Water Diversion from the Great Lakes: Is a Cooperative Approach Possible?

The concern about other states diverting water from the Great Lakes has prompted the Great Lakes States and provinces to adopt institutional arrangements that have effectively blocked any new diversions.Since the current arrangements do not allow diversions, important opportunities may be lost in the future. This article considers the possibility of 'economically desirable diversions' and how the gains should be allocated among the states and provinces to foster cooperation. The study shows that in most cases, new institutional arrangements will be needed before agreements can be reached. Game theory is used to determine how coalitions may be formed to reach cooperative agreements for diversions. Five different lake diversion games are tried involving Lake Ontario, Lake Superior, Lake Erie, Lake Michigan-Huron, and finally, all the lakes together. Diversions from Lake Ontario may offer the best opportunity for cooperation since there are no interlake effects.     

International Water Management in the Aral Sea Basin

ABSTRACT

The collapse of the Soviet Union in late 1991 has created five new states in the Aral Sea basin in Central Asia. In addition to the turmoil resulting from this political change, this section of the Aral Sea basin suffers from serious environmental degradation, including the desiccation of the Aral Sea itself This situation has arisen from the Soviet government's decision to develop the region as a center for cotton production from the early 1960s onward, a policy requiring heavy applications of agricultural chemicals and enormous irrigation diversions from the basin's two main rivers. the Amu and Syr Darya. Consequently the jive new states in the region have inherited a complex environmental and water management problem from a time when this part of the basin was managed by a singlegovernment. Any attempts to ameliorate the serious environmental degradation found in some parts of the basin now requires cooperation between the new states. This article reports on the measures taken by the new states and their likelihood of success. Overall, it appears that while the new states have enshrined valuable concepts of cooperation in their international water treaties, these concepts do not, as yet, appear to be supported either with adequate funding or with sufficient legislation at the national level.     

Eutrophication, phytoplankton dynamics and nutrient removal in two man-made urban lakes (Palácio de Cristal and Serralves), Porto, Portugal

Urban lakes are prone to eutrophication because of a number of factors, including a high water residence time (slow flushing rate), and high nutrient loads from artificial feeding of waterfowl and fish by visitors and from waterfowl faeces, falling leaves and nutrient run‐off from adjacent areas. This study focuses on the ecology of two similar‐sized urban lakes in Porto, Portugal, that exhibit some differing characteristics conducive to different trophic states and nutrient removal efficiencies. Although similar in many aspects, the two reservoirs developed quite diverse phytoplankton communities. The higher nitrogen load to Palácio de Cristal Lake could be the result of the higher concentration in its underground influent stream, while a less‐oxidized nitrogen form (ammonia) is higher in Serralves Lake. Nitrate concentrations are higher in Palácio de Cristal Lake than in Serralves as a result mainly of high nitrate loads (maximum values above 80 mg L⁻¹) in its influent stream. Interestingly, however, its nitrate removal efficiency is greater than for Serralves Lake. Cyanobacteria are the dominal phytoplankton In both lakes throughout the year. However, only one genus of this group (Pseudoanabaena mucicola) was the dominant phytoplankton in Palácio de Cristal Lake, while five Cyanobacteria species co‐dominated in Serralves lake. Regular monitoring of Cyanobacteria and their toxins in urban recreation lakes is advised.     

Fundamental differential equation of flow of a fluid with a variable mass in the case of bilateral water diversion

Conclusions 1.The relationships (26) and (27) obtained indicate that at the site of division of the flow there occurs a change in the depths h_o and h_cr related to the law of variation of discharge. Hence the line of the normal and the line of the critical depths will have a curvilinear outline. 2.For bilateral symmetric diversion of water the specific energy of the basic flow in section I-I is greater than the half-sum of the specific energies of the dividing flows.If we assume that E _l.d = E_r.d = E_d, then E_b1>E_d.Actually, the piezometric head in section I-I in the case of passage of part of the discharge into the diversions is partially expended on overcoming the losses and is partially transformed into kinetic energy of the diverted flows. 3.The fundamental differential equation of steady fluid flow obtained in the case of bilateral water diversion in open channels can be used only in the case when the distance between axes of the diversions is taken within limits from 0 tol.If the diversions are spaced at a distance greater thanl or symmetric pairs of diversions are located at a distance at which the interaction of these symmetric pairs of diversions with each other is not observed, then a system of fundamental differential equations of steady flow of a fluid with a variable mass obtained for each pair of diversions separately is set up. 4.Design engineers should bear in mind that the schemes of flow division shown in Figs. 3–6 are possible only for the case when part of the discharge is throughgoing along the main channel. It is necessary to calculate the main channel with consideration that there is enough water for all diversion channels.Translated from Gidrotekhnicheskoe Stroitel'stvo, No. 4, pp. 17–22, April, 1984.     

Alternative stable states in large shallow lakes?

Many lakes worldwide are experiencing great change due to eutrophication. Consequently, species composition changes, toxic algal blooms proliferate, and drinking water supplies dwindle. The transition to the deteriorated state can be catastrophic with an abrupt change from macrophyte to phytoplankton domination. This has been shown repeatedly in small lakes. Whether such alternative stable states also exist in large shallow lakes is less clear, however. Here we discuss the characteristics that give rise to alternative stable states in large shallow lakes either in the lake as whole or restricted to specific regions of the lake. We include the effect of lake size, spatial heterogeneity and internal connectivity on a lake's response along the eutrophication axis. As a case study, we outline the eutrophication history of Lake Taihu (China) and illustrate how lake size, spatial heterogeneity and internal connectivity can explain the observed spatial presence of different states. We discuss whether these states can be alternatively stable by comparing the data with model output (PCLake). These findings are generalised for other large, shallow lakes. We conclude that locations with prevailing size effects generally lack macrophytes; and, therefore, alternative stable states are unlikely to occur there. However, most large shallow lakes have macrophytes whose presence remains unexplained when only size effect is taken into account. By including spatial heterogeneity in the analysis, the presence of macrophytes and alternative stable states in large shallow lakes is better understood. Finally, internal connectivity is important because a high internal connectivity reduces the stability of alternative states.     

Understanding the Water Crisis in Northern China: What the Government and Farmers are Doing

The overall aim of this paper is to attempt to discover the true facts in order to ascertain whether or not there is a water crisis in China, and if there is, to identify the responses of the different stakeholders—government water officials, community leaders and farmers. In order to achieve this goal, several specific objectives are pursued. First, the paper evaluates the status of China's groundwater economy, examining whether or not the groundwater table is systematically falling. Second, in the parts of China that face a water crisis (or potential crisis), the paper documents the regulations and policies that the government—both local and regional—have implemented and discusses whether they have been successfully implemented. Third, it describes how farmers have responded to the water crisis and tries to assess whether or not their roles have helped alleviate the water scarcities or exacerbated the crisis. To meet these objectives, two large field surveys are used that cover seven provinces in northern China. The findings demonstrate that, although the water table is not falling everywhere in northern China, there are still a substantial number of communities that appear to be facing a water crisis. When there is a water crisis, the data show that the government in China has begun to make a number of policy responses, but the implementation is not always effective. Where water is becoming scarce, farmers and community leaders have also responded in numerous ways. However, farmers do not necessarily respond in ways that effectively save water, mostly because they do not always have incentives to do so. With good incentives, the research shows that they do save water. Hence, the government cannot ignore the way that farmers respond. Indeed, good policy needs to use this responsiveness to reduce the adverse effects of water scarcities and encourage conservation.     

Editorial

Abstract

Defining and measuring sustainability is a major challenge. This article argues these limitations need not stop us from trying to identify and value the possible impacts of what we are doing, or are thinking about doing, over time periods much longer than the lives of our investments, or even of the lives of those of us living today. Sustainability is a relative concept that must be applied in an environment undergoing multiple changes, changes that are occurring over different temporal and spatial scales. We depend on our water resource systems for our survival and welfare. Yet no one expects them to be restored to, or survive in, their most productive pristine states in the face of increasing development pressures for land in their watersheds and for water in their streams, rivers, lakes, and aquifers. A continuing task of water resource planners and managers is to identify the multiple impacts and tradeoffs resulting from what we who are living today may wish to do for ourselves and our immediate children and what we can only guess our yet-to-be-born descendants may wish us to do, or not do, for them in some distant future. This task must involve professionals from other disciplines in a context much broader than just water management. Once these impacts and tradeoffs are identified, it is then up to the political process to make choices when they are in conflict. All of us need to be a part of this decision-making process.     

The Abuja Ministerial Declaration on Water

Abstract

Africa faces major problems in its water resources sector, manifested in the periodic droughts and floods and compounded by population growth, urbanization, and environmental degradation. Africa has a large number of shared rivers, lakes, and aquifers, and the uses and protection of most are not regulated by any agreements between the riparian states. Where such agreements exist, they do not encompass all the riparians. A number of instruments were concluded by the African leaders with the view of addressing these problems. The most recent of those instruments is “the Abuja Ministerial Declaration on Water: A Key to Sustainable Development,” which was adopted in April 2002 and which establishes the African Ministerial Conference on Water. This article reviews the water resources problems in Africa and analyzes the various attempts to address them, including the Abuja Declaration.     

Predicted Native Fish Response,Potential Rewards and Risks from Flow Alteration in a New Mexico Arid Mountain Stream

Water and natural resource managers are concerned with evaluating how fish habitat and populations may respond to water diversions and small‐scale flow augmentations. We used two‐dimensional hydraulic models, habitat suitability curves and an individual‐based population viability model to assess whether flow augmentations of about 0.28–0.57 m³/s would create suitable habitat for federally listed native fish loach minnow Rhinichthys cobitis and spikedace Meda fulgida in a reach of the Gila River, New Mexico, and then examined how fish population viability may change under a variety of colonization and extinction scenarios. These simulations help to inform water management decisions in a reach of the Gila River where river diversions currently exist and new diversions and augmentations are being proposed. Our results suggest that the flow augmentations evaluated will result in small changes (on average across life stages, ?0.22% to 4.06%) in suitable habitat for loach minnow and spikedace depending on augmentation scenario and fish life stage. While these percent changes are small, they would result in a reduction in the dewatering of the river channel in a river reach where native fish abundance is thought to be low. Actual native fish responses to these habitat changes are unknown; however, these flow augmentations could potentially allow these native species to re‐colonize this river segment from upstream or downstream sources increasing species distribution and likely population viability. Maintaining viable populations of native fish in this river reach is dependent on complex factors including persistence of suitable habitat for multiple life stages, connectivity with other populations and minimizing risk of invasion from non‐native species. We recommend that these predictions from the habitat and population models be tested and verified in an adaptive management framework linking modelling, experimental management, monitoring and reassessment to inform water management decisions in the Gila River. Copyright © 2017 John Wiley & Sons, Ltd.     

Quantification of the Lake Trophic Typologies of Naumann (Surface Quality) and Thienemann (Oxygen) with Special Reference to the Great Lakes

Separate trophic scales and indices are developed for two of the most significant symptoms of eutrophication: surface water quality and hypolimnetic dissolved oxygen depletion. The scales are made comparable by expressing them in dimensionless form with a lower bound of zero and a mesotrophic range from 5 to 10. In this way, the two symptoms can be compared and their relative importance judged. This is done for the Great Lakes with the result that for both scales Lakes Superior, Huron, and Michigan are classified as oligotrophic. However, while central and eastern Lake Erie and Lake Ontario are classified as mesotrophic in terms of surface water quality, they range from eutrophic (central Lake Erie) to oligotrophic (Lake Ontario) on the oxygen scale. This is because, although these lakes are similar in surface water quality, their hypolimnion thicknesses range from approximately 4 m for central Erie to 70 m for Lake Ontario. Because of its shallowness, western Lake Erie does not have a persistent oxygen problem. In terms of surface quality it is classified as eutrophic.We have attempted to relate the two scales by correlating surface primary production and areal depletion rate. The results indicate that for lakes of similar primary production, areal oxygen depletion is directly proportional to hypolimnion thickness.