Simply put, gutter down spouts are one of the main contributors to water problems. The first step in removing unwanted water is to pipe it away from your home.
Perforated pipe is designed for drainage. Its advantage is the perforated or ribbed interior. Ribbed/perforation slow water down so when water exits the pipe it does not have a destructive force, causing erosion or upset neighbors. PVC has advantages as well. Water in transport runs very fast, away from the source. PVC is also very durable, so it is good for under sidewalks, patios and solid sources. Cost is also a determining factor, as PVC is more expensive. Many drainage systems incorporate both types of pipes.
Most drainage systems are mistakenly referred to as French drain systems, but a true French drain uses corrugated pipe and drainage aggregate around the pipe to leach water from underground surfaces. Soil type plays an important role in how it is constructed. Filter fabric wrapping the aggregate or pipe is sometimes used to control sediment and to keep sediment build up from forming within the pipe. (Caution: French drain systems are used, but are not an effective technique for most Georgia soils.) Georgia soil is very silty and can mat around the outside of the filter fabric and create a clay shell that traps water inside the pipe. If filter fabric is not used, sediment builds in the pipe (like a clogging vein in the body) eventually clogging the entire pipe. French drains usually have a 2-3 year success rate in silty soils such as Georgia’s red clay.
Flow well systems are very effective in Georgia and are code in new construction projects in the city of Atlanta now. Flow wells are similar in nature to a septic tank except it’s designed to leach inward as a collection point and release outward as the ground dries. This is especially designed for areas with elevation problems. Because water moves in both directions through filter fabric it is less likely to mat on the outside. The water weight or hydro-static pressure forces water to percolate into the Earth’s surface faster. Flow wells are great for drying ground saturation problems as well and can be installed in conjunction with other drainage systems.
Excavation Width: The width of diameter is important to create the correct leaching area for flow wells to work at its full potential (approx. 6 ft. in diameter).
Excavation Depth: Water percolates in the ground at a fast rate, 4 ft. below the Earth’s surface.
Excavation Locations: Every property is different, but generally the lowest portion is the drainage area. Determining factors are elevation in conjunction with gutter down spout height and basement proximity (we do not want to collect and store water near a basement wall). We also want to make sure the placement does not interfere with surface functionality or future property expansion or upgrade projects. (i.e. plantings, patios, home additions, etc…)
Installation: The excavated area is lined with filter fabric and the assemble canister (approx. 24” in diameter x 28.75” high) in the middle of excavated area. After integrated into drainage system, the flow well is then surrounded by drainage aggregate on all sides. After drainage aggregate is installed it is covered by filter fabric and 6 in. to 1 ft. of soil.
A foundation drain is similar to a French drain except it is installed against a wall or along a foundation because only 25% to 50 % of the drain is exposed to silt. The success rate is much higher for drainage when installed with a good direct flow or flow well drainage system. Using waterproofing with foundation drains is a useful tool in assuring water residence to basement walls (see waterproofing for more information).
At the ending of a drainage system to the road there are 3 methods traditionally used:
The pro's and con's of each is important to consider. Cutting the curb, in many communities is prohibited by HOA, city or county. Just cutting the pipe at an angle is cost effective, but grass will grow over pipe ending and eventually into the pipe, causing problems. ACA recommends using a pop-up, which is a PVC elbow with a lid that raises when water pressure develops, dispensing water evenly into the grass adjacent to the curb. The lid looks similar to a termite baiting disc and is green to camouflage within the grass.
Drain boxes or catch basins in residential settings are usually 9 or 12 inches, high density plastic, with grates offered in green or black. They have inlets on either sides or the bottom for drain boxes that port one side. The port is 2-3 inches above the bottom. This is so sediment and debris get trapped in the box for manual clean out instead of going directly into the pipes. Decorative lids are available as well, for an additional cost.
Channel drains are elongated catch basins generally found around pools or across sidewalks and driveways. They are made of high density plastic and can support the weight of cars and pick-up trucks. These are great for catching shooting water crossing solid surfaces such as concrete.
Remember, drainage is only as effective as the knowledge and experience of the designer. Attention "do-it-yourselfers", be sure to buy quality components for durability.
Diversions are dry creek beds without stone generally surfaced with wheat straw and seed or turf. They both have the same purpose of diverting large amounts of water. A diversion is made of two parts: 1) a swell, which is excavating the soil lower than the grade to encourage water to flow within it and 2) a burm to keep the sides high enough to deflect water away from the swell to minimize erosion or contamination of the swell. Diversions are great for natural areas and property lines though they can be used in almost any portion of the property.
Dry creek beds can be almost any shape or size. The main differences are in the stone placement. As you look through the gallery of pictures take note of the styles you like! The most common dry creek beds are more natural in appearance using large boulders, river rock and fieldstone to help achieve this look. Plants can set the tone for how natural or how formal of a look you want. Formal dry creek beds are also appealing. Incorporating flagstone and statuary can make your landscape look outstanding. Formal dry creek beds can be integrated into rockscapes, fountains and water features. Rain water, of course, cannot be diverted into your pond, but with underground drainage hidden beneath the stone and using water sealant along the middle of the dry creek bed, can complete the illusion of continuous water flow. Don't be afraid to use your imagination! Sitting boulders can be added and wood or stone bridges can complete the vision. ACA is only limited by the customer’s imagination and budget.