. Knowing what method is best relies on multiple factors such as cost, algal species and the water body.

Methods to Preventing Algal Blooms in Dams

The following strategies to control harmful algal bloom use a combination of preventive and reactive methods.

Aeration and Mixing

Adding oxygen to the water through aeration is a popular way to limit the growth of algae. The oxygen is distributed throughout the water, encouraging aerobic bacteria that breaks down organic matter and reduces nutrients used by algae.

Sub-surface aerator air stations disperse oxygen bubbles evenly, allowing them to circulate large bodies of water and introduce oxygen more effectively. Aeration systems such as this are ideal for long-term oxygenation management.

Nanobubble aeration technology is a particularly effective aeration method for introducing oxygen into water without harsh chemicals or invasive equipment. Nanobubbles are nanoscopic and stay suspended in the water column for weeks or months. Nanobubbles easily reach deep layers to transfer impressive amounts of dissolved oxygen.

Mixing combines stratified layers to balance temperature and oxygen levels. In dams, the bottom is often cold and anoxic, which fosters algae growth.

Controlling Excessive Nutrients

Large algae blooms are often caused by nutrient buildup, which enters water in various ways, including agricultural runoff and urban activity. Nitrogen and phosphorus are among the most common nutrients that enter water bodies, providing a steady source of food for harmful species of algae.

Biotism is our range of probiotics that increase populations of “good” aerobic bacteria. These bacteria consume nutrients like nitrogen and phosphorus in your dam, effectively starving algae of the food sources they need to grow. It’s 100% natural and also helps remove the sludge algae uses as fertiliser.

To prevent potent toxins from mixing with freshwater environments, buffer zones made from shrubs and trees can be planted around the circumference of dams. They offer a natural solution to catching runoff and filtering it before reaching the water.

 

Learn more about eradicating algae from your dam here