How to Construct a Drywell Drainage System
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Bad drainage can turn your yard into a muddy mess whenever rain hits or send water downwards to pool against your foundation and flood your basement. Houses that sit on nearly-flat lots, or lots with slopes that send water toward the building.
A dry well is a simple way to relieve the burden by providing an easy channel for surface water to flow down into the subsoil and spread out. Not every property is suitable for a dry well; the subsoil must be relatively absorbent. If it is, installing a small dry well can be done with simple equipment.
Dig a four-foot-deep hole in the spot where you wish to locate your dry well, which should be in an area where water pools during the rain. Before installing the dry well, you need to test the soil's absorbency. The easiest way to dig the hole is with an auger (which looks like a large screw and can come motorised) or a post hole digger--two shovels joined like scissors.
- Bad drainage can turn your yard into a muddy mess whenever rain hits or send water downwards to pool against your foundation and flood your basement.
- Dig a four-foot-deep hole in the spot where you wish to locate your dry well, which should be in an area where water pools during the rain.
Inspect the soil coming out of the hole as you dig. If there is a lot of clay, this is not suitable for a dry well. You can try to dig deeper to get past thin clay layers. The best type of soil has a loose mix of large and small particles. If water immediately wells up as you dig, the water table is too high for a dry well.
- Inspect the soil coming out of the hole as you dig.
- If water immediately wells up as you dig, the water table is too high for a dry well.
Pour five gallons of water into the hole once it reaches a depth of four feet and time how long it takes for the water to sink in. An inch of water disappearing every three minutes indicates very good drainage. If the water pools in place for long, the soil would not suitable for a dry well. To be sure that it wasn't an artefact of locally dry subsoil, pour in a second five gallons and time it again.
Dig a round hole six to eight inches in diameter in the centre of the area you wish to drain. It should be approximately four feet deep.
Cut off an eight foot length of the fabric sleeve that is used to keep dirt out of corrugated drain pipe--you don't need the actual pipe.
Tie one end of the sleeve shut and pour a few shovelfuls of pea gravel into the other end. These will accumulate at the tied end, weighing it down.
Lower the tied end into the hole until it touches bottom, then fill the sleeve with more pea gravel until the gravel sits about 8 inches below the level of the surrounding lawn.
Tie off the open end of the sleeve and bury it under more gravel. For the best drainage, you should extend that gravel all the way up to the surface. If you wish to hide the dry well, stop one or two inches short of the surface level, then unroll some sod on top. Rain will drain through the sod into the dry well.
- Dig a round hole six to eight inches in diameter in the centre of the area you wish to drain.
- If you wish to hide the dry well, stop one or two inches short of the surface level, then unroll some sod on top.
- You can channel water into a dry well using corrugated drain pipe, also known as "french drains." To do this, just dig one or more dry wells underneath the path of the drain, which has openings facing downward. As long as the dry well is placed at the downhill end of the drain, it will serve as an outlet for water collected by it.
- Using a fabric sleeve will keep the well from clogging with soil, but it is also possible to build a basic dry well just by digging a hole and filling it with loose stones.
- Very large or complex dry well systems can involve installing large concrete or plastic holding tanks and a network of pipes beneath your lawn. Work of this scale is best left to professional contractors . A good alternative might be to build multiple small wells that you can take care of on your own.
Joshua Smyth started writing in 2003 and is based in St. John's, Newfoundland. He has written for the award-winning "Cord Weekly" and for "Blueprint Magazine" in Waterloo, Ontario, where he spent a year as editor-in-chief. He holds a Bachelor of Arts in political science and economics from Wilfrid Laurier University.