Well, we got some heavy rain here Tuesday. Almost 3" all day, but almost all of it in 1 hour.
Still, I had some problems with water getting into the basement, and I thought I had solved that with the extra-large raingutters installed 2 years ago and a drainage ditch I dug from the sunken patio. The sunken patio has been a problem for a decade at least. It properly slopes slightly away from the house. The water that collects at the lower end for a day or 2 is a minor (but annoying) problem.
It's the fact that the lawn level has raised over the years that really creates the problem. Grass grows, I mow it, the clippings become topsoil, etc. Well, that's why praries have dozens of feet of topsoil. I need to lower the lawn level at the edge of the deck, but that is back-breaking work and I keep avoiding it.
Instead, I dig a drainage ditch. 3"wide, 3" deep, and the lawn slopes downhill from the patio, so it works great. It can drain off even the heaviest rain. The problem? Soil moves. The ditch slowly fills in very slowly and I never notice when it is QUITE not capable of handling the occasionally heavy rainfall. So I have to run out in the downpour and rescrape the ditch with the grubhoe deep enough to drain the patio.
But I had an additional surprise this time! The raingutters ARE working just fine. But, apparently, the soil level raised just enough this Summer to direct the outflow back toward the patio instead of out into the downslope lawn.
I'm generally an optimist (though maybe not a rational one). I always expect things I fix to STAY fixed. To show the flaw in that, I also expect weeded areas of the garden to STAY weedless, repaired cars to STAY working, and structures I build to stay standing. Obviously, there is a flaw in my expectations.
So when I dig a ditch to drain rainfall away from the patio, I expect it to STAY a ditch... Even though I'm the smartest person in the house, I have some errors in my assumptions.
So I'm going to fix this rainfall-in-the-basement problem once and for all! I'm going to build a sealed 1' dike in front of my basement! Just kidding...
Seriously, I'm going to lower the lawn level 3" below the edge of the patio/lawn. I will dig a 1' deep trench along that edge and toward the downslope lawn, and I will install perforated drainage pipe buried in sand and landscaping fabric (however it is recommended). And I will attach a 4' extension to the existing downspout to get the rainfall from the roof away from the patio.