Engineers use a combination of physical, chemical, and operational measures to prevent algae growth in open reservoirs. One common approach is to design the reservoir with liners and steep side slopes, which limit areas where algae can easily attach and grow. Covers or floating shade structures are sometimes used as well, since reducing sunlight directly lowers the conditions algae need to thrive.
Chemical control is another tool. Disinfectants such as chlorine are added in carefully managed doses to maintain water safety and suppress algae development. In some systems, algaecides may be used, but these are applied cautiously to avoid affecting water quality. Operational practices also make a difference. Maintaining good circulation and turnover of water helps prevent stagnant zones, which are ideal for algae growth. Aeration systems, mixers, or pumps are sometimes installed to keep water moving and oxygen levels stable.
