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00 0 7t;~: /$,~~~~\ %'>):f '?A , :-~;;;._,f 5. Analyzing these theoretical relations in comparison with actual field observations and in determining how they are influenced by the val:ious parameters that affect them. The computer programs (3)3 used in the evaluation of written in FORTRAN IV for use with an IBM-1130 computer. available on request from the senior author. Generally, the engineer is interested in estimating the position of the water table at any given time and distance from the center of a recharge area during and after recharge. The general nature of the mathematical solutions offered by the heat flow analogy (6,14) are excellent for this purpose. How- ever, certain concessions must be made concerning the nature of ground water flow relative to ideal heat flow. These concessions, called the Dupuit- Forschheimer (D-F) assumptions (7,9), can be stated as follows: 1. Flow within the ground water body occurs along horizontal flow lines whose velocity is independent of depth. 2. The velocity along these horizontal streamlines is proportional to the slope of the free water surface. Several workers--Baumann (1), G1over,4 Bouwer (4,5), Bittinger and Tre1ease (3), Hantush (11), and Marmion (16)--have either applied 01: discussed their assumptions and the resulting mathematical solutions to the analysis of tran- sient gl:ound water mounds. Glover's theory, were These programs are COMPARISON OF FIELD OBSERVATIONAL DATA WITH THEORETICAL EVALUATIONS The best test of theories designed to describe ground water flow is to com- pare actual full scale field recharge water table responses with those predicted in theory by using constants experimentally evaluated at the site. This allows all the practical problems of errol:s in boundary value, definition, aquifer con- stant evaluation, and data acquisition to enter and be weighed in the compari- Son. For the most part, the application of mathematical theory to the descrip- tion of ground water mounds has evolved on assumptions which may bend nature into a form that can be handled by theory. These assumptions fall into three general categories: First, the mathematical relationship chosen to describe the flow pattern most likely to occur in the field; second, the mathematical de- scription of the geometric boundaries in the flow system; and third, the "con- stants" describing the aquifer through which flow occurs and the distribution of recharge as it enters the water table. A great deal of time has been spent on debating flow assumptions, but because of material requirements necessary for controlled field experiments the importance of the last two carries only bl:ief comment in the literature. Geometric Description and Location of Expel:imental Rechal:ge Ponds Two-acre ponds were located in western Fresno County, Calif., sloping alluvial fans, deposited by streams from the Diablo range. were approximately 13 miles apart, pond No. 1 near Five Points and Cantua. The surface soil was classed as a Panoche clay loam. The square, with observation wells (3IB-inch p~pe) jetted to below the along the perpendicular bisectors of the sides as shown in figures on the gently The ponds No. 2 near ponds were water table 1 and 2. 3Italic numbers in parentheses refer to Literature Cited, p. 15. 4See footnote 2. 2 ~'>";f.'..,t , :.:~~.~~~.:::t.;/j.:~:rr~t . .,'-:.i ';";':'....' ~ C;~){.~.----: ..0....-..... (t~~::;-.':-:-./:. -:~-./;- ,~..':.~......f................:~..:,.,.:~... . -~ : <:;f,!(: \:~~::~~:-- ';:~,':~':~,':;- ..,:,":....: "," .- - . ~f~'1.1i~it~~~1I"\Yi.fjit~l~;I~