6.4 Adopt or update local ordinances to provide guidelines for stormwater pond management

Key Message: Stormwater ponds and canals must be maintained to retain their nutrient removal efficiency, yet many lack consistent, long-term maintenance. Local ordinances can establish a framework for outreach, inspection, and certification to ensure that these systems are managed effectively to reduce nutrient pollution.

Importance

Sarasota County has approximately 4,666 stormwater ponds and over 600 miles of drainage ditches and canals that collect and treat suburban runoff before it discharges into local waterbodies. Most ponds are privately owned, while canals and ditches are primarily managed by public agencies. In older developments, pond maintenance—if it occurs—is typically the responsibility of homeowners or community associations. Common problems include algal blooms, invasive plant overgrowth, eroded shorelines, absent beneficial vegetation, and trash accumulation. Effective nutrient removal requires regular sediment removal, weed harvesting, and replanting.

Local ordinances would provide the authority to ensure long-term pond maintenance and nutrient management. Codified best management practices (BMPs) could be incorporated into private contracts with pond vendors. Municipal and county contractors could also follow these standards for public systems, such as the 372 miles of swales maintained under Sarasota County’s National Pollutant Discharge Elimination System (NPDES) permit (Sarasota County 2018b). Improved pond maintenance not only supports nutrient reduction but may also enhance pond biodiversity and boost nearby property values.

Overview

Typical dry and wet detention stormwater systems permitted by water management districts under state stormwater rules must be inspected and certified every five years by a professional engineer to ensure proper operation and maintenance (SWFWMD 2018). Certified systems are intended to provide reasonable assurance that stormwater BMPs function as initially designed and permitted for both water quality and flood protection. In practice, stormwater ponds and canals are often not maintained well, and professional inspections can be cursory and focused on aesthetics and flooding concerns, rather than water quality performance. In fact, flood prevention, not water quality, is the stated maintenance goal for all stormwater conveyance systems on private property under Sarasota County Code (Sec. 54-555).

Potential stormwater pond management issues (University of Central Florida 2015) may also include:

• Excess nutrients that stimulate algal growth;
• Carcinogenic hydrocarbons that can threaten aquatic life;
• Toxic heavy metals such as lead, zinc, iron, chromium, manganese, and copper;
• Floatable debris; and
• Bank erosion.

More detailed requirements and information on the cost and effectiveness of stormwater pond and waterway management are needed for property owners to improve maintenance outcomes for nutrients. Some communities have developed their own directives with the help of professional consultants and management experts. For example, the Gateway community in Fort Myers developed maintenance standards for its stormwater ponds, control structures, and wetlands that exceed the regulatory requirements of the South Florida Water Management District, Lee County, and the City of Fort Myers.

Approach

While education and outreach efforts to HOAs and residents (see Chapter 7.1 and Chapter 7.2) can help, codifying BMPs through local ordinances will increase compliance and clarity. Ordinances could include requirements such as:

• Maintaining vegetated buffers and littoral shelves as originally constructed
• Favoring mechanical harvesting over chemical treatments
• Restricting the use of well or reclaimed water to maintain dry-season pond levels

Clear maintenance guidelines would reduce conflict between planted vegetation management and routine mowing or herbicide application. Building codes for new developments could also require No Mow Zones around ponds with littoral shelves. In addition, adopting flood mitigation policies may yield co-benefits for water quality.

Sarasota County and municipalities could form an intergovernmental task force to evaluate and update current stormwater pond maintenance regulations. This collaborative process should engage residents, lake and landscape vendors, and regulatory staff. The outcome would be more robust, real-world management standards aligned with nutrient reduction goals and community expectations. This task force could also evaluate the cost-effectiveness of various management strategies (see Chapter 6.2).

For systems draining to nutrient-impaired waters, BMPs that improve nutrient removal should be incorporated into Reasonable Assurance Plans or Basin Management Action Plans. Local governments could partner with SWFWMD to enhance required inspections and ensure BMAP nutrient reduction goals are met. Parcels with certified, well-maintained systems could be eligible for stormwater utility fee credits.

Resources

Watershed Education Training Ponds Lakes and Neighborhoods

Status

No activity

Performance Measure

Local adoption of ordinances for stormwater pond management that enhance and perpetuate nutrient reduction efficiency

Experts or Leads

Abbey Tyrna, Suncoast Waterkeeper; Paul Semenec, Sarasota County Stormwater Division Manager; Jennifer Rudolph, Sarasota County NEST; Sandy Gilbert, START

Cost Estimate

$50,000-$100,000

Related Activities

Chapter 6.2, Chapter 7.1, Chapter 7.2