Groundwater hits home no matter where you live
Groundwater removal pays in a value added way with respect to your home. Hand excavated french drains are not easy to construct, and they are time intensive, but they pay much more than they cost.
The part of the world that you live will have challenges pertinent to that area. High clay soils or dirt makes wonderful hand excavated french drains. Those french drains run the water on the bottom of the french drain. It is like creating a piece of pottery in the earth.
I have installed hand excavated french drains at the beach here in Oregon where sand is about all you have to work with. Those systems work well too.
Once the sand gets wet, it runs the water right on the bottom of the hand excavated french drain. I did a project a few years ago on a home that was about 4 years old; on the ocean. The builder put the downspouts into the ground right at the side of the home. He reasoned that because of the sand soils, the roof water from the rain drains connected to the gutter system would just soak right through the sand into the earth. Well now, guess what?
The owner, who is a long time fishing buddy of mine, called me to say that he had sold the home, and that the pest-dryrot and structural inspection found 18″ of water in his crawlspace. The weather had been wet. In times where a small amount of rain was the norm, this might have worked, slowly at best. The insulation under the home had gotten wet and all fallen down. The water was over the top of the footings and touching the bottom of the floor joists. I designed a gravity flow hand excavated french drain groundwater removal system, starting at the base of a rock wall about 100 feet below the home, venting onto the beach at grade level. This is called a daylight vent.
I hand excavated to the side of the foundation, creating a grade to the beach of approximately 2″ per 10 feet, and excavated under the exterior foundation stem wall footing at about 18″ from the top grade. The water in the crawlspace drained to the beach in less that an hour. The fact that the water could have been pumped is true, but the low point drain was much more permanent and effective.
I also connected the downspouts into the hand excavated french drain from the rain drain discharges at the corners of the home, and merged them into the french drain aquaduct with solid pipe. The system contained a perforated pipe, and a solid pipe as well.
In areas of the world where it is very dry, flash flooding is a common scenerio. Arizona, California, Texas and other states here in the USA are examples of this. Extensive infrastructure in the way of massive aquaducts to handle large amounts of water that comes so quickly are constructed for this reason. These aquaducts, are usually connected to ponds and lakes that are designed to be storage vents for the drained groundwater. These mitigation areas are called stormwater retention ponds.If you live in an area of the world where this is common, you can benefit greatly by having hand excavated french drains constructed around your home, and along the edges of your property. These home drainage systems will route vast amounts of groundwater away from your site, and around your home.Areas of the world where rock is the main material in the ground are more of a challenge. If the ground will not perk effectively, the drywells are turned into sump wells where the groundwater is collected and pumped by electricity away from the home or building site, or daylighted vents are used if there is a sufficient grade.
In those areas the groundwater has a tendency to run on the surface, so grade and compaction next to the foundation is even more important. If the earth is comprised of an composition of soil and rock that allows the water to pass through it, you can construct the hand excavated french drains and utilize drywells to perk the water back into the earth.
If the area has mostly rock that groundwater can run through quickly, this can be an additional challenge that sometimes prevents the collection and flowing of groundwater adequately in french drains, as it runs through too quickly. Backfilled foundations with this type of rock can be a nightmare for an unsuspecting homeowner.
Have you ever looked at a lake that has been drained, or where water sat for a long time in your garden and then the soil dried out? You will most likely see cracks in the soil, that enlarge with drying, to form a checkerboard of cracks.
The groundwater will run right through those cracks if you leave a hose on next to them. The same thing happens to the bottom of your hand excavated drywell in areas where the ground perks.
Groundwater is conveyed to the drywell with the french drains, and the groundwater opens permanent cracks on the bottom of the drywell that perks the groundwater to the underground water storage areas we pump our wells from.
The same geology works to make a standard septic system work, except in the standard septic system a series of overflows are attached which we call a drain field, and then the water and waste perks into the soil.