scholarly journals Flood Control Versus Water Conservation in Reservoirs: A New Policy to Allocate Available Storage

Water ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 994
Author(s):  
Ivan Gabriel-Martin ◽  
Alvaro Sordo-Ward ◽  
David Santillán ◽  
Luis Garrote
Keyword(s):  
Return Period ◽  
Water Conservation ◽  
Flood Control ◽  
Global Optimum ◽  
Joint Optimization ◽  
Reservoir Level ◽  
Extreme Flood ◽  
Control Versus ◽  
Hydrological Safety ◽  
Reservoir Yield

The aim of this study is to contribute to solving conflicts that arise in the operation of multipurpose reservoirs when determining maximum conservation levels (MCLs). The specification of MCLs in reservoirs that are operated for water supply and flood control may imply a reduction in the volume of water supplied with a pre-defined reliability in the system. The procedure presented in this study consists of the joint optimization of the reservoir yield with a specific reliability subject to constraints imposed by hydrological dam safety and downstream river safety. We analyzed two different scenarios by considering constant or variable initial reservoir level prior to extreme flood events. In order to achieve the global optimum configuration of MCLs for each season, we propose the joint optimization of three variables: minimize the maximum reservoir level (return period of 1000 years), minimize the maximum released outflow (return period of 500 years) and maximize the reservoir yield with 90% reliability. We applied the methodology to Riaño Dam, jointly operated for irrigation and flood control. Improvements in the maximum reservoir yield (with 90% reliability) increased up to 10.1% with respect to the currently supplied annual demand (545 hm3) for the same level of dam and downstream hydrological safety. The improvement could increase up to 26.8% when compared to deterministic procedures. Moreover, dam stakeholders can select from a set of Pareto-optimal configurations depending on if their main emphasis is to maintain/increase the hydrological safety, or rather to maintain/increase the reservoir yield.

Sewer System for Improving Flood Control in Tokyo: A Step towards a Return Period of 70 Years

1994 ◽  
Vol 29 (1-2) ◽  
pp. 303-310 ◽  
Author(s):  
Kazuyuki Higuchi ◽  
Masahiro Maeda ◽  
Yasuyuki Shintani
Keyword(s):  
Return Period ◽  
Flood Control ◽  
Rainfall Intensity ◽  
Runoff Coefficient ◽  
Large Drop ◽  
Construction Costs ◽  
Sewer System ◽  
Construction Period ◽  
Metropolitan Government ◽  
Under Construction

The Tokyo Metropolitan Government has planned future flood control for a rainfall intensity of 100 mm/hr, which corresponds to a return period of 70 years, and a runoff coefficient of 0.8. Considering that the realization of this plan requires a long construction period and high construction costs, the decision was made to proceed by stages. In the first stage, the improvement of the facilities will be based on a rainfall intensity of 75 mm/hr (presently 50 mm/hr), corresponding to a return period of 17 years, and a runoff coefficient of 0.8. In the next stage the facilities will be improved to accommodate a rainfall intensity of 100 mm/hr. In the Nakano and Suginami regions, which suffer frequently from flooding, the plan of improvement based on a rainfall intensity of 75 mm/hr is being implemented before other areas. This facility will be used as a storage sewer for the time being. The Wada-Yayoi Trunk Sewer, as a project of this plan, will have a diameter of 8 m and a 50 m earth cover. This trunk sewer will be constructed considering several constraints. To resolve these problems, hydraulic experiments as well as an inventory study have been carried out. A large drop shaft for the trunk sewer is under construction.

scholarly journals Evaluation of flood risk as a step in determining the “Acceptable Risk” criteria. Case study: Dengkeng River, Klaten, Central Java

2021 ◽  
Vol 894 (1) ◽  
pp. 012045
Author(s):  
A Sarminingsih ◽  
M Hadiwidodo
Keyword(s):  
Control System ◽  
Return Period ◽  
Flood Risk ◽  
Flood Control ◽  
Public Works ◽  
Acceptable Risk ◽  
Performance Function ◽  
Central Java ◽  
Flood Discharge ◽  
Potential Risks

Abstract The planning of a flood control system in Indonesia is based on the planning criteria issued by the Ministry of Public Works. Flood control planning is based on flood discharge with a specific return period depending on the order of the river and the number of protected populations. Flood events in areas where the flood control system has been planned continue to occur almost every year, meaning that the probability of being exceeded is not as planned. This study is intended to evaluate the criteria for the magnitude of the designed flood discharge in flood control planning that considers the acceptable risk. Potential risks are evaluated against system reliability. The probability of failure of the flood control system occurs if the resistance is smaller than the load expressed as a performance function. By knowing the performance function associated with the level of flood risk, then the flood discharge can be selected with the appropriate return period according to the acceptable risk.

scholarly journals Hydro-meteorological characteristics and occurrence probability of extreme flood events in Moroccan High Atlas

2020 ◽  
Vol 11 (S1) ◽  
pp. 310-321 ◽  
Author(s):  
Mohamed El Mehdi Saidi ◽  
Tarik Saouabe ◽  
Abdelhafid El Alaoui El Fels ◽  
El Mahdi El Khalki ◽  
Abdessamad Hadri
Keyword(s):  
Return Period ◽  
Peak Flow ◽  
Extreme Event ◽  
Rare Event ◽  
Flood Frequency ◽  
Flood Frequency Analysis ◽  
High Atlas ◽  
Flood Water ◽  
Extreme Flood ◽  
Water Volumes

Abstract Flood frequency analysis could be a tool to help decision-makers to size hydraulic structures. To this end, this article aims to compare two analysis methods to see how rare an extreme hydrometeorological event is, and what could be its return period. This event caused many deadly floods in southwestern Morocco. It was the result of unusual atmospheric conditions, characterized by a very low atmospheric pressure off the Moroccan coast and the passage of the jet stream further south. Assessment of frequency and return period of this extreme event is performed in a High Atlas watershed (the Ghdat Wadi) using historical floods. We took into account, on the one hand, flood peak flows and, on the other hand, flood water volumes. Statistically, both parameters are better adjusted respectively to Gamma and Log Normal distributions. However, the peak flow approach underestimates the return period of long-duration hydrographs that do not have a high peak flow, like the 2014 event. The latter is indeed better evaluated, as a rare event, by taking into account the flood water volumes. Therefore, this parameter should not be omitted in the calculation of flood probabilities for watershed management and the sizing of flood protection infrastructure.

scholarly journals The Influence of Eco-water Retrieved by Quantitative Remote Sensing on Runoff in Upper Minjiang River Basin

2016 ◽  
Vol 20 (3) ◽  
pp. 1 ◽  
Author(s):  
Jin Huang ◽  
Wunian Yang ◽  
Wunian Yang ◽  
Xin Yang ◽  
Xin Yang ◽  
...  
Keyword(s):  
Remote Sensing ◽  
River Basin ◽  
Water Conservation ◽  
Quantitative Research ◽  
Flood Control ◽  
Water Layer ◽  
Climate Data ◽  
Minjiang River ◽  
Quantitative Remote Sensing ◽  
Del Rio

Remote sensing quantitative retrieval of ecological water (eco-water) has been foundational in systemic and quantitative research for water resources. Eco-water resource levels indicate conservation ability for the eco-water layer and influence of this on precipitation transformation and runoff regulation. The remote sensing quantitative inversion retrieved the MEC (Modulus of eco-water Conservation) of the Upper Minjiang River Basin study area in 1994 and 2001, and combined with climate data between 1990 and 2005, the influence of conservation water on the eco-water layer on runoff was then analyzed. Results revealed significant efficacy for flood control and water supply during the drought from the hydrologic cycle of ecowater. Thus protection and restoration of the eco-water layer for flood and drought prevention are crucial.  Influencia del agua ecológica en la escorrentía de la cuenca alta del río Minjiang medida a través de teledetección cuantitativa ResumenEl sondeo remoto del agua ecológica (del inglés Eco-water, agua conservada en la superficie terrestre) es indispensable en la investigación sistemática y cuantitativa de las fuentes de agua. Los niveles de suministros de agua ecológica indican la capacidad de conservación de la capa de agua ecológica y la influencia de esta en la transformación de precipitación y la regulación de escorrentía. La inversión cuantitativa por sondeo remoto estableció el Módulo de Conservación de Agua Ecológica (MEC, del inglés Modulus of Eco-Water Conservation) para el área de estudio en la cuenca alta del río Minjiang entre 1994 y 2001, y combinada con la información climática de entre 1990 y 2005, se analizó la influencia de conservacion de agua en la capa ecoacuática. Los resultados mostraron una gran eficacia en el control de inundaciones y en el suministro de agua durante la sequía a lo largo del ciclo hidrológico. Por esta razón, la protección y restauración de la capa de agua ecológica para la prevención de inundaciones y sequía es necesaria.

scholarly journals Study of Flood and Coastal Flood Control in Madukoro Area, Semarang City, Indonesia

2018 ◽  
Vol 4 (3) ◽  
pp. 189
Author(s):  
Dian Wahyu Jatmiko
Keyword(s):  
Water Level ◽  
Land Subsidence ◽  
Return Period ◽  
Flood Control ◽  
High Tide ◽  
Northern Coast ◽  
Flood Peak ◽  
Runoff Volume ◽  
Total Runoff ◽  
Drainage Channels

Madukoro area located on the northern coast of Semarang City has been prone to flooding caused by rainfall and seawater high-tide. Ineffective flood control management and land subsidence are considered as the cause of this problem. In order to understand land subsidence effect and flood control performance, location, water surface height of the inundation in West Flood Canal, western part of Madukoro area need to analyze. Flood analysis was conducted using HEC-HMS software and rational method. Flow hydraulics on five channels, i.e. the West Flood Canal, Ronggolawe River, Karangayu River, Arterial Channel and Madukoro were analyzed using HEC-RAS software. Increasing levee level and additional water pumps in Madukoro and Ronggolawe were chosen as flood control alternatives. Its performance was investigated through software simulation. The results showed total runoff volume in all drainage channels for 2-years return period discharge was about 80% of capacity with 0.7 m water depth. Runoff volume in West Flood Canal with 50-years return period discharge was about 40%. Land subsidence 4 cm/year affected the water level increase on West Flood Canal. Operation of 2 - 4 pump units could not significantly decrease water level at flood peak, yet increase flood recession time 6 - 8 hours. 

scholarly journals Predictive Performance Analysis of PDF – IDF Model Types Using Rainfall Observations from Fourteen Gauged Stations

2021 ◽  
pp. 125-143
Author(s):  
Ify L. Nwaogazie ◽  
M. G. Sam ◽  
A. O. David
Keyword(s):  
Return Period ◽  
Flood Control ◽  
Goodness Of Fit ◽  
Rainfall Intensity ◽  
Model Development ◽  
Predictive Performance ◽  
Specific Model ◽  
Data Set ◽  
Pearson Type ◽  
Significant Difference

The design of structures for flood mitigation depends on the adequate estimation of rainfall intensity over a given catchment which is achieved by the rainfall intensity duration frequency modelling. In this study, an extensive comparative analyses were carried out on the predictive performance of three PDF – IDF model types, namely: Gumbel Extreme Value Type 1 (GEVT – 1), Log-Pearson Type 3 (LPT – 3) and Normal Distribution (ND) in 14 selected cities in Southern Nigeria. This is to rank the order of best performance. The principle of general model development was adopted in which rainfall intensities at different durations and specified return periods were used as input data set. This is not same as return period specific model that involves rainfall intensities for various durations and a given return period. The predicted rainfall intensity values with the PDF – IDF model types indicate high goodness of fit (R2) and Mean Squared Errors (MSE) ranging from: (a) R2 = 0.875 – 0.992; MSE = 33.17 – 224.6 for GEVT – 1; (b) R2 = 0.849 – 0.990; MSE = 65.34 – 405.5 for LPT – 3 and (c) R2 = 0.839 – 0.992; MSE = 29.23 – 200.2 for ND. The comparative analysis of all the 42 general models (14 locations versus 3 model types) considered showed that the order of best performance is LPT – 3 1st, GEVT - 1 2nd and ND 3rd for each return period (10, 50 and 100 years). The Kruskal Wallis test of significance indicates that no significant difference exists in the predictive performance of the three General models across the board. This may be due to the fact that the fourteen locations of the study area are bordering with the Atlantic Ocean and seems to have similar climatology. These developed General models are recommended for the computation of intensities in the fourteen locations for the design of flood control structures; and the order of preference should be LPT – 3 > GEVT – 1 > ND.

Water Law in India

2018 ◽  
Keyword(s):  
Water Conservation ◽  
Flood Control ◽  
State Level ◽  
Water Law ◽  
Critical Gap ◽  
Rural Employment ◽  
Diverse Field ◽  
Comprehensive Survey ◽  
Employment Legislation ◽  
New Instruments

First published in 2011, Water Law in India is the only book to offer a comprehensive survey of the legal instruments concerning water in India. It presents a variety of national and state-level instruments that make up the complex and diverse field of water law and policy. This book fills a critical gap in the study of water law, providing a rich reference point for the entire gamut of legal mechanisms available in India. This edition has been extensively revised to include new instruments on water regulation, such as the draft National Water Framework Bill, 2016, and the Model Groundwater (Sustainable Management) Act, 2016; new water-related instruments in such varied fields as criminal law, land acquisition law, and rural employment legislation; and a chapter on international legal instruments. Chapters on drinking water supply, environmental dimensions of water conservation, water infrastructure for irrigation and flood control, groundwater regulation, and institutions catering to water have been thoroughly updated for a complete coverage of water law.

scholarly journals Flood frequency analysis supported by the largest historical flood

2014 ◽  
Vol 14 (6) ◽  
pp. 1543-1551 ◽  
Author(s):  
W. G. Strupczewski ◽  
K. Kochanek ◽  
E. Bogdanowicz
Keyword(s):  
Return Period ◽  
Historical Record ◽  
Flood Frequency ◽  
Flood Frequency Analysis ◽  
Historical Period ◽  
Time Period ◽  
Extreme Flood ◽  
Discrete Uniform Distribution ◽  
L Value ◽  
Discrete Uniform

Abstract. The use of non-systematic flood data for statistical purposes depends on the reliability of the assessment of both flood magnitudes and their return period. The earliest known extreme flood year is usually the beginning of the historical record. Even if one properly assesses the magnitudes of historic floods, the problem of their return periods remains unsolved. The matter at hand is that only the largest flood (XM) is known during whole historical period and its occurrence marks the beginning of the historical period and defines its length (L). It is common practice to use the earliest known flood year as the beginning of the record. It means that the L value selected is an empirical estimate of the lower bound on the effective historical length M. The estimation of the return period of XM based on its occurrence (L), i.e. ^M = L, gives a severe upward bias. The problem arises that to estimate the time period (M) representative of the largest observed flood XM. From the discrete uniform distribution with support 1, 2, ... , M of the probability of the L position of XM, one gets ^L = M/2. Therefore ^M = 2L has been taken as the return period of XM and as the effective historical record length as well this time. As in the systematic period (N) all its elements are smaller than XM, one can get ^M = 2t( L+N). The efficiency of using the largest historical flood (XM) for large quantile estimation (i.e. one with return period T = 100 years) has been assessed using the maximum likelihood (ML) method with various length of systematic record (N) and various estimates of the historical period length ^M comparing accuracy with the case when systematic records alone (N) are used only. The simulation procedure used for the purpose incorporates N systematic record and the largest historic flood (XMi) in the period M, which appeared in the Li year of the historical period. The simulation results for selected two-parameter distributions, values of their parameters, different N and M values are presented in terms of bias and root mean square error RMSEs of the quantile of interest are more widely discussed.

Management of Unanticipated Extreme Flood

2018 ◽  
Vol 1 (1) ◽  
pp. 22-37
Author(s):  
Partho Das ◽  
Rezaur Rahman
Keyword(s):  
South Asian ◽  
Flood Control ◽  
Management Practices ◽  
Flood Management ◽  
Floodplain Management ◽  
Asian Countries ◽  
Future Directions ◽  
Extreme Flood ◽  
Extreme Flooding ◽  
High Topography

South Asian countries (Nepal, India, and Bangladesh) experienced extreme flooding in August 2017 which is one of the deadliest in the recent few decades. Being the downstream country of this Himalayan region Bangladesh experienced immense flooding both in its flood prone and less flood prone areas. Northwest Bangladesh district Dinajpur is known for its high topography where flooding is not a common phenomenon. Due to this reason flood control and flood management practices by concerned agencies are very rare in this region. Such negligence in river and floodplain management turned this region a vulnerable one due to flood. The unexpected August 2017 flood in Dinajpur bears an example that this region is no longer flood free. This study aims to study the insights of this August 2017 flood event bi investigating causes, flood time and after flood recovery, existing management practices and damage information etc. Based on those primary and secondary assessment, future directions for flood management in this region has been proposed.

scholarly journals Preparing for climate change: an evaluative framework for prioritizing adaptation measures in Nepal

1970 ◽  
Vol 7 ◽  
pp. 35-42 ◽  
Author(s):  
Asheshwor Man Shrestha
Keyword(s):  
Climate Change ◽  
Risk Reduction ◽  
Water Conservation ◽  
Disaster Risk Reduction ◽  
Power Plants ◽  
Flood Control ◽  
Disaster Risk ◽  
Control Measures ◽  
Scoring Matrix ◽  
Adaptation Options

Severe potential climate threats for Nepal are expected to impact water resource, agriculture, biodiversity and livelihood. While adaptation and mitigation are both valid policy options to tackle climate change, it is advantageous for developing countries to opt for adaptation. It is also desirable that the most feasible adaptation actions be applied to protect development investment from climate risks and to ensure maximum preparedness. Adaptation strategies consist of a set of measures that are highly effective, affordable, technically and socially feasible and contribute towards disaster risk reduction. An evaluative framework using scoring matrix is utilized to prioritize adaptation options. Adaptation options for threat areas identified for Nepal are analyzed based on literature in the context of Nepal as well as for Asia and for least developed countries (LDCs). The measures are evaluated across multiple categories like public/private costs, effectiveness, social/cultural feasibility, speed, support for mitigation and aid in disaster preparedness. Based on the scoring matrix evaluation, following measures appear most feasible: (1) water conservation and management; (2) investment in smaller hydro-power plants; (3) research/planting of climate resistant crops; (4) diversification of agriculture; (5) development of early warning system for disasters; and (6) flood control measures downstream. Due to financial and technical constraints, it is advantageous to opt for ‘no-regrets’ strategies which benefit even without climate change. These set of measures can be carried out at low costs to reap sure benefits and should be prioritized for execution through environmental policies especially climate policies. Key-words: Adaptation; climate change; climate policy; disaster risk reduction; Nepal. DOI: 10.3126/botor.v7i0.4371Botanica Orientalis – Journal of Plant Science (2010) 7: 35-42

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