erosion control

Retaining Walls and Structures
Segmental Mortarless Concrete Block System, Concrete or Concrete Block (on concrete foundations), Pressure Treated Wood, Steel I-beam, and Stone, are all possible types of retaining walls. Some of these are easily faced with stucco, stone and stone-like veneer. They may need to be engineered. Almost all walls would have a drainage system behind the wall to minimize pressure and drain off subsurface water; surface water is caught in a catch basin set at grade. Sometimes after re-grading, all that is needed to stabilize a slope is a small "toe" wall.

Small "toe" walls are often used to help stabilize a slope.

A small segmental concrete block wall is used to support the patio and deck area.

Check dams to stabilize a North Coast gully.

Engineered concrete block wall, with stucco treatment.

Subsurface Drainage Systems
Subsurface drainage is the removal of excess water from the soil by drain systems placed below the surface. This removal has beneficial effects in terms of health of plants, water quality and drier house conditions. Solid pipes — these carry water from downspouts, catch basins and perforated pipe systems to a safe outfall location. Perforated pipes — these collect water from saturated areas or intercept subsurface water under slopes using filter fabric and crushed drain rock.
Surface Drainage


A commonly used concrete catch basin for surface water collection.

Inlet for new culvert to carry long roadway drainage.

Down drain “day lighting” to safe location below slope.
Slope Stabilization
Any changes on a slope require specific thought as to how to minimize future soil loss. Large storms, changes of uphill water distribution, grading and changes in vegetative cover all could weaken a hillside. Proper grading and compaction, water diversion and long-term vegetation establishment could then become critical. Low-water-requiring, often native, plants and grasses may be a direction to take. Annual grasses may be used first year to "lock" up the soil, before a more aesthetic plan can be implemented.
Contour grading and compacting are important for longevity and natural appearances.
Grading/Erosion Control Plans
If your project is large, intricate, or requiring of City or County approval, a grading / erosion control plan would be suggested or required. These scale drawings pin down the details for all parties to understand, approve, and follow.
Hillside Irrigation Systems
Even our most drought resistant plants need regular watering to become established. Most plants will perform much better with at least occasional summer water, even after establishment. Overhead low-precipitation sprinkler heads or a well-planned drip system will provide years of sustenance for healthy slope plantings. Liquid fertilization through the sprinklers is also a possibility.

Erosion blanket and silt fencing
Hillside Restoration
Quarry restoration
Quarry restoration
Residential hillside
Residential hillside
The two most common ways to cover bare ground and stabilize erodible slopes are hydro-seeding and blanket. Hydro-seeding is often used on larger areas, by applying a slurry of seed and mulch that is sprayed in a uniform layer on a slope. Erosion blanket, available in many forms and made of different biodegradable material, provide instant protection, anchored with staples, particularly the edges and the up-slope side, overlap joining sections to ensure site protection.
Straw wattles installed, help to stabilize slopes by shortening the slope length and by slowing, spreading and filtering overland water flow. This helps to prevent sheet erosion as well as rill and gully development, both of which occur when runoff flows uninterrupted down a slope. Storm water runoff carries sediment and seeds off slopes as it gathers velocity, but straw wattles capture that sediment and hold it on site, enabling seeds to settle and germinate, aiding the re-vegetation process..
Whenever possible, slope should be planted with plants native to the area; plants will already be adapted to the soil conditions and will need the least amount of maintenance. Native grasses often installed using plugs are our most common choice for long-term stability.
Slope Irrigation: plants need water initially. To insure the irrigation system, a master value is installed ahead of main control to assure proper valve function. A flow controller can be installed to monitor the amount of water flowing thru the system. 1 GPH emitters are used for deep watering.