The County experienced two historic rainstorms in 2017 between the dates of August 25 and September 10. While these two storm events covered a great deal of the County, some areas received more than 20 inches of rain during this short period of time. Rainfall at this intense level coupled with Hurricane Irma’s storm surge exceeded the carrying capacity of our natural and manmade drainage features. Consequently, the County is working on its stormwater system using the multi-faceted approach explained below.
Initial Flooding Assessments Map
This map depicts the study areas for the initial flood evaluation. Specifically, the outlined areas are the watersheds that caused or contributed to neighborhood flooding during the rainfall events of August 25-27 and Hurricane Irma. The different colors indicate the consultant chosen to conduct the work. Individual neighborhoods that experienced flooding are not shown.
Click on the map below to load an interactive map with data collected from the initial flood assessments.
Phase 3: Flooding Long Term Recovery
The goal is to establish a plan to reduce flooding on a larger regional scale. It is important to understand that water management in our area is a complex system and has to be addressed holistically. What you do in one part of the system or watershed can have unintended consequences elsewhere. To consider larger projects such as dredging, diking, diverting, berming or storing water, a series of tools are used to evaluate projects to ensure the project would perform as intended. Those with the most promise are then selected for budgeting and implementation. This next step includes grant applications, land acquisition (if necessary), permitting, design, bid and construction. Options will be presented to the Board at a to-be-determined date in 2020.
Lee County Flood Mitigation Plan
On October 16 the Lee County Board of County Commissioners approve award a contract to AIM Engineering & Surveying, Inc., in the total amount of $1.7 Million to provide consultant services to establish plans and recommend projects to reduce flooding on a larger regional scale, to include the development of the Lee County Food Mitigation Plan to cover Lehigh Acres, Southeast Lee County, South Lee County, and Whiskey Creek watersheds.
This long term plan will require a comprehensive evaluation of County watersheds, including hydrologic modeling, to predict flood level of service and ensure that all benefits of potential improvements are considered. Improvements considered will be evaluated utilizing a thorough methodology to ensure they function as intended. The comprehensive regional model will be developed to identify areas of flood high risk and to determine regional effects of proposed flood control projects. The model will be calibrated and validated using the available measured data for the years 2016 and 2017 with a focus on the wet seasons.
The figure above shows a potential model extent. The proposed northern boundary is the Caloosahatchee River. Model limits may be adjusted based on analysis of the hydraulic and topographic data and in consultation with the County and team members.
AIM will calibrate the model systematically adjusting a limited number of model parameters that are found to have the largest impact in the accuracy of the results. The study evaluation period will be from June 2016 to November 2017.
Once the regional model is developed and calibrated, AIM will incorporate in the regional model a maximum of 40 selected projects that will encompass all four planning areas, including Whiskey Creek, Lehigh Acres, South Ft. Myers, and Southeast Lee County. Each project would be either simulated independently or in combination with other project(s) if it is considered appropriate, identifying those enhancements that could be pursued in a partnership with other Stakeholders.
The Lee County Flood Mitigation Plan effort is expected to produce results in 2020.