Lake Okeechobee Drought 2007

Droughts Self-propagate, Just Like Wildfires

Excerpt from Ghent University on the website

Up to 30% of the rainfall deficit can be caused by “drought self-propagation,” the DRY–2–DRY European Research Council (ERC) project shows.

Unlike other weather extremes such as hurricanes or winter storms, droughts affect humans in most climatic zones around the world; from the arid steppes of the Sahel to the humid rainforests of Amazonia. Moreover, droughts are expected to intensify in many regions following global warming. The United Nations has recently described drought as “the next pandemic,” suggesting that the associated risks are currently overlooked. It is thus crucial to improve our understanding of drought, and particularly its causes, in order to be able to predict its future risk and enable adequate societal adaptation.

Rainfall deficits eventually manifest as dry soils. The land surface, though, also takes a very active role in the generation of rainfall, as it supplies moisture to the atmosphere through evaporation. What happens during a soil drought when far less water is evaporated than usual? It has been hypothesized that this can enable droughts to expand by themselves, as they provide less moisture for precipitation, not just locally, but also downwind. Until now, evidence of this drought self-propagation, fueled by the drying soils, had remained elusive. In a new study, published in Nature Geoscience, led by the Hydro-Climate Extremes Lab (H-CEL) at Ghent University (Belgium), this evidence is provided for the first time.

The authors analyzed the largest 40 droughts in recent history. For each event, the authors tracked the air over the drought regions as the drought area expanded. This allowed them to compute how much of the downwind rainfall deficits were caused by the upwind drying of the soils. Their conclusion was that in individual months, up to 30% of the rainfall deficit can be caused by this drought self-propagation. As Dominik Schumacher, first author of the study, states: “In essence, droughts behave similarly to wildfires: while fires propagate downwind by igniting more and more ‘fuel’ in their surroundings, droughts do so by reducing their own rainfall supply through the drying of the land surface.”

The authors find the strongest self-propagation in subtropical drylands, such as in Australia and Southern Africa—in these regions, the limiting effect of low soil moisture on evaporation is strongest. By definition, water is already scarce in drylands, yet these regions sustain a considerable fraction of the global human population and are also used extensively for farming.

Therefore, as drylands are projected to expand in light of climate change, the self-propagating character of droughts may lead to even larger and more rapidly evolving events in the future, and further exacerbate water scarcity as well as the attached socioeconomic and environmental consequences.

To find out more about current and historical droughts in Florida visit

Graph of drought in Florida from 2000 to present

Water drop image

April is Water Conservation Month

Palm Beach County Commission passed the Mandatory Year-Round Landscape Irrigation Conservation Ordinance. The provisions of this Ordinance apply to all users providing landscape irrigation from all water resources within the boundaries of unincorporated Palm Beach County with the following exceptions:

  1. Use of Reclaimed Water, which may or may not be supplemented from another source
  2. Irrigation for Agriculture
  3. Irrigation at Athletic Play Areas

Link to: PBC ‘s Year-Round Irrigation Ordinance


Aerial canal photo

LWDD Operations and Water Conservation

Florida is fortunate to receive over 50 inches of rainfall a year on average. Most of that amount is concentrated during the six-month rainy season (May through October). While some 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.

For large populations of people to live safely in south Florida, a massive regional water management system is required to balance the water supply needs of urban areas and agriculture against the requirement to maintain flood protection. If we did not provide adequate drainage to the region, 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 our homes and businesses, or worse yet, 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 LWDD help mitigate some of the water supply issues our region experiences.  The large network of LWDD canals plays 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 rain 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 water in the canals. This water in turn seeps through the sandy soils to recharge the groundwater and returns the water table to its normal elevation thus helping to protect drinking water supplies.

The LWDD’s efforts, to manage drainage canals at appropriate elevations to balance water supply needs and avoid ocean discharges when possible, plays a key role in comprehensive water conservation for South Florida.

Photo of low water level in pond

Expect Lower Water Levels In Ponds

It may surprise some residents within the Lake Worth Drainage District (LWDD) boundary to learn that the waterbody that is often referred to as the community lake is in fact a stormwater management pond. A stormwater management pond is an engineered structure built to gather surface water runoff (rainfall). The pond temporarily stores water and then releases it at a controlled rate until the designed water elevation in the pond is achieved.

Although stormwater ponds can be an attractive feature for the community, this may not be the case during Florida’s dry season that runs from approximately October to May. During the dry season it is expected that ponds will have a lower water elevation which may expose sandy banks and reduce the ability to utilize the pond for lawn irrigation. Since rainfall is the primary way stormwater ponds receive their water supply, and water from the LWDD canal system cannot be used to recharge ponds, these conditions will continue until additional rainfall occurs.

However, during the dry season when water levels are lower, it is the ideal time of year for communities to conduct inspections of their drainage infrastructure and make any necessary repairs. To ensure you have a well-maintained drainage system, communities should:

  • Keep swale areas free of debris & vegetation and mow regularly.
  • Clear trash and debris from street drains.
  • Inspect discharge points/outfalls into LWDD canals.
  • Have underground drainage pipes inspected every three to five years.
  • Exercise operable discharge control structures by opening and closing them a few times.
  • Visually inspect fixed discharge control structures for structural integrity and potential blockages.

More information on community drainage maintenance can be found on LWDD’s website at (Link: ).