scholarly journals Modeling of the Geological Probability Procedure for the Prediction of High Flows in Small Streams, Case Study of Medvednica Mt., Croatia

Hydrology ◽  
2021 ◽  
Vol 8 (2) ◽  
pp. 83
Author(s):  
Vedran Sudar ◽  
Tomislav Malvić ◽  
Tatjana Vujnović ◽  
Josip Ivšinović
Keyword(s):  
Water Waves ◽  
Soil Depth ◽  
Water Levels ◽  
Probability Method ◽  
Total Precipitation ◽  
Entire Area ◽  
Small Streams ◽  
Precipitation Total ◽  
Small Basin

Floods are defined by maximum water levels or flow of high-water waves. Here, we defined the deterministic method for the calculation of the probability of a high discharge event, named as the Probability Of Success (POS). The POS method previously developed for petroleum subsurface systems has been modified for the surface hydrological system with the purpose of flood prediction. The case study of this research is the small basin of Kašina Stream on Medvednica Mt. (NW Croatia). The data are obtained upstream from the hydrological station Gornja Kašina. The POS model is defined by four categories. Each geological category is described with accompanied events and probabilities. Floods are defined by four categories: total precipitation, total water flow, basement, and maximal water capacity in soil. The categories total precipitation and basement were divided into two sub-categories each: quantity and duration; porosity and soil depth. Data are collected for a hydrometeorological event, namely an intensive convective storm on 24–25 July 2020, when Zagreb was locally hit by heavy urban floods. The presented probability method yielded a probability of 1.76% that such an event could happen to the station. However, the flooding was not recorded. A comparison of the real event and the predicted probability supported the adequacy and applicability of the method, showing it has high reliability. The presented probability model could be easily applied, with small modifications, to the entire area of Northern Croatia for the prediction of small basin flooding events.

scholarly journals The Effects of Hydraulic Jumps Instability on a Natural River Confluence: The Case Study of the Chiaravagna River (Italy)

Water ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 2027 ◽  
Author(s):  
Annalisa De Leo ◽  
Alessia Ruffini ◽  
Matteo Postacchini ◽  
Marco Colombini ◽  
Alessandro Stocchino
Keyword(s):  
Physical Model ◽  
Hydraulic Jump ◽  
Low Frequency ◽  
Water Levels ◽  
Entire Area ◽  
Hydraulic Conditions ◽  
River Confluence ◽  
Series Of Experiments ◽  
Small River Basin

The occurrence and the effects of hydraulic jump instabilities on a natural river confluence in a small river basin in Liguria (Italy) is here investigated. Hydraulic jump instability has been extensively studied in controlled and simplified laboratory rectangular flumes. In the present study, a scaled physical model of the Chiaravagna River and Ruscarolo Creek confluence has been used, retaining the realistic geometry of the reaches. This reach has been subject to frequent floods in the last twenty years and the entire area of the confluence has been redesigned to decrease the flood risk. A series of experiments has been performed varying the discharge on the two reaches and the geometrical configurations. Free surface levels and two dimensional horizontal velocities have been measured in several positions along the physical model. The analysis of the water levels and velocities reveals that oscillations characterised by large amplitude and low frequency occur under particular hydraulic conditions. These oscillations have been found to be triggered by the hydraulic jump toe instability of the smallest reach of the confluence. Aiming at reducing the amplitude of the oscillations, which can be of the order of the flow depth, possible constructive solutions have been tested to control or damp the oscillations. Indeed, the insertion of a longitudinal dyke at the confluence has proven to be an effective solution to limit the amplitude of the transversal oscillations.

Site Suitability Analysis for Water Conservation Using AHP and GIS Techniques: A Case Study of Upper Sina River Catchment, Ahmednagar (India)

2020 ◽  
Vol 3 (2) ◽  
pp. 49-59 ◽  
Author(s):  
Yogesh Badhe ◽  
Ravindra Medhe ◽  
Tushar Shelar
Keyword(s):  
Water Conservation ◽  
Soil Depth ◽  
Land Use Land Cover ◽  
Suitability Analysis ◽  
Site Suitability ◽  
Gis Techniques ◽  
Multi Criteria Evaluation ◽  
Conservation Activity ◽  
Suitable Site

The site suitability for construction of water conservation structures is an important step towards groundwater conservation in arid and semi-arid regions. Water is the most crucial for maintaining an environment and ecosystem which is helpful to sustaining all forms of the life. The increasing water scarcity day to day has been one of the common problems over a period of time. On top of it, when the area is a part of rain shadow zone like Ahmednagar district, water conservation activities are become more important. The present study aims to identify the suitable zones for water conservation activity. Multi- criteria evaluation is carried out using Geographic Information System (GIS) techniques to help the choice makers in defining suitable site for construction of water conservation structures. Different layers which were considered for multi-criteria evaluation: slope, land use land cover, soil texture, lithology, soil depth, soil erosion, wells, lineaments and drainage network. Analytical Hierarchy Processes (AHP) is used for weighted sum to find suitable sites for implementation of water conservation activity using selected criterions. The site suitability map was classified into four classes: highly suitable, moderately suitable, less suitable and not suitable with area of 19.19%, 26%, 49.03% and 5.78, respectively. This map will help for selection of suitable sites for construction of Mati Nala Bund (MNB), Check Dam, Cement Nala Bund (CNB) and Continuous Contour Trenches (CCT) for conservation of groundwater resource in the region.

scholarly journals Investigation into the Cause of Iron-Related Clogging of Groundwater Bores Used for Viticulture in the Limestone Coast, South Australia

Water ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 683
Author(s):  
Birte Moser ◽  
Meruyert Beknazarova ◽  
Harriet Whiley ◽  
Thilini Piushani Keerthirathne ◽  
Nikki Harrington ◽  
...  
Keyword(s):  
Groundwater Resources ◽  
South Australia ◽  
Water Levels ◽  
Clear Correlation ◽  
Problem Analysis ◽  
Persistent Problem ◽  
Root Cause ◽  
Complex Interactions ◽  
Iron Manganese

Iron-related clogging of boreholes, pumps and dripper lines is a significant and costly problem for irrigators worldwide. The primary cause of iron-related clogging is still debated. Previous studies have described complex interactions between biological clogging and inorganic iron/manganese oxide precipitation. This case study examined groundwater bores used for viticulture irrigation in the Limestone Coast region, a highly productive wine growing area in the SE of South Australia. Iron clogging of bore screens, pumps and dripper systems has been a persistent problem in the region and the issue is perceived to be growing, with irrigators suggesting the widespread introduction of iron-related bacteria (IRB) through drilling equipment to be the root cause of the problem. Analysis of the groundwater microbiology and inorganic chemistry found no apparent correlation between the presence of IRB and the clogging status of wells. In fact, IRB proved to be widespread throughout the limestone aquifer. However, a clear correlation could be found between clogging affected bores and the redox potential of the groundwater with the most severely affected bores strongly oversaturated in respect to iron oxide minerals. Elevated dissolved concentrations of Fe(II) thereby tended to be found in deeper bores, which also were generally more recently drilled. Following decades of less than average rainfall, a tendency to deepen bores in response to widespread declines in water levels has been documented for the SE of South Australia. The gradually widening clogging problem in the region is postulated to be related to the changes in climate in the region, with irrigators increasingly driven to rely on deeper, anoxic iron-rich groundwater resources.

scholarly journals Rainfall Threshold for Flash Flood Warning Based on Model Output of Soil Moisture: Case Study Wernersbach, Germany

Water ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1061
Author(s):  
Thanh Thi Luong ◽  
Judith Pöschmann ◽  
Rico Kronenberg ◽  
Christian Bernhofer
Keyword(s):  
Soil Moisture ◽  
Flash Flood ◽  
Rainfall Threshold ◽  
Probability Of Detection ◽  
Water Levels ◽  
Critical Success ◽  
Flood Warning ◽  
Critical Discharge ◽  
Critical Success Index

Convective rainfall can cause dangerous flash floods within less than six hours. Thus, simple approaches are required for issuing quick warnings. The flash flood guidance (FFG) approach pre-calculates rainfall levels (thresholds) potentially causing critical water levels for a specific catchment. Afterwards, only rainfall and soil moisture information are required to issue warnings. This study applied the principle of FFG to the Wernersbach Catchment (Germany) with excellent data coverage using the BROOK90 water budget model. The rainfall thresholds were determined for durations of 1 to 24 h, by running BROOK90 in “inverse” mode, identifying rainfall values for each duration that led to exceedance of critical discharge (fixed value). After calibrating the model based on its runoff, we ran it in hourly mode with four precipitation types and various levels of initial soil moisture for the period 1996–2010. The rainfall threshold curves showed a very high probability of detection (POD) of 91% for the 40 extracted flash flood events in the study period, however, the false alarm rate (FAR) of 56% and the critical success index (CSI) of 42% should be improved in further studies. The proposed adjusted FFG approach has the potential to provide reliable support in flash flood forecasting.

COMPUTATION OF KARL PEARSON'S COEFFICIENT OF SKEWNESS AND BOWLEY'S COEFFICIENT OF SKEWNESS BETWEEN RAINFALLAND GROUND WATER LEVELS - A CASE STUDY

2021 ◽  
pp. 13-14
Author(s):  
Raju Sake
Keyword(s):  
Ground Water ◽  
Water Levels ◽  
Coefficient Of Skewness

Present paper deals with the Computation of Karl Pearson's Coefcient of Skewness (SK ) and Bowley's Coefcient of Skewness (SK ) to analyze P B Rainfall (RF) and Ground Water Levels (GWLs) in Anantapuramu district based on the data collected from January 2007 to December 2016. For the purpose of analysis the district is divided into ve Zones or Revenue Divisions (RD) namely, 1. Anantapuramu RD 2. Penukonda RD 3. Kadiri RD 4. Kalyandurg RD 5. Dharmavaram RD. I have calculated for the Karl Pearson's Coefcient of Skewness (SK ) and Bowley's Coefcient of P Skewness (SK ) between Rainfall and Ground Water Levels and compared among them by using the data.

scholarly journals An objective and efficient method for estimating probabilistic coastal inundation hazards

2019 ◽  
Vol 99 (2) ◽  
pp. 1105-1130 ◽  
Author(s):  
Kun Yang ◽  
Vladimir Paramygin ◽  
Y. Peter Sheng
Keyword(s):  
High Resolution ◽  
Storm Surge ◽  
Computational Cost ◽  
Joint Probability ◽  
Water Levels ◽  
Computational Time ◽  
Probability Method ◽  
Highly Efficient ◽  
Inundation Maps ◽  
Flood Elevation

Abstract The joint probability method (JPM) is the traditional way to determine the base flood elevation due to storm surge, and it usually requires simulation of storm surge response from tens of thousands of synthetic storms. The simulated storm surge is combined with probabilistic storm rates to create flood maps with various return periods. However, the map production requires enormous computational cost if state-of-the-art hydrodynamic models with high-resolution numerical grids are used; hence, optimal sampling (JPM-OS) with a small number of (~ 100–200) optimal (representative) storms is preferred. This paper presents a significantly improved JPM-OS, where a small number of optimal storms are objectively selected, and simulated storm surge responses of tens of thousands of storms are accurately interpolated from those for the optimal storms using a highly efficient kriging surrogate model. This study focuses on Southwest Florida and considers ~ 150 optimal storms that are selected based on simulations using either the low fidelity (with low resolution and simple physics) SLOSH model or the high fidelity (with high resolution and comprehensive physics) CH3D model. Surge responses to the optimal storms are simulated using both SLOSH and CH3D, and the flood elevations are calculated using JPM-OS with highly efficient kriging interpolations. For verification, the probabilistic inundation maps are compared to those obtained by the traditional JPM and variations of JPM-OS that employ different interpolation schemes, and computed probabilistic water levels are compared to those calculated by historical storm methods. The inundation maps obtained with the JPM-OS differ less than 10% from those obtained with JPM for 20,625 storms, with only 4% of the computational time.

scholarly journals Real-Time Hydraulic Interval State Estimation for Water Transport Networks: a Case Study

2017 ◽  
Author(s):  
Stelios G. Vrachimis ◽  
Demetrios G. Eliades ◽  
Marios M. Polycarpou
Keyword(s):  
State Estimation ◽  
Real Time ◽  
Water Distribution ◽  
Estimation Error ◽  
Distribution Networks ◽  
Water Levels ◽  
Water Distribution Networks ◽  
Unaccounted For Water ◽  
Tank Water

Abstract. Hydraulic state estimation in water distribution networks is the task of estimating water flows and pressures in the pipes and nodes of the network based on some sensor measurements. This requires a model of the network, as well as knowledge of demand outflow and tank water levels. Due to modeling and measurement uncertainty, standard state-estimation may result in inaccurate hydraulic estimates without any measure of the estimation error. This paper describes a methodology for generating hydraulic state bounding estimates based on interval bounds on the parametric and measurement uncertainties. The estimation error bounds provided by this method can be applied to estimate the unaccounted-for water in water distribution networks. As a case study, the method is applied to a transport network in Cyprus, using actual data in real-time.

scholarly journals IDENTIFIKASI SPESIES BEGONIA LITOFIT DI KABUPATEN BENGKAYANG KALIMANTAN BARAT

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Hasri Nurfadillah Rahyu Ningsih ◽  
Siti Masitoh Kartikawati ◽  
Muflihati Muflihati
Keyword(s):  
Entire Area ◽  
River Bank ◽  
Small Streams ◽  
Granite Rocks ◽  
Observation Path

Begonia is a plant from the flowering tribe of Begoniaceae which still has not revealed much diversity and potential. Begonia recorded in Borneo includes Brunei 21 species, Kalimantan 5 species, Sabah 82 species and Sarawak 96 species. Generally begonias are found in calcareous rocks also in sandy and granite rocks. Begonia can also be found around waterfalls or small streams. Begonia grows from lowlands to hilly forests. This study aims to identify the Begonia genus in Bengkayang Districts. This study uses an exploratory method by exploring the entire area from corner to corner by using the length of the observation path from the river bank to the height level representing ecosystems and vegetation on the location studied. Result of research there are species of Begonia serianensis C. W. Lin & C.-I Peng., Begonia promethea Ridl. Begonia calcarea Ridl., Begonia bawangensis Hughes. sp. nov. (in prep.) dan Begonia magnicarpa C.W.Lin & C. I Peng.Keywords: Bengkayang District, Identification, Litophyte Begonia.Begonia merupakan tumbuhan berbunga Begoniaceae yang masih belum banyak terungkap keanekaragaman dan potensinya. Begonia yang terdata di Borneo meliputi Brunei 21 spesies, Kalimantan 5 spesies, Sabah 82 spesies dan Sarawak 96 spesies. Umumnya begonia terdapat pada batuan berkapur juga di batuan berpasir dan granit. Begonia juga dapat ditemukan di sekitar air terjun atau aliran air kecil. Begonia tumbuh dari dataran rendah hingga hutan perbukitan. Penelitian ini bertujuan untuk mengidentifikasi spesies dari genus Begonia yang ada di Kabupaten Bengkayang. Penelitian ini menggunakan metode eksplorasi dengan menjelajah seluruh kawasan dari sudut ke sudut dengan mengunakan panjang jalur pengamatan baik dari tepi sungai sampai pada tingkat ketinggian yang dapat mewakili ekosistem maupun vegetasi pada lokasi yang diteliti. Hasil penelitian terdapat lima spesies, yaitu Begonia serianensis C. W. Lin & C.-I Peng., Begonia promethea Ridl. Begonia calcarea Ridl., Begonia bawangensis Hughes. sp. nov. (in prep.) dan Begonia magnicarpa C.W.Lin & C. I Peng.Kata kunci: Begonia litofit, Identifikasi, Kabupaten Bengkayang.

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