River Deltas - Recent Advances [Working Title]最新文献

{"title":"Anthropogenic Activities as a Source of Stress on Species Diversity in the Mekong River Delta","authors":"Charles Nyanga, Beatrice Njeri Obegi, Loi To Thi Bich","doi":"10.5772/intechopen.101172","DOIUrl":"https://doi.org/10.5772/intechopen.101172","url":null,"abstract":"Deltas are landforms, which come into existence when sediment carried by river or stream empties its load into another water body with slow flow rates or stagnant water. Sometimes, a river may empty its sediment load on land, although this is uncommon. The world’s deltas are amongst the most productive and in some cases more populated than even land. This chapter reviews the formation of deltas, the ecology and habitats of deltas as well as the biodiversity in coastal habitats and delta habitats. Additionally, the chapter looks at recent advances in deltas such as the loss of sediment and other stressors currently facing deltas with a focus on anthropogenic activities in the Mekong River Delta (MRD) that is amongst the most resource rich deltas in the world. The Mekong River Delta (MRD) is currently known to be in peril due to anthropogenic activities such as dam construction for hydropower and irrigation, overfishing, agricultural production amongst many others. Additionally, demographical trends like population increase have also been scrutinized to see the impacts on the MRD. The results of the review process have shown that at least 85% of the deltas in the world are subsiding and losing their fertility to the sea. Finally, the chapter has endeavored to come up with suggestions on how best to overcome some of these stressors resulting from the anthropogenic activities.","PeriodicalId":177667,"journal":{"name":"River Deltas - Recent Advances [Working Title]","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114750091","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An Assessment of Land Use and Land Cover Changes and Its Impact on the Surface Water Quality of the Crocodile River Catchment, South Africa","authors":"Nde Samuel Che, Sam Bett, Enyioma Chimaijem Okpara, Peter Oluwadamilare Olagbaju, Omolola Esther Fayemi, M. Mathuthu","doi":"10.5772/intechopen.95753","DOIUrl":"https://doi.org/10.5772/intechopen.95753","url":null,"abstract":"The degradation of surface water by anthropogenic activities is a global phenomenon. Surface water in the upper Crocodile River has been deteriorating over the past few decades by increased anthropogenic land use and land cover changes as areas of non-point sources of contamination. This study aimed to assess the spatial variation of physicochemical parameters and potentially toxic elements (PTEs) contamination in the Crocodile River influenced by land use and land cover change. 12 surface water samplings were collected every quarter from April 2017 to July 2018 and were analyzed by inductive coupled plasma spectrometry-mass spectrometry (ICP-MS). Landsat and Spot images for the period of 1999–2009 - 2018 were used for land use and land cover change detection for the upper Crocodile River catchment. Supervised approach with maximum likelihood classifier was used for the classification and generation of LULC maps for the selected periods. The results of the surface water concentrations of PTEs in the river are presented in order of abundance from Mn in October 2017 (0.34 mg/L), followed by Cu in July 2017 (0,21 mg/L), Fe in April 2017 (0,07 mg/L), Al in July 2017 (0.07 mg/L), while Zn in April 2017, October 2017 and April 2018 (0.05 mg/L). The concentrations of PTEs from water analysis reveal that Al, (0.04 mg/L), Mn (0.19 mg/L) and Fe (0.14 mg/L) exceeded the stipulated permissible threshold limit of DWAF (< 0.005 mg/L, 0.18 mg/L and 0.1 mg/L) respectively for aquatic environments. The values for Mn (0.19 mg/L) exceeded the permissible threshold limit of the US-EPA of 0.05 compromising the water quality trait expected to be good. Seasonal analysis of the PTEs concentrations in the river was significant (p > 0.05) between the wet season and the dry season. The spatial distribution of physicochemical parameters and PTEs were strongly correlated (p > 0.05) being influenced by different land use type along the river. Analysis of change detection suggests that; grassland, cropland and water bodies exhibited an increase of 26 612, 17 578 and 1 411 ha respectively, with land cover change of 23.42%, 15.05% and 1.18% respectively spanning from 1999 to 2018. Bare land and built-up declined from 1999 to 2018, with a net change of - 42 938 and − 2 663 ha respectively witnessing a land cover change of −36.81% and − 2.29% respectively from 1999 to 2018. In terms of the area under each land use and land cover change category observed within the chosen period, most significant annual change was observed in cropland (2.2%) between 1999 to 2009. Water bodies also increased by 0.1% between 1999 to 2009 and 2009 to 2018 respectively. Built-up and grassland witness an annual change rate in land use and land cover change category only between 2009 to 2018 of 0.1% and 2.7% respectively. This underscores a massive transformation driven by anthropogenic activities given rise to environmental issues in the Crocodile River catchment.","PeriodicalId":177667,"journal":{"name":"River Deltas - Recent Advances [Working Title]","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129834382","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Wave-Forced Dynamics at Microtidal River Mouths","authors":"M. Brocchini, M. Postacchini, Lorenzo Melito, Eleonora Perugini, A. Manning, Joseph P. Smith, J. Calantoni","doi":"10.5772/intechopen.99143","DOIUrl":"https://doi.org/10.5772/intechopen.99143","url":null,"abstract":"Microtidal river mouths are dynamic environments that evolve as a consequence of many forcing actions. Under the hydrodynamic viewpoint, river currents, sea waves and tides strongly interact, and their interplay determines specific sediment transport and morphological patterns. Beyond literature evidence, information comes from field observations made at the Misa River study site, a microtidal river along the Adriatic Sea (Italy), object of a long-going monitoring. The river runs for 48 km in a watershed of 383 km2, providing a discharge of about 400 m3/s for return periods of 100 years. The overall hydrodynamics, sediment transport and morphological evolution at the estuary are analyzed with particular attention to specific issues like: the generation of vortical flows at the river mouth, the influence of various wave modes (infragravity to tidal) propagating upriver, the role of sediment flocculation, the generation and evolution of bed features (river-mouth bars and longitudinal nearshore bars). Numerical simulations are also used to clarify specific mechanisms of interest.","PeriodicalId":177667,"journal":{"name":"River Deltas - Recent Advances [Working Title]","volume":"100 1-2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120890588","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Danube Delta: Water Management on the Sulina Channel in the Frame of Environmental Sustainability","authors":"I. Cretescu, Z. Kovács, L. Lazar, Adrian Burada, Madalina Sbarcea, L. Teodorof, Dan Padure, G. Soreanu","doi":"10.5772/INTECHOPEN.97877","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.97877","url":null,"abstract":"The Danube Delta is the newest land formed by both transporting sediments brought by Danube River, which flows into the Black Sea and by traversing an inland region where water spreads and deposits sediments. Diurnal tidal action is low (only 8–9 cm), therefore the sediments would wash out into the water body faster than the river deposits it. However, a seasonal fluctuation of water level of 20 cm was observed in the Black Sea, contributing to alluvial landscape evolution in the Danube Delta. The Danube Delta is a very low flat plain, lying 0.52 m above Mean Black Sea Level with a general gradient of 0.006 m/km and only 20% of the delta area is below zero level. The main control on deposition, which is a combination of river, wind-generated waves, and tidal processes, depends on the strength of each one. The other two factors that play a major role are landscape position and the grain size distribution of the source sediment entering the delta from the river. The Danube Delta is a natural protected area in the South-Eastern part of Romania, declared a Biosphere Reserve through the UNESCO “Man and Biosphere” Programme. Water is a determining factor for all the human settlements in the Biosphere Reserve, the whole Danube Delta being structured by the three branches of the Danube (Chilia, Sulina and Sfantu Gheorghe (Saint George)). Our case study is focused on the Sulina branch, also named Sulina Channel, which offers the shortest distance between the Black Sea (trough Sulina Port) and Tulcea (the most important city of the Danube Delta from economic, social and cultural points of view) for both fluvial and marine ships. The improvement of water resources management is the main topic of this chapter, in terms of water quality indicators, which will be presented in twenty-nine monitoring points, starting since a few years ago and updated to nowadays. During the study period, significant exceedances of the limit value were detected in case of nitrate-N (3.9–4.6 mg/L) at the confluence (CEATAL 2) with the Saint George branch and in the Sulina Channel after the Wastewaters Treatment Plant (WWTP) discharge area, as well as near two settlements, namely Gorgova and Maliuc. The higher concentrations of Nitrogen-based nutrients were caused by the leakage from the old sewage systems (where these exist) and the diffuse loads.","PeriodicalId":177667,"journal":{"name":"River Deltas - Recent Advances [Working Title]","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114889159","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impact of the Jamapa River Basin on the Gulf of Mexico","authors":"M. Castañeda-Chávez, F. Lango-Reynoso","doi":"10.5772/INTECHOPEN.97021","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.97021","url":null,"abstract":"The Jamapa River basin is located in the central region of the State of Veracruz, it is born in the Pico de Orizaba and connects with the Veracruz Reef System in the Gulf of Mexico, both protected natural areas. The lower part of the basin has the contribution of two important effluents, Arroyo Moreno, which is a protected natural area, strongly impacted due to municipal discharges from the metropolitan cities Veracruz-Boca del Río-Medellín. And the Estero, which is part of a complex aquatic system that discharges its waters from the Lagunar Mandinga system to the Gulf of Mexico. Currently, there is a diversity of chemical and biological compounds that the basin receives from different sources of freshwater pollution, such as industrial waste, sewage, agricultural and urban runoff, and the accumulation of sediments. The climatic seasons are the determining factors in the composition of its sediments, due to the force exerted on the bottom of the river by the increase in rainfall, the force of the winds mainly in the north wind season, where the greatest quantity of polluting materials.","PeriodicalId":177667,"journal":{"name":"River Deltas - Recent Advances [Working Title]","volume":"88 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123311373","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}