OCR Text |
Show GROUND WATER 61 and surface watercourses are hydrologically interconnected, and that each is ordinarily affected to some degree by withdrawals of water from the other. Ground water reservoirs also have values and potentials that can only be realized when surface waters are used in conjunction with them. For example, a ground water basin that is mined has value as a storage reservoir, much the same as a surface reservoir on a sur- face watercourse, which is partly empty and which may be filled during periods of high water, thus storing a supply to be drawn upon for subsequent use. Similarly, ground water basins which have been mined or drawn down can be recharged from surface water sup- plies, and the ground water basin then will be available to satisfy water demands subsequently placed upon it. One basic objective to be achieved in conjunctive management is that during times of heavy precipitation or high flows of surface watercourses, water which is in excess of that needed to satisfy sur- face water rights should, where physically feasible, be used to re- charge ground water reservoirs, rather than run to waste. During times of surplus in surface streams, those who pump from the ground water basin should refrain from doing so if they can obtain the water which they need from the surface surplus. This would per- mit a maximum use of surface water supplies in years when that supply is plentiful and also permit recharge of the underground basin. Then, in years of low surface runoff and short supplies of surface water, the ground water reservoirs could be called upon to satisfy the water demand, including not only those who normally pump ground water, but also those users who normally draw from surface supplies but whose water requirements cannot be satisfied from that source. While the law has been slow in requiring, or even permitting, State administrators to manage ground water basins conjunctively with surface watercourse, no one seriously disputes the need for such conjunctive management. In many cases, voluntary arrangements between State administrators and water users' organizations have resulted in a degree of conjunctive management, motivated by the prospect (and ultimate realization) that all users participating would benefit economically from that management. |