A verse from The Rhyme of the Ancient Mariner reveals a man surrounded by water that he wants but can’t have. Areas like the Pacific Northwest has lots of water in the wrong places and drainage is a common problem. Drainage falls into two categories: structural, which involves buildings, and topographical, which involves surfaces.
All buildings have a structural drainage system: Roofs capture the water, gutters manage it and down spouts and ground drains dispose of it. 90% of structural drainage problems start with the system design. When gutter size is determined by aesthetics, downspout placement by convenience and little thought given to carrying capacity, poor drainage is the result. If overflowing is occurring, design corrections are in order.
Improper installation of well designed systems is another variable. The proper functioning of all gutters, down spouts and ground drains is based in positive slope...water runs downhill. Resetting a negative slope can correct that issue.
Ground drains receive water from roofs, gutters and down spouts. They also accept leaves, twigs, bottle caps, nails, pieces of shingles and what-have-you that create blockage. Regular gutter and downspout cleaning helps maintain healthy ground drains. Periodically, however, a pipe rooting service is called for. As the name implies, many of the blockages can be attributable to roots getting in the pipes. This is particularly common in older systems that have cracked pipes or unsealed joints. If ground drain backups are frequent, it’s wise to have a preventive pre-winter rooting done to the system. If you forget, fear not. The flooding will remind you.
Now, on to topographical drainage. Some areas are blessed with a high clay content soil which "sponges" water. Positive grading is critical to move water downstream because clay won’t allow water to "percolate" out quickly enough to prevent ground saturation. Ground saturation creates swampy, soft areas and puts enormous pressure on building foundations. If the foundation has cracks, the water will find them, flooding crawlspaces and basements. If there are no cracks, the pressure will cause a weakness in the concrete and crack it. If these conditions exist, excavating around the foundation and installing a perforated drainage system to carry the water away is a possible solution.
Perforated pipe systems are a good solution as well for swampy landscaped areas where regrading isn’t possible. Another solution is a french drain system like an underground perforated 55 gallon drum set in the low or swampy area. Ground water accumulates in the drum and either slowly percolates out or is removed by drainage pipe system sometimes supplemented with a sump pump.
The rains of winter teach us much about weaknesses in our drainage systems. While the rains will pass, poor drainage will continue to damage the landscaping and buildings if not corrected. Take the time this winter to inspect your property for problem areas that can be corrected during fair weather. Before you undergo any substantial corrections, get detailed design specifications from a qualified engineer.