Classification of Springs

Among the common phenomena of nature, springs are notable because of their high usefulness. Since the earliest times the homes of men have clustered around them. In arid regions their number and size may limit the population. In many humid regions springs are so numerous and similar that distinctions between them are not recognized, yet they may be caused by so many principal and minor factors or by so many combinations of these factors as to make the origin of any one spring exceedingly complex or obscure. An interesting account of the many erroneous notions held by the ancients regarding the origin of springs can be found in Paramelle. In addition, their very familiarity has brought about an indifference which has led the average investigator to pass them by. Only springs with unusual characteristics have been thought worth study. Elaborate classifications have been suggested for so-called mineral springs-those whose water is exceptional because of gas or mineral content-but a complete classification of all springs has been attempted only by Keilhack. His classes are not mutually exclusive, and his primary division into descending (absteigende) springs and ascending (aufsteigende) springs separates, not waters of unlike origin, but only waters that have unlike paths to the surface. A number of authors have made incomplete classifications for the springs of a limited region or for some special reason. The principles involved and the names used have been helpful in preparing this classification. Such classifications may be found in the works of Gregory, Meinzer, Fuller, and Johnson, cited in this paper, and in those of Hill and Vaughan, Fournier, and Kilian. References to many articles on springs will be found in Meinzer's bibliography of ground water. The essential factors in the production of springs are the source of the water and the rock structure which brings it to the surface, and on these factors the classification outlined in this paper has been based. Temperature, dissolved salts, contained gases, rate and amount of flow, form and position of the spring opening are all characteristics of springs, which, while in many cases related to genesis, vary among springs of the same origin. It has seemed best to first divide springs into two groups based on character of the water and make further subdivisions on structural grounds. In the use of this classification difficulties will arise which are of two types. In the first place, the local structure in the vicinity of springs is difficult to determine, for the presence and passage of water facilitates weathering and destroys the evidence. The presence of luxuriant vegetation also tends to conceal the structure. Whatever the difficulties of determining the structural relations and origin of the water for single springs, the study of groups of springs will usually be successful. The second difficulty arises through various combinations of structures which may combine to produce a spring. The structure which plays the predominating r6le should then determine the classification of the spring. The common sense and judgment of the investigator will lead him to the proper decision, but his labor will be easier if he remembers that ground water moves through three dimensions, though our conventional methods of illustration show but two. Springs of diverse origin may, however, have peculiarities so remarkable or interesting as to justify their grouping under a common name. The proposed system is not intended to supplant the use of such descriptive terms as blowing springs and thermal springs, but to provide a series of terms expressive of genesis which will include all springs, particularly those now called, for want of a better term, "common springs."