scholarly journals Defining flood risk in a multivariate framework: Application on the Panaro watershed

2016 ◽  
Author(s):  
Eleni Maria Michailidi ◽  
Baldassare Bacchi
Keyword(s):  
Water Level ◽  
Copula Functions ◽  
Initial Water ◽  
Maximum Rainfall ◽  
Lake Water Level ◽  
Flood Peak ◽  
Risk Levels ◽  
Maximum Water Level ◽  
Natural Variable ◽  
Definition Of

Abstract. One of the most important tasks a hydrologist must face is to estimate the hydrological risk (i.e. probability) of a variable exceeding a certain threshold. This risk is often expressed in terms of a Return Period, T, and refers to the failure of the hydraulic structure which controls this variable. Sometimes the "structure" is simply the river embankmentsthe failure of which means their overtopping by the river. The widely adopted definition of T, in a problem regarding the maxima of hydro-logical variables, is "the average time elapsing between two successive occurrences of an event exceeding a given magnitude of the natural variables". Conventional approaches for the estimation of T involve a single natural variable (i.e. flood peak, maximum rainfall intensity, etc.) and its frequency analysis. However, a univariate approach in complex problems ignores the effect of other significant variables leading to different risk levels for each quantity of interest and resulting in an inaccurate estimate of the risk-often wrongfully set equal to the risk of the hydrological event. For example, if one considers the flood inflow in a lake around which establishments are positioned, the variable to be investigated relating to risk assessment is the lake water level. The same water level may occur from very different flood hydrographs, even when the same initial water level and specific spillway characteristics are taken into account. We considered this a result of the interaction of three joint factors: the hydrograph's peak, volume and shape. Consequently, we apply a multivariate distribution framework (using copula functions) in order to find a region where all underlying events are assigned to the same risk- associated here to the maximum water level.

Surge Associated With Air Expulsion in Near-Horizontal Pipelines

2003 ◽  
Author(s):  
Jose G. Vasconcelos ◽  
Steven J. Wright
Keyword(s):  
Water Level ◽  
Numerical Models ◽  
Ground Surface ◽  
Essential Elements ◽  
Filling Process ◽  
Initial Water ◽  
Maximum Water Level ◽  
Maximum Water ◽  
Flow Variables ◽  
Passive Phase

A number of situations of engineering interest are associated with the relatively rapid filling of a nearly horizontal pipeline. The displacement of the air may lead to a number of different transient conditions of concern in engineering design. Our specific application relates to the use of underground storage tunnels to mitigate combined sewage overflows. Historically, the operation of these system have created surges initiated when the tunnel passes to a surcharged condition that have resulted in “geysering” in which an air/water combination is expelled to the ground surface through manholes or other risers. Numerical models that have been created to describe the phenomena generally treat the air as a passive phase that exists at atmospheric pressure and disappears when the water fills the tunnel. In an attempt to understand the conditions leading to extreme surges, a physical model that reproduced the essential elements of the tunnel filling process was created. This model was filled at one end in a fill box in which the maximum water level was controlled with an overflow weir. A surge riser was mounted at the opposite end of the pipeline to observe the magnitudes of surges created under a number of different flows created by varying the inflow rate, the initial water level in the pipe, and the pipe slope. In general, initiation of the filling process generated a hydraulic bore that propagated through the system until the tunnel reached a surcharged state and the maximum surge generated depends on the dynamics of the bore. However, under certain flow conditions, the water level in the surge riser was observed to increase prior to the arrival of the bore, an occurrence that can only be explained by pressurization of the air in the pipe. Subsequent experiments confirmed this explanation and a modified experimental setup was created to elucidate the important effects of the air. Measurements were made of a number of key flow variables and are found to be consistent with the predictions of a numerical model that considers the elementary dynamics of the air.

Lake water level modeling using newly developed hybrid data intelligence model

2020 ◽  
Vol 141 (3-4) ◽  
pp. 1285-1300 ◽  
Author(s):  
Zaher Mundher Yaseen ◽  
Shabnam Naghshara ◽  
Sinan Q. Salih ◽  
Sungwon Kim ◽  
Anurag Malik ◽  
...  
Keyword(s):  
Water Level ◽  
Lake Water ◽  
Lake Water Level ◽  
Hybrid Data

Groundwater level assessment and prediction in the Nebraska Sand Hills using LIDAR-derived lake water level

2021 ◽  
pp. 126582
Author(s):  
Nawaraj Shrestha ◽  
Aaron Mittelstet ◽  
Aaron R. Young ◽  
Troy E. Gilmore ◽  
David C. Gosselin ◽  
...  
Keyword(s):  
Water Level ◽  
Lake Water ◽  
Groundwater Level ◽  
Lake Water Level ◽  
Nebraska Sand Hills ◽  
Sand Hills

scholarly journals Proglacial river dataset from the Akuliarusiarsuup Kuua River northern tributary, Southwest Greenland, 2008–2010

2011 ◽  
Vol 4 (1) ◽  
pp. 71-97 ◽  
Author(s):  
A. K. Rennermalm ◽  
L. C. Smith ◽  
V. W. Chu ◽  
R. R. Forster ◽  
J. E. Box ◽  
...  
Keyword(s):  
Water Level ◽  
Statistical Tests ◽  
Ice Sheet ◽  
High Water ◽  
Stream Channels ◽  
Discharge Data ◽  
Lake Water Level ◽  
Considerable Uncertainty ◽  
Added Uncertainty ◽  
Southwest Greenland

Abstract. Pressing scientific questions concerning the Greenland ice sheet's climatic sensitivity, hydrology, and contributions to current and future sea level rise require hydrological datasets to resolve. While direct observations of ice sheet meltwater losses can be obtained in terrestrial rivers draining the ice sheet and from lake levels, few such datasets exist. We present a new dataset of meltwater river discharge for the vicinity of Kangerlussuaq, Southwest Greenland. The dataset contains measurements of river water level and discharge for three sites along the Akuliarusiarsuup Kuua (Watson) River's northern tributary, with 30 min temporal resolution between June 2008 and August 2010. Additional data of water temperature, air pressure, and lake water level and temperature are also provided. Discharge data were measured at sites with near-ideal properties for such data collection. Regardless, high water bedload and turbulent flow introduce considerable uncertainty. These were constrained and quantified using statistical techniques, which revealed that the greatest discharge data uncertainties are associated with streambed elevation change and measurements. Large portions of stream channels deepened according to statistical tests, but poor precision of streambed depth measurements also added uncertainty. Data will periodically be extended, and are available in Open Access at doi:10.1594/PANGAEA.762818.

scholarly journals Evaluation of historic and operational satellite radar altimetry missions for constructing consistent long-term lake water level records

2021 ◽  
Vol 25 (3) ◽  
pp. 1643-1670
Author(s):  
Song Shu ◽  
Hongxing Liu ◽  
Richard A. Beck ◽  
Frédéric Frappart ◽  
Johanna Korhonen ◽  
...  
Keyword(s):  
Water Level ◽  
Lake Water ◽  
Small Lakes ◽  
Radar Altimetry ◽  
Lake Water Level ◽  
Systematic Biases ◽  
Data Missing ◽  
Satellite Radar ◽  
Satellite Radar Altimetry

Abstract. A total of 13 satellite missions have been launched since 1985, with different types of radar altimeters on board. This study intends to make a comprehensive evaluation of historic and currently operational satellite radar altimetry missions for lake water level retrieval over the same set of lakes and to develop a strategy for constructing consistent long-term water level records for inland lakes at global scale. The lake water level estimates produced by different retracking algorithms (retrackers) of the satellite missions were compared with the gauge measurements over 12 lakes in four countries. The performance of each retracker was assessed in terms of the data missing rate, the correlation coefficient r, the bias, and the root mean square error (RMSE) between the altimetry-derived lake water level estimates and the concurrent gauge measurements. The results show that the model-free retrackers (e.g., OCOG/Ice-1/Ice) outperform the model-based retrackers for most of the missions, particularly over small lakes. Among the satellite altimetry missions, Sentinel-3 gave the best results, followed by SARAL. ENVISAT has slightly better lake water level estimates than Jason-1 and Jason-2, but its data missing rate is higher. For small lakes, ERS-1 and ERS-2 missions provided more accurate lake water level estimates than the TOPEX/Poseidon mission. In contrast, for large lakes, TOPEX/Poseidon is a better option due to its lower data missing rate and shorter repeat cycle. GeoSat and GeoSat Follow-On (GFO) both have an extremely high data missing rate of lake water level estimates. Although several contemporary radar altimetry missions provide more accurate lake level estimates than GFO, GeoSat was the sole radar altimetry mission, between 1985 and 1990, that provided the lake water level estimates. With a full consideration of the performance and the operational duration, the best strategy for constructing long-term lake water level records should be a two-step bias correction and normalization procedure. In the first step, use Jason-2 as the initial reference to estimate the systematic biases with TOPEX/Poseidon, Jason-1, and Jason-3 and then normalize them to form a consistent TOPEX/Poseidon–Jason series. Then, use the TOPEX/Poseidon–Jason series as the reference to estimate and remove systematic biases with other radar altimetry missions to construct consistent long-term lake water level series for ungauged lakes.

scholarly journals Distribution of Flood Risk Area in Bodri Watershed of Kendal Regency

2021 ◽  
Vol 6 (2) ◽  
pp. 59-69
Author(s):  
Husna Fauzia ◽  
◽  
Eka Cahyaningsih ◽  
Hery Hariyanto ◽  
Satya Nugraha ◽  
...  
Keyword(s):  
Land Use ◽  
Spatial Modeling ◽  
Flood Risk ◽  
Flood Hazard ◽  
Risk Level ◽  
Flood Hazards ◽  
Risk Area ◽  
Flood Peak ◽  
Risk Levels ◽  
Central Java

Flooding is a catastrophic phenomenon that can occur due to various factors, such as uncontrolled landuse changes, climate change, and weather anomalies, and drainage infrastructure damage. The Bodri watershed in Kendal Regency is one of the watersheds in Central Java, which is categorized as critical based on Decree No.328/Menhut-II/2009. Some of the problems in the Bodri watershed include land use that is not suitable for its designation, flooding, erosion, and landslides. This study aims to conduct spatial modeling to create flood hazard maps and flood risk level maps in the Bodri watershed. The method used is hydrograph analysis, flood modeling, potential flood hazards, and flood risk levels. Analysis of the potential for flood hazards from the spatial modeling inundation map with the input of the flood peak return period of 2 years (Q2), 5 years (Q5), and 50 years (Q50). Vulnerability analysis based on land use maps of flood hazard areas. The distribution of flood-prone areas in the Bodri watershed is in Pidodo Kulon Village, Pidodo Wetan Village, and Bangunsari Village.

scholarly journals Failure of Zoned Earth Dam (An analysis of earth dam break)

2019 ◽  
Vol 27 (1) ◽  
pp. 344-353
Author(s):  
Abdul-Hassan K. Al-Shukur ◽  
Ranya Badea’ Mahmoud
Keyword(s):  
Water Level ◽  
Factor Of Safety ◽  
Limit Equilibrium ◽  
Water Flux ◽  
Dam Break ◽  
The Body ◽  
Earth Dam ◽  
Dam Failure ◽  
Maximum Water Level ◽  
Maximum Water

One of the most common type of embankment dam failure is the dam-break due to overtopping. In this study, the finite elements method has been used to analyze seepage and limit equilibrium method to study stability of the body of an earthfill dam during the flood condition. For this purpose, the software Geostudio 2012 is used through its subprograms SEEP/W and SLOPE/W. Al-Adhaim dam in Iraq has been chosen to analysis the 5 days of flood. It was found that the water flux of seepage during the flood reaches about 8.772*10-5. m3/sec when the water level 146.5 m at 2nd day. Seepage through the embankment at maximum water level increased by 55.1 % from maximum water level. It was concluded that the factor of safety against sliding in downstream side decrease with increasing water level and vice versa. It was also concluded that the deposits are getting more critical stability during the conditions of flood when the factor of safety value reaches 1.219 at 2nd day.

Lake water level response to drought in a lake-rich region explained by lake and landscape characteristics

2020 ◽  
Vol 77 (11) ◽  
pp. 1836-1845
Author(s):  
K. Martin Perales ◽  
Catherine L. Hein ◽  
Noah R. Lottig ◽  
M. Jake Vander Zanden
Keyword(s):  
Climate Change ◽  
Water Level ◽  
Lake Water ◽  
Water Levels ◽  
Water Level Fluctuations ◽  
Lake Area ◽  
Lake Water Level ◽  
Landscape Characteristics ◽  
Lake Ecology ◽  
Coarse Woody Habitat

Climate change is altering hydrologic regimes, with implications for lake water levels. While lakes within lake districts experience the same climate, lakes may exhibit differential climate vulnerability regarding water level response to drought. We took advantage of a recent drought (∼2005–2010) and estimated changes in lake area, water level, and shoreline position on 47 lakes in northern Wisconsin using high-resolution orthoimagery and hypsographic curves. We developed a model predicting water level response to drought to identify characteristics of the most vulnerable lakes in the region, which indicated that low-conductivity seepage lakes found high in the landscape, with little surrounding wetland and highly permeable soils, showed the greatest water level declines. To explore potential changes in the littoral zone, we estimated coarse woody habitat (CWH) loss during the drought and found that drainage lakes lost 0.8% CWH while seepage lakes were disproportionately impacted, with a mean loss of 40% CWH. Characterizing how lakes and lake districts respond to drought will further our understanding of how climate change may alter lake ecology via water level fluctuations.

scholarly journals Bathymetry Development and Flow Analyses Using Two-Dimensional Numerical Modeling Approach for Lake Victoria

Fluids ◽  
2019 ◽  
Vol 4 (4) ◽  
pp. 182 ◽  
Author(s):  
Seema Paul ◽  
Jesper Oppelstrup ◽  
Roger Thunvik ◽  
John Mango Magero ◽  
David Ddumba Walakira ◽  
...  
Keyword(s):  
Water Level ◽  
Lake Water ◽  
Lake Victoria ◽  
State Level ◽  
Linear Measurement ◽  
Two Dimensional ◽  
Mean Flow ◽  
Lake Water Level ◽  
Outflow Boundary Condition ◽  
Outflow Boundary

This study explored two-dimensional (2D) numerical hydrodynamic model simulations of Lake Victoria. Several methods were developed in Matlab to build the lake topography. Old depth soundings taken in smaller parts of the lake were combined with more recent extensive data to produce a smooth topographical model. The lake free surface numerical model in the COMSOL Multiphysics (CM) software was implemented using bathymetry and vertically integrated 2D shallow water equations. Validated by measurements of mean lake water level, the model predicted very low mean flow speeds and was thus close to being linear and time invariant, allowing long-time simulations with low-pass filtered inflow data. An outflow boundary condition allowed an accurate simulation to achieve the lake’s steady state level. The numerical accuracy of the linear measurement of lake water level was excellent.

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