River Diversion Project Research Articles

Effects of Rock Properties on the Wear of TBM Disc Cutter: A Case Study of the Yellow River Diversion Project, China

Effects of Rock Properties on the Wear of TBM Disc Cutter: A Case Study of the Yellow River Diversion Project, China

Rockburst and microseismicity characteristics in the Qinling water conveyance tunnel of the Hanjiang-to-Weihe River Diversion Project

The Qinling water conveyance tunnel of the Hanjiang-to-Weihe River Diversion Project is the first one to overgo the Qinling Mountains with the maximum burial depth of about 2000 m, and the project is seriously threatened by rockburst hazards. The microseismic monitoring technique capable of capturing microcracking and estimating damage of rock, was employed to monitor and predict rockbursts in the deep tunnel. To study the rockburst characteristics in the Qinling water conveyance tunnel, spatial distribution of 298 rockbursts at chainage K33 + 873.3 to K36 + 979.6 along the tunnel axis, in the cross-sectional direction, and relative to the working face was examined. Microseismic sequences and energy release of associated microseismic events for rockburst of different intensities were quantified to provide reference for predicting rockburst occurrence and intensity. Evolution of an intense rockburst in the #4 sub-tunnel of the Qinling water conveyance tunnel was interpreted by the source parameters and spatial-temporal distribution of microseismic activities. According to the statistical analysis of rockburst prediction, rockburst occurrence and location in the Qinling water conveyance tunnel were satisfactorily predicted with high success rates based on sufficient volume of microseismic data. This study is critical for rockburst management over the construction of the unexcavated Qinling water conveyance tunnel, and provides insights into rockburst control in other deep, hard-rock excavation projects.

Testing the applicability of zircon U‐Pb dating as a provenance method in a highly altered river system, Mississippi‐Missouri River, USA

AbstractSediment transport through the Mississippi River affects the lives and economies of millions of people along its course, so that understanding the controls on this process is of scientific and societal importance. Detrital U‐Pb geochronology, supported by grain size and major element data, can be a robust tool for constraining sediment provenance in clastic sedimentary systems that has been applied to the Mississippi. However, sediment storage and reworking can complicate interpretation, and this can be further exacerbated by anthropogenic alteration via the construction of levees, dams, locks and river diversion projects. In this study, we date zircons from the modern Mississippi River and compare them to previously acquired data to illustrate the difference between samples taken from the same catchment in order to better understand the downstream propagation of the modern detrital zircon signal. The modern Mississippi River and tributary systems show distinct similarities and are comparable between studies when samples are not too far separated (<100 km). We estimate that the Arkansas River is more important than previously proposed, at least in terms of sand supply, supplying 7%–11% of the total load. The largest supplier of sediment to the Mississippi is the Missouri River (33%–43%), which derives much of its sediment from sedimentary rocks in the foredeep deposited during the Sevier and Laramide events. Anthropogenic alteration of the modern river system can be seen in the downstream propagation of a Red River cut‐off signal following construction of the “River Control Structure”, implying slow zircon transport rates (<2.8 km/year). Differences in the degree of recycling caused by sampling locations and low numbers of grains introduce significant uncertainties to mixing calculations.

Disrupting Infrastructures of Colonial Hydro-Modernity: Lepcha and Dakelh Struggles against Temporal and Territorial Displacements

To be Indigenous within the modern nation-state is to live with a profound sense of territorial and temporal displacement. Colonial legal regimes situate indigeneity as a condition of temporal stasis, perpetuating the logic of territorial dispossession and erasure. Drawing on research in India and Canada, we focus on Indigenous experiences to theorize the relationship between colonial legal regimes, territory, temporality, and infrastructure. In the Indigenous territories of the Lepchas in the Indian Himalaya and the Dakelh in British Columbia, Canada, hydropower infrastructure effected displacements of Indigenous space-times and sovereignty. Although Indigenous peoples continue to assert legal claims challenging these massive infrastructural projects, colonial legal regimes normalize the often violent imposition of the space-times of state and capitalist development. The Dakelh have challenged the enduring impacts of a 1950s river diversion project; however, Canadian courts legitimized historic displacements, delimiting constitutional protections to current existing Dakelh rights. For the Lepchas, a recent infrastructural boom in the Indian Himalaya is threatening special constitutional provisions upholding tribal customary laws, raising concern among younger Lepchas over the future of their ancestral lands. Despite these threats, we demonstrate how Lepcha and Dakelh relations to time and territory exceed colonial containments. They call into question how the colonial present normalizes historic and ongoing displacements and demand responsibility for the past to craft alternative futures.

Effectiveness of Microbially Induced Calcite Precipitation for Treating Expansive Soils

Abstract Expansive soil is a high-plasticity clay that expands rapidly when wetted or soaked with water and shrinks and cracks when it dries. Soil expansion often causes instability problems during construction of roadbeds or embankments. Microbially induced calcite precipitation (MICP), a novel soil treatment method, has drawn increased attention in recent decades because of its environmental friendliness and good performance in soil solidification. In this paper, the expansive soil slope treatment with MICP for the Yangtze-Jiangxi-Huaihe River Diversion Project in China is presented. The effectiveness and mechanism of Sporosarcina pasteurii bacteria for inhibiting soil expansion were investigated experimentally. The results indicated that MICP treatment can significantly reduce the swelling and deformation of expansive soil and showed that the MICP treatment was feasible and effective in inhibiting soil expansion. X-ray diffraction and scanning electron microscopy were adopted to study the changes in soil mineralogy after MICP treatment. These techniques helped to reveal the mechanism of MICP in treating expansive soils.

Microseismic monitoring, analysis and early warning of rockburst

Rockburst hazard is one of the most outstanding problems in deep rock mechanics, which has become the bottleneck for deep underground engineering in China. Rockburst occurs with some evident precursors, however, the rockburst mechanism is not clearly revealed. The acoustic emissions (microcracks) occur before the failure of rockmaterial, and rockburst is the sudden failure of rock mass caused by the development of microcracks. Therefore, it is effective to study the microcrack precursors for the surrounding rock of deep-buried tunnels by the microseismic monitoring system, and to warn of the rockburst. A method for monitoring and warning of rockburst in deep underground engineering is proposed based on the study of rockburst mechanism and in situ experience for many years. Main points of the proposed method are numerical simulation based on the monitoring, warning of rockburst based on the numerical simulation, and control of rockburst based on the warning. The proposed method was applied and improved successively in the deep-buried tunnels of the Jinping II Hydropower Station and the Hanjiang-to-Weihe River Diversion Project, which may prevent the occurrence of rockburst or decrease the incidence of rockburst. The proposed method is fast, accurate and intelligent by integrating the microseismic monitoring, artificial intelligence, big data and large-scale numerical analysis, and may be promoted to other deep underground engineering.

Skills’ sets and shared benefits: perceptions of resettled people from the Yangtze-Huai River Diversion Project in China

ABSTRACT Development induced displacement and resettlement (DIDR) projects should share their benefits with those affected by them. This paper shows that in the case of the Yangtze-Huai River Diversion Project in China perceptions of compensation received differs amongst different groups of resettled people even if levels of compensation are similar. Based on a survey with displaced people, a fuzzy comprehensive evaluation concludes that those with generic skills’ sets are the most satisfied, mainly because they are able to find new work and re-establish livelihoods after resettlement more quickly. On the other hand, those with only agricultural skills find it difficult to re-establish their livelihood and are often dissatisfied. Finally, those who did not have any work before resettlement were found to be satisfied overall as their life quality is said to have improved. The skills of those affected are therefore a key explanatory factor for satisfaction with compensation following resettlement.

Study on the Long-Term Reliability of the Tangshuiya Reservoir Dam

Du, P. and Wang, Y.Y., 2020. Study on the long-term reliability of the tangshuiya reservoir dam. In: Bai, X. and Zhou, H. (eds.), Advances in Water Resources, Environmental Protection, and Sustainable Development. Journal of Coastal Research, Special Issue No. 115, pp. 556-560. Coconut Creek (Florida), ISSN 0749-0208.Weifang section of the Yellow River Diversion Project is a comprehensive large-scale water conservancy project, which mainly solves the water supply of Weifang, and also uses farmland irrigation, flood control and hydropower generation. The tangshuiya reservoir dam is a gravity earth rock dam. The research on the rheological properties of rock mass in the project area is the basis of analyzing the long-term stability of slope and cavern. The creep pattern under different levels of tri-axial stress has been experimentally studied. A creep damage model is established. By comparing the fitting result with the experimental data, the model can accurately predict the creep characteristics of shale at different stress levels. Based on the research results of this paper, it can provide guidance for flood control and disaster reduction, improve the creep resistance performance of the reservoir dam and river embankment, and avoid major disasters due to creep.

Spatio-temporal variation and risk assessment of hydrochemical indices in a large diversion project of the Yellow River, northern China, from 2008 to 2017.

Large-scale, inter-basin water diversion projects have been developed to relieve water scarcity crisis and water pollution problems. Environmental status and ecosystem impacts are largely unknown for the Wanjiazhai Yellow River Diversion Project (YRDP-WJZ), a water body critical in northern China. In the current study, twelve hydrochemical indices (including Mn, Cu, Zn, Hg, Pb, NH3-N, COD-Mn, DO, BOD5, COD, TP, and TN) were collected from 2008 to 2017 based on multiple analytical approaches to understand environmental status and ecological risks. Human health risk and threats to aquatic organisms from heavy metals were assessed. Heavy metals have no regular spatial distribution. Biochemical parameters and nutrients pollute seriously in midstream and downstream, respectively. Hydrochemical indices suggested high levels of pollution in the midstream section. Water quality improved downstream of the Fenhe Reservoir, but total nitrogen and total phosphorus in the downstream section increased in recent years. The Canadian Council of Ministers of the Environment Water Quality Index (CWQI) suggested midstream water quality was poor in general, and 80% of annual calculations had a marginal grade. For aquatic organisms, ecological risks of Cu and Zn were high. For local residents, drinking water was generally safe, but continued monitoring is critical due to ongoing threats to water quality in these areas.

Erosion wear on a double-suction centrifugal pump of the Zuncun Pumping Station based on two-fluid model

The Zuncun Pumping Station is located at Yuncheng of Shanxi Province, North China. This station consists of series of second-stage pump stations and is an important input part of the Yellow River Diversion Project (YRDP). Normal operations of double-suction centrifugal pumps in the Zuncun’s second-stage pump stations are always troubled seriously in sediment wear resulting from the Yellow River’s hyper concentrated sediment concentration and pump impeller’s high speed rotation. In general, the sediment wear occurs at seal rings, blades and volutes and results in an increment of seal clearance, deformation of volute tongue and decrement of impeller size. Therefore, the component life, efficiency and reliability of pump stations reduce largely. Especially in flood seasons, the sediment wear becomes much severe due to increments of sediment size and concentration and results in a large waste of energy and capital. Two-phase numerical models have been widely applied for sediment-laden flow in pumps to predict the distribution of sediment wear indirectly in recent years. Due to the theoretical insufficiency in modeling two phases’ turbulence behaviors, the previous two-phase numerical models are weak on the effects of sediment size and concentration which are the major factors for sediment wear. This paper mainly studies the effects of sediment size and concentration on sediment wear in the double-suction centrifugal pumps used in the Zuncun’s second-stage pump stations. A new developed Eulerian two-phase numerical model, which considers the turbulence effect into drag force and performs the change of water turbulence structure in sediment diffusion coefficient resulting from the turbulence scale effect (TSE), is applied for sediment-laden flow in the double-suction centrifugal pumps. The TSE consists of the turbulence intensity and the sediment dynamic scale to perform the combined turbulence behavior of flow strength and sediment. The k-e turbulence model is used for the closure of water phase, and Hinze-Tchen’s algebraic particle turbulence model is used for the sediment phase. Based on the two-phase numerical results, the sediment wear is calculated by the Oka model which takes into account the role of sediment size. Sixteen cases grouped by four typical sediment sizes are studied with four representative inlet sediment concentrations. Results demonstrate that the sediment wear mainly and severely occurs on the pump’s blade and volute in all cases. The sediment wear on the blade gradually increases along the radial direction and is severer on the pressure side than on the suction side. The severest regions are on the middle of pressure side and the trailing edge of suction side. The sediment wear on the volute inner surface increases as the decrement of the cross section area, and the severest wear region in the volute is at the volute tongue. As the increment of inlet sediment concentration, the sediment wear rate almost increases linearly. As the increment of inlet sediment size, the sediment wear rate increases slightly, and the increment speed gradually slows down. On this basis, it is suggested to prevent the Zuncun’s double-suction centrifugal pumps from sediment wear by reducing the sediment size and concentration of water through the pumps.

Temporal and spatial evolution trends of drought in northern Shaanxi of China: 1960–2100

Drought prediction and assessment are the basis for addressing climate change and extreme weather. Northern Shaanxi is an important energy base and ecological barrier in China. Mitigating the threat of drought is necessary for sustainable development of the economy and society of the region. There are great uncertainties in drought predication because of climate change. Based on historical meteorological data and a multi-model ensemble mean value, temporal and spatial variation characteristics of drought in northern Shaanxi during the historical time period (1960–2018) and the future time period (2020–2100) were analyzed by detrending, Mann–Kendall trend test (MK), empirical orthogonal function spatial analysis (EOF), and wavelet analysis. The results show that the multi-model ensemble mean value provides a better simulation of precipitation and temperature in northern Shaanxi. The application of the Standardized Precipitation Evapotranspiration Index (SPEI) in the region is superior to the Standardized Precipitation Index (SPI) and self-calibrated Palmer Drought Index (sc-PDSI). The interannual dry and wet changes in the northern Shaanxi region during the historical period (1960–2018) can be divided into two periods. Overall, the drought index showed a significant decrease, and spring drought increased. In the future, precipitation and temperature in the region will increase from south to north, with the largest increase in the west. In the middle and late twenty-first century, due to the significant increase in temperature, the aridification trend in northern Shaanxi may be aggravated, which is consistent with the trend of drought in northern China. The future of spring drought is grim, and summer drought has an increasingly frequent trend. Making full use of water resources and accelerating the construction of the Yellow River diversion project are effective ways to alleviate drought and water shortage in the region.

Aluminum distribution heterogeneity and relationship with nitrogen, phosphorus and humic acid content in the eutrophic lake sediment

Increasing amount of aluminum (Al) gets into aquatic ecosystem through anthropogenic activity, but the knowledge about Al migration and relationships with sediments possessing different physico-chemical properties in eutrophic lakes is limited. Here, the Al migration rule and relationships with sediment nutritions in the Hangzhou West Lake, China was investigated, where a certain amount of residual Al-salts can enter because of the pre-treatment of the Qiantang River diversion project every day. Results revealed the obvious spatial distribution heterogeneity of Al in sediment vertical direction and horizontal direction following water flow. The Al content in sediment ranged 0.463–1.154 g kg−1 in Maojiabu Lake, and ranged 9.862–40.442 g kg−1 in Xiaonanhu Lake. Higher Al content distributed in upper layer sediment in lake with more disturbance. Total nitrogen (TN) contents were higher 0.917–3.387 mg g−1 and 0.627–0.786 mg g−1 in upper layer sediment than that in lower layer in Maojiabu Lake and Xiaonanhu Lake, respectively. Total phosphorus (TP) content ranged 0.779–2.580 mg g−1, in which IP and Fe/Al-P contributed 24.9–80.8% and 17.0–51.6%, respectively. Correlations between Al content with nutrition, humic acid (HA) etc. of sediment regionally varied in Maojiabu and Xiaonanhu Lake. Spatial distribution of Al-salt in eutrophic lakes closely related with the physico-chemical characteristics of nutrients, humus, human disturbance and water division parameters. Results provides new insight into Al-salts migration and references for Al-risk evaluating in eutrophic lakes.

Changes of temperature and precipitation and their impacts on runoff in the upper Taohe River in northwest China from 1956 to 2014

Climate change has greatly affected regional hydrological processes at temporal and spatial scales, and much attention has been focused on how runoff changed under the background of global warming in recent years. In northwest China, Taohe River provides major water resource to several semi-arid regions. To quantificationally estimate water resource, the influence of precipitation and temperature on runoff needs to be further studied. In this paper, hydro-meteorological data from 1956 to 2014 were used to analyze the changes of temperature, precipitation and runoff based on Mann–Kendall test and double cumulative curve method. The main findings were that the temperature had a significant increasing trend (0.26 °C/10a), while precipitation showed an insignificant increasing trend (0.9 mm/10a). Runoff exhibited a significant decreasing trend (− 2.7 × 108 m3/10a) and break point of the runoff occurred in 1987. Thus, compared with benchmark value during the period 1956–1987, runoff after 1987 was reduced to 70.7% of the previous level on average, from 37.5 × 108 m3 in 1956–1987 to 26.5 × 108 m3 in 1988–2014, with a decreasing rate of 29.3%; and runoff changes in each month were all decreased after 1987, particularly in September by 41.29%. Double cumulative curve and correlation results revealed that precipitation was the dominant factor controlling changes in runoff and their correlation coefficient reached up to 0.73. The magnitude of precipitation dominated runoff from April to October, accounting for more than 95% of the total annual runoff. However, runoff decreased more dramatically than precipitation after 1987, which indicated that there were some non-precipitation factors, like the increase of evaporation caused by temperature rise and human activities, responsible for the decline of runoff from 1988 to 2014. Some large-scale climate factors had a good tele-connective relation with variability of runoff. Overall, this study exhibited a scientific fact of runoff decreasing in the upper Taohe River basin and aimed to provide a basic direction for reasonable allocation of water resources by the Taohe River Diversion Project sustainably.

Study on hydrodynamic and sediment transport characteristics considering implement of the Fuhe River Diversion Project in China

A movable-bed physical model is presented to investigate characteristics of hydrodynamic and sediment transport (ST) in a planned excavating channel downstream the Fuhe River (FHR) and the Qinglan Lake (QLL), Jiangxi Province, China. The model is validated by the observed water level and velocity data during the low water period in May 13 and high water period in June 21 2014, respectively, which shows well agreements between simulated and observed data. With repeating 6-years cycle of the runoff discharge and suspended sediment concentration condition from the Lijiadu hydrological station downstream the FHR during 2006 and 2008∼2012, experiments are conducted to predict bed evolution process in the excavated channel and QLL after the implement. The hydrodynamic results indicate that the cross-section averaged velocity generally increases both in the QLL and upstream of the excavated channel during a 20-year return period flood. The ST results show that erosion develops mainly in the left side of the channel and deposition occurs slightly upstream of the QLL after 30 years. Some deposition becomes visible in the center of the QLL after 90 years, and a relatively stable balance between deposition and erosion is observed in the whole QLL after 150 years.

Characterizing Rockbursts Along a Structural Plane in a Tunnel of the Hanjiang-to-Weihe River Diversion Project by Microseismic Monitoring

Rockbursts pose serious threats to the safety of personnel and equipment in tunnels of the Hanjiang-to-Weihe River Diversion Project. Small-scale structural planes around the tunnel play an important role in controlling the occurrence and intensity of rockbursts. To study the characteristics and evolution of rockbursts along a structural plane, three successive, intense rockbursts in the #4 sub-tunnel were summarized in detail and investigated by analyzing 492 recorded microseismic events. The rockbursts were closely related to the structural plane, because most events had a ratio of S-wave energy to P-wave energy larger than 10 and were associated with shearing along the existing structural plane. The statistical parameters, which include the energy index, cumulative apparent volume, and b value, were used to analyze the evolution of the three rockbursts. Quantitative interpretation of the source parameter and statistical parameters for a given microseismic data set provided a significant insight into characterization of rockbursts along the structural plane. In addition, some distinctive seismic precursors for rockbursts along the structural plane were acquired; therefore, rockbursts along the structural plane may be effectively predicted based on these seismic precursors. Preliminary results in the current study are valuable for predicting and mitigating rockburst hazards in tunnels with similar conditions.

Trends in the construction of on-farm irrigation reservoirs in response to aquifer decline in eastern Arkansas: Implications for conjunctive water resource management

As part of conjunctive water resource management, on-farm reservoirs have been constructed to address declines in the Mississippi River Valley Alluvial aquifer, the primary source of irrigation for most of the row crops grown in eastern Arkansas. These reservoirs and their associated infrastructure represent significant investments in financial and natural resources, and may cause producers to incur costs associated with foregone crop production and long-term maintenance. A better understanding of past trends in reservoir construction can allow for more efficient resource allocation towards future adoption of this practice. Thus, an analysis of reservoir construction trends in the Grand Prairie (GP) Critical Groundwater Area and Cache River (CR) Critical Groundwater Area was conducted. Between 1996 and 2015, on average, 16 ± 5 and 4 ± 1 reservoirs were constructed per year, corresponding to cumulative new reservoir surface areas of 161 ± 49 and 60 ± 18 ha yr−1, for GP and CR, respectively. In terms of reservoir locations relative to aquifer status, after 1996, 84.5% of 309 reservoirs constructed in GP and 91.0% of 78 in CR were located in areas with remaining saturated aquifer thicknesses of 50% or less. The majority of new reservoirs (74% in GP and 63% in CR) were constructed on previously productive cropland. The next most common land use, representing 11% and 15% of new reservoirs constructed in GP and CR, respectively, was the combination of a field edge and a ditch, stream, or other low-lying area. Less than 10% of post-1996 reservoirs were constructed on predominately low-lying land, and the use of this land cover decreased in both critical groundwater areas during the past 20 years. A reservoir footprint analysis indicated that 85% of the typical reservoir system consists of the reservoir pond itself with the remaining 15% of land area consisting of tailwater recovery ditches, and other associated features. The disparities in reservoir construction rates, locations, and prior land uses between the two critical groundwater areas is likely due to groundwater declines being first observed in GP as well as the existence of two large-scale river diversion projects under construction in GP that feature on-farm storage as a means to offset groundwater use. Results of this analysis can be used in the development of targeted resource allocation initiatives and conservation efforts in critical groundwater areas and other similarly water-scarce regions.

Re-thinking River Diversion Projects- A Political Ecology Perspective

The usage of pipelines to make water available to people has been widely discussed phenomenon throughout the world. Less argued are the projects which divert tributaries from larger rivers via small diversion channels for the sake of short-term goals that work around natural waterscape. River Khan is one such smaller stream which accumulates the entire waste of Indore city and has been diverted from its larger stream River Kshipra in the wake of KumbhMela 2016, to keep the larger stream clean. In this context, the paper investigates the discrepancies of this project and identifies the political and economic forces involved in the formation of such projects during events like KumbhMela. Using the theory of political ecology, the paper attempts to understand the complexities surrounding environment and development. Through government policies and influence of material conditions on culture, the paper also explores the unfair relations amid societies that influence the natural environment.

Risk Assessment of Pollution Emergencies in Water Source Areas of the Hanjiang-to-Weihe River Diversion Project

[Objective] This study quantitatively evaluated risk probabilities of sudden water pollution accidents under the influence of risk sources, thus providing an important guarantee for risk source identification during water diversion from the Hanjiang River to the Weihe River. [Methods] The research used Bayesian networks to represent the correlation between accidental risk sources. It also adopted the sequential Monte Carlo algorithm to combine water quality simulation with state simulation of risk sources, thereby determining standard-exceeding probabilities of sudden water pollution accidents. [Results] When the upstream inflow was 138.15 m3/s and the average accident duration was 48 h, the probabilities were 0.0416 and 0.0056 separately. When the upstream inflow was 55.29 m3/s and the average accident duration was 48 h, the probabilities were 0.0225 and 0.0028 separately. [Conclusions] The research conducted a risk assessment on sudden water pollution accidents, thereby providing an important guarantee for the smooth implementation, operation, and water quality of the Hanjiang-to-Weihe River Diversion Project.

Research on Polyurethane Elastomer Abrasion Protection for Impeller of Water Pump

The pumps used in the Guhai Pumping Irrigation Project were suffered from sediment abrasion in the long term and their flow passage components, including impellers and pump shells, were also seriously abraded, which led to common problems of poor reliability, low operation efficiency and high energy consumption in almost all the pump stations. Therefore, these problems had made these pumps unable to satisfy the requirements for construction of resource-saving society and development of hydraulic engineering modernization. The steel plate welded impeller technology was a new technique specially developed to solve the serious abrasion of pump impellers. However, the results of long-term application of this technology had demonstrated that the composite resin mortar coating had a limited capability to resist cavitation and thus the parts which are fragile to cavitation on the impellers will fall off easily, which further aggravated the impeller abrasion. After one irrigation season, there were multiple penetrated holes occurring on the impellers, which significantly affects the operation efficiency of the pumps. In order to solve the cavitation resistance issue of composite resin mortar. The polyurethane elastomer technology was developed for the first time, which the polyurethane material with the currently best performance in cavitation resistance was adopted, and the appropriate promoters were added into the polyurethane to improve its properties. In addition, high-strength binder and mechanical connection mode were developed in this technology, which greatly enhanced the binding strength between the polyurethane coating and the pump impellers. Besides, vacuum casting technique was adopted to obtain the pump impeller coating which had excellent performance in abrasion and cavitation resistance. This technology was firstly tested in the Guhai Dazhanchang Pump Station in March 2015. After one and half years operation, it is found that the coating had been improved obviously, and the pumps had long-term stable operation efficiency, which had reached the anticipated testing goal. It is provided reference for the pump stations in Yellow River Diversion Project and pump manufacturers to solve the pump impeller cavitation problem.

A River Runs through It: The Yellow River and The Chinese Civil War, 1946–1947

In June 1938 China's Nationalist government breached a major Yellow River dike in a drastic attempt to use flooding to slow the Japanese invasion. The strategic breach caused the Yellow River to abandon the northern course it had followed since 1855, and its new southeastern course led to eight years of catastrophic flooding. After World War II, the Nationalists, with extensive aid from the United Nations Relief and Rehabilitation Administration (UNRRA), aimed to close the breach and divert the river back to its pre-1938 course. However, the Chinese Communists had taken control of much of that course, and local interests there opposed the plan to bring back the river. The Yellow River diversion project thus became intensely politicized. This article examines how the diversion plan became embroiled in the Chinese Civil War of 1946–49, how the river's return to its northern course in 1947 impacted communities in its path, and how the Communists and Nationalists imagined the river and made different tactical and rhetorical uses of it during the war. I find that the campaign to reroute the river was complicated not only by the civil war but also by tension between local and national interests within the Communist Party, and that UNRRA's attempts to mediate between the Nationalists and Communists at times put the organization at odds with both parties. Moreover, in 1946 and 1947 the intense struggle to tame, make strategic use of, or cross the Yellow River became an important metaphor for the battle to control China.