The Art of Drainage
The art of drainage is the art of making it easier for water to flow where we want it to flow than anywhere else. Water is always a willing participant on the path of least resistance.
Water flows both through the ground and on the surface. In both cases it can be intentionally directed by either creating an easy path for it to flow away from the area in question once it arrives or by interrupting its path to the area and inviting it somewhere else.
Surface water can be invited anywhere by contouring the soil, concrete, pavers or grass that is present so that the easiest downhill slope is provided in the direction we want the water to go. If water runs down a driveway from the street, creating a little hump or lip at the top of the driveway to keep the water running down the street may be a lot simpler than installing a drain at the bottom. If water runs down from a neighbor, creating a small berm of heavy soil at the edge of your property may either spread the water out into a more even flow or take most of it away from your property altogether. If a berm is not as easy as a ditch to create do that. The ditch can be visible, or can consist of a trench filled in with gravel or larger rocks. A perforated pipe at the bottom of a ditch will speed up the flow of water in the ditch, allowing the ditch to be smaller while still accomplishing the same rate of flow.
A good drainage plan begins by taking a tip from water’s habit of taking the easy way and analyzing what is the easiest way for us to invite water to flow where we want it to go. Options include: Filling in soil to bury or eliminate low and soggy spots, inviting the uphill neighbors to pipe their gutters to the street, creating a berm, ditch or French drain to intercept both surface and ground water, funneling water into a low spot and either sump-pumping it or piping it away once it enters a collection chamber, channeling the water into a dry riverbed or directing the water into a bog or pond area.
If drainage pipe is part of your drainage plan I recommend using ridged and smooth PVC pipe rather than the flexible corrugated pipe for two reasons: The first is that the corrugated pipe tends to pop up out of the ground in areas when the trench is being backfilled with soil or gravel because it is so light and flexible. The more important reason is that mud, leaves and other debris inevitably get stuck in the corrugated pipe, making it very hard to clean and in time eliminating its effectiveness.
Many people see drainage issues as separate from landscape design. A good landscape design will often solve or avoid creating drainage problems while simultaneously enhancing visual beauty. For the most functional and beautiful home create an overall design in which each detail accomplishes multiple objectives, creating synergistic value.
By Dane Rose, Owner Mystical Landscapes