River Regulation Projects Research Articles

The Second Hungarian Conquest of the Carpathian Basin

Abstract During the nineteenth century many European scientists shared the view that a nation could compete successfully if only it improved its landscape via new infrastructures, such as large reclamation and river regulation projects, and via the intensive use of natural resources—for example, the scientifically planned use of forests. This “high” modernization path orchestrated by the political and scientific elites of Hungary sought to consolidate control over resources, landscapes, and competing ethnic groups and was in many respects similar to the many other versions of high modernism in Europe at the time. This version, however, represented a particular vision closely linked to the ecological systems of the Middle Danube area. Although questions of the political, economic, and technological “rise” of Hungary have attracted scholarly attention for centuries, historians have not fully explored the ecological consequences of modernization. Three of these consequences—deforestation, desertification, and flooding—are the subjects of this article. More broadly, the article aims to show how the political and economic goals of nationalism produced a science of ecological domination.

Rivers in Constrasted climates React Differently to dams: Geomorphological evidence from Chile

More than twenty large reservoirs (>20 hm3) are located along the latitudinal range of Chile and, so far, only a few investigations have been carried out into the geomorphological effects of reservoirs on this region. This research examines the morphological changes that occurred within the active channel downstream of two dams in gravel-bed rivers under contrasting climates in Chile: The Elqui River in the semiarid north of Chile and the Biobío River in the humid south. The former has been regulated by the Puclaro reservoir since 1999 and is used for irrigation, while the latter is regulated by three reservoirs: Pangue (closed in 1996), Ralco (closed in 2004), and Angostura (closed in 2014), and is used for hydropower generation. The morphological changes were evaluated using satellite images, in a 16 km-long segment on the Elqui River and an 88 km-long segment on the Biobío River. Analyses were carried out to quantify the changes in the morphological units (bars, islands), channel patterns, and flow magnitude and frequency alterations. The results show a 15% reduction in the magnitude of Q2 flows in the Elqui River and a 64% reduction in the Biobío River. The active channel areas were reduced by 58% in the Elqui (1994–2011) and by 26% in the Biobío (1994–2018). In both rivers, the active depositional areas (central bars) practically disappeared, which led to a simplification of the channel pattern. The main differences, in terms of geomorphological changes, were observed in the areas covered by vegetation; while in the Elqui, a decrease of 87% was detected and, in the Biobío, an increase of 20% was observed. Results support the working hypothesis, showing a higher intensity of morphological changes in the river of the semiarid zone, in line with the hydrological alteration identified in previous research. This research represents the first case study on the geomorphological effects of reservoirs on climatically contrasted Chilean rivers. These analyses provide relevant information to improve the understanding of these effects, as well as provide information on the undisturbed state of river systems that could serve as a reference for restoring and mitigating future river regulation projects.

Understanding the Physical Forcings Behind the Biogeochemical Productivity of the Hudson Bay Complex

AbstractMultiple factors influence the spatial and temporal chlorophyll‐a concentration of marine systems. The Hudson Bay Complex has historically been seen as a large, low‐production inland sea situated in the north of Canada. However, recent field campaigns, for the BaySys project, have provided new data on primary production in the bay. Due to the Hudson Bay complex's positioning, it experiences seasonal sea‐ice cover and has many rivers draining into it, resulting in a unique estuarine‐like environment. We use the biogeochemical model BLINGv0 + DIC, coupled to the online regional physical oceanographic and sea‐ice models, NEMOv3.6 and LIM2, respectively, forced with two bias‐corrected Coupled Model Intercomparison Project 5 climate forcings (MIROC5 and MRI) to simulate the base of the ecosystem. The simulations were evaluated with chlorophyll‐a satellite imagery and observations collected in 2018 and analyzed with Empirical Orthogonal Functions to understand the underlying physical forcings and key areas of chlorophyll‐a concentration distribution. The evaluation showed that both simulations successfully reproduced the sea‐ice melt, from west to east and formation, from north to south and correlated well with spatial bloom patterns. The main drivers of phytoplankton growth are the seasonal light and nutrient levels (48% and 54%), the mixed layer depth dynamics (18% and 14%), nutrient supply from rivers (13% and 8%), and sea ice production (7%) for the MIROC5 and MRI simulations, respectively. The sea‐ice dynamics and river runoff played a significant role in the system's productivity. Therefore, with future climate change and increased river regulation projects, up to 20% of overall chlorophyll‐a may be negatively impacted.

Channel Bed Adjustment of the Lowermost Yangtze River Estuary from 1983 to 2018: Causes and Implications

Deltaic channels are significant landforms at the interface of sediment transfer from land to oceanic realms. Understanding the dynamics of these channels is urgent because delta processes are sensitive to climate change and adjustments in human activity. To obtain a better understanding of the morphological processes of large deltaic channels, this study assessed the evolution and response mechanism of the South Channel and South Passage (SCSP) in the Yangtze Estuary between 1983 to 2018 using hydrology, multibeam echo sounding and historical bathymetry datasets. Decadal changes in riverbed volume and erosion/deposition patterns in the SCSP were assessed. The results showed that the SCSP experienced substantial deposition with a total volume of 26.90 × 107 m3 during 1983–2002, but significant bed erosion with a total volume of 26.04 ×107 m3 during 2003–2010. From 2011 to 2018, the estuarine riverbeds shifted from erosive to depositional, even though the deposition was relatively marginal (0.76 ×107 m3). We inferred that the SCSP have most likely changed from a net erosion phase to a deposition stage in response to local human activities including sand mining, river regulation project, and Deep Water Channel Regulation Project). The channel aggradation will possibly continue considering sea level rise and the ongoing anthropogenic impacts. This is the first field evidence reporting that the lowermost Yangtze River is reaching an equilibrium state in terms of channel erosion and, in fact, the Yangtze River Estuary channels are beginning to aggrade. The findings have relevant implications for the management of the Yangtze River and other lowland alluvial rivers in the world as global sea level continues rising and human intervention on estuarine systems persists.

Numerical Simulation of Wave Overtopping of an Ecologically Honeycomb-Type Revetment with Rigid Vegetation

Traditional concrete revetments can destroy the ecological environment and the water landscape. An increasing number of ecological revetment structures have been applied in coastal, lake, and river regulation projects. It has been found that honeycomb-type revetments display a better performance in the attenuation of wave overtopping when compared to experimental data collected using the Eurotop and Muttray’s formula; recording a 40% decrease in the wave run-up in comparison to the latter. To further investigate the wave run-up and overtopping of the ecologically vegetated honeycomb-type revetment, based on OpenFOAM, an open source computational fluid dynamics software, a three-dimensional numerical wave tank was established. The Discrete Particle Method (DPM) was used to simulate gravel movement, and the flexible plant move boundary model was developed to simulate vegetation. The results of wave run-up calculated by the numerical model and those obtained by the experiments were in good agreement, with errors less than 20%. The modeled results of wave overtopping were within the same order of magnitude as those from the experiments; however, critical limitations were noticed due to effects of plant generalization and grid restrictions imposed by DPM methods. The results showed that wave overtopping increased with increasing wave period and wave height. However, with an increase in the wave overtopping, the influence of the wave period on wave overtopping decreased. The increase in vegetation density effectively reduced wave overtopping. Furthermore, an empirical formula for wave overtopping, considering the effects of vegetation density, was proposed.

Concept and Practices Involved in Comprehensive River Control Based on the Synergy among Flood Control, Ecological Restoration, and Urban Development: A Case Study on a Valley Reach of Luanhe River in a Semiarid Region in North China

Many rivers in semiarid areas have ecological degradation and flood control problems that need to be addressed urgently. In order to maintain river health and to promote the sustainable development of cities near these rivers, a comprehensive river regulation project must be carried out. In this study, first, the factors influencing river health are discussed, and the principles and main restrictions involved in comprehensive regulations are studied. The scientific regulation mode is proposed, and new financing channels for water conservancy construction are also suggested. Second, a river reach adjacent to a city in the middle part of the Luanhe River in North China is used as a case study. The health status of the river is analyzed, and a comprehensive river regulation plan combined with urban development is put forward on this basis. The plan includes embankment construction, river regulations, multilevel rubber dam storage, ecological restoration, and artificial lake and riverside landscape construction. The influence of the engineering treatment on the river flood discharge capacity is examined, and the treatment effect is verified by a hydraulic scale model. After implementation of the comprehensive river regulations, the flood control safety of the city and river ecological environment are found to be significantly improved, with the hidden danger of dust storms eliminated. The treatment project incurs environmental, social, and economic benefits and preliminarily achieves the coordination and mutual promotion of river regulation and urban development.

Research on the Asymmetry of Cross-Sectional Shape and Water and Sediment Distribution in Wandering Channel

The construction of a river regulation project has changed the cross-sectional shape of a river and significantly impacted the evolution of the river regime. In this paper, an asymmetry index was proposed to characterize the changes in the shape of the river cross-section and the distribution of water and sediment factors. According to the transverse distribution formula of the river section and water and sediment factors, the asymmetry of the cross-sectional shape as well as water and sediment factors along with the transverse distribution in the wandering reach of the lower Yellow River before and after the construction project was calculated, respectively. The results showed that the cross-sectional shape of the river channel before and after the building was asymmetric, and the cross-sectional shape of the river channel after the construction was more asymmetric than that of the free development channel without engineering constraints; at the same time, under the action of a limited control boundary, the asymmetry of cross-section flow velocity and sediment concentration and other water and sediment factors along the transverse distribution were more prominent, the flow velocity and sediment concentration along the transverse distribution increased, the river flow was more concentrated, and the sediment transport capacity of the channel improved significantly under a large flow (5000 m3/s). This study revealed the positive effect of river regulation projects on the river regime evolution of the wandering river and provided new ideas for the study of river regime evolution.

Two-dimensional modeling of channel evolution under the influence of large-scale river regulation works

In the middle and lower reaches of alluvial rivers, various kinds of river regulation projects affecting natural channel evolution often are distributed due to the requirements of flood control, navigation, and channel stability. However, the influence of large-scale river regulation works on fluvial processes is not fully known. Therefore, a two-dimensional (2D) morphodynamic model has been improved to address this problem. The new detailed procedure is presented in this paper: (i) First, each node in the study domain was labeled using a specified point code to distinguish the zones with or without regulation works; and (ii) second, a 2D model was improved to consider the effect of river regulation works. In the refined model, the modules of sediment transport and bed deformation were treated separately in different zones. In the unprotected zones, both bed deposition and erosion were likely to occur. In the protected zones, bed erosion could not occur owing to the protection provided by the river regulation works, unless there was a deposition layer newly formed over the previous simulation periods. The observed data of the years 2004 and 2008 were used to calibrate and verify the improved 2D morphodynamic model which was applied in a 68-km-long reach of the Middle Yangtze River. Satisfactory results were obtained indicating that the improved model can better simulate the process of sediment transport and the morphology adjustment in three central bars in the study reach.

Review on the evaluation system of river regime change effect in the middle and lower reaches of the Yangtze River

In recent years, obvious changes have taken place in the middle and lower reaches of the Yangtze River, and some river regulation projects have gradually lost their original functions. Under the background of “great protection of the Yangtze River”, the rapid economic and social development along the Yangtze River and the continuous enhancement of ecological civilization construction put forward higher requirements for the Yangtze River governance research under the new situation. This paper systematically discusses the characteristics of various evaluation system research methods, introduces the main theories and advantages and disadvantages of AHP in detail, and selects flood control, shipping, beach, water resources utilization and water ecology as the evaluation indexes of APH, and summarizes the previous research results of each evaluation index under the condition of river regime change, so as to provide reference for the formulation and implementation of the control strategy of the middle and lower reaches of the Yangtze River Optimization provides theoretical support.

Disappearing reeds on Chongming Island: An environmental microhistory of Chinese eco-development

This paper critically examines current ecological development planning and practice in China through an environmental microhistory approach. By tracing the gradual disappearance of an indigenous plant – the common reed ( Phragmites australis) – on Chongming Island in Shanghai, which is known for the grand Eco-Islands development plan, this paper reveals the paradox of ecological destruction through eco-development in China. Based on data collected from archives, through oral history and through on-site fieldwork, we have reconstructed and analysed the transformation of Chongming Island’s reed ecology over time. Our research documents the historical importance of reeds to Chongming culture and identity. The transformation of the reed landscape mirrors, we argue, broader environmental and social transformations on the island. The near extinction of the once abundant reed in the coastal wetlands due to massive land reclamation projects for the purpose of industrialisation and urbanisation is a reflection of the prevailing pursuit for economic growth. Land reclamation projects in the early 2000s were facilitated by the planting of an invasive grass that replaced reeds and other native wetland plants. Ironically, the invasive grass served to legitimise continuous land reclamation as part of Chongming’s eco-development. Moreover, reeds that grew by the rivers and constituted a central part of local livelihoods were gradually wiped out as a result of a series of river regulation projects under the eco-development. Our research reveals that the current ecological agenda has privileged modern engineering solutions and aesthetics while largely ignoring local traditional knowledge. The case of Chongming delivers a sobering message that well-intentioned ecological initiatives can in fact have disastrous effects if the local environment, its ecological features, cultural characteristics, and historical and social contexts are not fully considered. Overall, this paper pioneers an environmental microhistory approach in evaluating contemporary urban ecological initiatives and contributes methodological and empirical insights to advance Chinese eco-developments.

Dynamics of mangrove forests in Shenzhen Bay in response to natural and anthropogenic factors from 1988 to 2017

Global mangrove forests have exhibited distinct changes in past decades owing to diverse environmental gradients and regional anthropogenic activities. Previous studies have mainly reported alarming mangrove loss. However, few studies have focused on the process of mangrove expansion, and its driving factors remain unclear. By integrating medium-resolution Landsat surface reflectance products and meteorological, hydrological and bathymetric data, the current study investigates the spatiotemporal changes of mangrove forests in Shenzhen Inner Bay (SZIB) of China over the past thirty years, and the relationship between mangrove changes and natural and anthropogenic factors was also identified. The results reveal that the area of mangrove forests in the SZIB increased at a rapid rate of 8.9 ha/yr despite sea level rise, reaching 527.1 ha in 2017. No statistically significant correlation between mangrove area and winter temperature and precipitation was found, whereas a significant positive correlation occurred between mangrove area and sea level rise, in contrast to the common consensus. Human activities affected the SZIB mangroves in two distinct ways. On the one hand, the area of mangrove deforestation occurred on 23.5 ha and 6.8 ha in the Futian and Mai Po reserves, respectively, with reforestation campaigns only compensating for 5.6 ha of the mangrove area lost in the Futian reserve. On the other hand, the reduced tidal prism due to the implementation of the Shenzhen Bay Land Reclamation Project (SZBLRP) resulted in significant deposition in the SZIB, which counterbalanced the negative effect of sea level rise, contributing to 209.9 ha of mangrove expansion by providing suitable accommodation space and accounting for 78.4% of the total mangrove gain. Moreover, the morphological adjustments in the SZIB caused by the Shenzhen River Regulation Project (SZRRP) also had a significant influence on the mangrove extent and distribution, with the mangrove expansion area of 22.7 ha being contributed by the SZRRP, accounting for 8.5% of the total mangrove expansion. The findings of the current study indicate that with the increased sediment supply and accretion rate induced by anthropogenic activities, mangrove forests with limited land retreat space can still expand in the face of sea level rise.

Weather Anomalies and Their Economic Consequences: Penury in Northeastern Hungary in the Late 1870s

This study investigates an episode of penury in 1879–1880 in Borsod and Zemplén Counties which occurred as one of the negative consequences of a short-term weather change which was experienced across Europe in the late 1870s and early 1880s. From the mid-1870s on, due to the wetter and cooler weather, the annual crop yields repeatedly fell below the usual and expected averages in Hungary. After a catastrophic harvest in the autumn of 1879, when the quantity of harvested cereals was sufficient neither for reserves nor for spring sowing, the situation became severe. 1878 had also been a bad year for agriculture: the severe floods in the second half of 1878 not only had washed the crops from the fields but had also covered them with thick sludge that made it impossible to sow in autumn. Since the spring of 1879 was characterized by unfavorable conditions for agriculture (increased rainfall, widespread floods, low average spring temperatures), the local and national authorities continuously kept their eyes on the crops. Thanks to this preliminary attention, the administration was able to respond quickly and in an organized manner to the bad harvest in July and August and could avert catastrophe at national level. The leadership of the two counties responded more or less in the same way to the near-famine conditions. First, they asked the Treasury to suspend tax collection until the next harvest at least so that the farmers who were facing financial difficulties would not have to go into debt. Second, they appealed to the government for financial and crop relief to save the unemployed population from starvation. For those who were able to work, they asked for the approval of public works and major construction projects from the Ministry of Transport and Public Works. For many, such state-funded road construction or river regulation projects were the only way to make a living. Third, the county administrations also gave seeds for spring sowing to the farmers. While Borsod county survived the years of bad harvests without dire problems due to the higher proportion of better quality fields, in the more mountainous region of Zemplén, most landowners had smaller and lower quality lands, and they often chose to emigrate to avoid starvation. These difficult conditions may have provided the initial impetus for mass emigration to Western Europe and America.

Prewhitened causality analysis for the chlorophyll-a concentration in the Yeongsan River system

Abstract Blooming of algae has been a primary issue of concern for heavily polluted aquatic ecosystems. The chlorophyll-a (Chl-a) concentration depends on various hydrological, biochemical and anthropogenic components, which makes prediction of algal blooms complicated. A river regulation project in Yeongsan River, South Korea, involving the construction of a weir, had substantially altered the flow regime. A prewhitened time series analysis is a useful method for delineation of a causal relationship between two environmental variables. This study explores the impact of river regulation on algal blooming using both the prewhitened cross-correlation method and principal factor analysis. Both individual and comprehensive causality structures were configured for the variation in Chl-a concentration. A prewhitened cross-correlation analysis indicates that the water quality response patterns of the river system were changed to those of a reservoir after the river regulation project. A principal factor analysis of correlations indicates that the weir construction had a stronger impact on algal concentration than both the hydro-meteorological factor and difference in sampling location. Variation in stochastic structures from nutrients and water quality factors to algal bloom was substantially reduced by the construction of a weir, which can be explained by the relatively uniform flow pattern throughout the river regulation practice.

Analysis and Application of River Surface Line in Hilly Area based on Hec-ras Model

For example—Cixian Fuyang River Regulation Project. Due to the character that Fuyang River is located in hilly areas of Cixian, we use the Hex-ras software to calculate the status of the river water surface line for the goal of determining the final treatment plan. We maintain the present situation of the river channel design as principle, select the most appropriate pushed water level and roughnessas the basic, and we combine the classification calculation of crossing structures of backwater and the encryption calculation section to get the more accurate result. We compare the water level elevation and the calculation of cross strait, analyze the design parameters, calculate repeated the water line section, analyze the rationality of the design plan, and then finally determine the applicability of Hex-rac software in the large continuous variation of cross section of embankment of river river surface line.

Morphology and mechanism of the very large dunes in the tidal reach of the Yangtze River, China

High-resolution multibeam data was used to interpret the surface morphology of very large dunes (VLDs) in the tidal reach of the Yangtze River, China. These VLDs can be divided into three categories according to their surface morphological characteristics. (1) VLDs-I: those with a smooth surface and cross-section; (2) VLDs-II: those accompanied by secondary dunes; (3) VLDs-III: those accompanied by secondary dunes and numerous elliptical pits. Parameters and spatial distribution of VLDs, and bed surface sediment were analyzed in the laboratory. Overall, channel morphology is an important factor affecting the development of VLDs, and channels with narrow and straight and certain water surface slope are facilitating the development of VLDs by constraining stream power. Meanwhile, distribution density of VLDs depicts a decreasing trend from Chizhou towards the estuary, are probably influenced by channel morphology and width. Associated pits in VLDs-III change the 3D dune morphology by distributing in secondary dunes as beads. The Three Gorges Dam project (TGP) leads to the bed surface sediment activity frequently and leads to the riverbed surface sediment coarsens, which promotes the further development of dunes. Moreover, other human activities, such as river regulation project, sand mining and Deep Water Channel Regulation Project have changed the regional river boundary conditions and hydrodynamic conditions are influential on the development of VLDs.

Endangered Golden mahseer Tor putitora Hamilton: a review of natural history

Golden mahseer, Tor putitora Hamilton, one of the largest freshwater fish of the Indian sub-continent, inhabits mainly Himalayan rivers in the foothills. Among numerous freshwater fishes of the sub-continent, Golden mahseer is the most striking due to its large size, attractive golden colour, sustenance and sporting values. Tor putitora is known by various common names such as king mahseer, mighty mahseer and the tiger of water. Being a migratory fish, Golden mahseer undertakes periodic upstream migration during pre-monsoon and monsoon seasons from large rivers and higher order streams in the foothills to lower order streams for spawning. In recent years, conservationists, anglers and commercial fishermen have expressed concern over the declining populations of Golden mahseer due to indiscriminate fishing of brooders and juveniles besides the adverse effects of dams. Despite its ecological and economic importance, specific conservation measures by way of protective legal provisos are lacking for Golden mahseer in India. In view of its physical features, ecology and vulnerable conservation status, there is an exigent need to promote the Golden mahseer as a flagship conservation species of the Himalayan rivers. In view of the recent reports of unprecedented river regulation projects on the Himalayan rivers and need to draw global attention of conservationists, we review various aspects of ecology, life history, interesting features, traits and threats associated with the reduced chances of survival of Golden mahseer.

Vegetation Succession on River Sediments along the Nakdong River, South Korea

We investigated successional vegetation on river sediments along the Nakdong River in South Korea at the time when a river regulation project, named the Four River Project, was launched. We sampled differently aged stages of succession in 63 plots of 10 × 10 m in 2010 using species cover estimations. To explain the observed species composition, we considered the following environmental variables: successional age, distance from the estuary, altitude, elevation above the river water line, texture of the substrate (silt, sand and gravel content) and cover of forest around each site within a radius of 1 km. We used ordination techniques to relate plant community characteristics to environmental variables. We distinguished three main successional vegetation types based on their floristic composition, which included especially a variety of willow species. Besides the cover of forest and certain components of substrate texture, all the variables exhibited significant effects on species composition of the vegetation over the course of succession. The most important factors determining the seral vegetation were the altitudinal gradient and successional age. Environmental factors in the riverine landscape together form a complex riverine environment and determine the vegetation pattern. Unfortunately, this environment has been largely destroyed by the massive river regulation project, but our results indicate that, under certain conditions, the riverine vegetation has a potential to at least partly recover even after such a large-scale disturbance.

Design and Application of Internal Flat-Pool Measuring Weir

Base on the mechanism of surge tank and measuring weir, an internal flat-pool measuring weir has been developed which can be applied in flow rate measuring area such as the hydraulics labs, the hydraulic engineering model labs and the river regulation project model labs. This new device functions well even with site limitation and unstable current. This passage introduces the mechanism of measuring weir with a few examples.

Impact of river training on the hydraulics of Shenzhen river

Shenzhen River is a tidal river on the border between Hong Kong and Shenzhen. It flows southwest towards Deep Bay in the Pearl River Estuary in south China. In the past, Shenzhen River was narrow, meandering and only capable of conveying floods of return period 2–5 years. To alleviate the flooding hazard, Hong Kong and Shenzhen governments have carried out the Shenzhen River Regulation Project jointly since 1995. The river downstream has been trained to cater for flooding of 50-year return period. However, unexpectedly, the trained Shenzhen River has been seriously silted by 3 m of sediment 5 years after the completion of river training. This diminishes the effectiveness of river training on enhancing flood discharge capacity. We present a study on the impact of river training on Shenzhen River hydraulics by an integrated three-dimensional numerical hydrodynamic model. The model is verified against field data and shows good agreement with the observed hydrodynamics; wetting and drying of inner Deep Bay tidal flats are successfully simulated. The model simulations show that river training has drastically altered the hydraulics of Shenzhen River. Tidal propagation in the river has changed from a damped tidal oscillation to a more standing wave character with less amplitude damping. Tidal current is reduced by about 50%. Vertical salinity stratification and gravitational circulations are formed within the trained river in the dry season. The bottom upstream residual current in the two-layered residual circulation strongly suggests the input of sediment from Deep Bay and sediment trapping in the river.

Effect of water and sediment regulation on lower Yellow River

According to the results of the water and sediment regulations of the Yellow River in year 2002–2007, the effect of erosion and deposition on the lower reaches, the amount and distribution of erosion and deposition in the river mouth area, the adjustment of river regime, the effect of river regulation projects and changes of flowing capacity of the channel are analyzed. It is revealed that the water and sediment regulation is efficient to reduce deposition and improve the flowing capacity and the conditions of sediment transport.