Great Lakes Levels and Flows: Past and Future

The many analyses of the more than 100 years’ record of Great Lakes levels and of precipitation in the basin are generally assumed to provide a reasonable basis for predicting, statistically, future lake levels. The usefulness of this assumption is questioned because of increasing consumptive use of Great Lakes waters, and probable climatic change over the next century. The International Joint Commission's 1981 report on consumptive use and diversions gives as its most likely scenario an annual growth of 2.7% in consumptive uses. By the year 2035, this would reduce Great Lakes outflows by about 708 m³ (25,000 cfs), with an estimated loss of “$200 million per year in hydro power production.” The climatic effects of the inexorable increases in atmospheric carbon dioxide (CO₂) due mainly to burning of fossil fuels are still difficult to predict. However, the best predictions available suggest that in the next 70 years or so, the mean air temperature in the Great Lakes basin will rise by approximately 3C° and may well be accompanied by slightly less precipitation. Increases in evaporation from the Great Lakes would be equivalent to 7–8% of the mean annual flow of the St. Lawrence. These two factors — increased evaporation and increased consumptive uses — suggest that significantly lower lake levels and flows of interconnecting channels and the St. Lawrence River are likely in the next century.     

改进的假设抽取法在产业部门用水关联分析中的应用

应用在纵向集成测算法及假设抽取法(HEM)基础上改进的产业用水关联分析方法,根据中国2000年水利用投入产出表数据,通过直接消耗水量与纵向集成消耗水量的对比,以及关联度分解因子构成分析,定量测算了产业部门间用水的关联作用.分析结果表明:(1)直接用水量最高的农业、轻工业、重工业部门,分别将其直接用水量的39.3%、26.4%、19.5%通过产业间产品交易间接输送给其余产业部门.其余产业部门为用水净输入部门,最终需求产品用水的90%以上间接来自购买其他部门的产品.其中农业、食品制造业在整个经济系统中用水输出和输入作用最为显著;(2)水利用部门的关联实际上是经济系统产业间水需求的转移,最终需求总量不变时,其结构调整不会对用水总量产生影响;(3)可以通过虚拟水战略等手段调整高用水系数部门的最终需求规模以缓解水资源供需矛盾,促进节水技术的提高以及节水结构的优化;(4)纵向集成测算法及其基础上改进的HEM法将系数比较转化为实际用水数量的分析,分解出影响部门用水的组成因素,量化了部门间以及部门内部用水关联关系.     

Probabilistic Water Demand Forecasting Using Projected Climatic Data for Blue Mountains Water Supply System in Australia

Long term water demand forecasting is needed for the efficient planning and management of water supply systems. A Monte Carlo simulation approach is adopted in this paper to quantify the uncertainties in long term water demand prediction due to the stochastic nature of predictor variables and their correlation structures. Three future climatic scenarios (A1B, A2 and B1) and four different levels of water restrictions are considered in the demand forecasting for single and multiple dwelling residential sectors in the Blue Mountains region, Australia. It is found that future water demand in 2040 would rise by 2 to 33 % (median rise by 11 %) and 72 to 94 % (median rise by 84 %) for the single and multiple dwelling residential sectors, respectively under different climatic and water restriction scenarios in comparison to water demand in 2010 (base year). The uncertainty band for single dwelling residential sector is found to be 0.3 to 0.4 GL/year, which represent 11 to 13 % variation around the median forecasted demand. It is found that the increase in future water demand is not notably affected by the projected climatic conditions but by the increase in the dwelling numbers in future i.e. the increase in total population. The modelling approach presented in this paper can provide realistic scenarios of forecasted water demands which would assist water authorities in devising appropriate management strategies to enhance the resilience of the water supply systems. The developed method can be adapted to other water supply systems in Australia and other countries.     

The benefits and costs of allocating space in an existing reservoir to river regulation

Subsequent to the selection of design capacity and the construction of a storage reservoir, water demands, valley land-use, and economic constraints may change and the reallocation of storage space in an existing reservoir may become desirable. The benefits of reallocating space to flood mitigation are the equivalent annual flood damages averted, while the costs arise from water shortages which would not have occurred if space had not been reallocated. These benefits and costs can be quantified for a particular region and the optimal airspace provision calculated. In a case study area, reallocation of part of the storage volume was justified, while excessive reallocation would result in significant net costs to the region. The optimum airspace allocation was not sensitive to the value assigned to water. The procedure used here could be applied to other river valleys, where the solution would be dependent on the intensity of land-use, as it influences both potential flood damages and the costs of water shortages.     

Multi-Objective Optimization Model for the Allocation of Water Resources in Arid Regions Based on the Maximization of Socioeconomic Efficiency

The escalating world population has led to a drastic increase in water demand in the municipal and drinking water, agriculture and industry sectors. This situation necessitates application of effective measures for the optimal and efficient management of water resources. With this respect, a two-objective socioeconomic model (aimed at job creation) has been presented in this study for the optimum allocation of water resources to industry, agriculture and municipal water sectors. In the agriculture sector, the production function of each product has been determined and then, based on the production functions, areas under cultivation, product yield and the income obtained from each product, the combined objective function has been specified. In the industry sector, since water demand is a function of the amount of produced products, price of supplied water and the price of other supplies, the demand function of this sector was determined regionally. Also, considering the existing necessity in meeting the municipal water requirement, the total amount of water needed by this sector was fully allocated. Then by using two meta-heuristic algorithms, i.e. genetic algorithm (GA) and particle swarm optimization (PSO), the objective functions were maximized and the water resources were optimally allocated between agriculture and industry sectors and the results were compared. Ultimately, comparing the results gained by PSO and GA algorithms, PSO with an economic and profit growth of 54 % and a 13 % rise in employment relative to the base condition, turned out to be more efficient in this application.     

Water Shortages in the Hunter Region of New South Wales

ABSTRACT

The Hunter region of New South Wales is one of the most rapidly developing mining and industrial areas in Australia. Popular belief exists that the great benefits portended by the new cycle of development will be stifled by water shortages. However, the essence of this study is that emerging water shortages are a function of institutional circumstances—circumstances which provide a privileged position to one class of water users, irrigators, to the detriment of others. If no additional water were to be provided to irrigation, it is seen that water shortages do not emerge until well into the next decade. Further, it is seen that current augmentation policies, rather than accommodating water shortages, tend to perpetuate them a t great social cost. Several institutional alternatives are considered to facilitate the more beneficial use of existing supplies.     

Quantifying the Poorly Known Role of Groundwater in Agriculture: the Case of Cyprus

Agriculture in the Mediterranean region is constrained by limited water resources and in many countries irrigation demand exceeds the renewable water supply. This paper presents a comprehensive approach to (a) quantify the consumptive green (soil moisture provided by precipitation) and blue (irrigation) water use for crop production, (b) distinguish the contribution of groundwater to irrigation supply and (c) estimate groundwater over-abstraction. A spatiotemporally explicit soil water balance model, based on the FAO-56 dual crop coefficient approach, which includes the computation of evaporation losses of the different irrigation systems, was applied to the 5,760-km² area of the Republic of Cyprus for the agro-meteorological years 1995–2009. The model uses national agricultural statistics, community-level data from the agricultural census and daily data from 34 meteorological stations and 70 precipitation gauges. Groundwater over-abstraction is quantified per groundwater body, based on the sustainable abstraction rates specified in the Cyprus River Basin Management Plan, as prepared for the EU Water Framework Directive. It was found that, on average, total agricultural water use was 506 Mm³/year, of which 62 % is attributed to green water use and 38 % to blue water use. Groundwater contributed, on average, 81 % (151 Mm³/year) to blue water use and exceeded the recommended abstraction rates by 45 % (47 Mm³/year). Even though the irrigated area decreased by 18 % during the 2008 drought year, relative to the wettest year (2003), total blue water use decreased by only 1 %. The limited surface water supply during the driest year resulted in a 37 % increase in groundwater use, relative to the wettest year, and exceeded the sustainable abstraction rate by 53 % (55 Mm³/year). Overall, the model provides objective and quantitative outcomes that can potentially contribute to the improvement of water resource management in Mediterranean environments, in the light of climate change and expected policy reforms.     

Advising Morocco: adopting recommendations of a water footprint assessment would increase risk and impair food security for the country and its farmers

ABSTRACT

A water footprint assessment is not an appropriate guide for allocating water efficiently in water-scarce regions such as Morocco. Water footprints contain too little information to identify policies or investments that will achieve public goals regarding agriculture, natural resources and livelihoods. In fact, they would impair efforts to enhance food security and sustain economic growth. The better way forward for Morocco and other countries is to analyze the full range of economic, social and environmental issues pertaining to water use in agriculture and other sectors.     

Economic Value of Tree Fruit Production in Jordan Valley from a Virtual Water Perspective

The continuous high demand of water resources for agricultural uses in Jordan is leading to a water crisis. A possible partial solution may be to import food which requires large amounts of water to grow instead of cultivating high water consuming crops. Crops such as banana and citrus cause a huge virtual water loss, which can be reduced by cultivating other less water-demanding crops. This paper focuses on analyzing the economic value of cultivating tree fruit from a virtual water perspective. The virtual water calculations in this study depend on the average rainfall, water quota, and the crops’ water requirements (CWR). The gross profit to the water use ratio showed that banana has the lowest value 0.085 JD/m³, while lemon has the highest value 1.65 JD/m³. The calculations show that the average embedded water in fruits varies from about 470 m³/ton for grapes to about 2,500 m³/ton for dates. Banana and citrus plantations consume about 21 and 71 million cubic meters (MCM) annually, respectively, which represent about 85% of the total water consumption in fruit tree plantation. The virtual water flow estimation embedded in fruits shows that Jordan imports about 77 MCM per year. However it exports about 29 MCM per year. The results were analyzed from an integrated water resources management (IWRM) perspective. The analysis shows that a way to recover some of the water costs involved in, e.g., banana production would be to increase the fertilizer cost by about 10%. This would double the water cost and increase the banana production cost by about 6.8%. Using this alternative could be a way to better manage the huge losses in virtual water involved in banana production in the Jordan Valley.     

Domestic Use of Irrigation Water: Health Hazard or Opportunity?

In an environment of growing scarcity and competition for water, there is increasing pressure on the irrigation sector to make irrigation for crop production more efficient and to transfer water to the urban, industrial and environmental sectors. However, irrigation water is extensively used for non-agricultural purposes, including domestic purposes, and an exclusive focus on water efficiency in agriculture could actually reduce the availability of domestic water within irrigated areas. It is argued, based on available literature, that this would have important health implications because in many developing countries the availability of water, rather than the quality of water, is of crucial importance to health. Two case studies are presented from Sri Lanka and Pakistan where people make use of irrigation water for a range of domestic activities. Water resource policies have to take these uses into account to avoid negative health implications for poor disadvantaged segments of the population. Barriers to optimizing benefits of linking the irrigation water supply to domestic needs seem to be institutional and psychological rather than medical, technical or economic.     

Water Policies for the Middle East in the 21st Century: The New Economic Realities

Although many researchers have claimed that the Middle East faces a desperate situation with regard to future water use, few have provided detailed analyses as to why this should be the case. In this paper it is claimed that with the changing nature of the economies of the countries of the region, together with rapid population growth, new water policies are required which recognize the growing significance of the service sector of the economy and the importance of urban communities. These policies should focus on the importance of commercial/industrial systems as the main wealth providers in the 21st century. Detailed analyses of the available water resources reveal that most of the countries of the Middle East will be able to meet the water needs of their citizens up to 2025 without too much difficulty. To achieve this the reallocation of at least some irrigation water to other uses will be necessary. However, the volumes of water needed are in many cases not huge. Three countries, Jordan, Oman and Tunisia, will experience major problems of water supply, but only Jordan can be regarded as approaching a crisis situation. Even here desalinated water could at least alleviate the situation for urban dwellers, though costs would be high.     

Impacts of Land-use Changes on the Hydrology of the Grande River Basin Headwaters,Southeastern Brazil

Land-use changes affect soil water balance. The Upper Grande River Basin (UGRB) headwaters have undergone intense modifications in land use. This study was conducted to simulate, using the LASH model, the impacts on the hydrological regime in the UGRB with five land-use trends: S₁ and S₂ – reforestation with eucalyptus covering 20 % and 50 %, respectively, from the current grassland area; S₃ – reforestation with eucalyptus covering 100 % of the current grassland area only in the sub-basins where this trend is predominant; S₄ and S₅ deforestation of 30 % and 70 % of the forest remnants in the Mantiqueira Range region for the cultivation of grasslands, respectively. Results demonstrate that runoff would be reduced due to the land-use changes by 51.65 mm yr^?1, 110.29 mm yr^?1 and 59.48 mm yr^?1 for scenarios S₁, S₂ and S₃, respectively. However, scenarios S₄ and S₅ could increase streamflow by 57.63 mm year^?1 and 156.78 mm year^?1, respectively. This indicates that land-use changes might make the basin more prone to flooding and other hazards associated with increased runoff.     

Water Saving and Energy Reduction through Pressure Management in Urban Water Distribution Networks

Water shortages and climate change are worldwide issues. Reduction in water leakage in distribution networks as well as the associated energy saving and environmental impacts have recently received increased attention by scientists and water industries. Pressure management has been proposed as a cost-effective approach for reduction in water leakage. This study conducted a real-world water pressure regulation experiment to establish the pressure-leakage relationship in a district metering area (DMA) of the water distribution network in Beijing, China. Results showed that flow into the DMA was sensitive to inlet water pressure. A 5.6 m reduction in inlet pressure (from 38.8 m to 33.2 m) led to an 83 % reduction (12.1 l/s) in minimal night flow, which is a good approximator of leakage. These reductions resulted in 62,633 m³ of water saved every year for every km pipe, as well as associated savings of 1.1?×?10⁶ MJ of energy and 68 t of CO₂ equivalent greenhouse gas emissions. The results of this study provide decision makers with advice for reducing leakage in water distribution networks with associated energy and environmental benefits.     

产业与部门用水关联及尺度效应分析

以河南省为例,应用基于纵向集成的改进假设抽取法,对该区域三次产业和八大部门的水资源消耗及转移状况进行量化分析,由分析结果可知:农业和基础工业是河南省的主要水资源净输出部门,轻工业、高科技工业和建筑业是主要的净输入部门。河南省用水关联性较强产业部门包括农业-轻工业、农业-高科技工业、基础工业-高科技工业以及农业-基础工业。对不同尺度的用水关联成果进行了分析,分析结果表明:不同分析尺度的纵向集成消耗总量是相等的,且与其直接消耗总量相同;用水关联具有非线性的尺度效应,不能通过线性运算实现不同尺度关联效应的转换;分析尺度越小,分类越细化,内部效应越低,系统中流动转移的水量就越多,反之则相反。研究成果可为区域产业结构调整和水资源管理政策的制定提供参考。     

Achieving water security in Nepal through unravelling the water-energy-agriculture nexus

ABSTRACT

This article investigates water security in Nepal from the perspective of the water-energy-agriculture (food) nexus, focusing on pathways to water security that originate in actions and policies related to other sectors. It identifies promoting development of Nepal’s hydropower potential to provide energy for pumping as way to improve water security in agriculture. Renewable groundwater reserves of 1.4 billion cubic meters (BCM), from an estimated available balance of 6.9 BCM, could be pumped to irrigate 613,000 ha of rainfed agricultural land in the Terai plains, with a potential direct economic gain of USD 1.1 billion annually and associated benefits including promotion of energy-based industry, food security and local employment. Governance also plays an important role in addressing water security. We conclude that a nexus-based approach is required for effective water management and governance.     

Pesticides and PCB in the Grand and Saugeen River Basins

The Grand and Saugeen rivers drain two major basins in the Province of Ontario. Information is presented on pesticide use and losses of pesticides and PCB into these two river systems and their delivery to the Great Lakes. Pesticides were divided into persistent (those that persisted from one season to the next) and non-persistent. Members of both categories appeared in upstream waters; however, only the former appeared at the mouth. Non-persistent pesticides found in the system occurred at the time of spraying or shortly thereafter in storm runoff waters but not at other times.Persistent pesticides found in the system included those that had been discontinued (i.e., dieldrin and DDT and its metabolites) and those in use throughout the study period [i.e., chlordane (and heptachlor epoxide), atrazine, and simazine]. All six compounds were identified in water or on suspended solids throughout the year.Atrazine was the most widely used pesticide in the basins and loadings at the mouth appeared to be 0.6% of that applied. Loadings of chlordane and heptachlor epoxide at the mouth suggested that greater inputs were coming from urban uses. PCB, an industrial chemical, was ubiquitous in the two basins and losses as measured at the river mouths were on the order of 30–40 and 7–10 kg/yr for the Grand River and Saugeen River watersheds, respectively. No residues of mirex were detected in either systems.     

Water-saving strategies for irrigation agriculture in Saudi Arabia

Agriculture policy changes in Saudi Arabia are investigated by water footprint (WF) assessment. WF is calculated with the model SPARE:WATER for 3758 irrigated sites. The WF of agriculture areas (WF_area, km³ yr^?1) has decreased (–17%) since the year 2000 to 13.84 km³ yr^?1 (2011), which is mainly caused by the reduction of cropland by –33%. Nevertheless, water consumption per field has increased about 16%, which can be attributed to the cultivation of fodder crops (+12%). A scenario analysis revealed that a shifting cropping pattern towards less fodder crops reduces WF_area by –15%, and implementing improved irrigation technology leads to a combined reduction of up to 32%     

Water management problems in a rapidly developing area: The hunter region of new south Wales

A rapid phase of resource development and industrial expansion in the Hunter region of New South Wales has brought into focus the impotence of an antiquated structure of water administration. The Hunter development boom, which has been inspired by the region's immense coal reserves, has given rise to a popular belief that severe water shortages existed and that such shortages threatened the very great benefits portended by resource development. However, it is found that the emerging high value demands will not cause significant stresses on the supply system until well into the next decade. Rather, the current perspective of water shortages within the region is found to be a function of the water tariff structure for irrigation and the ironic result is observed that planned supply augmentation will result in additional large volumes of water being diverted to irrigation, at great social cost. At the same time the existing characteristics of water shortages are likely to remain as a consequence of the existing institutional structure. The possibility of institutional reform to achieve more beneficial water use as well as to abrogate existing water shortages is then outlined.     

Groundwater Use for Irrigation and its Productivity: Status and Opportunities for Crop Intensification for Food Security in Bangladesh

Bangladesh has a large and growing population that will demand more food and place greater pressure on resources. Dry season irrigated Boro rice production is important for national food security. Dry season irrigation mainly uses groundwater, but the extent of its use is not well known. We assessed groundwater use and water productivity of Boro in the northwest region of Bangladesh using remote sensing based energy balance modelling, crop classification and secondary statistics. The energy balance modelling shows a large spatial variation in the actual evapotranspiration (ET_a) from about 325 to 470 mm, with an overall spatial average of 365 mm during dry season. The estimated values of ET_a correspond well with independent values from field and regional scale soil and water balance modelling results. From spatial estimates of ET_a and effective rainfall, we computed regional net groundwater use for Boro production in 2009 as 2.4 km³. Groundwater is being used unsustainably in some areas, and a spatial time series (1990 to 2010) of pre- and post-monsoon groundwater depth changes in the northwest region of Bangladesh suggests that, with the current level of groundwater use, falling groundwater levels may pose a long term threat to the sustainability of irrigated agriculture in much of the region. Boro water productivity varies from 0.95 to 1.35 kg/m³, allowing the identification of high performing “bright” and low performing “hot” spots and the development of strategies to reduce crop yield/productivity gaps and ensure future food security.     

基于MIKE BASIN的水资源合理配置方案对比分析——以长吉经济圈为例

针对东北部分地区水资源不足问题,以长吉经济圈为例,为实现该地区未来20年的水资源合理分配与调度,以2015年为基准年,采用灰色关联分析与多元线性回归模型相结合的方法,对2020及2030规划水平年进行需水量预测,分别提出供水效益最大化、经济效益最大化以及用水总量和用水效率双指标约束控制下的三种不同水资源配置方案,并利用MIKE BASIN建立水资源配置模型进行模拟。结果表明:在考虑河道生态基流量的基础上严格控制用水总量和用水效率双指标的方案可以满足研究区经济社会可持续发展长期用水需求;到2020年研究区总需水量为29.461×10~8m~3,只有吉林市工业缺水2 397×10~4m~3;2030年总需水量为33.122×10~8m~3,此时长春市工业、九台工业、双阳农业和工业、公主岭工业以及吉林市的工业和农业均存在少量的缺水,缺水量分别为750×10~4m~3、320×10~4m~3、228×10~4m~3、152×10~4m~3、460×10~4m~3、4 280×10~4m~3、1 070×10~4m~3,但相较于优化配置方案前已大大减少了缺水量。研究成果对该区未来20年的水资源可持续利用具有一定的指导意义。