In addition, a conventional storm water management approach would have cleared thousands of trees, increased runoff 180 percent, degraded downstream water quality, and caused a daily water table draw-down of 15 million gallons. The plan avoided or sharply reduced the impact of all these problems. The ultimate measure of The Woodlands' approach occurred one April day in 1979 when a record storm dropped nine inches of rainfall on the Houston area in less than five hours. No houses in The Woodlands experienced any flooding. But neighboring areas, with conventional storm water management systems, were hit hard by flood damage.
Subsurface runoff is supported by infiltration of rainfall from the surface.
The water table is the top of the saturated zone of soil - the top of the subsurface runoff. In urban areas, imperviousness reduces replenishment of subsurface flows and is directly reflected by drops in the water table. Stormwater Infiltration . Water, A Primer . Water Resources Center, University of Delaware Development of the Woodlands.