OPERATING POLICIES FOR A SURFACE/GROUND WATER SYSTEM1

The simulation of the conjunctive use of a surface reservoir and a limestone aquifer is described. The potential yields from each of the sources are of the same order. An important feature of the aquifer is that if the pumpage is reduced, much of the excess water is lost through springs. Five different operating policies are considered which determine whether pumpage should be taken from the reservoir or aquifer. The total safe yields for the historic period 1961–1977 are estimated for each policy and their relative advantages and disadvantages are discussed. The simulation is also carried out for 100 years of generated data to discover the long term consequences.     

Evaluating aquacultural use of thermal effluents: An application of system dynamics to environmental problem solving

Given the ecological burden imposed by power plants located in the coastal zone, efforts to improve the marginal benefits realized from their operation are warranted. Indeed, if this source of environmental pollution can be utilized to compensate for past ecological damage, then the benefits will be magnified many-fold.This study addresses the economic feasibility of utilizing heated effluent water from power plants to invigorate the growth of oysters raised under controlled conditions. The preliminary findings indicate that given proper combinations of system capacity, supplemental nutrient supplies, sea water flow and temperature gradients, such an operation is feasible.This is also a demonstration of a viable application of a sophisticated computer modeling approach to environmental problems. System Dynamics a technique pioneered at the Massachusetts Institute of Technology, is applied to evaluate the physical, biological, and economic interrelationships of the aquacultural system variables. It offers many advantages for the environmental manager and researcher, a number of which are realized in the present investigation.     

HYDROLOGIC CONSIDERATIONS OF THE UPPER ST. JOHNS RIVER BASIN,FLORIDA1

ABSTRACT: Since the early 1900's the Upper St. Johns River Basin, Florida, has been experiencing rapid agricultural development, through reclamation of the low-lying marshland by organized drainage districts, private land owners and corporations. These low-lying marsh areas, which constitute the floodplain, have been altered by the creation of levees, thereby reducing the natural storage capacity and permanently altering the regime of the system. This floodplain encroachment has resulted in both higher and lower water levels occurring in the upper basin area, and an increase in hydroperiod. This paper discusses the history and background of the basin accompanied by a hydrologic discussion, and suggests recommendations for a water management plan that could improve the overall operation and management of the Upper St. Johns River basin.     

WATER FOR ENERGY: AN APPROACH TO COMPREHENSIVE IMPACT ASSESSMENT1

ABSTRACT: The effects of energy development on the water resources of the Colorado River and Great Basin regions is expected to be substantial. Complex physical, economic and institutional interactions may be expected. Most research on these impacts appears single purpose, fragmented, uncoordinated, and often inaccessible to potential users - particularly those with responsibility for energy/water policy and program decisions. A comprehensive, integrative framework for assessing alternative water allocation decisions is outlined, taking a heuristic decision making model for evaluating impacts on maximization of gross (or net) regional product, and regional social welfare, and for assessing the region's contribution to national objectives. The suggested model provides a structure for application and integration of data of various kinds to a range of situations arising from possible impacts from energy proposals. The focus is on water and energy relationships but the model may provide a framework for comprehensive analysis of a variety of environmental actions and resulting system perturbations and effects.     

THE LEGALIZATION OF GROUNDWATER STORAGE1

ABSTRACT: California's courts have recently recognized the existence of underground aquifer storage rights that permit public agencies to (1) store imported waters in aquifers; (2) prevent others from expropriating that water; and (3) recapture the stored water when it is needed. The article describes the two appellate decisions that represent the common-law development of aquifer storage rights. Each decision related to separate aquifers that were subject to separate types of groundwater management programs. One decision involved an aquifer under the southeastern San Francisco Bay area that was managed under statutory authority and is entitled, Niles Sand and Gravel Co. v. Alameda County Water District 37 C.A.3d 924 (1974); cert. denied 419 US 869. The other decision involved an aquifer under Southern California's San Fernando Valley that was managed under judicial authority and is entitled, City of Los Angeles v. City of San Fernando 14 Cal.3d 199 (1975). The two decisions provide separate, but complimentary, public interest rationales for aquifer storage rights: (1) to protect water supplies necessary for the overlying community; and (2) to increase water supply efficiencies by using natural underground reservoirs wherever practicable. The Article reviews the relationship of aquifer storage rights to conventional groundwater rights and indicates aspects of the storage right that may need additional development.     

SURFACE WATER RESOURCES OF ST. JOHNS RIVER,FLORIDA1

ABSTRACT: The St. Johns River basin is the largest watershed entirely within the State of Florida, and is one of the few northward flowing rivers in the United States. The river basin contains 11,431 square miles, of which 9,430 square miles are drained by the river and its tributaries. The remainder drains into the Atlantic Ocean or the Intracoastal Waterway. Its largest sub-basin is the Oklawaha River basin, which has a drainage area of 2,870 square miles. Ground elevations range from sea level to 200 feet above mean sea level in the main river basin and as high as 300 feet above mean sea level in the Oklawaha River basin. This study was designed to investigate the surface water resources of the St. Johns River and the existing consumptive uses. The analysis revealed that the river is an extremely large and valuable resource which has been under-utilized and could play a much stronger role in serving the needs of the people in the basin.     

WATER DATA - A NEW AWARENESS1

ABSTRACT: One of the most significant changes m the field of hydrology in the past few years has been the increase m demand for basic data resulting from a new awareness on the part of planners, developers and managers of the essential nature of such data. For many years data collection has been an onerous, routine operation, following which the data were processed and stored - either in publications or file drawers - and the job considered completed. Two developments have changed that picture: the realization that we are drastically altering OUT environment, and the advent of the computer. The first forced us into a recognition of our need for accurate basic data and the second provided a new methodology for handling and using it. The change is evidenced m many ways and numerous activities are underway at both State and Federal level for all facets of the acquisition and handling of water data. The collection of basic data still involves hard routine work and a conscientious-effort to maintain a high level of quality. Hopefully, recognition of the absolutely essential nature of an adequate data base will result in the continued enhancement of the basic data collector and the concomitant increase in support of his activities.     

MAN ON THE HYDROLOGIC CYCLE1

ABSTRACT: Man is the one biological factor that can either make environment fit his needs or unknowingly ruin it. The major phases of the hydrologic cycle, in which man can interfere are: precipitation, storage and evaporation. A change m any one phase will generally cause modification to the other phases of the cycle: the only certainity is that the water balance will indeed balance.