Water Diversion Scheme Research Articles

The influence of 10 years of water conveyances on groundwater and juvenile Populus euphratica of the lower Tarim River

The changes in the depth of groundwater were studied from the period before water conveyance through 2010, and the TDS of groundwater was analyzed in the lower reaches of the Tarim River during the period 2001–2010. Besides, the numbers of juvenile P. euphratica were investigated in the lower reaches of the Tarim River during the period 2001–2010. The findings indicate that: (1) the hydrological environment of the lower reaches has slowly deteriorated again; and (2) few juvenile P. euphratica were observed along the channel. These results show that the positive influence of the ecological water conveyance project on the ecosystem of the lower Tarim River should be beneficial in the long term; however, the long-term stability of the ecosystem cannot be achieved by the current water diversion scheme.

Method for Calculation of Water Demand by Pollutant Dilution and Purification in River Networks and its Application to the Zhongmu Baisha District River Networks

The laws of pollutant dilution, dispersion and purification are discussed for river networks. And then a calculation model for water demand by pollutant dilution is developed, and methods for determination of the total volume of water diversion and flow rate are also given. With the Zhongmu Baisha district river system as an example, the overall plan and its feasibility are studied. With the calculation model for river networks, and by comparison of various water diversion schemes and assessment of the effect of water diversion, a reasonable scheme and the volume of water diversion are determined. The research provides a theoretical basis and technical support for the water quality guarantee of Zhongmu Baisha district river networks.

Optimal Model of Hydrodynamic Controlling on Pumps and Slice Gates for Water Quality Improvement

In order to evaluate the effective of the hydrodynamic control of pumps and slice gates in plain river network on the water quality improvement, an optimal mathematic model of hydrodynamic controlling on the pumps and slice gates in plain river network was established by combining the water quality objective function and the cost objective function together. The cost function has been set as the main objective function, while the water quality objective function was simplified as the restrained condition for every required water quality index, through which the multi-objective optimization was transferred into a single-objective optimization. Then, this optimal model was solved by coupling the water environmental model with the hybrid genetic algorithm. The case study of Jiaxing river network shows that the proposed hydrodynamic controlling optimal model in this paper can develop the optimal water diversion scheme for water quality improvement and cut its cost. It works better compared to the traditional water quality objective function and can be used in the engineering practice.

Research on Tactics of Water Diversion of Lake Dong

Lake Dong located in Wuhan is the largest urban lake in China. It has lost ecosystem functions with the economic development in recent years. The Lake Dong Ecological Water Network Project will reestablish the hydraulic connection between the Yangtze River and Lake Dong by diverting water from the river. In order to make a scientific water diversion scheme, a hydrodynamic and water quality model was established. Orthogonal curvilinear coordinate in horizontal direction and sigma coordination transformation in vertical direction were used. The model was verified using the observed COD concentration and applied to simulate three scenes of water diversion. By comparing the average COD of some sub-lakes in different scenes, a tactics of water diversion was proposed so as to provide a scientific basis for the project.

Development of a coupled reservoir operation and water diversion model: Balancing human and environmental flow requirements

Maintaining a natural flow regime helps preserve the health of riverine ecosystems. Conventional studies on reservoir operations have focused mainly on identifying optimal operational schemes for satisfying human water demands. To systematically reflect the ecological effects of both natural and human-induced hydrologic alterations, water diversions downstream of the reservoirs should be considered as well. This research focused on a coupled reservoir operation and water diversion (CROWD) model, created through the integration of a reservoir operation model and a water diversion model. The proposed model considers both human and environmental flow requirements, and represents a compromise that balances ecological protection (preservation of the natural flow regime of a river) and human needs (reduced water shortages). In the reservoir operation model, the reservoir space is divided into three zones and different operating rules are developed for directing reservoir operation when water levels are in different zones; in the water diversion model, different water users are assigned different supply priorities with the instream flows no more than the minimum environmental flows having the highest priority; and the two models are coupled by the water mass balance between the two hydraulic facilities. The non-dominated-sorting genetic algorithm II (NSGA-II) was used to determine the parameters of the developed CROWD model and the model was applied to support the joint operational management of the Tanghe Reservoir and the Liaoyang Diversion in the Tang river basin, China. The resulting reservoir operation and water diversion schemes indicate that the CROWD model is useful for optimizing the operation of reservoirs and water diversion schemes. Moreover, it helps to analyze tradeoffs between human and environmental water needs, resulting in solutions that reduce the risk of water shortages and minimize ecological integrity disturbances.

Changes in groundwater induced by water diversion in the Lower Tarim River, Xinjiang Uygur, NW China: Evidence from environmental isotopes and water chemistry

summary The Lower Tarim River in NW China is under severe ecosystem degradation due to stopped stream flow and diminished groundwater recharge. Since year 2000, eight water diversions from the upper stream and from the neighboring Kaidu–Kongque River have been implemented to alleviate the ecosystem disaster. In order to assess the effectiveness of the water diversion project and to identify proper tracers of groundwater dynamics, we sampled the riparian groundwater system in 2007 and 2008 along the 350 km-long river channel through the 40 monitoring wells situated along nine transects perpendicular to the river and three soil profiles. Measurements on the samples have included environmental isotopes ( 18 O, 2 H, 3 H) and water chemistry. The results show that remarkable changes have been induced by the water diversions. The observed response of riparian groundwater system includes general decrease in total dissolved solid (TDS) and rise of water table. Scope with greater than 1 m rise in water table is within �700 m from the riverbank in the upper segments and �300 m in the lower ones. Greater rise of water table occurs near the river bank. Tritium data show that the extent of modern recharge (since 1960s), including that from the diverted water, is limited to 600 m from the riverbank at the upper segments and 200 m at the lower ones. Stable isotopes show that groundwaters, regardless of modern or pre-modern, are enriched in heavy isotopes and are plotted in parallel to the meteoric water line in the d–d plot, attributed to evaporation during recharge. Groundwater is generally of Na–Mg–Cl–SO4 type and is formed by dissolution of minerals, such as halite, sulfate, and carbonates, based on component correlation matrices analysis. The salinity of groundwater is mainly affected by that of the diverted water and of the local antecedent groundwater, salts in the unsaturated zone, evapotranspiration during recharge. As the zone of smaller groundwater depth (less than 5 m) suitable for the most existing Populus euphratica and Tamarix ramosissima, the main species targeted by the rescue effort, restricts to 200 m from the riverbank, and narrows down towards downstream, long-term stability of the ecosystem cannot be achieved by the current water diversion scheme and regulating/saving water in source-streams and the Upper/Middle Tarim River is crucial for continuing water diversion.

Assessing indicators for water diversion based on improving water quality of shallow lakes

Based on the goal of water diversion for shallow lakes, taking the requirement of ecological hydraulics and economic factor into consideration, an attempt to establish an assessing indicator system for water diversion scheme of shallow lakes is put forward in this paper. The indicators are consisted of lake quality-improving indicators, hydraulic indicators and economic indicator. By the case of Lake Xuanwu, a 2-D water-quality model is adopted to simulate different schemes of water diversion for Lake Xuanwu with different flow flux, diversion mode, flow distribution of inlets, and flow distribution of outlets. Detailed assessing indicators of statistic results are obtained, and then the optimum water diversion scheme is assessed. The method can be applied to the assessment of water diversion on similar shallow lakes.

Hydrological responses to climate change and irrigation in the Aral Sea drainage basin

Hydrological model interpretation of the water flow development in the Aral Sea Drainage Basin (ASDB) indicates that the water diversion and irrigation schemes in this region have considerably increased evapotranspiration and thereby decreased net water flux (precipitation minus evapotranspiration) from the atmosphere to the surface of the ASDB. Increased evapotranspiration cools the irrigated areas, and the decrease of net atmospheric water influx to the ASDB may also have non‐local effects outside the basin. Such effects have previously been estimated by atmospheric modeling, assuming a global average evapotranspiration return flow to the atmosphere of about 40% of irrigation. Our results indicate larger return flows, of nearly 100% of the applied irrigation water in the ASDB, which may also imply considerably larger than previously estimated non‐local water and climate effects of the world's irrigated areas.

Water discharge and sediment load to Sepetiba Bay from an anthropogenically-altered drainage basin, SE Brazil

Summary Empirical relationships coupled with the field measurements were used to assess water discharge and sediment load from an anthropogenically-altered drainage basin into Sepetiba Bay in southeastern Brazil. Discharge into Sepetiba Bay is modified by large-scale water diversion from the Paraiba do Sul River, which is one of the more important and impacted rivers in Brazil. The discharge into Sepetiba Bay has increased threefold, from 41 to 129 m 3 /s on average, since the water redistribution began. Sediment budget calculations indicate retention of a large fraction of the sediment load by five reservoirs within the drainage system but with highly variable infilling rates. As a consequence the water diversion scheme has lead to a 28% increase in sediment delivery to Sepetiba Bay or 270 × 10 3 t/yr. The Paraiba do Sul River contributes most of the freshwater input into Sepetiba Bay, whereas the sediment load to the bay is mainly contributed by the local drainage basins.

Assessment of hydrologic alterations caused by Chi‐Chi diversion weir in Chou‐Shui Creek, Taiwan: opportunities for restoring natural flow conditions

AbstractThe Range of Variability Approach (RVA) is used to investigate the hydrologic impacts of a diversion weir on Chou‐Shui Creek, Taiwan. Thirty‐two hydrologic parameters, called Indicators of Hydrologic Alteration (IHA), are used to evaluate the flow conditions before and after weir construction. One standard deviation from the mean for each of the pre‐construction hydrologic parameters is set as the management target range. Under the prevailing diversion rules, large hydrologic alterations are observed, especially for low flows. The means of 19 hydrologic parameters presently fall outside of the targets and the average non‐attainment rate for the 32 indicators is 73.2%. Increasing the instream flow release or reducing diversions could mitigate the hydrologic impacts of weir construction. Increasing the instream flow to 40 m3/s and reducing monthly water demands by variable percentages significantly improves the altered flow conditions. Under the proposed water release and diversion scheme, 29 hydrologic parameters will fall within the management targets and the average non‐attainment rate will be reduced to 35.6%, much closer to the pre‐construction value of 25.3%. Restoring the natural flow variability is expected to promote the natural stream biota. Copyright © 2004 John Wiley & Sons, Ltd.

Supply and flux of sediment along hydrological pathways: research for the 21st century

It has become increasingly difficult to assess the impact of changes in the sediment flux to the coastal zone because of the conflicting impacts of humans. Globally, soil erosion is accelerating (e.g., deforestation, some agriculture practices), while at the same time sediment flux to the coastal zone is globally decelerating (e.g., water diversion schemes, dams). Reduced loads delivered to the coastal zone result in an accelerated coastal erosion and a decrease in habitat. The reduction of the seasonal flood waves also means that sediment is dispersed over smaller areas of the continental margin. One of the great challenges facing hydrologists, with regard to our understanding of anthropogenic versus climate-change impacts on the hydrological cycle, is the quality and duration coverage of hydrological data, particularly on pristine rivers. For many rivers, the length of hydrological coverage is measured in years rather than decades, with no rivers with reliable observations across centuries. In other words, if a river's discharge is monitored during periods where the impacts of humans or nature produce a long-term trend, then the return-interval concept for floods and droughts, for instance, becomes meaningless. In addition, river systems are conditioned by events that are largely prehistorical. Forensic studies of paleoriver systems provide us with some ability to assess and discern the impacts of humans versus climate.

Government Watch: China approves massive water diversion scheme

Government Watch: China approves massive water diversion scheme

Coastal Erosion Along the Changjiang Deltaic Shoreline, China: History and Prospective

There are three large engineering works that are now under construction or to be constructed in the coming decade in the Changjiang (Yangtze) River catchment and its estuary, i.e. the Three-gorge Dam, the south-to-north water diversion schemes and the deepwater navigation channel. These engineering works are expected to reduce significantly the sediment supply into the deltaic coastal system, slow or reverse the development of the Changjiang River delta and enhance coastal erosion processes. Consequently, these changes will reduce land resources for reclamation and threaten the coastal defence, which are of primary importance for the protection of Shanghai's socio-economic development. In order to understand further the mechanism of the Changjiang delta development, especially of coastal erosion, this paper examines historical responses of the Changjiang delta growth and its shoreline movement to the sediment supply from the river basin in a millennium to decade time scale. This study shows that the deltaic growth rate has been very sensitive to the changes in sediment supply to the deltaic coastal system, though the mechanism that induced such changes may be different. Based on an estimate of 10–20% decrease in sediment discharge caused by the three engineering works, not to mention an additional impact of future global sea-level rise, it is believed that coastal erosion along the deltaic shoreline will become inevitable, resulting in a great stress on the land resource and coastal protection for Shanghai in the coming decades.

Environmental factors in Soviet interbasin water transfer policy

Over 60% of the USSRs river discharge crosses sparsely settled regions and flows into the Arctic Ocean, whereas the most densely settled and economically developed southern regions possess only 12% of surface flow. Consequently, the Soviets perceive an urgent need to redistribute water resources to avoid future shortages. The Soviet government is diligently pursuing development of schemes for the mass transfer of water from northern to southern drainage basins. Because of their grand scale, these could have major, pervasive, and long-term environmental impacts. Although environmental factors were given minimal attention in earlier designs for interbasin water transfers, present proposals are being subjected to thorough, careful, and thoughtful environmental evaluation. The Academy of Sciences and the Hydrometeorological Service as well as several national ministries have been assigned responsibility for evaluating the potential environmental ramifications of alternative schemes including formulation of systems of mathematical models for quantitative estimation of these effects. Indeed, a guiding principle for the development of an “acceptable” diversion system is that it be environmentally sound. This requires identification and estimation of the magnitude of significant adverse environmental impacts and, where possible, formulation of mitigative measures; reasonable economic-environmental tradeoffs; and a negligible potential for irreversible catastrophic environmental changes. It appears that environmental factors are of major importance in devising Soviet interbasin water transfer policy and that resolution of key environmental questions is to precede implemention of any large-scale water diversion scheme.

New Estimates of the Welfare Loss to Monopoly, United States: 1956-1969

The estimates of welfare loss to monopoly reported here are substantially lower than anticipated when this research was undertaken. The cumulative bias introduced to overestimate the size of the welfare loss should, it seemed a priori, produce an estimated welfare loss of at least 5 percent. I can only conclude that there is very little ground for the common belief that a large loss of welfare exists due to the economic impact of monopoly power. It is possible that the fault lies with the measurements and not with the (viscerally sensed) reality, but as a social scientist I believe that the burden of proof now rests on those who believe the loss is large. A reallocation of economists' time toward the public sector may be indicated. Greater welfare losses to misallocation may exist as a consequence of such government activities as oil import quotas, water diversion schemes, standards enforced to safeguard common property resources such as air, water, and fish, and other programs asserted to be in the public rather than the private interest. [Авторский текст]