Laserfiche WebLink
<br />OGB'{~ <br /> <br />1. <br /> <br />" <br /> <br />NarES ON GROUND-WATER PROBLEMS IN COLORADO <br />by <br />W. E. Code <br />Professor Emeritus of Engineering <br />Colorado State University <br /> <br />., <br /> <br />Because it will develop subsequently in this discussion, it is my <br />opinion that our ground water must be placed in at least two major classi- <br />fications ignoring for the moment artesian water: I. Ground water that <br />lies adjacent or close to streams carrying appropriated water, the ex- <br />traction of which may affect stream flow promptly or within an irrigation <br />season; II. Ground water occurring remot e or reasonably so from streams <br />carrying appropriated water, the extraction of which will not affect streat:l <br />flow except after a very long period of time, perbaps never, and at the <br />maximum would be inconsequential. There will be zones of time E.nd <br />quantity effect through which boundaries shall have to be arbitrarily <br />drawn. These boundaries will have to be set where tributaries, normall~r <br />dry, debouch into major streams. It will not be easy to set such bounda.:-ies. <br />Whoever sets them must be able'to defend himself with factual knowledge. <br />There will be other occurrences where recoverable ground water exists <br />at a considerable distance from a stream and not in a recognizable channel. <br /> <br />A study of water-table fluctuations reveals a rather consistent <br />difference between areas where replenishment by irrigation exists end <br />where replenishment occurs through natural conditions. In both of these <br />cases it is assumed that irrigation from wells is also a factor. <br /> <br />.' <br /> <br />In the first instance it will be fou nd that normally, where there is <br />a balance of conditions, the lowest water table occurs in the spring bef' :'e <br />irrigation starts and reaches a high point at the end of the irrigation season. <br />In drought pericds, when the pumping rate is high and surface water <br />supplies low, this pattern can be upset. It will be noticed that fre- <br />quently the seasonal amplitude of the swing is greater at a distance from <br />a flowing stream than near it. The total swing between the extremes <br />is also much greater at a distance than near a stream. At a distance, <br />when the trend is downard, water is being taken from storage. When <br />the trend is upward water is goi ng into storage. Normally, near a strea:!l, <br />instead of water going into storage, it is discharged rather soon to the <br />stream. If a consistency could be found here, a criterion might be de- <br />veloped to aid in drawing an arbitrary boundary dividing ground water <br />closely associated with stream flow and that which is not. The trouble <br />