INTERNATIONAL MANAGEMENT OF THE RIO GRANDE BASIN THE UNITED STATES AND MEXICO1

ABSTRACT. Despite radical differences in water laws, water management agencies, approaches to water planning, and financial resources, Mexico and the United States forged a common program to manage water and related land on the Rio Grande. Actions of Rio Grande Commissions related to stream gaging, boundary definition, and multiple-purpose construction projects are among the more successful international water-management efforts in the world. Cost-sharing arrangements promoted rapid completing of international works. However, joint action accomplished only part of expectations. International developments were competitive rather than complementary until basin water appropriation was virtually complete. Moreover, Commissions were not empowered to consider long-range competitive water needs, or regional water requirements, throughout the basin. International groundwater use coordination does not exist. International structures produce less than anticipated benefits. Hydroelectric generators are financial liabilities, irrigated acreage exceeds dependable streamflow, and soil salinization is experienced. Unanticipated environmental changes occurred in every major program. The Rio Grande experience points to the need for society to specify goals to which the use of water should contribute and to specify priorities for water use among different sectors of river basins and various segments of society.     

AN ANALYSIS OF RISING IRRIGATION COSTS IN THE GREAT PLAINS1

ABSTRACT: Irrigation costs are rising rapidly on the 32 million acres irrigated with ground water. Ground water levels are declining under about 15 million of those acres adding to increased costs. However, from 1975 to 1982, 75 to 80 percent of increased ground water irrigation costs were due to higher nominal energy prices and interest rates. In real dollars, adjusted for inflation, these costs have risen faster than other irrigation costs and the real rise in commodity prices has been very small. A continuation of rapidly rising costs and slowly rising prices will shorten the economic life of those aquifers experiencing declining water levels. That same condition of prices and costs place all ground water irrigators in a disadvantaged position compared to nonirrigators and could cause a decline in ground water irrigation.     

MATHEMATICAL MODELS: PLANNING TOOLS FOR THE GREAT LAKES1

The Great Lakes Basin Commission has initiated a Framework Study to assess the present and projected water- and related land-resource problems and demands in the Great Lakes Basin. Poorly defined objectives; incomplete and inconsistent data arrays; unknown air, biota, water, and sediment interactions; and multiple planning considerations for interconnected, large lake systems hinder objective planning. To incorporate mathematical modeling as a planning tool for the Great Lakes, a two-phase program, comprising a feasibility and design study followed by contracted and in-house modeling, data assembly, and plan development, has been initiated. The models will be used to identify sensitivities of the lakes to planning and management alternatives, insufficiencies in the data base, and inadequately understood ecosystem interactions. For the first time objective testing of resource-utilization plans to identify potential conflicts will provide a rational and cost-effective approach to Great Lakes management. Because disciplines will be interrelated, the long-term effects of planning alternatives and their impacts on neighboring lakes and states can be evaluated. Testing of the consequences of environmental accidents and increased pollution levels can be evaluated, and risks to the resource determined. Examples are cited to demonstrate the use of such planning tools.     

EVALUATION OF GREAT LAKES NET BASIN SUPPLY FORECASTS1

ABSTRACT: Evaluation of the Great Lakes Environmental Research Laboratory's (GLERL's) physically-based monthly net basin supply forecast method reveals component errors and the effects of model improvements for use on the Laurentian Great Lakes. While designed for probabilistic outlooks, it is assessed for giving deterministic outlooks along with other net basin supply forecast methods of the U.S. Army Corps of Engineers and Environment Canada, and with a stochastic approach commissioned by the Corps. The methods are compared to a simple clima-tological forecast and to actual time series of net basin supplies. Aetual net basin supplies are currently determined by estimating all components directly, instead of as water-balance residuals. This is judged more accurate and appropriate for both forecasting and simulation. GLERL's physically-based method forecasts component supplies while the other methods are based on residual supplies. These other methods should be rederived to be based on component supplies. For each of these other methods, differences between their outlooks and residual supplies are used as error estimates for the rederived methods and component supplies. The evaluations are made over a recent period of record high levels followed by a record drought. Net basin supply outlooks are better than climatology, and GLERL's physically-based method performs best with regard to either component or residual net basin supplies. Until advances are made in long-range climate outlooks, deterministic supply outlooks cannot be improved significantly.     

GROUNDWATER MANAGEMENT ON THE TEXAS HIGH PLAINS1

ABSTRACT The effects of major water management practices on the pumping requirement from the Ogallala aquifer are discussed. Demand on the aquifer may be reduced as much as 15 percent by recycling irrigation runoff, 25 percent by recycling irrigation runoff and irrigating with water from playas, and 29 percent by recycling irrigation water in combination with irrigation from playas and artificial recharge of playa water to the aquifer. Other practices that can result in more efficient use of precipitation and groundwater are limited irrigation, land forming, soil profile modification, and improved irrigation systems, thereby reducing the pumping demand on the Ogallala. Additional water supplies can possibly be obtained by water harvesting, weather modification, and water importation. Conclusions reached were that the overdraft on the aquifer can be reduced by the application of sound water management practices on an area-wide basis.     

IMPACT OF DROUGHT ON QUALITY OF POTENTIAL WATER SUPPLY SOURCES IN THE SANGAMON RIVER BASIN1

ABSTRACT: The analysis of stream flow and several water quality parameters in six Illinois rivers showed both deterioration and improvement in quality indicators during 1976–1977 drought. The adverse impacts were an increase of ammonia and manganese concentrations and, to a lesser degree, increased concentrations of phenol and specific conductance. At the worst point during the drought, the 12-month moving average of monthly ammonia concentration in the Sangamon River was about 620 percent higher than the antecedent value. On the other hand, average concentrations of nitrites and nitrates, total iron, and the number of coliform bacteria significantly decreased. This positive response suggests that streams which are considered unsuitable for municipal supply due to high levels of these quality indicators may be used as emergency sources during droughts.     

MULTIPLE CRITERIA SCREENING OF A LARGE WATER POLICY SUBSET SELECTION PROBLEM1

ABSTRACT: A new screening approach is applied to a large‐scale multiple criteria water management problem to remove actions that cannot possibly be in the best subset. An inherent advantage of the approach is its ability to identify inferior actions by examining them individually, rather than within subsets. In a case study involving the selection of actions to address high water levels in the Great Lakes‐St. Lawrence Basin, two statistical indicators, the mode and the mean, are used to aggregate the opinions of experts and representatives of interest groups on the impacts of actions according to various criteria. Application of the screening approach shows that some of the proposed actions can be removed as they can never be in the optimal subset, thereby reducing the size of the problem.     

A SURVEY OF STATE WATER CONSERVATION PROGRAMS IN THE U.S.1

ABSTRACT: Adequate water supplies are critical to the maintenance of a community's health and economic well-being. Across the nation communities are struggling to meet an expanding demand for water from municipal, industrial, agricultural, recreation, water quality, and power generation users. As the demand grows and communities actively compete with one another for a limited water supply, states are being called upon to help solve the problem. One possible solution that is being used in many areas is the development and implementation of a water conservation program to stretch the limited supply as far as possible. using a mailed survey, state water conservation programs and some of the characteristics of the different programs were documented. Responses to the nationwide survey were obtained from all 50 states. The specific water conservation program elements on which information was received from the survey included laws and restricted use, community assistance, education, research, and other services. Recommendations for states developing or considering the development of a water conservation program are outlined.     

SIMPLE TROPHIC STATE CLASSIFICATION OF THE CANADIAN NEARSHORE WATERS OF THE GREAT LAKES1

ABSTRACT: Trophic classification of the Canadian nearshore waters of the Great Lakes is attempted using summer, surface water quality data for the early 1970's. A generalized Composite Trophic Index is developed using paired linear relationships for total phosphorus, chlorophyll a, and Secchi depth data for 66 defined nearshore regions. The chlorophyll a and total phosphorus relationship indicates that the nearshore waters contain a low chlorophyll a concentration for a given total phosphorus concentration than observed for the open waters of the Great Lakes or for smaller Canadian lakes. The most eutrophic nearshore regions occur in areas of relatively restricted circulation and/or high nutrient loadings. These include the Bay of Quinte, Toronto and Hamilton harbours, and portions of Lake We's Western Basin. Lakes Huron and Superior are generally oligotrophic, except for some embayments. Although nearshore water quality is highly variable, this apprach represents a reasonable compromise with respect to analytical complexity. The Composite Trophic Index removes biases introduced through the use of a single trophic state indicator and uniquely describes the nearshore water quality in terms generally comparable to other water bodies.     

ALTERNATIVES FOR SALINITY MANAGEMENT IN THE COLORADO RIVER BASIN1

ABSTRACT The Colorado River Basin faces the dilemma of an increasing demand for water while presently struggling with salinity concentrations approaching critical levels for some water uses. Based upon projected development salinity concentrations are predicted to exceed 1200 mg/1 at Imperial Dam by the year 2010. Annual losses to the basin economy associated with increased salinity will exceed $50 million by the year 2010. Although methods of controlling salt discharges are relatively unrefined, certain conclusions, based upon Bayesian statistical methods, can be reached. Five basic alternatives for coping with the problem are presented and evaluated in this paper: (1) do nothing; (2) adopt arbitrary salinity standards; (3) limit development; (4) control salt discharges at a cost equal to the cost of doing nothing, or (5) minimize total costs to the basin. Total costs associated with any given alternative, or the given salinity resulting, are the sum of salinity detriments (cost to users for water of increased salinity plus economic multiplier effects) plus the cost of constructing salt discharge control works. These impacts upon basin economy and Colorado River water quality for each alternative are presented and related to questions of equity which will play a role in arriving at any long-term solution to the Basin's problem.     

PHOSPHORUS MANAGEMENT TO PROTECT LAKE WATER QUALITY1

ABSTRACT: The Hallett Quarry gravel pit lakes are an active sand and gravel extraction operation located 0.4 km north of the City of Ames, Iowa. During periods of drought, these lakes serve as a supplemental water supply for Ames. A modified version of the Vollenweider input-output model was used to predict future water quality under various watershed land use, drainage, and lake configurations. The dominant factor controlling the future water quality of the lakes was found to be the nutrient input. It is recommended that a management plan to protect the future water quality should be oriented towards reducing the sources of phosphorus to the lakes.     

ATMOSPHERIC CONTROLS OF WATER EXCHANGE IN GREAT LAKES BASIN1

ABSTRACT Existing meteorological controls of water exchange by precipitation and evaporation on the Great Lakes are almost entirely inadvertent and related to man's urban-industrial complexes and their effect upon precipitation processes. These inadvertent effects have led to 10 to 40% increases in precipitation in localized areas within the basin. Envisioned growth of urban-industrial complexes within the Great Lakes region should lead to more inadvertent weather modification in the Basin. The only existing planned weather modification efforts are those at Lake Erie which are attempting to eliminate by redistribution the concentration of lake-derived heavy snowfall along the south shore. It appears reasonable to assume that practical increases of lake precipitation on the order of 5-20% could be achieved on an operational basis over the Great Lakes in the next 10 years, but the time of accomplishment will depend on national priorities, international cooperation, and economic factors. These activities would certainly produce a sizeable increase in the water quantity of the Great Lakes and should result in an improvement in water quality. Operational methods of evaporation suppression applicable to the lakes are just not available. Meteorological controls to ameliorate certain undesirable lake-effect snowstorms are a near reality.     

EFFECTS OF DIVERSIONS ON THE NORTH AMERICAN GREAT LAKES1

ABSTRACT: Water level fluctuations of the Great Lakes often have created regional controversies among the states and Canadian provinces that share this vast resource. Even though the 100-year range of their water levels is only four to five feet, episodes of high and low Great Lakes water levels have been a recurring problem throughout the twentieth century. The possibility of increased diversion and consumptive use has exacerbated the existing conflicts over how to manage this water resource. A research project evaluated the effects of interbasin diversion on the Great Lakes system and on the industries that depend on the maintenance of historical water levels, namely hydropower and commercial navigation. The simulation approach employed in this research and some of the important findings are presented. The approach is similar to that used in recent government studies of Great Lakes water level regulation. Several significant modifications were made specifically addressing the diversion issue. Aggregate annual impacts to hydropower and shipping resulting from a diversion of 10,000 cubic feet per second were found to vary from 60 to 100 million dollars. Increases in impacts as a function of diversion rate are nonlinear for the navigation industry.     

HYDROELECTRIC POWER AND SCENIC PROVISIONS OF THE 1950 NIAGARA TREATY1

ABSTRACT: An important international Niagara River management issue concerns allocation of the average 202,000 cubic feet per second river discharge for hydroelectric power and scenic purposes. Major water diversions from Niagara Falls are necessary for power production. Flow is allocated by the 1950 Niagara Treaty which is intended to maximize power benefits and preserve and enhance the scenic fals spectacle. This paper examines the extent to which the Treaty objectives have been achieved. Based on analyses of government documents, engineering data, and falls-viewing patterns, it is concluded that the 1950 Treaty led to enhancement of the falls spectacle and increased power generation. But significant additional power diversions probably are attainable without adverse effect upon the existing falls spectacle. Reducing daytime summer Horseshoe Falls flow and scheduling spring and autumn flow according to viewing patterns are possible means of increasing power diversions. Existing generating facilities could use considerably more water and the value of additional Niagara hydroelectricity is very high in terms of generation-cost savings over alternative power sources. Because of the cultural importance of the falls, Treaty modifications to permit increased power diversions are not recommended without prior public opinion sampling and on-site viewing experiments. These findings highlight the need for more careful study before long-term international agreements are concluded and illustrate the need for more flexible treaty arrangements to permit periodic adjustments for changing conditions.     

ON THE NECESSARY AND SUFFICIENT CONDITIONS FOR A LONG-TERM IRRIGATED AGRICULTURE1

ABSTRACT. Salinization and water logging have been the nemesis of irrigated agriculture societies since Babylonian times. Low quality water substitutes for high quality water for irrigation at an increasing rate up to the limits of the soil's ability to transmit the additional water and remove excess salts from the root zone. Soil transmissibility can be increased by additional investment in drainage ditches and underground tile. Low valued-high salt tolerant crops can be substituted for higher valued-salt sensitive crops to maintain production in areas served by irrigation water sources of deteriorating quality. Thus physical factors specify the necessary conditions for survival of an irrigated agriculture. The sufficient conditions for survival must be in terms of a positive net income in each subplanning period discounted to its present value.     

CLIMATIC VARIATION AND SURFACE WATER RESOURCES IN THE GREAT BASIN REGION1

ABSTRACT: There is mounting evidence that increasing amounts of atmospheric carbon dioxide may lead to significant changes in global climate during the next century. The possible effects of such climatic changes on surface runoff in the Great Basin Region of the western United States has been investigated by applying water balance models to four watersheds in Nevada and Utah. The most probable change, a 2°C increase in average annual temperature coupled with a 10 percent decrease in precipitation, would reduce runoff from 17 to 28 percent of the present mean, with drier basins showing the greatest change. Decreasing precipitation by 25 percent causes runoff reductions of 33 to 51 percent. Equivalent changes to a cooler and wetter climate show corresponding increases in runoff of approximately the same magnitude, but such a shift is not considered likely. Based on projected water requirements for the year 2000, a change to a warmer and drier climate would cause severe water shortages in many parts of the Great Basin.     

THE EFFECTS OF AGE AND WATER FLUCTUATIONS ON FISH POPULATIONS1

ABSTRACT Two lakes having similar soil types were studied to determine the effects of age and water fluctuations on plankton, benthos and fish populations. Bluff Lake is an older man-made lake which is drawn down in the mid-summer. Oktibbeha County Lake is a young lake and the water levels are maintained. Chemistry data from the two lakes indicate that their chemical properties are very similar. Neither lake would be considered very fertile. Net plankton populations in Bluff Lake and Oktibbeha County Lake were comparable when analyzed on a number of organisms per liter basis. Fluctuations of water levels did not seem to have an effect on the net plankton populations. The benthic population in Bluff Lake is slightly higher than that found in Oktibbeha County Lake. This is true for both numbers and weight per square meter. The species composition of benthic organisms in the two lakes were similar. Based on one-acre samples from each lake, Bluff Lake has a more balanced fish population than does Oktibbeha County Lake. Neither, however, seems to support populations of game fish in which a high percentage of these are in the available or harvestable range. Both lakes contain high populations of gizzard shad.     

EMERGING CONCEPTS FOR THE CONDUCT OF STATE WATER RESOURES PLANNING1

ABSTRACT: The development of water resources planning at the state level is discussed. Although there are significant specific differences among state planning programs, some common general principles of state water resources planning are emerging over time. In the interest of reconciling conflict over water allocation states are engaged in policy clarification, mediation of interst group conflict, and provision of baseline information.     

MODELING THE IMPACTS OF WATER LEVEL CHANGES ON A GREAT LAKES COMMUNITY1

ABSTRACT: Recent research that couples climate change scenarios based on general circulation models (GCM) with Great Lakes hydrologic models has indicated that average water levels are projected to decline in the future. This paper outlines a methodology to assess the potential impact of declining water levels on Great Lakes waterfront communities, using the Lake Huron shoreline at Goderich, Ontario, as an example. The methodology utilizes a geographic information system (GIS) to combine topographic and bathymetric datasets. A digital elevation surface is used to model projected shoreline change for 2050 using water level scenarios. An arbitrary scenario, based on a 1 m decline from February 2001 lake levels, is also modeled. By creating a series of shoreline scenarios, a range of impact and cost scenarios are generated for the Goderich Harbor and adjacent marinas. Additional harbor and marina dredging could cost as much as CDN $7.6 million. Lake freighters may experience a 30 percent loss in vessel capacity. The methodology is used to provide initial estimates of the potential impacts of climate change that can be readily updated as more robust climate change scenarios become available and is adaptable for use in other Great Lakes coastal communities.     

IMPACT OF WATER CUTBACK ON SUGARCANE PRODUCTION IN THE FLORIDA EVERGLADES1

ABSTRACT: Sugarcane (Saccharum spp.) was planted in six lysimeters containing Pahokee muck (Lithic Mediaprist) where water tables were maintained at 30, 60, and 90 cm depths. The main objective was to study the impact of a 40 percent water cutback (108 mm) on sugarcane production during the period near the end of the dry season (i.e., May). The water cutback treatment was simulated through manipulation of water table depth. Due to the high available water capacity of the muck soil and selection of a sugarcane cultivar ‘CP63-588’ (which has a high tolerance of water table fluctuations), the sugarcane growth, and the yields of sugarcane biomass and sugar were not significantly different as a result of the treatments with and without 40 percent water cutback during a period of two months. This result is in good agreement with the 1981 cane yield in the Everglades Agricultural Area where a 35 percent water cutback was imposed during the 1981 drought.