Dispersion Plumes in Open Ocean Disposal Sites of Dredged Sediment

Elisa Helena Fernandes; Pablo Dias da Silva; Glauber Acunha Gonçalves; Osmar Olinto Möller

doi:10.3390/w13060808

Dispersion Plumes in Open Ocean Disposal Sites of Dredged Sediment

Water ◽

10.3390/w13060808 ◽

2021 ◽

Vol 13 (6) ◽

pp. 808

Author(s):

Elisa Helena Fernandes ◽

Pablo Dias da Silva ◽

Glauber Acunha Gonçalves ◽

Osmar Olinto Möller

Keyword(s):

Suspended Sediment ◽

Ecological Impact ◽

Rio Grande ◽

Open Ocean ◽

Dredged Material ◽

Dredged Sediment ◽

Anthropogenic Pressures ◽

Patos Lagoon ◽

Dredging Operation ◽

Ocean Disposal

Management of estuarine systems under anthropogenic pressures related to port settlement and development requires thorough understanding about the long-term sediment dynamics in the area. In an era of growing shipping traffic and of ever larger ships; millions of tons of bottom sediments are dredged annually all over the world and the major question concerning dredging operations is not whether they should be done, because it is obvious that they are extremely important and necessary, but where the dredged sediments can be disposed of with the least possible ecological impact. The present study involves the evaluation of transport trends of dredged material from a turbid estuary disposed of in four different open ocean disposal sites using numerical model techniques, aiming to contribute to minimizing potential environmental impacts and maximizing efficiency of the dredging operation. The study is carried out in southern Brazil, investigating the fate of dredged material from the Port of Rio Grande, located inside the Patos Lagoon estuary. Simulations were carried with the TELEMAC-3D model coupled with the suspended sediment (SEDI-3D) module and incorporating results from the wave module (TOMAWAC) to evaluate the dispersion of the suspended sediment plume and its interaction with coastal currents. This modeling structure proved to be a valuable tool to study the hydrodynamics and sediment transport pathways in estuarine and coastal areas. Results indicate that the natural Patos Lagoon coastal plume was observed under the predominant ebb flows and NE winds, promoting fine sediment entrapment south of the mouth of the lagoon (in front of Cassino Beach). The dispersion plumes in the disposal sites responded to the wind intensity and direction and did not present any transport tendency towards Cassino Beach. Part of the dredged sediment disposed of in the proposed alternative sites located in deeper areas (Sites B and C) left the site and was transported parallel to the coast (SW–NE direction) according to the wind direction (NE–SW). The area where the disposal sites were located took around 4 days to recover from the dredging operation and reach the usual suspended sediment concentrations and the actual Port of Rio Grande Licensed Site for dredged material proved to be the best alternative among the investigated options

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Sewage and Solids Disposal: Are Processes Such as Ocean Disposal Proper? The Case of Rio de Janeiro (Brazil)

Water Science & Technology ◽

10.2166/wst.1990.0098 ◽

1990 ◽

Vol 22 (12) ◽

pp. 33-43 ◽

Cited By ~ 2

Author(s):

Eduardo P. Jordão ◽

Jorge R. Leitão

Keyword(s):

Environmental Impact ◽

Rio De Janeiro ◽

Marine Ecosystem ◽

Ecological Impact ◽

Monitoring Program ◽

Quality Criteria ◽

Water Quality Criteria ◽

Federal Regulations ◽

Concrete Pipe ◽

Ocean Disposal

In developing countries, as is the case of Brazil, solutions proposed for sewage and sludge treatment and disposal must meet not only public environmental demands and obey proper legal regulations, but also take into account the availability of funds for new investments and operation of existing systems. Brazilian federal regulations allow ocean disposal of sewage and solids, according to certain water quality criteria and specific standards. On the other hand, federal regulations require that submarine outfalls must be studied by means of an Environmental Impact Assessment, and that a Report on the Environmental Impact be produced. Such studies must demonstrate that the site will be protected and that ocean disposal will not impair the environment and the beneficial uses, such as fisihing, recreation, navigation, or propagation of marine life. The State of Rio de Janeiro has monitored its Ipanema Submarine Outfall since 1974, one year prior to going into operation. Present flow is 6m3/sec (140 mgd) of bar-screened domestic sewage. The submarine outfall is a 2.4m diameter concrete pipe, 4.3 km (2.7mi) long, and discharges at a depth of 27m (89ft). The paper presents and discusses existing regulations and data on the seawater monitoring program which is still in practice, having produced more than 90,000 analyses. Discussion covers the period 1974 - 1988, and shows that no adverse ecological impact has been noted on the marine ecosystem.

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Chapter 15: ENVIRONMENTAL MONITORING OF NEARSHORE DREDGED MATERIAL OCEAN DISPOSAL SITES

Handbook of Environment and Waste Management ◽

10.1142/9789814449175_0015 ◽

2014 ◽

pp. 887-947

Author(s):

Kok-Leng Tay ◽

Russell Parrott ◽

Ken Doe ◽

Adrian MacDonald ◽

Yung-Tse Hung

Keyword(s):

Environmental Monitoring ◽

Dredged Material ◽

Ocean Disposal

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Recognizing Different Lifeways and Subsistence Practices through Analysis of the Material Cultures of Mound Sites in Rio Grande do Sul, Brazil

Latin American Antiquity ◽

10.1017/laq.2020.18 ◽

2020 ◽

Vol 31 (2) ◽

pp. 308-324

Author(s):

Anderson Marques Garcia

Keyword(s):

Central Region ◽

Rio Grande ◽

Rio Grande Do Sul ◽

Hunter Gatherers ◽

Patos Lagoon ◽

Projectile Points ◽

Brazilian State ◽

Subsistence Practices ◽

Mound Sites

In the Brazilian state of Rio Grande do Sul, the term cerrito was traditionally used to designate archaeological phenomena that emerge in the form of mounds in different landscapes. Except for recent research developed in the southwestern region of the Patos Lagoon, few advances have occurred since the 1980s in the study of cerritos in Brazil. This article presents an analysis of the lithic industries of sites with mounds in the southwestern region of the Patos Lagoon and in the central region in the current territory of Rio Grande do Sul. The results, along with other data from the sites, suggest that coastal sites were occupied by sedentary fisher-hunter-gatherers, who also possibly domesticated certain plants. Lithic material was scarce there and was mainly produced from pebbles and quartz cobbles using the anvil technique. In contrast, central region formations presented mounds on outcrops, using land, pebbles, and boulders; the area was occupied by a hunter-gatherer group that had projectile points and other instruments carved mainly by façonnage and débitage.

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Conjunction of a newly proposed emotional ANN (EANN) and wavelet transform for suspended sediment load modeling

Water Science & Technology Water Supply ◽

10.2166/ws.2019.044 ◽

2019 ◽

Vol 19 (6) ◽

pp. 1726-1734 ◽

Cited By ~ 9

Author(s):

Elnaz Sharghi ◽

Vahid Nourani ◽

Hessam Najafi ◽

Huseyin Gokcekus

Keyword(s):

Suspended Sediment ◽

Sediment Load ◽

Rio Grande ◽

Suspended Sediment Load ◽

Load Modeling ◽

Ann Models ◽

Upper Rio Grande ◽

Model Versus ◽

Artificial Neural Network Ann ◽

Correct Estimation

Abstract Suspended sediment load (SSL) time series have three principal inherent components (autoregressive trend, seasonality and stochastic terms) and the overall performance of an SSL modeling tool is associated with the correct estimation of these components. In this study, novel developments of artificial neural network (ANN) models, emotional ANN (EANN) and hybrid wavelet-EANN (WEANN), are employed to estimate the daily and monthly SSL of two rivers (Upper Rio Grande and Lighvanchai) with different hydro-geomorphological conditions. The overall results obtained via autoregressive models, the ANN and EANN, specify the supremacy of EANN (with a few hormonal parameters) against ANN due to the EANN better training the model versus extreme conditions. Also, the obtained results exhibit that the WEANN model could improve the SSL modeling up to 42% and 14% for daily modeling and up to 141% and 87% for monthly modeling in the Upper Rio Grande and Lighvanchai Rivers, respectively.

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Dredged Material Quality in Anthropogenically Exploited Catchment Area

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.838.118 ◽

2020 ◽

Vol 838 ◽

pp. 118-124

Author(s):

Natalia Junakova ◽

Eva Šelingova ◽

Lenka Demkova

Keyword(s):

Heavy Metals ◽

Water Quality ◽

Catchment Area ◽

Anthropogenic Activity ◽

Dredged Material ◽

Mining Activities ◽

Dredged Sediment ◽

Limit Values ◽

Long Time ◽

Reservoir Watershed

The paper is focused on the research of pollutants in dredged material and water in the watershed of the Sigord reservoir (Eastern Slovakia), which is influenced by anthropogenic activity. The monitored area extends to the cadastral area of Zlatá Baňa, which has been used for a long time and intensively for mining of gold, antimony and mercury. After the end of mining activities (at the beginning of the 20th century) the territory remained devastated by numerous remains of mining activities and no attention has been paid to this area in terms of scientific research. Therefore, the monitoring of dredged sediment and water quality has been carried out. The results show that the limit values of selected heavy metals (such as Sb, As, Hg, Pb, Cu, Zn, Ni, Fe and Al) are exceeded in both sediments and water in the reservoir watershed, as a result of the former mining activities around Sigord.

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Revised sediment transport model for estimation of suspended sediment flux and chemical composition of the Irrawaddy and Salween rivers

10.5194/egusphere-egu2020-10918 ◽

2020 ◽

Author(s):

J. Jotautas Baronas ◽

Edward T. Tipper ◽

Michael J. Bickle ◽

Robert G. Hilton ◽

Emily I. Stevenson ◽

...

Keyword(s):

Chemical Composition ◽

Organic Carbon ◽

Suspended Sediment ◽

Transport Model ◽

Sediment Concentration ◽

Sediment Flux ◽

Sediment Discharge ◽

Anthropogenic Pressures ◽

Modeling Framework ◽

Sediment Delivery

A large portion of freshwater and sediment is exported to the ocean by just several of the world's major rivers. Many of these mega-rivers are under significant anthropogenic pressures, such as damming and sand mining, which are having a significant impact on water and sediment delivery to deltaic ecosystems. However, accurately measuring the total sediment flux and its mean physicochemical composition is difficult in large rivers due to hydrodynamic sorting of sediments. To account for this, we developed an updated semi-empirical Rouse modeling framework, which synoptically predicts sediment concentration, grain size distribution, and mean chemical composition (organic carbon wt%, Al/Si ratio) with depth and across the river channel.We applied this model to derive new sediment flux estimates for the Irrawaddy and the Salween, the last two free-flowing mega-rivers in Southeast Asia, using a newly collected set of suspended sediment depth samples, coupled to ADCP-measured flow velocity data. Constructing sediment-discharge rating curves, we calculated an annual sediment flux of 326 (68% confidence interval of 256-417) Mt/yr for the Irrawaddy and 159 (109-237) Mt/yr for the Salween, together accounting for 2-3% of total global riverine sediment discharge. The mean flux-weighted sediment exported by the Irrawaddy is significantly coarser (D84 = 193 &#177; 13 &#181;m) and OC-poorer (0.29 &#177; 0.08 wt%) compared to the Salween (112 &#177; 27 &#181;m and 0.59 &#177; 0.16 wt%, respectively). Both rivers export similar amounts of particulate organic carbon, with a total of 1.9 (1.0-3.3) Mt C/yr, contributing ~1% of the total riverine POC export to the ocean. These results underline the global significance of the Irrawaddy and Salween rivers and warrant continued monitoring of their sediment fluxes, given the increasing anthropogenic pressures on these river basins.

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