Silt Fence

A silt fence is a temporary sediment control device used on construction sites to protect water quality in nearby streams, rivers, lakes and bays.

A typical fence consists of a piece of synthetic filter fabric (also called a geotextile) stretched between a series of wooden or metal stakes. The stakes are installed on the downhill side of the fence, and the bottom edge of the fabric is trenched in the soil and backfilled on the uphill side. The fence is installed on a site before soil disturbance (earth moving) begins, down-slope from the disturbance area.

Some government jurisdictions in the United States recommend or require the use of a reinforced fence, sometimes called a "super" silt fence, on some construction sites. This design uses filter fabric reinforced by a wire mesh or chain link fence. The metal backing gives the fence increased strength to resist the weight of soil and water which may be trapped by the fence in a large drainage area, and also discourages construction site operators from driving vehicles over the fence. However, an improper installation of a super silt fence can create an inadvertent sediment basin if the filter fabric becomes clogged. This typically causes flooding, failure of the fence, and increased downsteam pollution.

Silt fences are perimeter controls, typically used in combination with (properly designed) sediment basins and sediment traps, as well as erosion controls, which are designed to retain sediment in place where soil is being disturbed by construction processes.

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Hydroseeding

(or hydraulic mulch seeding, hydro-mulching, hydraseeding) is a planting process which utilizes a slurry of seed and mulch. The slurry is transported in a tank, either truck or trailer mounted and sprayed over prepared ground in a uniform layer; helicopters may be used in cases where larger areas must be covered. Hydroseeding is an alternative to the traditional process of broadcasting or sowing dry seed. It promotes quick germination and inhibits soil erosion.

The mulch in the hydroseed mixture helps maintain the moisture level of the seed and seedlings. The slurry often has other ingredients including fertilizer, tackifying agents, green dye and other additives.

Advantages of hydroseeding
Hydroseeding is used to seed grass on commercial sites (highways/motorways etc.), golf courses, lawns and areas too large, inaccessible or unsuitable for conventional methods. Starting a lawn by hydroseeding is considerably cheaper than laying sod/turf and quicker than using seed. It is also used to spread mixtures of wildflower and tree/shrub seeds or turf grasses for erosion control. The process is called sprigging (or hydro-sprigging) when the slurry contains stolons or rhizomes instead of seed.

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Rip Rap

(also known as rip rap, rubble, shot rock or rock armour)
is rock or other material used to armor shorelines and streambeds against water and sometimes ice erosion.

It is normally made from hard rock, commonly granite or concrete rubble recycled from construction sites, and is used to protect coastlines from erosion and other coastal processes caused by the sea. It is also used inland on lakes, rivers, and other waterways to protect the banks from erosion.

It normally works by absorbing the impact of a wave before the wave reaches the cliff or sea defence, and so minimises the erosion caused by the wave.

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