CLIMATE CHANGE AND ITS INFLUENCE ON DESIGN FLOOD ESTIMATION

Research into potential implications of climate change on flood hazard has made significant progress over the past decade, yet efforts to translate this research into practical guidance for flood estimation remain in their infancy. In this commentary, we address the question: how best can practical flood guidance be modified to incorporate the additional uncertainty due to climate change? We begin by summarizing the physical causes of changes in flooding and then discuss common methods of design flood estimation in the context of uncertainty. We find that although climate science operates across aleatory, epistemic and deep uncertainty, engineering practitioners generally only address aleatory uncertainty associated with natural variability through standards-based approaches. A review of existing literature and flood guidance reveals that although research efforts in hydrology do not always reflect the methods used in flood estimation, significant progress has been made with many jurisdictions around the world now incorporating climate change in their flood guidance. We conclude that the deep uncertainty that climate change brings signals a need to shift towards more flexible design and planning approaches, and future research effort should focus on providing information that supports the range of flood estimation methods used in practice. This article is part of a discussion meeting issue ‘Intensification of short-duration rainfall extremes and implications for flash flood risks'.

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The Future Design Flood Estimation of Yangfanggou Hydropower Station under the Climate Change Scenario

Journal of Water Resources Research ◽

10.12677/jwrr.2021.104043 ◽

2021 ◽

Vol 10 (04) ◽

pp. 399-407

Author(s):

金华刘

Keyword(s):

Climate Change ◽

Climate Change Scenario ◽

Hydropower Station ◽

Change Scenario ◽

Design Flood ◽

Future Design ◽

The Future ◽

Flood Estimation

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Nonstationary Design Flood Estimation in Response to Climate Change, Population Growth and Cascade Reservoir Regulation

Water ◽

10.3390/w13192687 ◽

2021 ◽

Vol 13 (19) ◽

pp. 2687

Author(s):

Yuzuo Xie ◽

Shenglian Guo ◽

Lihua Xiong ◽

Jing Tian ◽

Feng Xiong

Keyword(s):

Climate Change ◽

Population Growth ◽

Change Point Detection ◽

Flood Frequency Analysis ◽

Data Series ◽

Flood Events ◽

Design Flood ◽

Cascade Reservoirs ◽

Han River ◽

Flood Estimation

The hydrologic data series are nonstationary due to climate change and local anthropogenic activities. The existing nonstationary design flood estimation methods usually focus on the statistical nonstationarity of the flow data series in the catchment, which neglect the hydraulic approach, such as reservoir flood regulation. In this paper, a novel approach to comprehensively consider the driving factors of non-stationarities in design flood estimation is proposed, which involves three main steps: (1) implementation of the candidate predictors with trend tests and change point detection for preliminary analysis; (2) application of the nonstationary flood frequency analysis with the principle of Equivalent Reliability (ER) for design flood volumes; (3) development of a nonstationary most likely regional composition (NS-MLRC) method, and the estimation of a design flood hydrograph at downstream cascade reservoirs. The proposed framework is applied to the cascade reservoirs in the Han River, China. The results imply that: (1) the NS-MLRC method provides a much better explanation for the nonstationary spatial correlation of the flood events in Han River basin, and the multiple nonstationary driving forces can be precisely quantified by the proposed design flood estimation framework; (2) the impacts of climate change and population growth are long-lasting processes with significant risk of flood events compared with stationary distribution conditions; and (3) the swift effects of cascade reservoirs are reflected in design flood hydrographs with lower peaks and lesser volumes. This study can provide a more integrated template for downstream flood risk management under the impact of climate change and human activities.

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Climate change impacts on the seasonality and generation processes of floods in catchments with mixed snowmelt/rainfall regimes: projections and uncertainties

Hydrology and Earth System Sciences Discussions ◽

10.5194/hessd-11-6273-2014 ◽

2014 ◽

Vol 11 (6) ◽

pp. 6273-6309 ◽

Cited By ~ 2

Author(s):

K. Vormoor ◽

D. Lawrence ◽

M. Heistermann ◽

A. Bronstert

Keyword(s):

Climate Change ◽

Production Management ◽

Climate Change Impacts ◽

Climate Projections ◽

High Mountain ◽

Relative Role ◽

Design Flood ◽

Flood Estimation ◽

Projected Changes ◽

Rainfall Regimes

Abstract. Climate change is likely to impact the seasonality and generation processes of floods in the Nordic countries, which has direct implications for flood risk assessment, design flood estimation, and hydropower production management. Using a multi-model/multi-parameter approach, we analysed the projected changes in flood seasonality and its underlying generation processes in six catchments with mixed snowmelt/rainfall regimes in Norway. We found that autumn/winter events become more frequent in all catchments considered which leads to an intensification of the current autumn/winter flood regime for the coastal catchments, a reduction of the dominance of spring/summer flood regimes in a high-mountain catchment, and a possible systematic shift in the current flood regimes from spring/summer to autumn/winter in catchments in northern and south-eastern Norway. The changes in flood regimes results from increasing event magnitudes or frequencies, or a combination of both during autumn and winter. Changes towards more dominant autumn/winter events correspond to an increasing relevance of rainfall as a flood generating process (FGP) which is most pronounced in those catchments with the largest shifts in flood seasonality. Here, rainfall replaces snowmelt as the dominant FGP. We further analysed the ensemble components in contributing to overall uncertainty in the projected changes and found that the climate projections and the methods for downscaling or bias-correction tend to be the largest contributors. The relative role of hydrological parameter uncertainty, however, is highest for those catchments showing the largest changes in flood seasonality which confirms the lack of robustness in hydrological model parameterization for simulations under transient hydrometeorological conditions.

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A Classic Hydroinformatic Problem - Floods

10.29007/w8g4 ◽

2018 ◽

Author(s):

James Ball

Keyword(s):

Climate Change ◽

Digital Computer ◽

Subsequent Development ◽

Engineering Profession ◽

Design Flood ◽

Data Manipulation ◽

Computational Capacity ◽

Recent Developments ◽

Flood Estimation ◽

The Many

While previous editions of ARR have served the engineering profession well, a number of issues have necessitated the production of a new edition. These issues include the many recent developments in knowledge about flood producing processes, the increased computational capacity and data manipulation available to engineers, and the rapidly expanding body of information about climate change. There is a need, therefore, to produce a new edition of ARR. As part of the development of this new edition, it has been necessary to review the methods used and the implications of assumptions necessary for implementation of these methods. An outcome of this review has been recognition of changes in design flood estimation since development of the digital computer and the subsequent development of hydroinformatics. This has led to recasting design flood estimation as a problem in hydroinformatics. Presented herein is the background to and a discussion of this concept.

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On the impact of the hydrological model and catchment hydrology on the design flood estimation in a small catchment in Central Italy affected by the recent 2016 earthquake events

10.5194/egusphere-egu2020-13571 ◽

2020 ◽

Author(s):

Shima Azimi ◽

Silvia Barbetta ◽

Tommaso Moramarco ◽

Angelica Tarpanelli ◽

Stefania Camici ◽

...

Keyword(s):

Climate Change ◽

Time Series ◽

River Discharge ◽

Hydrological Model ◽

Central Italy ◽

Change Scenario ◽

Catchment Hydrology ◽

Design Flood ◽

Flood Estimation ◽

The Impact

Flood is one of the most frequent disasters which dangerously impacts societies and economies worldwide. Floodplain management and hydraulic risk analysis based on design flood estimation are essential tools to reduce damages and save human lives. Flood Frequency Analysis (FFA) has been classically used to derive design river discharge estimates, however, the scarce availability of discharge observations, especially in small catchments (<150 km2), makes its application not always possible. In addition, with the projections foreseen by the International Panel on Climate Change (IPCC) the use of FFA might lead to incorrect estimates of design river discharge as FFA is based on the concept of stationarity. Generally, long rainfall and temperature time series are much more available than discharge observations but their temporal coverage is often not sufficient for carrying out FFA via a hydrological simulation.To handle these drawbacks, the combination of a stochastic generation of rainfall and temperature time series, Regional Circulation Model (RCM) projections and continuous hydrological models provides a reliable tool for obtaining long river discharge time series to implement FFA. However, design flood estimations can be significantly uncertain due to several factors such as 1) the specific model structure, parameterizations and processes representation, 2) the catchment hydrology and 3) the specific climate change scenario.The primary objective of this study is to explore the sensitivity of the design river discharge estimates to the hydrological model complexity and parameterization. For this, three continuous hydrological distributed models named the Modello Idrologico SemiDistribuito in continuo (MISDc), the Soil & Water Assessment Tool (SWAT) and GEOFrame NewAGE model are forced with long timeseries of rainfall and temperature obtained via the Neyman-Scott rectangular pulse model (NSRP) for stochastic rainfall generation, and the fractionally differenced ARIMA model (FARIMA) for stochastic temperature generation. A secondary objective is to understand the impact of climate change and the catchment hydrology on the design river discharge estimates via the use of different RCM projections.The study is carried in the Upper Nera catchment in Central Italy which was impacted by the recent 2016 earthquake and for which is necessary to identify hydraulic risk mitigation measures and adaptation for a forward planning in the floodplain areas where new settlements will be rebuilt.Preliminary results suggest the high dependency of the design river discharge estimates to the chosen hydrological model and a different response of the sub-catchments to the climate change scenario.

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