Karen Lee Rix, age 11, of Chetwynd, B.C., Canada, for her questions:

What is the water table?

In olden days, a water table was a sort of gutter to drain rain from a building. Nowadays we use the term to mean the top level of the ground water. Everywhere we go, there is a lot of water trapped down there in the ground. Every shower adds to this supply of ground water. So do the melting snows. When it rains, some of the moisture evaporates. Some is used up by plants, animals and people and some of it runs away in rivers. And some sinks down through the soggy soil. In the whole world, more than two million cubic miles of water are buried down in the ground. About half of this is more than a mile deep. The top level of this ground water is called the water table. In some places it is just a few feet below the surface. When we dig down to it, well water seeps into the hole. Elsewhere the water table is hundreds of feet below. In any case, the level rises higher during the seasons of rains and melting snows. It drops lower during a long dry spell  ¬which is when and why some wells tend to run dry