To the north of Miami the formations contain greater amounts of sand than to the south, therefore, wells are more difficult to develop, the yield is not so large, and drawdown is greater, The same salt water encroachment safety factors apply here as mentioned above.
In Dade County, generally speaking, it would be unsafe to attempt the development of a large supply east of the S. A. L. Railroad as far south as South Miami, and beyond this point U. S. Highway 1 would be the dividing line.
Under factor (4) agricultural, commercial, industrial, and sanitary aspects should be considered. For instance, should unrestricted development ever take place adjacent to or surrounding the area chosen for development of a well field, drainage might be demanded that would result in salt water gaining access to the site either through new canals or eventually by a further lowering of the water table and consequent farther movement to the west of the average annual two and one-half foot contour on the water table.
The development of such commercial and industrial or sanitary
interests as the Miami Intransit Air Depot, the proposed City of Miami sewage disposal plant, and a proposed airfield for privately owned airplanes and "dusters" have to be considered. The Miami Intransit Air Depot is soon to start pumping one and one-half to two million gallons per day of ground water and will develop a small cone of depression around its well field. There is no estimate of what the total pumpage may be in the future, but should a well field e located nearby, the two cones of depression would merge into one large one.* The sewage plant would have large quantities of waste to dispose of daily, possibly by emptying the treated