Ding Darling, "THE STORY OF THE GROUND WATER TABLE"
THE STORY OF THE GROUND WATER TABLE
by JAY N. "DING" DARLING
Founder and Honorary President, National Wildlife Federation
School Nature League Bulletin 15:1 (New York: National Audubon Society, September 1944)
ASK ANYONE TO NAME the three things he would rather have than anything else in the world, the first would probably be riches and the other two, more riches, which shows how little man knows what's good for him. If he had no air he would die in a few seconds, if he had no water he would die of thirst in a few days, and if there were no land he could have no food and would slowly die of starvation. But all three of these working together in the sunshine produce everything the richest man in the world can possess: food, clothing, forests, and all the living creatures on earth. Leave out any one of the three and the other two are powerless to keep us alive.
This is the story of water and how man, by his carelessness, is in danger of losing one of the most important sources of supply on which he and all life depends; namely, the ground water storage, commonly called the "water table."
Ordinarily, when we think of the part water plays in our lives we think first of rivers, lakes, and oceans and perhaps rain and the city water works. Few ever think of the vast amount of under-ground moisture stored away deep in the soil which scientists call "the most instantaneous and effective of all fresh water reservoirs." The reason we never think of it is because it is invisible and hardly anyone ever sees it except perhaps at the bottom of a well. Probably the simplest way to define the "Ground Water Table" is to say it is the underground water supply to which people dig when they need a well. Only those who have ever had to dig a well with a spade and shovel know how important it is to have that water table not too far down in the ground.
In earlier days, before cities and towns had public water works and started piping water to their homes, most people had their own wells, or patronized the town pump. One of the first things the early pioneers always looked for before choosing a piece of farm land or establishing a settlement was to see how deep down in the earth they would have to dig to get water. Many a large city in the United States owes its beginning to the fact that the ground water table could be easily reached without too much digging by hand with the spade and shovel. It never seemed to have occurred to anyone at that time that this same underground water supply might have other very important influences on their lives, climate, vegetation and wildlife.
It was a long time after that (let's say about forty years) that things began to happen which jogged everyone's memory about the forgotten underground water table. Farmers who still depended on their old dug wells for their water supply found their wells gone dry.
Springs which used to flow from the ground at the bottom of a hill in the pasture and furnish fresh water for the cattle and horses, stopped flowing altogether, except in very wet weather.
Little creeks and rivers which used to have plenty of water in them the year 'round, were dried up in the summertime instead of furnishing a good place to go fishing and swimming. Of course, the fish that had once lived in the little rivers and creeks had no place to go and wait until the water came back when the fall rains came, so they died and there weren't any parent fishes to raise new families of little fish to take their place when they were gone.
When the springs also went dry and the water in the creeks ceased to flow in the summer, the birds and fur-bearing animals -- particularly those that live near water, like the beaver, mink, martin, muskrat, and the ducks, sandpipers, and killdeer had to move away to new living quarters where water and food supplies had not disappeared so mysteriously.
And something else very important seemed to be wrong. Everyone could remember when the summer farm crops and pastures in the earlier days could go without much rain for several weeks without being completely destroyed. Now they could no longer stand a drought nearly so well. Some years the crops were so poor it hardly paid to harvest the grain. The cattle lacked water and the pastures burned up from lack of moisture, and even the local summer showers that used to fill the cisterns seemed to have joined the general conspiracy and became less and less frequent.
All these changes had come about so gradually that no one tried to discover the reasons, until conditions got worse and worse and finally so bad that something had to be done about it or else the people, like the birds and animals, would have to move away. In some sections of the west many of them did, and lost their farms. Land became unsalable where conditions were very bad. Most everyone said it was all because the climate had changed and there wasn't enough rain anymore. No one -- at least, not many -- thought that the ground water table, could have anything to do with the changed conditions.
Then a group of scientists who started to study the situation and its causes, remembered the old water table which used to be near the surface of the ground, sometimes not more than 12 or 15 feet deep on the average. That same water table was now much lower, sometimes twice its original depth, and in one state in the middle west, it had fallen to 59 feet, where once it had been only 8 to 10 feet below the surface of the ground. Nearly everywhere in the United States the water table had fallen considerably since the days of the pioneers.
Small wonder that the farmers' wells had gone dry. And because natural springs were only places where the underground water table came so near the surface that it bubbled forth out of the ground, naturally the springs went dry too when the water table dropped. And if the springs no longer flowed into the little creeks and from the creeks into the rivers, it was easy to see why the streams dried up (or nearly so) in mid-summer. And if there was less water on the ground, naturally the air became drier from lack of evaporation.
The same group of scientists reasoned that if the old water table was double the distance from the surface, and roots had to be twice as long to reach the moisture, it was to be expected that the plants might get twice as thirsty in dry seasons. Of course, corn, oats, and wheat have very shallow roots and no one thought that they ever depended directly for their moisture on their roots reaching the water table; yet in the neighboring fields where the native deep-rooted vegetation had never been disturbed, the plants remained green long after the short-rooted domestic crops had perished from the drought.
Many theories were explored and not all of the supposed causes have yet been sufficiently proved to satisfy the scientific investigators. There are, however, some established facts which can be given that are known to have played a large part in lowering the water table. The most important ones are as follows:
The underground water table gets its supply from only one source and that is the moisture which falls on the surface of the land in rain or melted snows. If the water from rains or melted snow runs off the surface of the land too fast it does not have a chance to soak into the ground. Anything that speeds the "run-off" therefore, robs the underground water table of its normal supply. This moisture must make its way slowly down into the soil until it comes to a stratum of rock or impervious clay and can go no farther. There it is held in storage for the many uses which nature requires. As moisture thus absorbed increases in quantity, the surface of the water table rises just as the surface of the water rises in a tub when more water is added. If it falls, it is a sign that the new supply of moisture has for some reason been prevented from working its way down through the soil.
At first, it was thought that the falling water table had been caused by a decrease in the general rainfall, which of course would have been a very simple explanation. But examination of records over a period of several wet years showed that the water table had continued to fall even in periods of heavy rainfall and only a little less rapidly than in a dry cycle of years.
There was a time not many years ago when rains and melting snows were held on the surface of the land in marshes, ponds and shallow lakes. In those pools the water stayed often the year 'round and had plenty of time to soak into the soil and replenish the water table.
Millions of acres of these marshes and sloughs, and even some of the shallow lakes, have been drained off through man-made drainage ditches in order to make more dry land for farming. That is one thing we know lowered the water table.
Forests and underbrush, with their thick carpet of old leaves and decaying logs and deep matted roots, once occupied much more of the land than now, and rain and snow falling in the great natural forests was held in the spongy blanket of vegetation until the moisture slowly seeped down into the ground to join the underground water supply. When we cleared the forests and underbrush from the land we destroyed another of nature's methods of retarding the run-off of surface waters. The water was gone before it had time to soak into the ground.
Our prairies and meadows, when our pioneers first saw them, were waist high with a heavy growth of native grasses which caught the snows and rains and held the water in their matted roots almost as effectively as the forests. When we mowed those fields or plowed them for planting, or when our sheep and cattle grazed them down close to the ground, they no longer held back the moisture until it had time to seep into the earth.
Now, just as though lowering the ground water table was not enough of a calamity in itself to convict man of criminal carelessness, he seems to be guilty of a double crime, for by the same acts with which he destroyed his own habitat, he robbed wildlife -- song birds, fish, wild ducks and geese, and furbearing animals of their natural homes. Their breeding grounds were destroyed, their food and water supplies were just as badly affected as man's living conditions. No matter how carefully we protect wildlife from human molestation, they cannot multiply when their natural homes are destroyed.
There is much more to the story than can be told here and the rest of it promises to be much more surprising and exciting than this first chapter.
For instance, there is the story of the part trees and deep-rooted vegetation play not only in holding the water on the surface until it soaks into the ground, but how that same vegetation serves as nature's pump to bring up the same water again from the ground and literally pour it back into the air through the pores in the leaves. Scientists have measured the amount of water an average-sized tree will pump up and give off into the air on a dry, windy day, if its roots can reach the underground water. Impossible as it sounds, a tree will bring up from the ground and give off through its leaves more water, and faster, than a man with a 3-gallon bucket can carry water by ladder to the top of the tree, working a full eight-hour day. A whole forest of trees working together could imaginably have a startling effect on the content of moisture in the air, and atmosphere heavily charged with moisture is a promising condition far a local summer shower.
Just what kind of picture this whole jig-saw puzzle of ground water table, trees, marshes, sloughs, springs, dried-up creeks, disappearing wildlife and floods will make when all the pieces are accurately fitted together is a mystery which has not yet been wholly solved, but the solution of the puzzle is likely to make a great deal of difference in the future happiness of man and wildlife if the fallen ground water table can be restored.
If the above analysis of the importance of the ground water table seems too fanciful for ready belief, there are several experimental areas on which the above mentioned principles applicable to restoration of the ground water table have been successfully applied. For example, an area of more than 80 square miles north of Minot, North Dakota, and a semi-arid area of approximately a million acres in northern Nevada can be cited as suitable subjects for study because of their wide variation in geographic location and environmental conditions. In both cases the ground water table had fallen to a dangerously low level, springs had dried up, wells had gone completely dry, vegetation had been practically eliminated. Both of these broad stretches of land had been famous hardly 50 years ago for the prolific amount of wildlife -- ducks, prairie chicken, antelope, deer, muskrat, sage grouse, and song birds which made their homes there before man had destroyed their natural environment. By 1934, all wildlife had either perished or moved out and man was on the way.
In one area the primary cause was over-drainage of surface waters. In the other case, it was overgrazing, which left no vegetation to hold the winter snows or sparse spring rains. Taking a tip from nature, the water from the rains and snows were held where they fell on these areas. Check dams were built to hold back the run-off, drainage ditches were stopped up and the water retained until it had time to soak into the ground. Vegetation began to appear around the small water-soaked spots and then spread over the entire acreage. From that time on nature took over the job of holding back the natural precipitation and storing it underground. In less than ten years from the time these corrective measures were applied both areas were pretty well back to normal; soil erosion has been stopped entirely, springs are flowing again, vegetation is luxuriant, the birds and mammals, prairie chickens, ducks, sage grouse, and antelope have returned in great numbers to live and multiply. Productive life is again possible for both wildlife and man and even the reappearance of local summer showers on those restored areas threatens to upset the mental comfort of those who denied that the ground water table could possibly have anything to do with the amount of rainfall.
One of the most interesting and instructive discussions that was ever written on this subject has been published under the title of "Little Waters," and copies can be had from the U. S. Government Printing Office, Washington, D. C.
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