THE ENVIRONMENTAL PROTECTION AND GROWTH MANAGEMENT DEPARTMENT AND THE ENVIRONMENTAL PLANNING AND COMMUNITY RESILIENCE DIVISION (EPCRD) RECOMMEND APPROVAL OF THE ABOVE MOTIONS.
This item supports the County Commission’s Value: Encouraging investments in renewable energy, sustainable practices and environmental protection; and Goals to: 1) Seek funding for, implement policies and pursue projects promoting, the use of alternative energy, resource conservation, sustainable practices and environmental protection; 2) Proactively lead in the planning , design, and construction of projects to support community resilience and climate adaptation, including coordination with other entities to foster resilient design as part of all local and regional projects; and 3) Increase water quality protection efforts and lead creative approaches to water storage and aquifer recharge, as well as diversification of water supplies regionally.
To ensure the resiliency of current and future infrastructure investments, it is necessary to modernize many aspects of regional planning and licensing requirements. With the influence of climate change, and the impacts of sea level rise in particular, no longer is it prudent to rely solely upon historic and current environmental conditions as the basis for infrastructure planning, design and permitting.
To further resilience planning in Broward County, on November 10, 2015, the Broward County Board of County Commissioners accepted the Updated Regional Sea Level Rise Projection (2015) of the Southeast Florida Regional Climate Change Compact, and directed staff to use the updated projection as the basis for sea level rise adaptation planning (Item 32). Consistent with this direction, staff is preparing to update the County’s Average Wet Season Water Table map for future conditions predicted in 2060-2069, as an important step in formally addressing future flood risk in the design and licensing of surface water management systems in Broward County.
The Environmental Protection and Growth Management Department is responsible for protecting the waters of Broward County in accordance with Chapter 27, Article V of the Broward County Code of Ordinances, pertaining to water resource management. These protections include licensing the construction and operation of surface water management systems and the establishment of design criteria to ensure adequate flood and water quality protections are provided by land and site development plans for the life of the project.
There are a number of physical and environmental conditions that must be addressed to ensure that drainage and surface water management systems achieve appropriate storage and water quality treatment levels. Perhaps the most fundamental of these is the depth from surface to groundwater, a parameter that influences soil storage, flood condition, site-specific water management options, and the effectiveness of drainage system components. The Board of County Commissioners adopted design criteria including Plate WM 2.1, Average Wet Season Water Table, to reference in developing site plan designs to address storm and rainfall events and surface water management requirements.
During the last several decades, this approach has provided a strong basis for effective water management and strong water quality protections in Broward County. However, the current average wet season water table map cannot account for conditions expected during the lifecycle of new structures or provide an appropriate tool for long-term infrastructure and site planning. Due to the porous geology that underlines our region, sea level rise has dramatic implications for regional hydrology and flood protection measures. Measured increases in regional sea level have contributed to an increase in regional groundwater elevations measured in the coastal area, a condition that compromises the function of drainage wells and retention ponds, necessitating the installation of pumps and the retrofit of recently constructed systems to achieve water management requirements. This trend will continue as sea level continues to increase, with an estimated 24 inches of additional rise possible in the 2060-2069 timeframe. The porous nature of our geology means that changes in groundwater elevation are predicted to extend several miles inland. Establishing and applying Future Conditions Average Wet Season Water Level map for conditions predicted in 2060-2069 will ensure that these expected increases are accounted for in the design and construction of surface water management systems and will help to ensure that these investments will deliver the necessary level of flood protection and water quality treatment during their expected useful lifespan. This map will also serve as a key step forward in advancing the resiliency standards and investments needed across our region and will ultimately help to protect both public and private infrastructure, preserve the quality of our environment, and ensure a vibrant and competitive economy.
The proposed map is supported by the Water Advisory Board to the Broward County Board of County Commissioners and its Technical Advisory Committee.