Springs constitute an important source of water in east Tennessee, and many individual springs are capable of supplying the large quantities needed for municipal and industrial supplies.Most of the springs in east Tennessee issue from solution openings and fractured and faulted zones in limestone and dolomite of the Knox Group, Chickamauga Limestone, and Conasauga Group. The ability of these rocks to yield a sustained flow of water to springs is dependent on a system of interconnected openings through which water can infiltrate from the land surface and move to points of natural discharge.Ninety springs were selected for detailed study, and 84 of these are analyzed in terms of magnitude and variability of discharge. Of the 84 springs analyzed, 4 flow at an average rate of 10 to 100 cfs (cubic feet per second), 62 at an average rate of 1 to 10 cfs, and 18 at an average rate of 1 cfs or less. Of the 90 springs, 75 are variable in their discharge; that is, the ratio of their fluctuations to their average discharges exceeds 100 percent.Mathematical analysis of the flow recession curve of Mill Spring near Jefferson City shows that the hydrologic system contributing to the flow of the spring has an effective capacity of about 70 million cubic feet of water. The rate of depletion of this volume of water, in the absence of significant precipitation, averages 0.0056 cfs per day between the time when the hydrologic system is full and the time when the spring ceases to flow. From such a curve it is possible to determine at any time the residual volume of water remaining in the system and the expected rate of decrease in discharge from that time to cessation of flow.Correlation of discharge measurements of 22 springs with those of Mill Spring shows that rough approximations of discharge can be projected for springs for which few measurements are available. Seventeen of the springs analyzed in this manner show good correlation with Mill Spring: that is, their coefficients of correlation were 0.70 or better as compared with a perfect correlation factor of 1.00

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Surface water _________________________________________________ Ground water_________________________________________________ Geologic units and their water-bearing properties._____________ Consolidated rocks___________________________________ Unconsolidated alluvial deposits.-_______________________ Source, movement, and discharge____________________________ Adequacy and permanence of the ground-water supply_________ Existing water-supply facilities._____________________________________ Development of a ground-water supply_____________________________ Adequacy of the alluvial deposits as a storage reservoir___________ Methods of developing a ground-water supply_____________________ References.-______________________________________________________ ILLUSTRATIONS FIGURE 1. Index map showing location of Hoopa Valley______________ C-3 2. Well-numbering system___________________________________ 3. Geologic map of the Hoopa Valley area___________________ 4. Geologic section along line A-A' through Hoopa Valley._____ 11 5. Geologic sections along lines B-B' and C-C' across Hoopa Valley______________________________________________ in WATER SUPPLY OF INDIAN RESERVATIONS WATER-RESOURCES RECONNAISSANCE OF HOOPA VALLEY,

Vast quantities of saline ground water await new commercial uses and economical demineralization processes for recognition as a valuable resource. Saline ground water is more widely distributed than any other natural resource, occurring throughout the United States and in geologic formations ranging from the oldest to the youngest. The Coastal Plain has the greatest reserve of fresh water in the country, but at depths ranging from a few feet to about 3,500 feet most of the fresh‐water aquifers also contain large quantities of brackish water. Paleozoic formations in the east‐central United States have long been producers of saline water as commercial brines and in association with oil and gas. The volume of saline ground water perhaps exceeds the fresh ground‐water supply in the Great Plains Region. The greater part of the Western Mountain Region is generally deficient in fresh ground water; however, saline water is present in highly permeable deposits in numerous closed basins and along saline streams. In each of these major ground‐water regions small to very large amounts of saline water can be pumped from wells ranging from a few tens of feet to several thousand feet in depth. Knowledge of saline water distribution is general and inadequate, having been attained as a by‐product of investigations of fresh‐water supplies. This knowledge should be expanded as technological advances in demineralization processes enhance the importance of saline water for potential supply in numerous water‐deficient areas.

Atlantic and Gulf Coastal Plain region___________________________ Cretaceous__________________________________________ Tertiary_________________________________ Quaternary _______________________________________________ East-Central region of Paleozoic and other old rocks______________ 40 Precambrian_______________________________ 4O Cambrian.______________________________________________ Ordovician______________________________________________ 42" Silurian._________________________________________________ Devonian_____________________________________________ Mississippian ____ _ ______________________________________ 45-Pennsylvanian_ ___________________________________________ 4ft Permian________________________________________________ Glacial drift__________________________________ Great Plains region____________________________________________ Paleozoic-___-_-______-________-__-__-________-_____-_._ 50 Mesozoie.______________________________________________ Tertiary______________________________________________ §4 Quaternary alluvium and glacial drift________________________ 56 m IV CONTENTS Western Mountain region____________ ___________. Paleo/oic__ _________________________________ Mesozoic. _________________________________. Tertiary_____________________________________ Quaternary alluvium____ ___________________ Summary of saline ground water.__________________. Atlantic and Gulf Coastal Plain region____-__.____. East-Central region of Paleozoic and other old rocks-Great Plains region_____________________________. Western Mountain region_______________________ Literature cited.________________________________________ Tables of measurements and analyses___________.__. Index. _______________________________.___.