Clay Slope Erosion Control in Atlanta, GA

Clay slope erosion control in Atlanta is about one thing: holding bare soil in place long enough for roots to grow through it. Cut banks behind new houses, fill slopes along driveways, drainage swales, ditches and pond banks all shed water fast, and on Piedmont red clay that water leaves orange. Our erosion control services cover those areas with hydromulch, bonded fiber matrix or erosion control blankets, seeded with grass that will take over once it is established. Homeowners call us when a backyard slope keeps sliding into the lawn; builders and site contractors call when an inspector flags exposed slopes.

Why Atlanta slopes wash

Several things stack up here. The metro sits in the Piedmont foothills, and Atlanta itself is built on a ridge, so very few lots are flat. Cecil soils, the most widespread red clay in the region, have a thin sandy loam surface over clay subsoil, and once that surface is cut away the exposed clay sheds rain rather than soaking it up. Kaolinite clay recovers poorly from compaction, so slopes that were tracked by equipment stay dense and slick. Then there is the rain: about 50 inches a year, with every month averaging more than 3 inches. A raw slope here will see a real storm within weeks.

Hydromulch and bonded fiber matrix

Hydromulch, or hydro mulching, is the same spray process as a lawn but with a heavier load of wood or paper fiber and more tackifier. It forms a cover that holds seed and moisture against the slope. On steeper or longer slopes we move up to bonded fiber matrix, a sprayed product that bonds fibers together into a continuous erosion-resistant layer once it cures. Both work best when the slope has been roughened across its face, not smoothed, so water slows down instead of sheeting off. Both are sprayed from the truck, which means no one has to walk a steep bank carrying rolls of material.

Erosion control blankets

Where water concentrates, in swales, ditch bottoms, along downspout outlets and on the steepest cut banks, sprayed mulch alone may not be enough. Erosion control blankets, also called straw blankets, are rolls of straw, coconut fiber or a blend held in netting. They are laid on top of seeded soil, overlapped and pinned with staples, and the grass grows up through them. Straw-coconut blends suit most residential slopes; all-coconut (coir) blankets last longer for channels and steeper banks. We pick the blanket from the slope, flow and how long cover is needed.

The law behind it

Georgia's Erosion and Sedimentation Act asks for more than a lawn on permitted sites. It requires adequate provisions to minimize damage from surface water to cut faces and the sloping surfaces of fills, requires that cuts and fills not endanger adjoining property, and calls for disturbed soil to be stabilized as quickly as practicable with temporary vegetation or mulching on exposed critical areas. On a homeowner's yard none of that may be enforced, but the same physics apply: a slope that drops mud onto a neighbor's driveway is a problem whatever the permit status.

Choosing the grass for a slope

Slope stabilization depends on roots. Tall fescue has a deeper root system than other cool-season grasses and is sometimes planted specifically to stabilize soil, so it is a common choice on shaded or north-facing banks. Bermudagrass spreads by runners and rhizomes into a dense mat and puts down deep roots, which suits sunny, south-facing slopes seeded in late spring. We often add a quick temporary cover to the mix so there is green on the slope fast while the permanent grass establishes.

Signs a slope needs more than seed

• Rills or small gullies forming down the face after rain
• Orange water or mud fans at the base of the slope
• Seed that sprouted and then washed into the bottom
• Bare soil that stays bare because it is too steep to mow or rake