8.1 Restore and enhance wetland and shoreline hydrology and habitats to increase nutrient uptake and storage by plants

Key Message: Protecting, restoring, and enhancing wetlands and shorelines is among the most cost-effective tools available to reduce nutrient pollution and mitigate climate impacts. Public policy, regulation, and outreach should support innovative approaches to restoring canals, ditches, and shorelines to deliver multiple ecosystem benefits.

Importance

The natural hydrologic function of wetlands filters, stores, and processes water and nutrients, offering both water quality protection and flood mitigation. Coastal wetlands—such as mangrove forests and salt marshes—occupy the vital land–water transition zone and play a central role in stabilizing shorelines, absorbing storm surges, and filtering runoff. They also provide critical habitat for wildlife and nursery areas for recreational and commercial fish species. Coastal wetlands store carbon in plants and soil at rates up to 25 times greater than temperate and tropical forests (McLeod 2011). Restoring freshwater and coastal wetlands and modifying manmade ditches and shorelines can help reestablish natural water flow, reduce nutrient pollution, and curb harmful algal blooms. Vegetation harvesting from ditches and canals is another effective maintenance strategy. In 2024, Sarasota County Public Works removed 257,647 pounds of nitrogen through monthly vegetation management.

Overview

Wetlands

Historically, freshwater and coastal wetlands in Sarasota County have been heavily altered through dredge-and-fill activities to support development. Land was cleared, marshes were drained, and shorelines were armored to reduce mosquitoes and make way for buildings. A 2003 shoreline habitat survey found that 55% (225 miles) of shoreline between Anna Maria and Venice Inlet is hardened with bulkheads and riprap (Serviss and Sauers 2003). Wetlands currently make up only 37% of shorelines, though their areal extent has remained stable due to regulatory protections and ongoing restoration (Leverone et al. 2017).

The SBEP and CHNEP have restored thousands of acres of wetlands in Sarasota County over the past three decades. These efforts include native plantings, invasive species removal, shoreline enhancements, habitat creation, and hydrologic restoration. Local governments and volunteers have improved over a mile of shoreline at bayfront parks and preserves. For example, Sarasota County added wetlands and native shoreline plantings at Red Bug Slough Preserve, with projected monthly nitrogen reductions of 30–68%. In 2023, the City of Sarasota reopened the Bobby Jones Golf Course & Nature Park—now its largest green space at 307 acres—with 20 acres of wetlands, 14.5 acres of native grasses, and 49,000 aquatic plants. This site filters stormwater from 5,800 acres, removing an estimated 900 pounds of nitrogen and 300 pounds of phosphorus annually.

Other recent and planned wetland restoration projects include North and South Lido Key, Thaxton Preserve, Murphy Marsh, Myakka Headwaters Preserve.

Two large-scale constructed wetland projects treat runoff and enhance flood protection. Sarasota County’s Celery Fields Regional Stormwater Facility (CFRSF) created 440 acres of wetlands and ponds to reduce flooding and improve water quality in Phillippi Creek. The facility also serves as a birding destination and recreation area. Following the CFRSF model, Sarasota County and SWFWMD are developing a similar wetland system to redirect excess freshwater from Cow Pen Slough to Dona Bay. Phase 1 removed 18,000 pounds of nitrogen, and Phase 2 removed 1,800 pounds. In 2024, 6,981 tons of water hyacinth were harvested from the project area, removing 7,636 pounds of nitrogen. The Dona Bay Project received the 2024 Excellence Award from the Florida Stormwater Association.

Ditches and Canals

The force of piped and channelized runoff causes erosion, inhibits shoreline vegetation, and degrades water quality. A Sarasota County study of Phillippi Creek tributaries recommends retrofitting stormwater canals to improve flood control, water quality, and habitat with less maintenance (WEIS 2019). Typical maintenance involves herbicide application, mowing, canal and culvert cleaning, obstruction removal, and occasional dredging. However, dredging and straightening creeks to maximize drainage—or clearing and leaving bank vegetation to decay in the ditch—can be counterproductive for water quality and habitat protection.

Instead, manmade ditches and altered shorelines can be restored through a variety of enhancement techniques. Strategic removal of weirs or dams in natural streams can improve water quality. Shorelines can be stabilized with organic-rich soils, native vegetation, and trees. For example, woody vegetation in suitable areas can stabilize banks more effectively than turf grass, reduce mowing costs, and increase nutrient uptake (Figure 8.1.1).

Regenerative stormwater conveyance systems offer in-stream treatment using a series of pools and riffles built over sand or gravel beds, enabling filtration and microbial nutrient reduction. Where space allows, reintroducing meanders to straight ditches can reduce flow velocity and enhance nutrient processing. In-stream features such as snags, holes, and fish ladders can improve habitat and connectivity.

These enhancements help restore ecosystem functions, increase long-term stability, and reduce maintenance costs—priorities identified by Sarasota County Stormwater Environmental Utility, CHNEP, and SBEP. As available land for water quality and flood reduction projects becomes limited, maximizing the utility of existing systems is critical.

In 2019, multiple partners collaborated on the ecological restoration of Warm Mineral Springs Creek and Salt Creek using these best practices. Removing invasive plants and sediment while stabilizing the shoreline improved manatee habitat, reduced erosion, and minimized future maintenance needs.

In 2022, Sarasota County received a $14.5 million National Oceanic and Atmospheric Administration (NOAA) grant for the Alligator Creek Stream Restoration Project, which will enhance water quality and habitat across 42 acres by stabilizing banks, removing stream barriers, and transforming the corridor. Alligator Creek—a tidal basin covering 11 square miles and comprising 20% of the Lemon Bay watershed—has experienced habitat loss and altered hydrology due to nutrient loading and erosion. By 2027, the project will deliver 54 acres of new functional wetlands, 3 miles of restored channels and lagoons, 76 acres of snook and tarpon rearing area, and removal of 1,500 pounds of nitrogen annually (Boone and Kiefer 2022). Similar designs are in development for northwest Phillippi Creek.

Living Shorelines

In 2018, ESA Scheda and the SBEP prepared a living shoreline guidance document for homeowners, marine contractors, regulators, scientists, and coastal engineers, outlining nature-based shoreline stabilization strategies. The document helps evaluate vegetated shorelines as viable stabilization options. Over 50 public waterfront parcels in Sarasota County have been identified as candidates for living shorelines (ESA Scheda 2018). Most of these are suited to seawall enhancements or hybrid designs combining natural and structural elements (Dobbs et al. 2017) (Figure 8.1.2). As of fall 2023, SBEP has plans for $1.1 million in shoreline restoration at three county sites: Dr. MLK Jr. Memorial Park, Longboat Key Bayfront Park Shoreline, and City of Sarasota Bayfront Park.

Unlike hardened shorelines, living shorelines allow upslope migration of wetland ecosystems as sea levels rise, enabling plant species to adjust to changing depth and salinity conditions. Coastal development and shoreline armoring have caused a “coastal squeeze” that prevents these ecosystems from migrating inland. Where protected uplands exist, living shorelines can preserve and restore beaches, mangroves, and salt marshes in the face of rising sea level, while providing a natural filtration buffer for runoff (Figure 8.1.3).

With Sarasota Bay’s limited natural shoreline and the strong water quality benefits of mangrove and other vegetated shorelines, these habitats are crucial to nutrient filtration. However, mangroves face pressure from redevelopment and illegal or excessive trimming. Suncoast Waterkeeper’s Mangrove Rangers program conducts annual canopy health surveys, and their “Eyes on the Suncoast” app enables residents to report trimming violations. Between 2023 and 2024, 25 cases of illegal mangrove trimming or removal were reported—only one resulted in a fine.

With many aging seawalls ongoing coastal redevelopment in the region, broad public outreach is needed. Florida Sea Grant, Sarasota County’s NEST Program, SBEP, and CHNEP promote living shorelines and mangrove protection through presentations and brochures (Figure 8.1.4). Florida Sea Grant offers a two-day Living Shorelines Course covering design, permitting, installation, and cost-benefit analysis, including CEUs for marine contractors.

Living shoreline permits issued by USACE and FDEP have specific design standards. Cities and counties should codify and streamline their own permitting processes to encourage adoption. Intergovernmental coordination and agreement on design and permitting of living shorelines can facilitate progress and prevent undesirable fill material from contaminating creeks and bays.

Approach

Drainage Canal and Wetland Enhancement

• Install pilot projects of varying scale with robust monitoring to evaluate nutrient removal and cost-effectiveness. Techniques may include constructed wetlands, native vegetation, meanders, and regenerative stormwater conveyance systems. USACE maintains a library of relevant tools.
• Assess Phillippi Creek and Gulf Gate Golf Course systems for hydrologic and habitat restoration opportunities that improve water quality and mitigate flooding.
  Convene a regional network of stormwater professionals to host workshops, webinars, and design charrettes focused on real projects.

Shoreline Protection and Restoration

• Form a local intergovernmental task force to create design criteria and permitting pathways for living shorelines and seawall enhancements.
• Expand training for marine contractors on permitting, seawall removal, and installation of living shorelines.
• Construct demonstration projects in highly visible locations to showcase aesthetics and performance (see Chapter 7.4).
• Increase outreach to homeowners and marine contractors, using suitability assessments (Dobbs et al., 2017) to target efforts.
• Strengthen mangrove protection enforcement and penalties. Review current policies and propose improvements.

Resources

• Living Shorelines Guidance for Sarasota Bay Watershed
• Living Shorelines Training for Marine Contractors
• Sarasota Bay Estuary Programs Five Year Habitat Restoration Plan
• Phillippi Creek Open Channel Assessment Project

Status

Planning

Performance Measure

• Establishment of a regional working group for drainage ditch enhancement and maintenance BMPs
• Streamlined permitting and education for living shorelines and seawall enhancements
• Number of acres restored, miles of shoreline enhanced, and pilot projects implemented
• New data on nutrient removal and habitat benefits of rehabilitation designs

Experts or Leads

Ryan Gandy, Sarasota Bay Estuary Program; Jennifer Hecker, Coastal & Heartland National Estuary Partnership; Tom Ries, Ecosphere Restoration Institute; Fara Ilami, FWC; Armando Ubeda, Sea Grant Agent Sarasota County; Brianna Dobbs, City of Sarasota; John Keifer, Black & Veatch; Paul Semenec, Sarasota County Stormwater Environmental Utility; Jennifer Rudolph, Sarasota County Neighborhood Environmental Stewardship Team

Cost Estimate

$1,000,000+

Related Activities

Chapter 7.4