River Shore Research Articles

The Destruction of the Foundations of Structures in Coastal Areas of the Volgograd Region

The article discusses the problem of protecting the foundations of buildings and structures constructed on coastal bases and subject to destruction under the influence of abrasion and erosion-landslide processes. The problem is vital for the cities of the Southern Federal district. Almost all settlements on the banks of the Volgograd and Tsimlyansk reservoirs and the rivers Volga, Don and Ahtuba are situated in the hazardous areas. The results of a study of hydrological and geological conditions are based on the monitoring processing of the shores of reservoirs and rivers of the Volgograd region. The research is based on the application of new scientific and the methodological principles of lithomonitoring. The results of the research must have a methodical and information basis for the establishment and functioning of the monitoring system of ecological safety and protection of the coastal areas of the Volgograd region from destruction on the basis of GIS-technologies.

Parasites as Health Indicators in Wild Fish Populations

More often than not, when we are watching TV or reading the news, we see these images of piles of fish agonizing and dying on the shores of numerous rivers and lakes, and we can’t help to wonder what is happening with the aquatic ecosystems worldwide. Can we drink that water and eat those fish anymore? We also think. In the last few decades, since the first studies on fish parasitology until now, the scientific community has made great advances on this subject and can provide us with some useful information regarding management and prevention. Here, we present you another opinion, based on the conclusions of some researchers, about a new role for the fish parasite communities, this time as helpers and indicators of the health status of the wild fish populations and the whole aquatic ecosystem.

Redox zonation and oscillation in the hyporheic zone of the Ganges-Brahmaputra-Meghna Delta: Implications for the fate of groundwater arsenic during discharge

Riverbank sediment cores and pore waters, shallow well waters, seepage waters and river waters were collected along the Meghna Riverbank in Gazaria Upazila, Bangladesh in Jan. 2006 and Oct.–Nov. 2007 to investigate hydrogeochemical processes controlling the fate of groundwater As during discharge. Redox transition zones from suboxic (0–2 m depth) to reducing (2–5 m depth) then suboxic conditions (5–7 m depth) exist at sites with sandy surficial deposits, as evidenced by depth profiles of pore water (n = 7) and sediment (n = 11; diffuse reflectance, Fe(III)/Fe ratios and Fe(III) concentrations). The sediment As enrichment zone (up to ∼700 mg kg−1) is associated with the suboxic zones mostly between 0 and 2 m depth and less frequently between 5 and 7 m depth. The As enriched zones consist of several 5–10 cm-thick dispersed layers and span a length of ∼5–15 m horizontally from the river shore. Depth profiles of riverbank pore water deployed along a 32 m transect perpendicular to the river shore show elevated levels of dissolved Fe (11.6 ± 11.7 mg L−1) and As (118 ± 91 μg L−1, mostly as arsenite) between 2 and 5 m depth, but lower concentrations between 0 and 2 m depth (0.13 ± 0.19 mg L−1 Fe, 1 ± 1 μg L−1 As) and between 5 and 6 m depth (1.14 ± 0.45 mg L−1 Fe, 28 ± 17 μg L−1 As). Because it would take more than a few hundred years of steady groundwater discharge (∼10 m yr−1) to accumulate hundreds of mg kg−1 of As in the riverbank sediment, it is concluded that groundwater As must have been naturally elevated prior to anthropogenic pumping of the aquifer since the 1970s. Not only does this lend unequivocal support to the argument that As occurrence in the Ganges-Brahmaputra-Meghna Delta groundwater is of geogenic origin, it also calls attention to the fate of this As enriched sediment as it may recycle As into the aquifer.

Sediment composition mediates the invasibility of aquatic ecosystems by a non-native Poaceae species

Aim: To test the invasibility of aquatic ecosystems by an exotic species, we used the invasive macrophyte Urochloa arrecta, which has invaded many Neotropical waterbodies and has reduced biodiversity in these habitats. The extensive growth of this macrophyte can be related to its affinity for mud-rich sediments, which occur primarily in secondary river channels and lentic habitats.MethodsTo test this hypothesis, we cultivated U. arrecta in trays with different percentages of mud and we measured the sprout length and biomass of the plants after 75 days.ResultsOur results showed a positive and significant relationship between sediment mud percentage and nitrogen, phosphorus and organic matter. Both plant length and biomass increased significantly and continuously with increasing mud content, indicating that the growth of this species is not limited even at the highest levels of mud, which is shown to be toxic for other species of macrophytes. Thus, it is probable that sand-rich sites, such as river shores, are less vulnerable to invasion by this species than relatively mud-rich sites, such as lakes.ConclusionsThis finding indicates that relatively mud-rich ecosystems should be prioritised in monitoring programs to prevent invasion by this species. In addition, the slow development of this species in sandy sediments opens a potential window for its management, at least on small spatial scales. However, despite the reduced growth of U. arrecta in sand-rich sediments, this grass is able to grow in several types of sediments, which explains its spread in a variety of habitats in Neotropical freshwater ecosystems.

Occurrence and Spatial Distribution of Microplastics in River Shore Sediments of the Rhine-Main Area in Germany.

Plastic debris is one of the most significant organic pollutants in the aquatic environment. Because of properties such as buoyancy and extreme durability, synthetic polymers are present in rivers, lakes, and oceans and accumulate in sediments all over the world. However, freshwater sediments have attracted less attention than the investigation of sediments in marine ecosystems. For this reason, river shore sediments of the rivers Rhine and Main in the Rhine-Main area in Germany were analyzed. The sample locations comprised shore sediment of a large European river (Rhine) and a river characterized by industrial influence (Main) in areas with varying population sizes as well as sites in proximity to nature reserves. All sediments analyzed contained microplastic particles (<5 mm) with mass fractions of up to 1 g kg⁻¹ or 4000 particles kg⁻¹. Analysis of the plastics by infrared spectroscopy showed a large abundance of polyethylene, polypropylene, and polystyrene, which covered more than 75% of all polymer types identified in the sediment. Short distance transport of plastic particles from the tributary to the main stream could be confirmed by the identification of pellets, which were separated from shore sediment samples of both rivers. This systematic study shows the emerging pollution of inland river sediments with microplastics and, as a consequence thereof, underlines the importance of rivers as vectors of transport of microplastics into the ocean.

Assessment of the efficiency in trapping North American mink (Neovison vison) for population control in Patagonia

Introduced species can have a major negative impact on biodiversity; an example is the American mink, which was introduced in the 1930s in Patagonia. While there is a consensus that reversing alien mustelids continental scale invasions remains unfeasible, there is little consensus, given a maximum cost or investment, on the feasibility and efficiency of region-wide control or eradication. Thus, our goal was to provide information about efficiency for mink control in Patagonia. Between January 2009 and February 2013 this study was conducted in ten study sites (4 km to 15 km long) between 39°S to 45°S latitude. Minks were trapped using cage traps operated by two trappers. We estimated the population density at each study site assuming they were close populations, exhibit intrasexual territoriality and the home range of females were smaller than those of males. We obtained a theoretical population and a modeled population from our trapping results. Sixty five minks were trapped over 2190 trap nights (0.03 mink/trap night). Mink captures were higher in the first six days and in the first trapping campaigns. A two person team was able to control a maximum distance of approximately 6 km of river shore by foot and 15 km of sea and lake shores by boat. There was an over linear increase of operational costs as time passed. Our modeled population was 91% of the theoretical population. We believe that to trap and remove a minimum of 70% of the mink population in a region under ideal circumstances, traps should be deployed every 200 m and after the sixth day should be moved to another new transect. We suggest an annual repetition of this strategy as the more efficient for controlling mink populations in terms of trapping success and reduced costs. The number of traps will depend on the number of trappers participating and also on habitat characteristics.

Spatial Variability of Escherichia coli in Rivers of Northern Coastal Ecuador.

The use of contaminated surface water continues to be a pressing issue in areas of the world where people lack improved drinking water sources. In northern coastal Ecuador, many communities rely on untreated surface water as their primary source of drinking water. We undertook a study to explore how microscale river hydrodynamics affect microbial water quality at community water collection locations at three rivers with varying stream velocity and turbidity profiles. To examine how the distance from river shore and physiochemical water quality variables affect microbial contamination levels in the rivers; we collected a total of 355 water samples within six villages on three rivers; and tested for Escherichia coli concentrations using the IDEXX Quanti-tray method. We found that log10 E. coli concentrations decreased with increasing distance from shore (β = −0.017; p = 0.003). Water in the main channel had E. coli concentrations on average 0.12 log10 lower than within eddies along the river shore and 0.27 log10 lower between the sample closest to shore and any sample >6 m from the shore. Higher E. coli concentrations were also significantly associated with increased turbidity (β = 0.003; p < 0.0001) and decreased dissolved oxygen levels (β = −0.310; p < 0.0001). The results of this study can help inform community members about the safest locations to collect drinking water and also provide information on watershed scale transport of microbial contaminants between villages.

GrimShaw Proposal for Tirana River Shore Regeneration: Survival of the Waterfront

The study analyses the possible transformations of the Tirana river shore, foreseen by GrimShaw proposal, presented in the competition organized by the municipality for the master-plan of Tirana. Understanding and balancing different aspects of the project decisions in changing the vision of Tirana goes along with the emphasis of the desirable conditions of this specific riverside environment. The regeneration of the urban river waterfront is one of the main urban and design issues of our cities. It is seen as a potential for future urban transformations and attraction to investments, employment, industries, publicity, by focusing in a special case study: a self-made structure where people try to create their own model of living in the natural environment of Tirana. This descriptive and analytical work can serve to Albania's professionals on decision-making, but also to other cities of similar scale and nature of development as Tirana. The expectation of this research is to help the interest groups with a concern for waterfront regeneration, recreation and cultural heritage conservation, with this specific experience in the riverside planning and redevelopment of Tirana.

Remote-sensing perspective and GPR subsurface perception on the growth of a recently emerged spit at Talashil coast, west coast of India

The growth as well as the internal structure of the recently emerged Talashil spit along the west coast of India was studied using multidate satellite images coupled with ground-penetrating radar (GPR) information. Decadal changes (2003–2013) in configuration, geomorphology and erosion and accretion pockets along the spit were traced and compared. A 170 m long subsurface profile across the spit from shoreline to river shore was generated using GPR. Historical satellite images from 1973 to 2013 illustrate a rapid transformation of a linear sand bar into a matured spit. The growth trend over the period 2003–2013 shows mainly accretion along the seashore and erosion along the river shore. Three dynamic hot spot locations were noticed where erosion and accretion were alternately dominating. The radar facies clearly distinguishes zones of fluvial, dune and inter-tidal dominance and substantiates the interpretation of the satellite images. This study indicates spit formation following build up and emergence of a submerged shoal due to fluvial sedimentation, after which an equilibrium between erosion and accumulation was reached. The data indicate that the growth of the spit has reached its mature stage and only lateral oscillation of the spit is likely in the future unless sizable disturbances caused by either tectonic or anthropogenic processes influence this region.

Mowing regime has different effects on reed stands in relation to habitat

Reed (Phragmites australis) is widespread in aquatic habitats in Europe where it plays an important ecological role, especially as stabilizer of lake and river shores and as filter against pollutants. Reed is also abundant in ecotones towards terrestrial habitats, especially fen meadows, where its expansion can out-compete rare slowly-growing fen species. Therefore, defining appropriate guidelines for managing reed in wetlands has to consider differences in the ecological roles that reed plays in different wetland habitats. In a small pre-alpine lake in N Italy, we mowed reed stands in three plant communities located along a transect from the lake shore to the periphery. In each community, three areas were subjected to reed mowing in late winter, as traditionally done in the past. Three additional areas were subjected to mowing in winter and summer, while three areas served as un-treated controls. Summer mowing was carried out in August, when the nesting period of birds was concluded. Mowing in winter did not affect reed aboveground biomass (RAB) in any community but enhanced the efficiency of removing nutrients by reducing litter accumulation in the soil. Mowing in winter and summer only slightly decreased RAB in the riparian community, not at all in the intermediate community but significantly diminished RAB in fen meadows. Phosphorus deficiency and/or reduced competition with other species probably accounted for RAB reduction in fen meadows. In conclusion, winter mowing can be overall recommended for preventing eutrophication of littoral habitats while summer mowing is advisable for preventing reed expansion in fen meadows. However, the timing of summer mowing has to be defined considering all requirements needed for optimal management of each individual site.

Ecological and geographical separation of three varieties of &lt;em&gt;Sporobolus vaginiflorus&lt;/em&gt; (Poaceae) in eastern Ontario

Field and herbarium studies of the three varieties of Sporobolus vaginiflorus (var. inaequalis, var. vaginiflorus, and var. ozarkanus) in eastern Ontario found that (1) there is a strong tendency for the varieties to occur alone; (2) var. inaequalis occurs primarily on roadside gravels, river shores, and granite barrens and is the only variety associated with acid as well as alkaline substrates; and (3) both var. vaginiflorus and var. ozarkanus are confined to alvar landscapes but occupy different geographical regions. The ecological and geographical differentiation of these taxa supports their taxonomic recognition and the protection of alvar landscapes to conserve subspecific variants.

River scale model of a training dam using lightweight granulates

Replacing existing river groynes with longitudinal training dams is considered as a promising flood mitigation measure in the main Dutch rivers, which can also serve to guarantee navigability during low flows and to create conditions favourable for ecological development. Whereas the bed response in the streamwise uniform part of a river trained by a longitudinal dam can be readily predicted, the bed response at the transition zones is unclear. In the present study, we investigate the local morphological effects resulting at the intake section of a longitudinal training dam, where the flow is distributed over the main channel and a side channel in between the dam and the river shore. A sediment recirculating model with a nearly undistorted geometry with respect to the prototype was setup. Lightweight polystyrene granulates were used as a surrogate for sediment, to properly scale the Shields parameter without compromising Froude scaling, and reach dynamical similarity. A laser scanner allowed collecting high-resolution bed elevation data. Results obtained under typical low flow and high flow conditions show a general deepening of the bed in the area adjacent to the training dam, in response to narrowing of the main channel. Scour at an upstream river groyne embedded in the model showed a scour hole which was deeper than realistic. Throughout the entire domain, bedforms developed featuring geometrical properties that reproduced the prototype conditions appropriately. Based on a comparison with characteristics from the River Waal, regarded as the prototype without a longitudinal dam, lightweight sediments were considered to be a proper choice for this study, in which bedload is the main sediment transport mode. The main conclusion regards the absence of significant morphodynamic developments at the intake section, both during the high flow experiment and during the low flow experiment, which can be attributed to the alignment of the dam with the local streamlines.

On the application of hierarchical cluster analysis for synthesizing low-level wind fields obtained with a mesoscale boundary layer model

Hierarchical clustering is applied to a boundary layer model output that describes the low-level wind field over the La Plata River region of South America. The model output consists of 180 17-dimensional vectors per season that include wind direction frequencies, calms and mean wind speeds per wind sector. The cluster approach is intended to assist the discussion of meteorological phenomena, and is also employed to define regionality. Results show that the 180 original vectors can be well represented by a small number of vectors, and the 18, 12 and 6 group cluster solutions share a similar layout. However, the 12 and the 6 group clusters seem both appropriate solutions when a threshold of 10% in wind direction frequency, including calms, is taken as a reference in order to decide significant differences between groups. All solutions show more groups along the northeastern than along the southwestern river shore, evidencing a complex sea-land breeze circulation pattern. The analysis of the observations at nine weather stations supports the findings of the cluster analysis conducted with the model outputs. The advantage of the hierarchical cluster analysis in synthesizing information becomes clearly evident when compared to the traditional method of visual inspection. Besides, the actual distribution of weather stations in the region is not very far from the regionality that suggests the obtained cluster distribution. However, in order to match the latter, more observing points would be needed particularly over the river and towards the northeastern shore.

황강 수생태계에 대한 하천 자연도 평가 연구

I investigated the river morphology and river naturality according to the environment of the Hwang River. The numbers of flexions at the upstream regions were more than those of downstream regions. The Hwang River showed very low overall diversity of the flow. Materials of river shore at low channel width were mainly boulders or gravel at the upstream regions, and the middle and downstream were silts and clay. Artificial masonry and natural materials were mixed from materials of river levees. The Hwang River was some of the natural herbaceous vegetation to riparian zones. Land utilities for floodplain were extremely overall farmland were predominant, and partly used by natural vegetation in the forest, a soccer field, some park facilities, residential, and commercial facilities. The water was width sleep / rivers beam ratio of 10 to 20%. Currently estimation for river naturality widely used in rivers were consisted of a narrow wide a variety of items and did not reflect the actual.

An Experimental Investigation of Temperature Distribution in Different Urban Locations in Aswan, Egypt of Hot and Dry Climate

This paper describes the measurements and analysis of an experimental campaign performed in different urban street in Aswan, Egypt. The present study is focused on the experimental investigation of thermal characteristics during summer 2012 of five different regions location (building on Nile river shore, building in front of a mountain, building under high power transmission line, two building opposite other in resident region, finally ship in Nile river) aiming at the investigation of the impact of urban location on the potential of natural and hybrid ventilation under hot weather conditions. The temporal and spatial distribution of air and surface temperatures is examined. Emphasis was given on the vertical distribution of air and surface temperatures. The results showed that the measured surface temperature across the street was the highest value than the air and wall temperature where temperature difference between street and air temperature could reach 35℃ and this favored the overheating of lower air levels. Buoyancy generated mainly from asphalt-street heating resulted in the development of the predominant recirculation inside the street canyon. The results also show that air temperature for two building opposite other has a lower value followed by building on Nile river shore followed by building at front of mountain.

Leafcutter Ant (Atta sexdens) (Hymenoptera: Formicidae) Nest Distribution Responds to Canopy Removal and Changes in Micro-Climate in the Southern Colombian Amazon.

At regional scales, leafcutter ant nest distribution is regulated by environmental factors such as vegetation, predators, soil and climate. This study investigated the effect of micro-climate on Atta sexdens (L.) nest distribution. It was carried out on a farm located on the Colombian Amazon River shore, where an extension of secondary forest was felled. Prior to felling, we located 20 A. sexdens nests and monitored them over the course of one year. Ten of the nests became exposed to the sun as a result of tree felling, and ten nests, located in neighboring unlogged forest, remained unaffected. Within six weeks, five of the exposed nests had moved to the cover of nearby vegetation patches and the remaining five nests had died. The ten unexposed nests remained active at the same location. In comparison with relocated nests, exposed nests experienced significantly higher air and soil temp, and lower soil moisture. The results of this study suggest that changes in micro-climate may trigger nest relocation and therefore play an important role in local A. sexdens nest distribution.

Investigation of macro-turbulent flow structures interaction with a vertical hydrokinetic river turbine

Reported are a series of river velocity measurements taken one diameter upstream of a 25 kW vertical axis river kinetic turbine deployed in the Winnipeg River at Pointe du Bois, located 150 km northeast of Winnipeg. A load-bank located on the river shore provides a resistive load for the turbine generator. An acoustic Doppler velocimeter measures velocity fluctuations at a sample rate of 200 Hz. Analysis of acoustics Doppler velocimeter data measured upstream of the turbine quantifies the variation in the mean and fluctuating components of river flow velocity. Results show that in this particular test site the river contains eddies with the same order of magnitude as the turbine diameter or greater. Measurements upstream of the operating turbine indicate reduction in the mean velocity with eddies breaking down into smaller sizes. These smaller eddies increase the turbulence intensity of the incoming flow and increase the high frequencies energy level in the power spectra. ► Velocity measurements upstream of a 25-kW vertical turbine in a river are obtained. ► Solutions for ADV signal quality and signal despiking provided. ► Inflow is non-uniform and contains large eddies in the river. ► Operating turbine increases turbulence intensity and breaks large eddies in upstream. ► Higher turbulence intensity induces higher levels of fatigue damage.

Biodiversity in Hudson River shore zones: influence of shoreline type and physical structure

The shore zones of the Hudson River, like those of many developed waterways, are highly varied, containing a mix of seminatural and highly engineered shores. Our goal was to document the biodiversity supported by different kinds of shore zones in the Hudson. We chose six common types of shore zones, three of them “natural” (sand, unconsolidated rock, and bedrock), and three of them engineered (riprap, cribbing, and bulkheads). We measured selected physical characteristics (shore zone width, exposure, substrate roughness and grain size, shoreline complexity) of three examples of each of these shore types, and also sampled communities of terrestrial plants, fishes, and aquatic and terrestrial invertebrates. Community composition of most taxa differed across shore types, and frequently differed between wide, sheltered shores and narrow, exposed shores. Alien plant species were especially well represented along engineered shores. Nevertheless, a great deal of variation in biological communities was not explained by our six-class categorization of shore zones or the physical variables that we measured. No single shore type supported the highest values of all kinds of biodiversity, but engineered shore zones (especially cribbing and bulkheads) tended to have less desirable biodiversity characteristics than “natural” shore zones.

Study on Flood Control Demonstration of Huangshi Navigation Sign Maintenance Project of Wuhan Yangtze River Waterway Bureau

In the paper, the recent river channel evolution characteristics of the Huangshi river section, where the Huangshi Yangtze navigation sign maintenance project will be located, is analyzed. The effect on the water level and flow speed caused by the project is studied by using the river hydraulics calculating method. The river shore slope stability and dyke seepage are calculated. The effect on the river regime, flood discharge and flood control works is comprehensively discussed. Studying results show that the effect caused by the project on the river regime and flood control works etc. is very limited.

TƯƠNG QUAN XÓI LỞ - BỒI TỤ MỘT SỐ KHU VỰC LÒNG SÔNG TIỀN, SÔNG HẬU

Correlation of erosion - aggradation in areas along Tien and Hau RiversRiverside erosion, one of the most severe natural disasters, has been occuring along the banks of Tien river and Hau for many years. Many segments in Tan Chau, Hong Ngu, Sa Dec,… are seriously affected by the disaster. There are numbers of studies that have indentified levels, causes of the erosion process and proposed solutions for the decrease of erosional negative influences. Based on analysing satellite images, map, monitoring a series of channel cross - sections by echosounder and the study of geomorphology, the study concluded that erosion and deposition, specific natural processes of braided and meandering river in flood plains, balance one another. Bulding stone jetties and uncomprehensive management have accelerated both two processes: erosion and deposition. Combining the dredge river bed and exploitation of materials for construction is the most effective solution to reduce river shore erosion.