Dover/Plant City Water Use Caution Area

The District established the Dover/Plant City Water Use Caution Area (D/PCWUCA) and a Recovery Strategy to address issues that followed an “unprecedented” cold event. An assessment done in 2020 indicates that a Recovery Strategy is no longer required.


In January 2010 there was a cold-weather event in the Dover/Plant City area when temperatures dropped below 34 degrees for nine nights over an 11-day period.  

For local farmers, it is common practice to spray water on their crops during frost/freeze events, which is referred to as crop protection. The main crops in this area that require crop protection are strawberries, citrus, blueberries and plant nurseries. 

About 2.7 billion gallons of water was used during this 11-day period to protect crops. This significantly lowered the aquifer level and created many unforeseen problems. About 760 wells were negatively affected and 140 sinkholes formed in the area causing about $8 million in damages. To address these issues, the District established the D/PCWUCA which encompasses 259 square miles. 

Dover/Plant City Water Use Caution Area (D/PCWUCA)

The D/PCWUCA established restrictions for new Upper Floridan Aquifer groundwater withdrawals used for crop protection, new standards for well construction, and incentive programs to encourage growers to use best management practices for cold protection through the Facilitating Agricultural Resource Management Systems (FARMS) program. In addition, a Minimum Aquifer Level Protection Zone (MALPZ) encompassing approximately 66 square miles was also established within the water use caution area where no future cold protection quantities are allocated. The protective measures are outlined below:    

  • Daily restrictions are placed on groundwater withdrawals used for cold protection within the MALPZ and surrounding area.  
  • Well construction permitting requirements are established for wells drilled within and surrounding the D/PCWUCA. New wells are to be constructed to better standards, avoiding future potential cold protection impacts.  
  • The District grants 75% funding for projects that decrease groundwater use for cold protection within the D/PCWUCA through the FARMS program.  
  • The District created a tool to better assign well pumping responsibility to water use permittees, so that domestic well owners in the area who are adversely affected by cold protection events are appropriately mitigated by permittees.  
  • The District also improved its ability to monitor groundwater levels in “real-time” in the recovery area and to react to cold protection events by installing automatic meter reading devices on all cold protection withdrawals. Data from these devices is collected by the District and used to better understand and predict water usage.   
  • The District also improved its notification system to growers in the area of potential frost/freeze events to allow them greater time to prepare. 

Recovery Strategy

The objective of the District’s Recovery Strategy is a 20% reduction in groundwater withdrawals used for cold protection for a frost/freeze event that was based on the unprecedented 2010 event. Growers were assured during the development of this Recovery Strategy that it was not the District’s intent to limit the growth of agriculture in the region and that alternative methods of cold protection would be required if acreage increases were proposed. However, a recent assessment completed in 2020 determined the chance of the 2010 11-day event reoccurring was once in 570 years.

Area Assessment

The 2020 assessment the District conducted was a comprehensive analysis that evaluated a variety of relevant factors such as long-term trends associated with groundwater levels, agriculture production, weather trends, and the frequency of frost/events.  In evaluating the status of the minimum aquifer level, the assessment utilized an updated computer modeling frost/freeze event that captured 95 percent of the cold protection events that have been observed since the late-1800s. The District concluded the minimum aquifer level was being met and the protective measures required by the D/PCWUCA should remain in place.   

Since the minimum aquifer level is being met, the District reevaluated the need to implement the currently required Recovery Strategy. As part of this evaluation the District identified key trends such as an increasing warming trend in air temperature, decrease in frost/freeze events, an ongoing and projected decrease in agricultural production in the area over the next 30 years due to urbanization, and increasing Upper Floridan aquifer water levels over the last decade. In addition, staff reevaluated whether it was appropriate to base a Recovery Strategy on an unprecedented event with an approximate occurrence of once every 570 years. As a result, it was determined that utilizing a frost/freeze event that captures 95 percent of the frost/freeze events was a more reasonable approach to address the area’s resource concern. Based on the assessment utilizing the updated frost/freeze event, maintaining the D/PCWUCA, and the trends that were identified in the analysis, the District is recommending the Recovery Strategy be eliminated. 

The District will ensure the protective measures remain in place to prevent resource impacts from occurring due to the potential of increased withdrawals during more common frost/freeze events. In addition to the protective measures previously identified, the District will continue to conduct annual assessments to monitor groundwater withdrawals and minimum aquifer levels, crop production trends, new sinkhole formation and dry well reports in the area. The FARMS program will continue to provide incentives to decrease the use of groundwater for cold protection and other crop production quantities in this area. These recommendations will be presented to the District’s Governing Board during the summer of 2021.