David Rogers is one of our most prolific experts here at Missouri S&T. He knows as much as anyone about things relating to levees, floods, hurricanes, and so on. So, after pumping out the ex-wife's flooded basement for the fourth time in four months last week (this is in Springfield), I sent Dr. Rogers an email to ask him some questions about basements and water. I'm passing his response on as a sort of public service announcement:

In regards to your basement:

1) We have had record rainfall this year, even greater than in 1993, so it should be no surprise that you are experiencing some seepage
2) seepage always occurs "bottom-up", just as you describe, because of hydraulic pressure increasing with depth, at rate of 62.4 pounds per cubic foot per foot of depth. The more hydraulic pressure you get against the basement wall, the more seepage that can pass through a hairline crack at the base of the wall stem, where it joins the foundation footing. There is usually a "cold pour" joint at that location which develops a shrinkage crack, and that's where the moisture typically seeps in. So, seepage is all about hydraulic pressure (depth of water on opposite side of the wall), more than any other factor. We've had a really wet year, so all the pores in the soil become saturated, incapable of accepting additional moisture. When it rains the water presure increases very quickly. The other problem is anteceedant mositure. When the ground is near-saturated, rain can't be absorbed by the soil, so runoff increases, dramatically. That's why it floods with a so-called "normal storm (about 1.5 hrs duration), that never previiously caused problems. In the Midwest all of the flooding is intimately tied to anteceedant moisture levels, looking at the past 72 hrs, 1 week, 2 months, and even past 3 months, depending on the size of the watershed.

The bad news is it took months to get into the predicament we find ourselves in right now, and it will take another 6 months or so for us to get out of the "flood danger window," because the anteceedant moisture levels are so high. For example, the Gasconade River experienced its highest recorded flow this past spring, greater than 1983 (the previous record) or even 1993. So from here on everything devolves down to the rainfall patterns that develop this summer, with the most important factors being the duration of dry spells between storms.

Hope that info helps you understand what's going on.