Herbicide Application

Algae Blooms

Most algae in District canals is not harmful to human health and provides a food source for aquatic life 

Algae are simple organisms that grow through photosynthesis, a process by which sunlight is used to metabolize nutrients. Algae are a basic component of the food chain and can be found in marine, estuarine, fresh water lakes, canal systems and even swimming pools. Algae appear as green, red or yellowish-brown particles that float on the water surface.

Most algae found in District’s canals, while visually unappealing, are not harmful to human health. However, some types, like “Blue-green” algae, which is a cyanobacteria, secrete toxins that may be harmful. The algae toxins can be inhaled by people living around the waterbody. It will aggravate respiratory illnesses like asthma. Symptoms of exposure to toxic algae include difficulty breathing, wheezing, skin rashes, headaches, and possibly tingling in the fingers and toes if the water was consumed.

Although algae are a normal component of an aquatic ecosystem, nutrient-rich waters warmed by the summer sun, provide a favorable medium for the overgrowth. This overgrowth is called an ‘algae bloom’. Herbicide or chemical treatments for the removal of algae uses a heavy metal compound that may adversely impact the waterbody. Since algae is a food source for aquatic animals and does not impact flood control operations, the District does not regularly treat its canal system for algae blooms. Most algae growth in our canals is harmless and will dissipate on its own or will be flushed out after a heavy rainfall.

Additional information on algae toxins can be found at the US Environmental Protection Agency and the Center for Disease Control website at www.epa.gov/nutrientpollution/harmful-algal-blooms.

aerial canal photo

LWDD’s Water Conservation Role

Comprehensive water conservation requires proper canal operations

South Florida is fortunate to receive over 50 inches of rainfall a year on average. Most of that amount is concentrated during the 6-month rainy season (May-October). While much of the runoff from these rains is discharged to the ocean to avoid flooding, a significant amount soaks into the ground and recharges the freshwater aquifers that supply our drinking water wellfields, lakes and wetlands.

In order for large populations of people to live safely in south Florida, a massive regional water management system is required that must balance the water supply needs for both urban and agriculture uses and flood control. Without adequate drainage, human health and safety would be jeopardized and extensive property damage could occur. Similarly, if regional groundwater levels were not properly maintained, wellfields would be unable to deliver water to homes and businesses and the underground inland migration of salt water from the ocean could permanently contaminate the drinking water supply rendering it unsafe for potable uses. Water conservation efforts by the District help mitigate for some of the water supply issues our region experiences.

The District’s large network of canals play a critical role in conservation by maintaining groundwater levels which in turn supports the water levels in lakes, ponds and wetlands across the region. During dry periods, groundwater levels tend to slowly fall in response to low rainfall and high evaporation. When this occurs, water managers in the region look to large regional storage areas like the Water Conservation Areas in the Everglades or to Lake Okeechobee as a source of supplemental water. Water from these sources is released into the canal network to raise the level of the water in the canals. This water in turn seeps through the sandy soils to recharge groundwater and return the water table to its normal elevation.

The District has successfully managed water conditions in the area for over 100 years. This collective operational experience in water control operations is unrivaled in the State. Numerous manual and automated readings of water levels across the 500 miles of canals are collected daily. Depending on conditions, staff make decisions to open water control gates and release water to minimize the possibility of flooding, or to hold back water and pump additional flow into the system for water supply purposes. In each of these situations, staff personally mobilize to the individual water control sites and make necessary operational changes.

Future water conservation enhancements are planned for the District. The installation of SCADA, an acronym for Supervisory Control and Data Acquisition systems, is scheduled to be completed by 2018. The SCADA system will essentially automate the operation of water control gates and pumps throughout the 200 square miles of the District’s service boundary. The system will link 10 of the District’s most critical water control structures to a wireless, hurricane hardened communication system that will automate the remote operation of the gates and pumps to react immediately in real-time to significant changes in water levels. If water rises too fast, the gates will automatically open (day or night). Similarly, if levels are too low, water supply pumps will activate to restore normal water levels. The automated process will occur more frequently and many times faster than staff can react and travel in the field. The implementation of the new SCADA system will significantly reduce overall response.

Comprehensive water conservation requires efficient operation and  management of drainage canals. Avoiding discharges to the ocean when possible and maintaining canals at appropriate elevations is an important water conservation role the District contributes in Palm Beach County.