Erosion Control & Bank Stabilization in Sarasota, FL

Erosion control and bank stabilization in Sarasota means one thing above all: keeping sand on the bank and out of the pond, canal or bay below it. The land here is flat, but it is cut through with retention ponds, drainage ditches, swales and canals, and every one of them has a graded edge. Bare sand on those edges moves easily in a summer storm. As erosion control contractors, our job is to cover that ground quickly and hold it until grass has rooted, using hydromulch, bonded fiber matrix, erosion control blankets or a mix of them.

Why flat ground still erodes

It seems odd to worry about erosion where the city's elevation is about 20 feet. But Sarasota's rain is concentrated: about 60 percent of the year's total falls from June through September, with August alone averaging 9.11 inches. Afternoon storms dump water fast, and it runs off rooftops, driveways and compacted fill toward the nearest low spot. That flow concentrates in swales and on pond banks, and loose sand with almost no clay or silt to bind it does not resist much.

Sarasota County's code sets lot side slopes at a maximum of 4 horizontal to 1 vertical and requires drainage swales to have a longitudinal slope of at least 0.2 percent. Those gentle numbers still produce long faces of bare sand on new construction, and bank faces around ponds are often steeper.

Choosing the right cover

• Hydromulch. Seed, wood fiber and tackifier sprayed together in a single slurry. It works on gentle slopes and broad areas where water sheets across rather than channels. It is the least expensive cover and goes on with the same truck as the seed.
• Bonded fiber matrix (BFM). A heavier hydraulic mulch with a stronger binder that forms a tougher, longer-lasting surface. We use it on steeper banks and in spots where a storm could come before seedlings are established.
• Erosion control blankets. Rolled mats of straw, a straw and coconut blend, or pure coir (coconut fiber), stapled over seeded ground. These are the choice in channels, at pipe outfalls, and on bank faces where water runs fast. UF/IFAS recommends that steep swales be sodded or lined with an erosion-resistant material designed for the flow, and blankets are that material.

Timing around the wet season and the fertilizer ban

The best time to stabilize a bank is before June. Ground seeded in April or May has a head start on roots when the heavy rain arrives, though it needs irrigation through the dry spring. Ground opened during the rainy season needs immediate cover, which usually means blankets or BFM instead of light hydromulch. Through the summer, Sarasota County's June 1 to September 30 ban on fertilizer containing nitrogen or phosphorus applies to bank seeding too, and with good reason: those banks drain straight into the water the ban protects. Our summer mix has no N or P.

Salt, tide and bay edges

Along tidal canals and bay edges, salt in the soil and spray limits what grows. UF/IFAS notes that St. Augustinegrass has relatively good salt tolerance, but it must be sodded or plugged, so on salt-exposed banks we often combine blankets with plugs or sod rather than seed. Where the edge is protected mangrove or wetland, we stay off it, set our controls at the upland line, and stabilize only the upland side.

What happens after installation

We check stabilized areas after heavy storms during the first season and repair rills or blanket edges that lift. Hydromulch and BFM break down as the grass grows through them. Straw blankets degrade over months and coir lasts longer, which is why coir is used where the grass will take longest to establish. Get a free estimate