B24. ANNUAL REPORT SMITHSONIAN INSTITUTION, 1949 
In addition to the cooperative investigations with States and local 
agencies, certain investigations primarily of Federal interest are being 
carried out with use of Federal funds only. For example, an extensive 
program of ground-water investigations is being conducted in the 
Missouri River Basin to provide basic information needed for planning 
and constructing the various water projects that are authorized or 
planned. This information will include determination of existing 
ground-water conditions and probable effect of irrigation on ground- 
water levels, especially with reference to waterlogging and drainage, 
canal locations with reference to seepage, areas where irrigation with 
ground water is feasible, the location of potential sources for farmstead 
and municipal water supplies, and so on. Other investigations, such 
as that recently started in the Central Valley of California, will provide 
basic information needed in the project to use excess floodwaters for 
recharging the heavily pumped ground-water reservoirs in the San 
Joaquin portion of the valley. Several projects also are under way 
in connection with defense plans. 
A large program of measurement of ground-water levels in observa- 
tion wells has long been an integral part of the cooperative program. 
Recently a small Federal fund was provided for extending this pro- 
eram, analyzing the data, and determining the current status of our 
ground-water supplies on a Nation-wide scale. The program includes 
the investigation of the possibilities of forecasting low-stage stream 
flows from fluctuations of ground-water levels, enabling more efficient 
control of reservoir and river stages in the operation of hydroelectric 
plants and permitting considerable economies in the generation of 
power. Conversely, base flow is an index of ground-water storage. 
As the ability of the ground-water reservoirs to absorb water ma- 
terially affects the runoff to be expected from rainfall, the analysis 
of data on ground-water levels should aid in flood forecasting. 
In addition to and as part of the above program, several research 
projects are under way, including the study of movement of water 
through soils and water-bearing materials; infiltration from streams 
and its effect on the temperature and quality of the ground water; 
the occurrence of ground water in fractures and solutional openings 
in impermeable rocks, such as limestone, tightly cemented sandstone, 
granite, etc., and the improvement of our techniques for locating 
producing wells in such rocks; earth subsidence resulting from the 
withdrawal of ground water, and related problems connected with 
elasticity and compressibility of artesian aquifers; methods of analyz- 
ing results of pumping tests to determine coefficients of transmis- 
sibility and storage; and a number of other projects. 
With respect to the probable future of ground-water investigations, 
it should be pointed out that ground-water development was expand- 
