scholarly journals Impact of Sediments and Constructions on River Flooding in Coimbra, Portugal

10.29007/v6th ◽  
2018 ◽  
Author(s):  
Jose Alfeu Sa Marques ◽  
Nuno Simoes ◽  
Lucas Maluf ◽  
Fernando Seabra Santos ◽  
Jose Vieira ◽  
...  
Keyword(s):  
River Flow ◽  
Sediment Accumulation ◽  
Hydrological Regime ◽  
River System ◽  
Water Levels ◽  
River Flooding ◽  
Operation Rules ◽  
Dam Operation ◽  
Upstream Part ◽  
Flooding Events

In Coimbra city, Portugal, the riverbanks have suffered several floods events in the past, due to its hydrological regime, the low slope and consequent lack of capacity of the Mondego River in its final 30 km. The construction of several dams in the upstream part of the river catchment has improved the use of the hydraulic capacity of the river system and reduced the number and intensity of flooding events in Coimbra. Nevertheless, intense rainfall events combined with inadequate procedures of the dam operation rules and lack of monitoring of sediments dynamics can still originate inundation in Coimbra such as those registered between 9th and 11th of January 2016. This work presents modelling scenarios demonstrating the influence of the sediment accumulation into the riverbed and its effect on the water levels. It also presents the influence that piers from a new bridge can have into the river flow dynamics.

scholarly journals Socio-hydrology: conceptualising human-flood interactions

2013 ◽  
Vol 10 (4) ◽  
pp. 4515-4536 ◽  
Author(s):  
G. Di Baldassarre ◽  
A. Viglione ◽  
G. Carr ◽  
L. Kuil ◽  
J. L. Salinas ◽  
...  
Keyword(s):  
Flood Control ◽  
Technological Development ◽  
River System ◽  
High Water ◽  
Social Processes ◽  
Individual Characteristics ◽  
Water Levels ◽  
Control Structures ◽  
Flooding Events

Abstract. Over history, humankind has tended to settle near streams because of the role of rivers as transportation corridors and the fertility of riparian areas. However, human settlements in floodplains have been threatened by the risk of flooding. Possible responses have been to resettle away and/or modify the river system by building flood control structures. This has led to a complex web of interactions and feedback mechanisms between hydrological and social processes in settled floodplains. This paper is an attempt to conceptualise these interplays for hypothetical human-flood systems. We develop a simple, dynamic model to represent the interactions and feedback loops between hydrological and social processes. The model is then used to explore the dynamics of the human-flood system and the effect of changing individual characteristics, including external forcing such as technological development. The results show that the conceptual model is able to reproduce reciprocal effects between floods and people as well as the emergence of typical patterns. For instance, when levees are built or raised to protect floodplain areas, their presence not only reduces the frequency of flooding, but also exacerbates high water levels. Then, because of this exacerbation, higher flood protection levels are required by the society. As a result, more and more flooding events are avoided, but rare and catastrophic events take place.

scholarly journals Socio-hydrology: conceptualising human-flood interactions

2013 ◽  
Vol 17 (8) ◽  
pp. 3295-3303 ◽  
Author(s):  
G. Di Baldassarre ◽  
A. Viglione ◽  
G. Carr ◽  
L. Kuil ◽  
J. L. Salinas ◽  
...  
Keyword(s):  
Flood Control ◽  
Technological Development ◽  
River System ◽  
High Water ◽  
Social Processes ◽  
Individual Characteristics ◽  
Water Levels ◽  
Control Structures ◽  
Flooding Events

Abstract. Over history, humankind has tended to settle near streams because of the role of rivers as transportation corridors and the fertility of riparian areas. However, human settlements in floodplains have been threatened by the risk of flooding. Possible responses have been to resettle away and/or modify the river system by building flood control structures. This has led to a complex web of interactions and feedback mechanisms between hydrological and social processes in settled floodplains. This paper is an attempt to conceptualise these interplays for hypothetical human-flood systems. We develop a simple, dynamic model to represent the interactions and feedback loops between hydrological and social processes. The model is then used to explore the dynamics of the human-flood system and the effect of changing individual characteristics, including external forcing such as technological development. The results show that the conceptual model is able to reproduce reciprocal effects between floods and people as well as the emergence of typical patterns. For instance, when levees are built or raised to protect floodplain areas, their presence not only reduces the frequency of flooding, but also exacerbates high water levels. Then, because of this exacerbation, higher flood protection levels are required by society. As a result, more and more flooding events are avoided, but rare and catastrophic events take place.

scholarly journals THE RIVER TESHA HYDROLOGICAL REGIME ASSESSMENT IN THE ARZAMAS TOWN AREA WHEN JUSTIFYING PROJECT DECISIONS

2020 ◽  
pp. 11-24
Author(s):  
Alexander N. Sitnov ◽  
Natalia V. Kochkurova
Keyword(s):  
Hydrological Regime ◽  
High Water ◽  
Water Levels ◽  
Flow Rates ◽  
River Flooding ◽  
Project Study ◽  
Cross Section Area ◽  
Section Area ◽  
Long Term Observation

The article gives an assessment of the hydrological regime on the River Tesha sector . The assessment was obtained during the pre-project study of the object and allows making project decisions on clearing the riverbed. The River Tesha Basin has been well studied in the past. However, there was no data based on long-term observation of the river's hydrological regime parameters in the area under consideration; hence, the authors performed calculations for data recovery by interpolation between existing hydrological posts, as well as for obtaining their representative series and determining their hydrological characteristics. Correlation between changes in flow rates and water levels in the river was found, as well as between the riverbed morphological parameters (depth, width, cross-section area) and its hydraulic characteristics (flow rate, flow rates). The completed assessment of the hydrological regime makes it possible to forecast river flooding at high water levels as well as flooding of the surrounding area, and to make project decisions thereafter, including the identification of flooding areas, the dump sites choice, these sites functioning period f that depends on when and for how long they will be flooded during the year.

scholarly journals Aswan High Dam Reservoir management system

2013 ◽  
Vol 15 (4) ◽  
pp. 1491-1510 ◽  
Author(s):  
Noha Donia
Keyword(s):  
Climate Change ◽  
Management System ◽  
Reservoir Management ◽  
Water Levels ◽  
Emission Scenarios ◽  
Dam Reservoir ◽  
Global Emission ◽  
Operation Rules ◽  
Dam Operation ◽  
Aswan High Dam

The Aswan High Dam Reservoir management system was developed to simulate dam operation under varying boundary conditions taking as example climate change and Millennium Dam construction, and analyze the optimal operation rules of the reservoir taking into account a large number of objectives, including hydropower production and water supply for irrigation purposes. The developed system runs on Windows platforms and comprises three basic modules: a user-friendly graphical interface managing all graphic features, a computational engine where all the algorithms are implemented, and a database and files module managing hydrological and operational data. The developed model was calibrated. The future hydrologic scenarios developed have been used to assess the expected impacts of potential climate change (baseline and three periods with two global emission scenarios) and the Millennium Dam. The new operation rules were used for scenarios analysis. It was concluded that overall applying the new operation rules will decrease the percentage of occurrence of minimum water levels. Also, the Millennium Dam will increase the percentage of occurrence of minimum water levels. Finally, the period III (2070–2099) for the two global emission scenarios is very critical for the dam operation.

scholarly journals A New Tool for Assessing Environmental Impacts of Altering Short-Term Flow and Water Level Regimes

Water ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2913
Author(s):  
María Dolores Bejarano ◽  
Jaime H. García-Palacios ◽  
Alvaro Sordo-Ward ◽  
Luis Garrote ◽  
Christer Nilsson
Keyword(s):  
River Flow ◽  
Water Levels ◽  
Computational Tool ◽  
Short Term ◽  
Stream Flows ◽  
Glen Canyon Dam ◽  
Rates Of Change ◽  
Hydrological Alteration ◽  
Dam Operation

The computational tool InSTHAn (indicators of short-term hydrological alteration) was developed to summarize data on subdaily stream flows or water levels into manageable, comprehensive and ecologically meaningful metrics, and to qualify and quantify their deviation from unaltered states. The pronunciation of the acronym refers to the recording interval of input data (i.e., instant). We compared InSTHAn with the tool COSH-Tool in a characterization of the subdaily flow variability of the Colorado River downstream from the Glen Canyon dam, and in an evaluation of the effects of the dam on this variability. Both tools captured the hydropeaking caused by a dam operation, but only InSTHAn quantified the alteration of key flow attributes, highlighting significant increases in the range of within-day flow variations and in their rates of change. This information is vital to evaluate the potential ecological consequences of the hydrological alteration, and whether they may be irreversible, making InSTHAn a key tool for river flow management.

scholarly journals Sanility intrustion in Sai Gon-Dong Nai river system under the effects of the tides and sea level rising in Vung Tau estuary – East Sea, South of Vietnam

2016 ◽  
Vol 19 (1) ◽  
pp. 140-150
Author(s):  
Thong Chi Ho ◽  
Ngo Van Dau ◽  
Oanh Thi Phi Tran
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Hydrological Regime ◽  
River System ◽  
Measured Data ◽  
Water Levels ◽  
Ho Chi Minh City ◽  
Oscillation Phase ◽  
Salinity Regime ◽  
Domestic Regulation

A mathematical model was used by the authors (software developed by Dr. F28 Le Song Giang) to study the change of the salt boundary river systems Saigon - Dong Nai under the effect of sea level rise in the different cases for Ho Chi Minh City, taking into account the change of amplitude and phase shift of the South China Sea tide. Results of the study indicated that: 1. There is a pretty good resemblance between model running results and results of water levels measurement. Salinity, calculated results have a larger amplitude slightly from measured data but this difference and oscillation phase can be acceptable. 2. Salinity 1 g / l - 3 g / l is increasingly encroaching into the infield under the sea level rise scenarios. Salt accounts is greater than 5 g / l and the margin of 10-15 g / l is also approaching deeply, so the future of Ho Chi Minh City will face to some water supply problems. 3. Saline in basin downstream Saigon - Dong Nai river is quite sensitive to the hydrological regime of the river, therefore, domestic regulation of irrigation reservoirs upstream can be used to push salt and improve salinity regime in the downstream part of the river

Morphotectonic Analysis of Tanjung Bungo Area Based on Geological Structure Control, Central Sumatera Basin

2020 ◽  
Author(s):  
D., A., L., A. Putri
Keyword(s):  
Natural Resources ◽  
River Flow ◽  
Measurement Data ◽  
River System ◽  
Flow Patterns ◽  
Source Rocks ◽  
Aerial Photographs ◽  
Morphological Data ◽  
Tectonic Activity ◽  
Geological Structures

Tectonic activity in an area could result in various impacts such as changes in elevation, level of slope percentages, river flow patterns and systems, and the formation of geological structures both locally and regionally, which will form a new landscape. The tectonic activity also affects the stratigraphic sequences of the area. Therefore, it is necessary to study morphotectonic or landscape forms that are influenced by active tectonic activities, both those occur recently and in the past. These geological results help provide information of the potential of natural resources in and around Tanjung Bungo area. Morphological data are based on three main aspects including morphogenesis, morphometry, and morphography. The data are collected in two ways, the first is field survey by directly observing and taking field data such as measuring geological structures, rock positions, and outcrop profiles. The second way is to interpret them through Digital Elevation Model (DEM) and aerial photographs by analyzing river flow patterns and lineament analysis. The field measurement data are processed using WinTensor, Dips, and SedLog Software. The supporting data such as Topographic Maps, Morphological Elevation Maps, Slope Maps, Flow Pattern Maps, and Lineament Maps are based on DEM data and are processed using ArcGis Software 10.6.1 and PCI Geomatica. Morphotectonically, the Tanjung Bungo area is at a moderate to high-class level of tectonic activity taken place actively resulted in several joints, faults, and folds. The formation of geological structures has affected the morphological conditions of the area as seen from the development of steep slopes, structural flow patterns such as radial, rectangular, and dendritic, as well as illustrated by rough surface relief in Tanjung Bungo area. This area has the potential for oil and gas resources as indicated by the Telisa Formation, consisting of calcareous silts rich in planktonic and benthonic fossils, which may be source rocks and its contact with the Menggala Formation which is braided river system deposits that could be good reservoirs. Further research needs to be done since current research is only an interpretation of surface data. Current natural resources being exploited in Tanjung Bungo region are coals. The coals have thicknesses of 5-7 cm and are classified as bituminous coals.

scholarly journals Design of Optimal Rainfall Monitoring Network Using Radar and Road Networks

Entropy ◽  
2021 ◽  
Vol 23 (3) ◽  
pp. 378
Author(s):  
Taeyong Kwon ◽  
Seongsim Yoon ◽  
Sanghoo Yoon
Keyword(s):  
Road Networks ◽  
Monitoring Network ◽  
Conditional Entropy ◽  
Radar Data ◽  
Disaster Risk ◽  
Water Levels ◽  
The Road ◽  
Dam Operation ◽  
A Site ◽  
High Degree

Uncertainty in the rainfall network can lead to mistakes in dam operation. Sudden increases in dam water levels due to rainfall uncertainty are a high disaster risk. In order to prevent these losses, it is necessary to configure an appropriate rainfall network that can effectively reflect the characteristics of the watershed. In this study, conditional entropy was used to calculate the uncertainty of the watershed using rainfall and radar data observed from 2018 to 2019 in the Goesan Dam and Hwacheon Dam watersheds. The results identified radar data suitable for the characteristics of the watershed and proposed a site for an additional rainfall gauge. It is also necessary to select the location of the additional rainfall gauged by limiting the points where smooth movement and installation, for example crossing national borders, are difficult. The proposed site emphasized accessibility and usability by leveraging road information and selecting a radar grid near the road. As a practice result, the uncertainty of precipitation in the Goesan and Hwacheon Dam watersheds could be decreased by 70.0% and 67.9%, respectively, when four and three additional gauge sites were installed without any restriction. When these were installed near to the road, with five and four additional gauge sites, the uncertainty in the Goesan Dam and Hwacheon Dam watersheds were reduced by up to 71.1%. Therefore, due to the high degree of uncertainty, it is necessary to measure precipitation. The operation of the rainfall gauge can provide a smooth site and configure an appropriate monitoring network.

Vegetation, hydrology, and development of a coastal mire in Hokkaido, Japan, affected by flooding and tephra deposition

2001 ◽  
Vol 79 (3) ◽  
pp. 341-361 ◽  
Author(s):  
Stefan Hotes ◽  
Peter Poschlod ◽  
Hiroshige Sakai ◽  
Takashi Inoue
Keyword(s):  
Sea Water ◽  
Ionic Composition ◽  
Plant Macrofossils ◽  
Vegetation Pattern ◽  
Water Levels ◽  
Myrica Gale ◽  
Mineral Deposition ◽  
Volcanic Ejecta ◽  
Induced Changes ◽  
Flooding Events

Mires in coastal lowlands in Hokkaido, northern Japan, have repeatedly been affected by flooding events and tephra (aerially transported volcanic ejecta) deposition during their development. Vegetation, hydrology, and stratigraphy of Kiritappu Mire in eastern Hokkaido were investigated along two transects and are discussed in relation to disturbance by mineral deposition. The vegetation pattern showed little relation to past geologic events. Five plant communities, two of which (A and C) could be further divided into subgroups, were distinguished (A, Alnus japonica - Spiraea salicifolia community; B, Sasa chartacea community; C, Myrica gale var. tomentosa - Sphagnum fuscum community; D, Carex lyngbyei community; E, Carex subspathacea - Aster tripolium community). Water levels, pH, electric conductivity, and ionic composition of groundwater and surface water were measured in communities A-C. Mean water levels were similar in communities A and C; in community B, it was lower. The pH was higher in community A than in communities B and C. Ion concentrations were influenced by sea water at some sites. Plant macrofossils and ash contents of 31 cores were analysed. Sedge roots were the dominant peat component, often mixed with remains of Phragmites australis, Sphagnum spp., and Polytrichum juniperinum var. strictum. Ash contents were high, and up to nine different mineral layers consisting of tephra, sand, silt, and clay were detected. In some cases, mineral deposition induced changes in the macrofossil composition of the peat. However, in a greater number of cases, no changes in the macrofossil composition were found at the mineral layers, and most shifts were not related to mineral deposition.Key words: mire, vegetation, hydrology, disturbance, flooding, tephra.

scholarly journals Analysis of the risk associated to coastal flooding hazards: A new historical extreme storm surges dataset for Dunkirk, France

2017 ◽  
Author(s):  
Yasser Hamdi ◽  
Emmanuel Garnier ◽  
Nathalie Giloy ◽  
Claire-Marie Duluc ◽  
Vincent Rebour
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Historical Data ◽  
Storm Surges ◽  
Coastal Hazards ◽  
Historical Study ◽  
Frequency Model ◽  
River Flooding ◽  
Flooding Hazards ◽  
Flooding Events

Abstract. This paper aims to demonstrate the technical feasibility of a historical study devoted to French Nuclear Power Plants (NPPs) which can be prone to the extreme marine flooding events. It has been shown in the literature that the use of HI can significantly improve the probabilistic and statistical modeling of extreme events. There is a significant lack of historical data about marine flooding (storms and storm surges) compared to river flooding events. To address this data scarcity and to improve the estimation of the risk associated to the marine flooding hazards, a dataset of historical storms and storm surges that hit the Nord-Pas-de-Calais region during the five past centuries were recovered from archival sources, examined and used in a frequency analysis (FA) in order to assess its impact on the frequency estimations. This work on the Dunkirk site (representative of the Gravelines NPP) is a continuation of previous work performed on the La Rochelle site in France. Indeed, the frequency model (FM) used in the present paper had some success in the field of coastal hazards and it has been applied in previous studies to surge datasets to prevent marine flooding in the La Rochelle region in France. In a first step, only information collected from the literature (published reports, journal papers and PhD theses) is considered. A 1954 Coastal Engineering journal issue (Le Gorgeu and Guitonneau, 1954) on the reconstruction of the eastern dyke in Dunkirk has been more than a reference for this paper. It has indeed served as a main source of historical information (HI) in this study. Although this first historical dataset has extended the gauged record back in time to 1897, serious questions related to the exhaustiveness of the information and about the validity of the developed FM have remained unanswered. Additional qualitative and quantitative HI were extracted in a second step from many older archival sources. This work has led to the construction of storms and marine flooding sheets summarizing key data on each identified event. The quality control and the cross-validation of the collected information, which have been carried out systematically, indicate that it is valid and complete as regards extreme storms and storm surges. Most of the HI gathered displays a good agreement with other archival sources and documentary climate reconstructions. The probabilistic and statistical analysis of a dataset containing an exceptional observation considered as an outlier (i.e. the 1953 storm surge) has been significantly improved when the additional HI gathered in both literature and archives are used. As the historical data tend to be extreme, the right tail of the distribution has been reinforced and the 1953 exceptional event don't appear as an outlier any more. This new dataset provides a valuable source of information on storm surges for future characterization of coastal hazards.

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