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Poyang Lake in the Changjiang (Yangtze) River catchment has undergone frequent spring drought since 2003, and some researchers attributed this phenomenon to sand mining and the lakebed deformation in the outlet channel linking the lake with Changjiang River main channel. However, there is still a lack of high-resolution subaqueous geomorphological evidence of how sand mining led to lakebed deformation in the outlet channel. We examined the bed morphology and sub-bottom sedimentary structure of the outlet channel, using a multibeam echo sounder and sub-bottom profiler in Poyang Lake. We found that: (1) the subaqueous micro-topography types of the outlet channel are characterized by sand mining disturbance, natural erosional topography, and flat bed and dunes, accounting for 44.9%, 21.4%, 28.6%, and 5.1% of the channel area, respectively; and (2) sand mining activity affects the local bed topography extensively and significantly. The depth of sandpits caused by sand mining varied from 1.4 m to 12 m deeper than the surrounding bed surface, with 4.41 m of depth increase on average. Hence, the large-scale high-intensity sand mining activities and their significant geomorphic effects demand for an improved assessment for future management and longer-term sustainability. Because of the large-scale and ongoing high-intensity sand mining activities in the Poyang Lake outlet channel, these effects should raise caution in the future and contribute to monitoring efforts that are essential to implement sustainable management solutions. The present study and techniques implemented can serve as a scientific reference for dam construction and sand mining within the Poyang Lake basin. [ABSTRACT FROM AUTHOR]

There is little data delineating relationships between health and worker musculoskeletal symptoms (MSS), particularly among stone, sand, and gravel mine (SSGM) workers. There is also little data detailing the relationships between physical activity and MSS among these workers. A cross-sectional study using data from 459 SSGM workers was completed. Logistic regression analyses assessed relationships between health factors, physical activity, and low back, neck, shoulder, and knee MSS. Those who reported their health as very good/excellent were less likely to suffer low back and knee MSS. Those who indicated their health was poor/fair were more likely to suffer shoulder, neck, and knee MSS. Obese workers were more likely to experience knee MSS and those who smoked in the past had higher odds of neck MSS. Vigorous physical activity was mostly protective, but those performing more than 5 h of moderate physical activity each week had greater odds of shoulder and neck MSS. Given these results, workers in SSGM may benefit from targeted interventions that bolster vigorous physical activity and improve health. Further, health protection efforts need to be initiated by SSGM operations to address work issues and to sustain health as job roles and work hours impacted MSS as well. [ABSTRACT FROM AUTHOR]

Kobashi, D. and Jose, F., 2018. Potential impacts of sand mining on hydrodynamics and fine sediment suspension and deposition on an inner-shelf shoal. In: Almar, R.; Almeida, L.P.; Trung Viet, N., and Sall, M. (eds.), Tropical Coastal and Estuarine Dynamics. Journal of Coastal Research, Special Issue No. 81, pp. 76–85. Coconut Creek (Florida), ISSN 0749-0208. Wave and hydrodynamic models are implemented to investigate whether sand mining on a transgressive sand shoal could influence hydrodynamic processes and sedimentary environment of the shoal covered with fine sediments. An effort is made to evaluating shoal hydrodynamic response to a hypothetical dredging scenario under a host of probable storm conditions. The model results show that changes in hydrodynamic and sedimentary environment strongly depend on the storm conditions and the shoal bathymetry. Wave dissipation, flow conditions and sediment re-suspension are significantly higher on the shallower western shoal and gradually decrease toward the deeper eastern section of the shoal. The finding suggests that the deeper eastern shoal can be exposed to frequent deposition of fine sediments, as opposed to the western shoal, despite its location farther away from the nearby major river mouth. It is concluded that large-scale sand mining, in particular from the shallower western shoal, is expected to profoundly alter the hydrodynamics and sediment suspension and deposition processes, which may also influence the benthic ecology of the shoal. The mining from the deeper eastern shoal may result in lesser impacts than the mining from the ecologically sensitive western shoal. [ABSTRACT FROM AUTHOR]

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Invertebrate drift plays an important role in river ecosystems. Although drift has been studied extensively, the relative importance of the various factors that initiate drift during disturbances remains unclear. Instream gravel mining releases fine sediment and so provides an opportunity to assess the influence of suspended sediment on drift, without the confounding effects of hydraulic changes and bed-material entrainment associated with floods. This paper examines invertebrate drift responses to increases in suspended sediment during an episode of mining in a Pyrenean river. During short periods of mining activity, suspended sediment concentrations and thus suspended sediment loads (SSLs) increased one order of magnitude at downstream monitoring sections, with maxima similar to those observed during natural floods in the river. Maximum SSLs were recorded at the sections closest to the mining, with downstream transport patterns suggesting that the majority of suspended material was deposited within 1.5 km. Invertebrate drift rates, the number of taxa drifting and the taxonomic structure of the drift changed at sections close to the mining when suspended sediment concentrations and SSLs were high; such changes were not observed at the section 1.5 km downstream. There were significant relationships between SSL and drift, positive for some groups (Ephemeroptera, Plecoptera and Trichoptera) and negative for others (Chironomidae). Our work shows that increases in suspended sediment alone are sufficient to trigger changes in drift, although further studies are needed to elucidate the underlying mechanisms, and especially to explain the varying responses shown by different taxonomic groups. Copyright © 2017 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Rivers are considered to be the most important sources of fresh water and principled mining of materials is momentous. To provide appropriate solutions for reducing the negative impacts of sand and gravel mining is the great challenge in the field of river materials mining. Many of the world's rivers have suffered a lot of problems due to superfluous mining of sand and gravel. The matrix method is one of the most common international methods for evaluating the site of sand and gravel mining from rivers. In the matrix method, based on river characteristics and the materials mining area, it is recognized whether the river has the potential for mining of materials or not, and also which method should be utilized to mine sand and gravel from the river in order to reduce the negative environmental impacts. In this research, a matrix method is applied to a reach of the Dez river in Iran. Dez river is located in the range between the Dez diversion dam to the Hamid-Abad Bridge with braided pattern and a matrix particular to braided river is used to evaluate the mine area of the materials. In the results section, the characteristics table of the mining area of river materials in the studied reach is presented from the Dez river. In addition, the research results show that the volume of sand and gravel mining is about 50 thousand cubic metres and scraped extraction is a suitable method for extracting materials in the studied area. [ABSTRACT FROM AUTHOR]

Gravel mining has been a widespread activity in ephemeral rivers worldwide whose long-lasting hydrogeomorphological impacts preclude effective implementation of water and environmental policies. This paper presents a GIS-based method for temporal assessment of morphosedimentary changes in relation to in-channel gravel mining in a typical ephemeral Mediterranean stream, namely the Rambla de la Viuda (eastern Spain). The aims of this work were to identify morphosedimentary changes and responses to human activities and floods, quantify river degradations and analyze factors favoring fluvial recovery for further applications in other rivers. Aerial photographs and LiDAR topography data were studied to analyze geomorphic evolution over the past 70 years along a 7.5-km reach of an ephemeral gravel stream that has been mined intensively since the 1970s. To evaluate changes in the riverbed, we mapped comparable units applying morphological, hydraulic, and stability (based on vegetation density and elevation) criteria to 13 sets of aerial photographs taken from 1946 to 2012. A detailed spatiotemporal analysis of comparable units revealed a 50% reduction in the active section and a 20% increase in stable areas, compared to the conditions observed prior to gravel mining. Instream mining was first observed in 1976 aerial photograph covering already up to 50% of the 1956 riverbed area. River degradation since then was quantified by means of a LiDAR DTM and RTK-GPS measurements, which revealed a 3.5-m incision that had started simultaneously with gravel mining. Climate and land use changes were present but the effects were completely masked by changes produced by instream gravel mining. Therefore, river incision/degradation was triggered by scarcity of sediment and lack of longitudinal sedimentary connection, creating an unbalanced river system that is still adjusting to the present hydrosedimentary conditions. [ABSTRACT FROM AUTHOR]

India’s Sand Mafia, which illegally mines sand for construction, generates approximately USD 17 million per month in revenues. Despite the devastating environmental, physical, and economical harms caused, there is a dearth of criminological research on this organized crime group. This paper develops a tripartite model of organized crime that is used to explore the Sand Mafia’s modus operandi, modus vivendi, and modus coordināti. It conducts document analysis of 75 media and environmental documents published between 2010 and 2015. This group operates as numerous, fragmented structures with transient memberships, and uses violence, political affiliation, and regenerative properties to ensure continued operation. Other factors, such as inadequate manpower, poor enforcement, rapid economic development, and limited acceptance of alternatives to sand, collectively compound the problem of illicit sand mining. Recommendations for alleviating the problem, such as imposing stricter regulations, implementing an independent regulatory body, and empowering local residents, are also examined. Future lines of research inquiry, such as conducting harms analysis via multidisciplinary research, are also offered. [ABSTRACT FROM PUBLISHER]

In-channel sand mining by dredge removes large quantities of bed sediment and alters channel morphodynamic processes. While the reach-scale impacts of dredging are well documented, the effects of the dredged borrow pit on the local flow and sediment transport are poorly understood. These local effects are important because they control the post-dredge evolution of the borrow pit, setting the pit lifespan and affecting reach-scale channel morphology. This study documents the observed morphological evolution of a large (1.6 million m³) borrow pit mined on a lateral sandbar in the lower Mississippi River using a time-series of multibeam bathymetric surveys. During the 2.5 year time-series, 53% of the initial pit volume infilled with sediment, decreasing pit depth by an average of 0.88 m yr-1. To explore the controls of the observed infilling, a morphodynamic model (Delft3D) was used to simulate flow and sediment transport within the affected river reach. The model indicated that infilling rates were primarily related to the riverine sediment supply and pit geometry. The pit depth and length influenced the predicted magnitude of the pit bed shear stress relative to its pre-dredged value, i.e. the bed-stress reduction ratio (R*), a metric that was correlated with the magnitude and spatial distribution of infilling. A one-dimensional reduced-complexity model was derived using predicted sediment supply and R* to simulate patterns of pit infilling. This simplified model of borrow-pit evolution was able to closely approximate the amount and patterns of sediment deposition during the study period. Additional model experiments indicate that, for a borrow pit of a set volume, creating deep, longitudinally-shorter borrow pits significantly increased infilling rates relative to elongated pits. Study results provide insight into the resilience of alluvial river channels after a disturbance and the sustainability of sand mining as a sediment source for coastal restoration. [ABSTRACT FROM AUTHOR]

The multi-scale hierarchical framework developed within the REFORM project, for the study of the functioning of river reaches and their catchments, was applied to the Magra River catchment (Northern Tuscany, Italy). The Magra River is a quite dynamic gravel-bed river that has undergone severe channel adjustments over the last century (i.e. incision and narrowing). The REFORM framework was then applied in order to (1) explore the locations and causes of these adjustments, and (2) assess how different river reaches responded to specific human activities (i.e. land use changes, dams, gravel mining). The work aims at providing information to aid sustainable river management and restoration. In accordance with the framework, initially, all the relevant spatial units (i.e. from the catchment to the reach scale) were delineated and then characterised in further detail. Then, a summary of the trajectories of change following human impact was provided. Combined with an overview of the main human pressures still influencing the river system, this allowed us to define the current conditions at the river reach scale. Finally, the knowledge acquired in the previous parts was assembled to build a better understanding of current river conditions and controls on past changes, as well as to enable the formulation of some future scenarios. The latter analysis was focussed on a couple of reaches located in a sensitive and relatively low impacted segment, in order to better highlight the interpretative power of the hierarchical framework. The framework was applied by combining the knowledge derived from previous studies and the computation of additional and relevant indicators. This study demonstrated the helpfulness of the hierarchical framework in diagnosing problems and supporting management strategies for a medium-sized, gravel-bed river catchment. [ABSTRACT FROM AUTHOR]

The water resources in Turkey are under immense pressure due to various kinds of anthropogenic activities among which sand and gravel mining is the most disastrous one due to its adverse environmental impacts. In this study, impacts of the sand and gravel mining activities in the city of Tirebolu, Giresun Province, on the water quality of the stream Harşit, which courses in the Eastern Black Sea Basin of Turkey, are investigated in terms of ten water quality indicators, namely turbidity (T), electrical conductivity (EC), dissolved oxygen (DO), pH, suspended sediment concentration (SSC), water hardness (WH), aluminum ion (Al), manganese ion (Mn), total chromium and total iron. Based on the average annual values of the studied water-quality indicators, it was concluded that the stream water quality was not impacted with regard to EC, DO, pH, WH, and Al despite the seventeen sand and gravel pits operated in the stream Harşit. Due to the fact that sand and gravel mining has used the stream Harşit surface water for material washing, an increase of 125 % in T, 134 % in SSC, 63 % in Mn, 98 % in total chromium, and 111 % in total iron has been determined, respectively, and so the stream water quality has been deteriorated. It is thought that this deterioration may affect the groundwater quality of the stream Harşit aquifer from there a groundwater of two-and-a-half million cubic meters per year of which has been drawn for domestic water demand of the people in the city of Tirebolu. [ABSTRACT FROM AUTHOR]

The gravel pits are exploitations to extract granular materials, sand and gravel in the alluvial river areas. Excavated voids are not very deep, unlike quarries and generally result in flooded areas. The company building materials in Holguin province has concessioned four deposit and within a gravel pit. The areas damaged by the exploitation of construction materials in the territory occupy about 75 ha, which causes a strong impact on the environment. For this reason it is proposed to develop a procedure to recover the deposit mined area in the gravel - sand Rio Sagua de Holguín as to achieve responsible mining. With the application of scientific methods analyzed the factors influencing the choice of recovery uses the mined area in the study area and developed a procedure consisting of five main stages. With the development of the procedure was shown that it can improve the social and environmental quality in the area affected by the mining activity [ABSTRACT FROM AUTHOR]

Hwang, S.W.; Lee, H.G.; Choi, K.H.; Kim, C.K., and Lee, T.W., 2014. Impact of sand extraction on fish assemblages in Gyeonggi Bay, Korea During 2006 and 2007, 35.0 × 106 m3 of marine sand was extracted by the construction industry from Gyeonggi Bay, which is an area within the coastal waters off the Taean District of Korea. The goal of our study was to compare the catches and assemblage structure of fish in this sand mining area (SMA) with those of two other nonmining areas (NMAs) in the bay. An otter trawl was used to obtain fish samples in each area. Both cluster analysis and nonmetric multidimensional scaling of the species composition in the sampled areas showed a higher similarity between the two NMAs than between the NMAs and the SMA. Furthermore, the SMA had significantly lower species richness ( R1), species diversity ( H′), and fish abundance compared with the two NMAs. These results could be associated with bottom disturbance related to the mining of seabed sediments. In conclusion, we confirm that sand mining processes directly influence the Gyeonggi Bay sea floor ecosystem and have a continuous effect on the assemblage of fish in this ecosystem. [ABSTRACT FROM AUTHOR]

Effects of sediment extraction and dam construction on changes of riverbed characteristics over yearly to decadal scales in the lower Tedori River of Japan are clarified. Over 1950-1991, the riverbed degraded in excess of 0.5-3.5 m. Concurrently, riverbed sediment volume of the 0-16 km reach decreased by 12.7 × 10 m. Intensive sediment extraction was the dominant cause of riverbed degradation during the period. During 1991-2007, an increase in riverbed sediment volume of 0.6 × 10 m resulted in accretion of the riverbed by average depth 0.04 m. The cessation of sand and gravel mining (SGM), coupled with Tedorigawa Dam operation since 1980, was responsible for that accretion. Temporal change in riverbed elevation during 1950-2007 indicates that there were five phases of vertical adjustment. Combination of nonlinear regression models described four of these phases well. During 1950-1979, the first four modes of empirical orthogonal function analysis successfully captured temporal and spatial responses of the riverbed to natural and anthropogenic impacts. That is, the first mode explained the mean riverbed profile and temporal variation in riverbed sediment volume. The second through fourth spatial eigenfunctions reflected spatial variation in vertical adjustment rate for phases II, III and I, respectively. The corresponding temporal eigenfunctions explained the respective effects on the riverbed of SGM, of imbalance between sediment transport capacity and sediment supply, and of dredging activity. [ABSTRACT FROM AUTHOR]

Abstract: Many Taiwanese river channels have been affected by human activity, such as engineering works and gravel mining. Environmental conditions such as high seasonal precipitation and young sedimentary bedrock exaggerate the narrowing and incising of river channels. The Bachang River is located in southwestern Taiwan, and the 11-km-long channel at its midstream reach has been incised to a maximum depth of approximately 30m within several decades. Therefore, the morphologic evolution of the Bachang River in southwestern Taiwan provides an illustration of channel changes in response to human activity. The historical data used for this analysis of morphology change include one set of topographic maps and six sets of aerial photographs from the past 100years. The channel changes are analyzed qualitatively and quantitatively and include the channel planform, longitudinal profiles, channel incision, channel width, and channel cross sections. The results indicate that remarkable channel changes have occurred since the 1980s as a result of human influence. The 11-km-long study reach transformed from an alluvial-type channel to a gorge-type channel within several decades. The maximum accumulated depth of the channel incision is approximately 30m, with a meter-scale annual average incision rate; the maximum width has been decreased to approximately one-sixth of the original width (448m). The process of channel evolution is divided into four stages, and we have concluded that the causes of channel change include six factors from two categories: natural factors that include geological conditions, hydrological conditions, and the process of bedrock erosion; and human factors that include gravel mining, lateral structures, and levees. The initiation of channel evolution is triggered by human factors. Finally, we discuss the potential future channel evolution and lessons learned from the case study. [Copyright &y& Elsevier]

Large expanses of natural deposits of gravel and sand are known to be available in many parts of the Southwestern Nigeria, which are being used for concrete production but with no standards. This study investigates the effects of using raw and washed dug-up gravel on the strength properties of concrete with a view to provide some standards for their usage. Field survey of quarry sites around Ile-Ife identified two commonly used dug-up gravel ( Tiwantiwa), gravel A and ( Majeroku), gravel B, which were selected for investigation. Prescribed mix proportions (measurements by weight) of 1:2:4 (cement:fine aggregate:washed/raw gravel) and 1:6 (cement:raw gravel) were used to produce the concrete cubes and beams for compressive and flexural strength tests. The results showed that using gravel A in raw form without sand and in washed form with sand have almost the same compressive strength (CS), while washing gravel B before use and with sand improved the CS of concrete. At 28 days, the CSs of concretes made from raw with no sand (RNS) of gravels A and B were 17.07 and 12.47 N/mm, while those of raw with sand (RWS) and washed with sand (WWS) were 14.73 and 16.80 N/mm for gravel A and 11.93 and 16.00 N/mm for gravel B, respectively. Characteristic strength of 15 N/mm is recommended for concrete made with RNS and WWS of gravel A, while 11 and 14 N/mm are recommended for those of gravel B, respectively. [ABSTRACT FROM AUTHOR]

This report provides a brief overview of the German mining industry with some specific examples of planning and equipment used in underground and open-cast coal mining, in potash mining as well as in sand and gravel quarries. [ABSTRACT FROM AUTHOR]

Highly layered soils are prevalent in several areas of current offshore activity and in particular in emerging provinces and fields. However, no investigation has been carried out for spudcan penetration in stratified sediments with more than two layers. This paper reports centrifuge modelling of spudcan foundations penetrating through 3∼6 clay layers with interbedded stronger clay, silica sand and carbonate sand layers. The aim was to provide insight into the behaviour of spudcan foundations in stratified sediments comprising layers of different drainage conditions and mineralogy. The motivation for this paper emanated directly from the future needs identified by the recent revised version of ISO 19905-1. It was found that the downward soil deformation was extended into 3∼4 underlying layers of sand and clay with thickness ratios (/) less than 0·6. The limiting squeezing depth was 0·17∼0·18 when approaching stiff clay-moderate clay layers and 0·28 when approaching dense sand-stiff clay layers. These depths were enhanced (to 0·3∼0·35) by the soil plug trapped beneath the advancing spudcan. The values obtained using the ISO criteria either overestimated or underestimated these depths. Punch-through failure at a shallow penetration depth occurred with a load-spreading gradient of 1 (horizontal):3 (vertical) in silica sand and with a much smaller gradient of 1:7 in carbonate sand. In both sands, the spreading angle reduced with increasing depth of punch-through failure, and diminished quickly immediately after a failure. In contrast to ISO guidelines, the plug base, where the end bearing was mobilised, was located in one of the lower layers moved down with the advancing spudcan. For all cases, a soil plug developed at the base of the advancing spudcan, with the height of the plug accumulating through trapped clay and sand, regardless of their strength, from layers above and below the advancing spudcan. The height of a soil plug was reduced partly by soil backflow and squeezing out from contact with a strong layer. The observed soil failure mechanisms and corresponding penetration resistance profiles highlight uncertainties in ISO 19905-1. Guidelines are provided to improve the suggested punch-through and squeezing methods in ISO 19905-1. Implications for the bottom-up design approach proposed by ISO, and also a top-down design approach used by some practitioners, are discussed. [ABSTRACT FROM AUTHOR]

The vast and ecologically diversified hyporheic realm and the adjacent riparian areas of India have received scant attention from the standpoint of biodiversity studies. Analysis of about 2500 samples collected from the alluvial sediments of certain rivers and streams, besides some bores in the riparian zone, mainly in the coastal deltaic belt of the rivers Krishna and Godavari in Andhra Pradesh State during 2000-2012 yielded 41 copepod and bathynellacean species. Of these, 31 new species have been formally described during the ongoing studies whereas the remainder are previously known ones. An annotated checklist of all these taxa is presented, giving the type locality and other localities of occurrence, methods of sampling, chief references, and also some taxonomic and/or ecological remarks wherever necessary. The harpacticoid copepod family Parastenocarididae and the eumalacostracan order Bathynellacea are two significant, major groups of stygofauna that have been recorded for the first time from India. Both these groups and also some cyclopoid copepods have clear-cut Gondwanan lineages, representing the remnants of unique ancient fauna that require urgent attention from conservationists in order that the overall evolutionary history of the Indian biota is preserved. A note is also added on the devastating influence of the ongoing rampant sand mining activity on the hyporheic biodiversity. [ABSTRACT FROM AUTHOR]

ABSTRACT Channel elevation change since the early 20th century was characterized for 31 alpine braided river reaches (total length of 129 km), representing about 20% of the braided river network length in SE France. Present-day long profiles were surveyed in the field and compared with historical profiles measured between 1894 and 1930. Forty-four cross sections of active channels including terrace boundaries were also surveyed to study morphological signatures of braided channels characterized by different channel responses (aggradation or degradation). Results show that 56% of the sampling river length is characterized by degradation, 24% by stability and 20% by aggradation. Gravel mining is recognized as the main factor explaining degradation of braided channels. It is also demonstrated that aggrading braided channels are those where sediment supply from active torrents and bank erosion have been best preserved. The comparison of morphological signatures associated with aggrading and degrading channels reveals significant differences in cross-section morphometry. A normalized bed relief index is proposed as a reliable indicator of the channel response. Field observations show that long-term aggraded braided channels have a lower bed relief index than degraded channels, as already established by some laboratory experiments. This index can be used to determine the position of the braided channel in the cycle of degradation-recovery following the cessation of gravel mining. It is also established that aggraded channels develops wider active channels than degraded channels for a same drainage area. This study provides new insights for the assessment of spontaneous recovery potential of braided channels impacted by gravel mining. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

ABSTRACT There is a paucity of data and insight in the mechanisms of, and controls on flow separation and recirculation at natural sharply-curved river bends. Herein we report on successful laboratory experiments that elucidate flow structure in one constant-width bend and a second bend with an outer-bank widening. The experiments were performed with both a flat immobile gravel bed and mobile sand bed with dominant bedload sediment transport. In the constant-width bend with immobile bed, a zone of mainly horizontal flow separation (vertical rotational axis) formed at the inner bank that did not contain detectable flow recirculation, and an outer-bank cell of secondary flow with streamwise oriented rotational axis. Surprisingly, the bend with widening at the outer bank and immobile bed did not lead to a transverse expansion of the flow. Rather, flow in the outer-bank widening weakly recirculated around a vertical axis and hardly interacted with the inner part of the bend, which behaved as a constant-width bend. In the mobile bed experiment, downstream of the bend apex a pronounced depositional bar developed at the inside of the bend and pronounced scour occurred at the outside. Moreover the deformed bed promoted flow separation over the bar, including return currents. In the constant-width bend, the topographic steering impeded the generation of an outer-bank cell of secondary flow. In the bend with outer-bank widening, the topographic steering induced an outward expansion of the flow, whereby the major part of the discharge was conveyed in the central part of the widening section. Flow in the outer-bank widening was highly three dimensional and included return currents near the bottom. In conclusion, the experiments elucidated three distinct processes of flow separation common in sharp bends: flow separation at the inner bank, an outer-bank cell of secondary flow, and flow separation and recirculation in an outer-bank widening. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Tree establishment on degraded sites has failed in many tropical areas due to invasive plants and competition with herbs. The cultivation of plants that are capable of maintaining a site can avoid the dominance of invasive species. Some native species of the genus Stylosanthes (family Fabaceae) have been reported to effectively block invasive plants off ecosystems that are under restoration in Brazil. The aim of this study was therefore to evaluate the influence of perennial Stylosanthes spp. on plant colonization in a rehabilitated gravel mine in the Brazilian savanna region. Half of the mining area was sown with a mixture of three perennial Styloshantes species (treatment), while half of it remained unsown (control). The line intercept method was used to sample recruited plants within the mine after five years of site rehabilitation. Results showed that 31 plant species recruited in the gravel mine: 27 in the area sown with Stylosanthes spp. and 17 in the control area. Native species contributed for 47 % of the importance value index (IVI) in the treated area and 26 % in the control area. Two invasive exotic grasses made up 31 % of the plant community IVI in the treated area and 59 % in the control area. Perennial Stylosanthes spp. were supposed to block the development of incoming plants, but their presence actually allowed the area to be colonized by 1.6-fold more plant species than the control area. Ultimately, the area covered with Stylosanthes spp. evolved into a plant community that was more diverse and less dominated by exotic species than the control area. [ABSTRACT FROM AUTHOR]

ABSTRACT In the twentieth century Polish Carpathian rivers were considerably modified by channelization and gravel mining, with significant detrimental effects to their ecological integrity, vertical stability of the streambeds and flood hazard to downstream river reaches. Restoration of the rivers is thus necessary to improve their ecological status and re-establish geomorphic dynamic equilibrium conditions. Various approaches to defining hydromorphological reference conditions, proposed to date in river restoration literature, have serious deficiencies. In particular, environmental changes that took place in the catchments of Carpathian rivers during the twentieth century invalidate the historical state of the rivers as reference for their restoration. This is illustrated by a change from bar-braided to island-braided channel pattern that occurred in the past century in unmanaged sections of the Czarny Dunajec in response to a reduction in flow and sediment dynamics of the river. We indicate that reference conditions should be defined as those which exist or would exist under present environmental conditions in the catchment but without human influence on the channel, riparian zone and floodplain of the river which is to be restored. This assumption was tested through the evaluation of hydromorphological river quality of the Czarny Dunajec according to the European Standard EN-14614. The evaluation confirmed a high-status hydromorphological quality in an unmanaged channel section, which can thus be used as a reference for restoration of impacted river sections. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The development of karst landforms of the Aggtelek Plateau was investigated concerning the role of these valleys in the genesis of the Baradla Cave, which is located on the Plateau. New data were collected by geophysical method (Vertical Electrical Sounding) from a few dolines of a selected valley of the Aggtelek Plateau. The geophysical profiles confirm that the dolines of the valley bottom did not develop from sinkholes, but they are solution dolines. Morphological characteristics of the valleys of the Plateau suggest that these valleys are not the continuation of the valley of the recent covered karst. The former catchment area of these valleys might have been on the Plateau and north of Kecső valley. Their bottoms tilted into southern direction. Therefore the subsurface capture places of their streams might have been near to the recent sinking line. The sediments (Borsodi Gravel Formation) which were eroded from the above mentioned areas also contributed to the genesis of the Baradla Cave. [ABSTRACT FROM AUTHOR]

In 1999 the author reported the results of an 18 year study into the accuracy of sand and gravel reserve calculations. Since that time some changes have been made in the company’s resource investigation practices in certain types of deposit, and the data gathering has continued. The paper presents the results of significantly more data than previously, considered on their own and in combination with those from the first exercise. The analysis shows closely similar outcomes in respect of accuracies, the distribution of results, and the magnitude of excursions from the bulk of results. Conclusions and the statistics from the 1999 study are supported by the greater volume of data, and it can be suggested that attempting to improve accuracy by the last few per cent could be disproportionately expensive. [ABSTRACT FROM AUTHOR]

River sediment depositions on the bottom of rivers most frequently consist of sand and gravel particles, which make them particularly valuable for the building construction. Knowledge of radioactivity present in building material enables one to assess any possible radiological hazard to mankind by the use of such materials. The natural radionuclide (U, Th and K) contents have been analyzed for the recently excavated sediment samples of Cauvery, Vellar, Ponnaiyar and Palaru rivers with an aim of evaluating the radiation hazard nature. To know the radiological characteristics of the sediment, the different radiological parameters are calculated. Natural radioactivity level is higher in Palaru river and it is lower in Vellar river sediments. In all the rivers, concentration of U is decreased, and concentrations of Th and K are increased towards the river mouth. Granulometric analysis shows that the sand is the main constituent in all the river sediment samples. Content of sand is gradually decreased, and contents of silt and clay are gradually increased towards the river mouth. Cluster analysis was carried out to find the similarity level between the radioactivity and granulometric measurements. The radioactivity level of all the four river sediments mainly depends upon the contents of silt and clay. Averages of the all calculated radiation hazard indices are lower than recommended level in Cauvery, Vellar and Ponnaiyar river sediments. Therefore, the sediment of the above rivers does not pose any significant radiological threat to the population when it is used as a building construction material. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, beach profile surveys acquired over more than a decade at a sandy beach (Narrabeen Beach, New South Wales, Australia) and a composite sand–gravel beach (Milford-on-Sea, Christchurch Bay, UK) are analysed to compare and contrast cross-shore morphodynamics of the two beach types. The different behavioural characteristics of the two beach types at decadal, inter-annual and intra-annual time scales are investigated. Comparisons of beach profiles with Dean''s equilibrium profile and Vellinga''s erosion profile show that the Dean''s profile satisfactorily represents the time mean profiles of both beach types. Statistical and Empirical Orthogonal Function (EOF) analyses confirm the generally accepted model that the inter-tidal zone is the most morphodynamically active region on a sandy beach whereas the swash zone is the most dynamic region on a mixed sand–gravel beach. The results also imply that during storms composite sand–gravel beaches may become unstable due to cutback of the upper beach while sandy beaches are more likely to be unstable as a result of beach lowering due to sediment transport from the inter-tidal zone to the sub-tidal zone during storms. EOF results also show that Milford-on-Sea beach is in a state of steady recession while the Narrabeen Beach shows a cyclic erosion–accretion variability. A multivariate technique (Canonical Correlation Analysis, CCA) shows that on the composite beach a strong correlation exists between incident wave steepness and profile response, which could be attributed to the unsaturated surf zone, whereas on the sandy beach any correlation is much less evident. [Copyright &y& Elsevier]

In this paper the spatial and temporal responses of the Somesu Mic River (Romania) to natural and anthropogenic controls over the past 150 years are analysed, based on a series of morphometric parameters extracted from five successive sets of topographic maps and one set of orthophotos. Prior to the intensive hydrotechnical interventions of the last four decades, the river was characterized by a complex alternation of different channel types, resulting in a mixture of alluvial and mixed sinuous -meandering - sinuous anabranched - meandering anabranched reaches, each a few hundred metres to a few kilometres long. The main cause for this spatial behaviour was the local geology. Its effects were intensified by a larger scale slope, slightly higher than along a longitudinal profile with normal concavity, as a consequence of the presence of a 400m elevation knick-point located in the catchment area. A generalized maintenance of river in the floodplain perimeter during the entire interval of study (centennial scale), with local planform adjustments and lack of median scale avulsion in lateral tilting areas and along the anabranched reaches, channel lengthening and meander development during hydrological stable periods and channel shortening and increasing of natural cutoffs during periods with higher incidence of floods (decadal scale), and the incapacity of local morphologic changes resulted from human interventions to completely counterbalance general trends (decadal scale), supports the idea of decreasing the amplitude and frequency of important floods, after the end of the Little Ice Age. Channel metamorphosis by canalization, diminishing/elimination of overflows and medium-scale avulsions by changes in flow regimes (dams) and the presence of dykes in the floodplain perimeter, channel narrowing (43%) and incision (at least after 1945) downstream from dams, and probably because of in-channel gravel mining are the main anthropically induced changes along the Somesu Mic River. Even if human impact is important, both at the drainage basin scale and along the Somesu Mic River, it has only local impacts, subordinated to climate. The low level of human impact on this river could be the consequence of the higher general slope downstreamfrom 400melevation knick-point, which probably forces the positioning of its effects under an important internal threshold of the fluvial system. This boundary condition defines Somesu Mic River as an atypical river. This study supports the idea that climate has a more important role in the post-Little Ice Age (LIA) rivers' behaviour than currently accepted. Copyright©2011 JohnWiley&Sons, Ltd. [ABSTRACT FROM AUTHOR]

Sediment flows naturally through the drainage network, from source areas to deposition zones. Sedimentary disequilibrium in rivers and coastlines is related to the imbalance within the fluvial system caused mostly by dams, instream mining, and changes in land use. This phenomenon is also responsible for ecological perturbations in rivers and streams. A broad need exists to establish comprehensive management strategies (soft measures) that would go beyond site-specific engineering practices (technical measures) typically taken to solve particular problems. Long-term programs are also required to monitor sediment transport in river basins, in order to assess the magnitude and variability of sediment transfer and potential deficits. This paper shows examples of rivers with important sediment disequilibrium in the Ebro and adjacent basins. These basins, like most in the Iberian Peninsula, experience sediment discontinuity in the catchment-river-coast system. Reservoir siltation is the main quantitative issue. Land use change and especially gravel mining downstream from dams accentuate the process. We also present and discuss recent developments on water and sediment management undertaken to improve the morphosedimentary dynamics of rivers. Integr Environ Assess Manag 2011;7:256-268. © 2010 SETAC [ABSTRACT FROM AUTHOR]

Abstract: Numerous large coastal dune fields occur on the western coast of Lower Michigan. These dunes are an important ecological, geological, and recreational resource in the state. They also serve as a significant source of foundry sand for Michigan''s automotive industry and thus have been mined intensively. Although Michigan contains extensive sand deposits besides those in coastal dunes, no studies have yet investigated alternative foundry sources from a distinct geographical perspective. Acceptable alternative sand deposits must be sufficiently large and close to transportation networks to be economically viable. Using a GIS, water-well log stratigraphic data were employed to estimate sand thickness and rail line data were used to determine accessibility of deposits. Based on this information, 53 sites in 16 counties were selected, sampled, and tested for appropriate physical and chemical characteristics to determine their viability as inland sources of foundry sand. Results indicate that many cubic kilometers of inland sand suitable for foundry use are in close proximity to existing transportation networks. Three regions that show the most potential to be inland sand sources for the foundry industry are: 1) Wexford and southeastern Grand Traverse Counties, 2) northern Newaygo and southern Lake Counties, and 3) central Alger County. Sand in these areas will likely require preprocessing but should nonetheless be considered as a feasible and more ethically responsible alternative to mining coastal dunes. [Copyright &y& Elsevier]

Using hydro-acoustic survey techniques (side-scan sonar and multibeam), high-resolution bathymetric and acoustic images (sonographs) of former marine aggregate extractions, from Tromper Wiek (Rugen Island, Baltic German Coast) were obtained. These data, together with ground-truthing (underwater video and seabed sediment samples) are used to describe the present condition of marks generated by mining, in terms of their morphology and superficial grain size distribution. Different features (pits and furrows), generated by different extraction techniques (anchor suction dredging and trailer hopper suction dredging, respectively) were detected at both of the study sites: Tromper Wiek 1 (sandy gravel seabed) and Tromper Wick East (sandy seabed). Regeneration varies, depending upon the material extracted and the mining technique applied. In general, it is rapid during the first years following the extraction, becoming almost undetectable over a longer period of time. However, the marks are still detectable after more than 10 years, since they were generated. [ABSTRACT FROM AUTHOR]

Objectives. We evaluated the impact of a safety training regulation, implemented by the US Department of Labors Mine Safety and Health Administration (MSHA) in 1999, on injury rates at stone, sand, and gravel mining operations. Methods. We applied a time-series design and analyses with quarterly counts of nonfatal injuries and employment hours from 7998 surface aggregate mines from 1995 through 2006. Covariates included standard industrial classification codes, ownership, and injury severity. Results. Overall crude rates of injuries declined over the 12-year period. Reductions in incident rates for medical treatment only, restricted duty, and lost-time injuries were consistent with temporal trends and provided no evidence of an intervention effect attributable to the MSHA regulation. Rates of permanently disabling injuries (PDIs) declined markedly. Regression analyses documented a statistically significant reduction in the risk rate in the post-intervention time period (risk rate=0.591; 95% confidence interval=0.529, 0.661). Conclusions. Although a causal relationship between the regulatory intervention and the decline in the rate of PDIs is plausible, inconsistency in the results with the other injury-severity categories preclude attributing the observed outcome to the MSHA regulation. Further analyses of these data are needed. [ABSTRACT FROM AUTHOR]

Abstract: The use of key-block theory for the analysis of blocky rock mass structures in mining and civil engineering is well established. Such methods have traditionally been used to analyse the stability of rock blocks at free surfaces only. These methods have also been limited to the analysis of relatively few discontinuities, usually assumed to be infinitely persistent. Development of more advanced algorithms has removed these limitations and allowed the development of a modeller capable of handling multiple curved, finite persistent discontinuities. We discuss this modeller and its capability of predicting the existence of polyhedra with unlimited facets and morphologies. This paper describes the use of this polyhedral modeller for the study of the stability of an underground excavation and offers significant advantages over the algorithm recently reported by Menéndez-Díaz et al. (2009) which is restricted to the analysis of pentahedral blocks formed by four discontinuity sets. [Copyright &y& Elsevier]

The evolution of the coast of Hawke's Bay, New Zealand, and its erosion problems have been governed by multiple factors, including its tectonic setting with an earthquake in 1931 that altered land elevations along its shore, ranging from a 2-m uplift at its north end to 1-m subsidence at its south. Human environmental impacts have also been important, including the deforestation of the watersheds of rivers and the mining of gravel and sand from their channels, having decreased the sediment supplies to the beaches. Significant erosion has occurred at the south end of the Hawke's Bay shore, attributed in part to its subsidence in 1931, together with the net northward longshore transport of the beach sediment that is greater than the volumes being supplied by the rivers, the beach-sediment budget being significantly ''in the red.'' Midway along the Bay's shore, the construction of the Port of Napier's breakwater in 1887-90, extending seaward from the Buff Hill headland within that city, is interpreted by some investigators to have been the cause of the erosion experienced at Westshore, a development located immediately north of the breakwater. The assumption has been that this erosion was the result of the breakwater having blocked the northward longshore transport of sediment that formerly had bypassed Bluff Hill, this being an example of down-drift beach erosion. However, a reexamination of the history of the Port's development, the resulting shoreline changes, differences in beach gravels on the shores north and south of Bluff Hill, as well as other evidence, support the conclusion that the breakwater was not the cause of the erosion; instead, the impacts to Westshore at the time of the breakwater construction can be attributed primarily to a series of major storms, which produced erosion at a number of sites along the Hawke's Bay shore. There has been minimal erosion at Westshore since the completion of the breakwater a century ago, its northward extending arm acting to shelter the development from the waves of major storms. Investigations by coastal scientists and engineers of the Hawke's Bay coast, together with a comprehensive beachsurvey monitoring program, support its sound management based on an understanding of the multiple factors that are important to its responses during storms, and to its long-term changes. [ABSTRACT FROM AUTHOR]

The objective of this research was to identify the areas of high mineral potential within the region with gravel and sand deposits associated to the fluvial system. The investigation was conducted in the southern plain of Pinar del Río, excluding the southern-western portion. Various types of evidence maps representing the criteria produced by the descriptive models for this type of ore body were used in the forecast as well as data of the geological processes that originate them. Boolean logic models and indexed overlay were used in order to integrate the maps in GIS (Geografic System Information) platform. The weight of the attributes was estimated based on the available geological data about ore bodies of this kind. The integration methodology used indicated that the plain had high potential of having deposits of sand to be used for construction purposes, revealing 24 potential sectors; the majority is no farther than 15 kms from the main towns and cities. A detailed study on the fluvial system allowed dividing the plain into 6 areas with sub-homogenous drainage patterns and different favorability levels. The most potential sector within the plain is an elongated and narrow strip of land to the NE-SW; which takes up the central portion of the plain, below the pre-mountain. Lastly, the gamma-ray spectrometry (potassium channel) is proven to be useful in regional studies for identifying potential alluvial ore bodies of sand and gravel. [ABSTRACT FROM AUTHOR]

The objective of this investigation was to evaluate whether the southwestern plain of Pinar del Río is a potential mineral resource containing sand and gravel deposits. The procedure used is based on geographic information technologies (SIG) to process and integrate all available geoscientific information and weight up notable evidence maps. The data-based integration methods: indexed overlay and evidential belief functions were implemented in this field of study where deposits models are not well formalized and the number of proven aggregate deposits is limited. The significance of the characteristics was evaluated based on quantification of spatial association among proven deposits and available data. The study was carried out in alternate stages of fieldwork and data processing, which allowed that the results were validated as well as the insertion of new identified areas whose characteristics are more typical than expected. It was proven that the implementation of the spatial analysis is viable to identify gravel and sand deposits. New potential areas, representing less than 5% of the extent of the studied areas, were identified. The model of aggregate deposits was completed and formalized and the geologic factors (soil and vegetation) that control the location of sand and gravel deposits in the area were also identified. [ABSTRACT FROM AUTHOR]

Relatively few studies have examined the ecological effects of instream sand and gravel mining, which occurs in many streams and rivers worldwide. The objective of this study was to evaluate fish community composition at sand dredged and unmodified (control) sites in the Kansas River, Kansas. Fish and habitat sampling were conducted at two control sites and one dredged site in September 1979 and 1980. The same sites and one additional dredged site were sampled in September 2006. In 2006, dredged sites were deeper and had slower current velocities than control sites. Similarity indices determined that fish community at control sites in 2006 were 80% similar to the same sites in 1979 and 1980, despite 26 years between sampling. Dredged sites had more variable species composition, but one site still had large-river species (blue sucker, shovelnose sturgeon), which were sampled above the actual dredge in fast, shallow vvater. Native river fish species were similarly present in 1979-1980 and 2006, but lentic and non-native fishes (e.g.. centrarchids), although still in low abundance, increased in 2006 particularly in dredged sites. These results suggest that sand dredging provided habitats that were suitable for lentic fishes, but other anthropogenic effects (reservoir construction, urbanization) also likely contributed to fish assemblage changes in the Kansas River. [ABSTRACT FROM AUTHOR]

Based on this preliminary study, existing sand and gravel mining regulations (in Maine, USA) can be inferred to provide some protection to water resources. Sand and gravel deposits are important natural resources that have dual uses: mining for construction material and pumping for drinking water. How the mining of sand and gravel affects aquifers and change aquifer vulnerability to contamination is not well documented. Mining regulations vary greatly by state and local jurisdiction. This study test metrics to measure the effectiveness of mining regulations. The sand and gravel aquifer system studied is covered with former and active gravel pits to nearly 25% of its areal extent. Data from homeowner interviews and field measurements found scant evidence of changes in water quantity. Water quality analyses collected from springs, streams, ponds and wells indicate that the aquifer was vulnerable to contamination by chloride and nitrate. However, water quality changes can not be related directly to mining activities. [ABSTRACT FROM AUTHOR]

Four sand pit lakes, at the Rio de Janeiro Sand Mining District, were monitored from November 2003 to November 2005, in order to characterize their hydrogeochemistry aiming to provide information to their possible use as fishponds at the end of mining activities. The results show diluted waters (low electrical conductivity) with low pH (<4) and relatively high sulfate and aluminum concentrations. The major water components (in particular Fe, Mn, SiO2, Al and SO4) are related to water acidity, since it controls solubility of aluminum silicate minerals and Mn and Fe oxides. Fe, Mn and Al availability in these waters are probably associated to organic colloids formation. On the other hand, the SiO2 content, as well as the decrease of sand mining in rainy season, may partially control Al availability by the formation of hydroxi-aluminum silicates. These geochemical processes together with the interruption of sand mining in the rainy season and the dilution of sand pit lakes water by rainwater can support the use of these pit lakes as fishpond for aquaculture. [ABSTRACT FROM AUTHOR]

Abstract: Within-channel alluvial gravel extraction is one of the most important forms of anthropogenically induced morphological change in river channels. In British rivers commercial gravel extraction was widespread between the 1930s and 1960s, and limited gravel extraction operations to reduce flood risk or maintain navigation continue to the present day. Despite this, gravel extraction has received little attention in UK river studies. This paper examines the significance of within-channel gravel extraction, during the period 1945–1960, on the planform of the River Wear in northern England. The study focuses on two 3 km piedmont reaches at Wolsingham and Harperley Park, located at the margin of the upland zone. Examination of detailed archival accounts of the gravel extraction operations, supplemented by the analysis of aerial photographs has enabled the impact of gravel extraction on the channel of the River Wear to be determined. Sediment budget calculations suggest large sediment deficits in both study reaches, however, assessing potential impacts simply in terms of a sediment deficit may be misleading as channel adjustments depend on local factors and a detailed consideration of the reach-scale sediment budget. Differences in the nature of channel adjustments of both reaches were found to be primarily a function of the method of gravel extraction employed. Overall patterns of channel change along the extraction reaches, over the past 150 years, were similar to reaches where gravel extraction was not practiced. This highlights the difficulty of trying to establish the significance of different processes where both local (gravel extraction) and catchment-scale factors (climate and land use) are operating. [Copyright &y& Elsevier]

Coastal erosion is an islandwide problem in Taiwan. On the basis of the result of the most recent survey, more than 80% of the island's sandy coasts have undergone erosion over the past 3 decades. Naturally and historically with the specific tectonic environment and uplifting rate in Taiwan, sufficient sediments had been yielded and transported to the coastal area, resulting in an advancing shoreline along the trailing edge coast during the last several centuries. However, human interventions have contributed significantly to the erosion in more recent times. In this paper, documented examples are chosen to address how human-induced changes have made profound impacts on the coastal erosion in Taiwan. The information presented will provide a better understanding of the coastal processes, and solutions to the erosion problem for the benefit of others in different parts of the world. [ABSTRACT FROM AUTHOR]

This work presents the main characteristics of 97 quarry wastes, collected in 23 gravel pits, from the Jarama river area, Madrid province, Spain. In this area, more than 2.5 × 106 ton of silty-clay waste are generated every year, and no applications have as yet been defined for them. This work is the first systematic study of the fine fractions generated from the Jarama river quaternary deposits, playing part in the comprehension of this complex terrace systems. Quartz, potassium feldspar, plagioclase, calcite, and complex mixtures of phyllosilicates, such as smectite, illite, kaolinite, chlorite and illite/smectite mixed layer, have been detected. Two sets of waste which are recognized according to the calcite content, have been directly related with the terrace level beneficed in the Jarama river, and the position along the valley. Calcite concentrates in the wastes produced in the lower course, where Henares and Tajuña tributaries promote an extensive change in the geochemistry of underground water, and locally, in the petrology of quarried conglomerates. This clear distinction by location between calcite-bearing and calcite-free wastes is essential for potential applications, such as soil conditioning, raw materials for brick or tiles, etc. The wastes studied can be considered as a potential source of industrial raw materials because of their uniformity and large volume. This suggestion is now being carried out, with an attempt at assessing the possibilities of using these mining wastes as ceramic raw materials. [ABSTRACT FROM AUTHOR]

The article presents the proceedings of the British Columbia Supreme Court case "Queacker-Komoyue Nation v. British Columbia (Attorney General)." The Queacker-Komoyue Nation challenged the approval of a sand and gravel project by the British Columbia Minister of the Environment on land that is part of the tribe's traditional territory.

Abstract: The growing demand for marine mineral resources introduces anthropogenic impacts in the coastal zone, among others also through aggregate dredging. Pits created by anchor hopper dredging may affect local sediment budgets, local hydrodynamics and biological habitats. In this study we investigate the processes and time-scales of pits refilling at two extraction sites over 6years following cessation of dredging. We focused on the evolution of a single pit at a gravel extraction site and the development of a group of three pits located at a sand extraction site. In the case of the gravel pit, a series of six sonograph and two multibeam surveys were evaluated. We observed a spatial expansion of the edge of the pit, decreasing availability of screened sand in the neighbourhood of the pit (a possible source of refilling), and a slowing down of the refilling process with time. At the sandy pit site a series of seven sonographs and two multibeam surveys were available. We observed a smoothing of the edges and larger mean refilling rates than in the gravel pit case. We conclude that the most effective method for monitoring of pit evolution is to make measurements every six months by simultaneously deploying sidescan sonar and multibeam devices. [Copyright &y& Elsevier]