!!!See the author's notes at the bottom of the column!!!
Geology - We interact with the Earth
My major in college was geology. I was very interested in the subject. I learned a lot about groundwater movement in my clay mineralogy, hydrology and geomorphology course. WOW! I can't not believe that I remember these enigmatic names.
The point is this: Very few areas of the United States have well-drained (sandy) soils. The majority of soils are rich in clay, especially in the Midwest, East, and West. you dig deeper into clay soil, it becomes denser. There is less space for air. The part of the soil that has the most air provides the best route for water movement.
Just as water drains down your driveway, it drains below the surface of the ground. Retaining walls, basement walls, etc. can often try to block this movement. If the wall has no cracks, the water could go around the wall. If there is a crack, the water may find it easier to enter than to circumvent. You know, the path of least resistance.
A curtain drain can capture and divert this groundwater. A previous bulletin, #70 - Linear French Drain, explains in detail how to build these wonderful devices. They consist of a narrow trench, a four-inch perforated pipe and huge amounts of large rounded gravel.
When I built my house many years ago, the back of my lot was extremely wet. I was "receiving" water uphill. I installed a curtain drain to intercept this water. worked every spring. My neighbor's yard is spongy, while mine is dry! These are great DIY projects.
Author's notes:
You might be wondering if my advice is worth anything. Well, read what Jim Sanders wrote to me when he was out of breath:
"Hi, I just wanted to write to you with the results of my 'Trench Drain'. I have had a wet crawl space for 15 years. Water would sometimes fill the crawl space, so we had to drill as soon as it would enter the basement and eventually the sump pump.
I tried everything. Several contractors said the only thing we could do was bring the water into the house via drain pipes and let it into the sump pump. It would work, but as I live at an elevation of 6ft there is no reason i have any water issues it went like clockwork...when it was raining we would rush home from the lake or the where we were on vacation so we could be ready to start the backup generator, in case the power went out. We even had our alarm company install a sump alarm on our system, so that it could notify us of a power outage. Battery backup was not an option as sometimes we lose power for days and during any rain our sump would run every 7 minutes... like clockwork.
I found your site and read the article on the French trench or drain. At first it sounded a bit like "holistic healing" to me. I couldn't understand why a 2 foot deep trench, at 4 feet from the house, would be good. How could this simple thing fix an extreme water problem that has plagued me for years, cracked my foundation, sagged my garage floor, and ruined almost my entire vacation?
The current linear French drain trench of the house. PHOTO CREDIT: Jim Sanders
I decided "what is it". I had to dig by hand using a spade and pickaxe because the builder backfilled our property with brick and bitumen. Took quite a while. Because the ground level varies so much on this side of the house, I couldn't get exactly 2 feet deep. It varied from 18" to 30" in places, but the slope was downhill. The trench is about 80 feet long. Sometimes I thought about filling it all in, because I just didn't believe it would work.
I stoned it, tiled it, and filled it with #1 round stone. I shod the pipe just for safety and also used geotextile fabric on top, so I could cover with dirt and of grass. I also ordered clay and threw it from the house down the drain.
After a short rain, water pours out of the house. PHOTO CREDIT: Jim Sanders
Result? In the past month, we have had 7 or 8 torrential rains, the worst of which was last night. It rained so hard that our lawn was washed out in places due to the high clay content. Our sump pump , which normally ran every 7 minutes during and after rain, has not turned on for 4 weeks. The silt at the bottom of the sump pit is now dry and cracked. Our crawl space showed no water marks or even humidity.
Since I couldn't see fixing the foundation cracks or the garage floor sagging and tilting until I fixed the source of the problem, I waited to see if the trench drain worked first.
This week I had a company perform a kind of "mud-jacking" technique on the garage floor, which worked perfectly. foundation.
A dry sump pump. PHOTO CREDIT: Jim Sanders
I just wanted you to know how it worked. I've been stressing over this problem for many years and the solution wasn't nearly as hard as I thought it would be.
By the way, I went to the end of the drain tile during a heavy rain to see what was going on. Water was flowing out of the drain tile in about the same exact volume as it had previously flowed from the holes drain from my crawl space. This winter will be interesting, because last year the ground next to the house was so saturated that during a thaw, my sump was constantly leaking. I guess the ground between the trench and the house will probably be drier now this winter. »
- Jim Sanders, Upstate Region - New York
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Column B119
