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It was found that the results of the investigation of underground waters were of great interest to the public, and the rapid development of many areas in the West through the use of underground water for irrigation, the application of well waters to the irrigation of rice in the Southern States, and the ever-growing importance of deep well waters as sources of public water supplies have led in the last few years to a great increase in the work involved in their investigation. In order satisfactorily to meet the new demands and to develop, specialize, and systematize the work, the investigations relating to underground waters were segregated from the division of hydrography and grouped into a distinct organization known as the division of hydro-geology, or hydrology. This organization was made at the beginning of 1903, with two sections, western and eastern, the first including the so-called reclamation States and Territories and Texas, and the second embracing the States east of the Mississippi and those bordering that river on the west. Each of these sections was placed in charge of a geologist assigned from the division of geology and working under the general supervision of the chief hydrographer.
In the western section there are three assistant geologists, two field assistants engaged throughout the year, and five field assistants engaged for a portion of each season. Special investigations are being conducted by several other geologists, in most cases State geologists and professors of geology at the State universities. In the eastern section there are several assistant geologists and many temporary field assistants. Arrangements have been made for cooperation by a number of local geologists, and several members of the geologic branch are giving special attention to restricted areas.
The work of the division includes the gathering, filing, and publication of statistical information relating to the occurrence of water in artesian and other deep wells; the gathering and publication of data pertaining to springs; the investigation of the geologic occurrence, from both stratigraphic and structural standpoints, of underground waters and springs; a study of the laws governing the variations due to tidal, temperature, and barometric fluctuations; direct measurements of rate of underflow; detailed surveys of regions in which water problems are of great importance and urgency, and the publication of reports on irrigation, city water supplies, and other important uses of underground waters.
To serve as a basis in outlining plans for field work, it was found desirable to undertake a preliminary correspondence by means of printed requests for the addresses of drillers, well owners, spring owners, etc., and for information relating to town water supplies, wells, and springs. Requests for addresses are first sent to postmasters, and to the addresses thus obtained special blanks are sent. The same system is used in gathering information from scattered
points which it is impracticable to visit on account of expense. The information thus obtained has been found to be of great value and assistance in carrying out the work of the division. The data are recorded on printed cards of three types, designed for information
FIG. 4.—Map showing progress of work on underground waters in western half of United
States in 1903-4.
relating to city or town water supplies, deep wells, and springs. The cards are so arranged that they can be submitted directly to the printer as copy for tabular reports. Plans have been made whereby bibliographies covering hydrography and hydrology, similar to those which have proved of so much value to geologists, will be prepared annually.
Arrangements have also been made for cooperation of both geologists and topographers in furnishing information of new water developments and such facts relating to the occurrence of underground waters as come to their attention.
During the last few years hydrologic work has been done, either directly in the field or through cooperation with State officials or by correspondence, in practically every State and Territory. Among the more important investigations under way may be enumerated the following:
In the eastern section, geology and water resources of Long Island,
New York; measurement of velocity of underflow of water in sands and gravels; springs of New York State; underground water supplies of New Jersey; pollution of underground waters of Georgia; underground water resources of Louisiana and Arkansas; springs of Missouri; and artesian waters of Minnesota and Wisconsin.
In part the field work has consisted of the running of levels connecting wells with railroad levels, thereby establishing a basis for determining the structure of water-bearing formations. Such work has been conducted with success in southern Arkansas and Louisiana, where it is expected that it will aid in determining the most available water horizons for the supply of towns and cities, and perhaps lead to more extended use of underground water for the irrigation of rice. In Missouri promising results include the discovery of new artesian areas and the relations of temperatures of cavern and surface springs at similar horizons, the development of caves and sinks by underground drainage, and surface modifications resulting therefrom; and, in general, the origin, flow, and temperature of all underground waters and their economic uses.
In the western section, among the more important results so far obtained are the amounts of variation in water levels at localities where water is being extensively utilized for irrigation, as in Salt River Valley in Arizona and San Joaquin Valley in California. In these and similar areas tests to determine the movements of underground waters have been made, and much light has already been thrown upon these obscure phenomena.
In the Dakotas much attention has been given to special geologic work, with a view to ascertaining the relations of underground waters to the geologic structure. Reports and maps have been prepared giving a review of the artesian conditions in the great central plains.
Figs. 4 and 5 show the progress of the hydrologic work.
For publications on hydrologic subjects see the Survey's list of publications.
DIVISION OF HYDRO-ECONOMICS.
The entire hydrographic work of the Survey is, to a more or less extent, of an economic character. The special work of the division of hydro-economics may, however, be said to have been started with the gaging of rivers in the eastern portion of the United States, as the reason for this development was the need of data for water-power and other economic purposes. The first investigation of this nature was a study of the Potomac drainage basin, begun in April, 1891.
Another development took place in 1895 with a general reconnaissance and establishment of gaging stations in the southern Atlantic drainage basins in the States of Virginia, West Virginia, North Caro
lina, and Georgia. The work has since constantly enlarged from year to year, until it now includes every State in the humid region.
A special department of the work, and one of a distinctly economic character, was established in 1897, when a detailed study of the sources of pollution of the Potomac Basin was undertaken. Samples of water for bacteriologic examination were collected in sterilized bottles at the mouths of all important tributaries, and at such other points along the river as were of special interest, as at locations of sawmills, tanneries, and immediately below important towns.
At about this time in the New England States, especially in Maine, the study of water powers was commenced. In four years the subject was fairly well covered, and the results were published in WaterSupply Paper No. 69.
During 1895, 1896, and 1898 a study of the hydrography of the streams of New York State was undertaken by the State engineer's office and the United States Board of Engineers on Deep Waterways. During 1900 the Geological Survey assumed charge of the stations, and, in cooperation with the State engineer and surveyor, extended and continued the work.
In 1901, at the request of the water-supply department of the city of New York, a detailed study of the hydrography of the streams that might possibly furnish a water supply for the city was undertaken by. this Survey, and has been continued to date.
Owing to the increased demand for information on water powers, municipal water supplies, sanitary conditions of rivers, flood preventions, and other allied questions, the division of hydro-economics was established in January, 1902. At that time its work was confined to reviewing chemical and board-of-health reports and extracting therefrom such matter as applied directly to the quality of natural waters. From the results of this work there was prepared a report entitled “Normal and Polluted Waters in Northeastern United States," which has been issued as Water-Supply and Irrigation Paper No. 79.
Subsequently cooperative relations with various laboratories throughout the country were established. The arrangements involve the study. of important problems concerning river pollution, river purification, and municipal water supply. The laboratories partaking in the initial scheme of cooperation were: Bowdoin College, Brunswick, Me.; Massachusetts Institute of Technology, Boston, Mass.; Rensselaer Polytechnic Institute, Troy, N. Y.; Cornell University, Ithaca, N. Y.; University of Rochester, Rochester, N. Y.; Dickinson College, Carlisle, Pa.; Earlham College, Richmond, Ind.; Central University of Kentucky, Danville, Ky.; University of St. Louis, St. Louis, Mo.; University of Missouri, School of Mines, Rolla, Mo.; University of Kansas, Lawrence, Kans.