by Archana Subramaniam by CNB![]()
Roanoke Times Copyright (c) 1995, Landmark Communications, Inc. DATE: THURSDAY, March 25, 1993 TAG: 9303250060 SECTION: VIRGINIA PAGE: A1 EDITION: METRO SOURCE: ED SHAMY STAFF WRITER DATELINE: LENGTH: Short
NATURE'S WAY OF SAVING IT FOR A NOT-SO-RAINY DAY
We've taken a drenching so far this month, pelted by every kind of precipitation Mother Nature seems capable of wadding up and hurling at us. We've had rain and snow and sleet and snow again and now rain and melted snow.If we're not flooded, we're hip-deep in mud or snow. The forecast is dotted with references to rain.
Think of it all, though, as money in the bank.
The Roanoke Valley normally can expect about 40 inches of precipitation in a year. We've already had more than a foot of it this year.
But March is the second-rainiest month of our year, according to statistics, and there is a natural cycle to all of this, said Lisa Hu, a geologist with the state Water Control Board.
Beneath our feet at varying depths beneath the valley is bedrock - a layer of granite that is fractured in places.
Those fractures trap water - not vast ponds of it but water soaked up in sediment and ground rock. Visualize it as a soaked sponge - just as you can't see water in a sponge, you can't see pools of water in the cracks.
Those are our aquifers. They fill with water that has percolated down from the valley's surface through hundreds of feet of soil. During these wetter months, we're putting water in those underground storage tanks.
In the drier months - through autumn and winter - we draw through springs and wells on those reserves.
By November, December and January - our drier months - we may well have forgotten these soggy days.
But we'll have our memories stored deep underground.