China
Africa
Explore chapters and articles related to this topic
Impact of Climate Change on Flooding
Published in Saeid Eslamian, Faezeh Eslamian, Flood Handbook, 2022
Finally, it is a standard practice to investigate trends in flooding using a series of annual maxima, but this in itself may not be particularly extreme (Bennett et al., 2018). For example, the design of infrastructure such as housing is generally planned around the 1-in-100-year flood level. As streamflow record lengths are generally only multiple decades in length (Do et al., 2018), either extrapolation is required or inferences have to be made using changes in the climatic drivers of flooding to understand changes in flooding relevant to engineering design (Villarini and Wasko, 2021). With this in mind, this chapter begins by discussing the physical basis of why flooding is changing with climate change, before discussing the changes in these physical drivers, and finally focusing on the observed changes in flooding itself. Additional considerations such as other anthropogenic factors are also presented. For brevity, the discussion of changes focuses on annual maxima, consistent with the majority of literature investigating historical trends in precipitation extremes and flooding.
Uncertainty
Published in Diane P. Michelfelder, Neelke Doorn, The Routledge Handbook of the Philosophy of Engineering, 2020
The next basic source of uncertainty that needs to be mitigated is randomness. Consider first how randomness in external stressors, such as environmental effects, can be mitigated. For instance, snow loads are an external stressor, and past maximum snow loads can be used to estimate future maximum snow loads (Bulleit 2008). The same can be done for flood magnitudes. A 100-year flood, a term most readers have heard, is a flood magnitude that on average will occur with probability 1/100 in any given year. Thus, the return period for this flood magnitude is 100 years. Engineers can use the return period flood or return period snow load for design, but to do that they must choose a design life. Many structures in the United States are designed using a design life of 50 years. This doesn’t mean that the structure is no longer usable after 50 years or even that it is guaranteed to last 50 years. It simply means that a load will be used in design that has a design return period combined with a defined design life. In some sense, both of these are arbitrary but, once chosen, are built into design specifications where the required capacity of the system is determined using these chosen design values (Bulleit 2008).
Climate Change Overlays
Published in Gregory T. Haugan, The New Triple Constraints for Sustainable Projects, Programs, and Portfolios, 2016
Overlay: Cities, communities, and property owners with tidal waterfront property must prepare for a conservatively estimated global sea level rise of between 4 and 7 feet by the end of the century For long-range planning, some are predicting double these numbers Communities should restrict construction within the Federal Emergency Management Agency (FEMA) 100-year flood plain or modify and adapt protective infrastructure for higher water levels. The 100-year flood is no longer a 1% statistical probability, but represents an area at much higher risk from frequent storms Problems of sea level rise such as erosion and flooding are exacerbated by storm surges and increasing tidal ranges Rain storms with high precipitation will increasingly result in inland rivers exceeding historic flood stages.
Flood dynamics and its spatial prediction using open-channel hydraulics and hydrodynamic model in the dam-controlled river of India
Published in Journal of Ecohydraulics, 2023
In pre-dam period a flood flow of 18112 m3s−1 (observed in 1935) has 26 years RT (Recurrence interval or return period), and it has 3.846 percent chance of being exceed in any one year. A 100-year flood, a flood event that has 1 percent probability or 1 in 100 chances of being equalled or exceeded in any given year, is estimated about 19018 m3s−1. Now, a maximum flood flow of 10919 m3s−1 has RT of 59 years, and it has only 1.604 percent chance of being exceed in any one year. At present, annual peak discharge of 1443–1434 m3s−1 has 1.11–1.09 years RT, and it has 89–91 percent chance of occurrence in any one year. The 100-year flood of post-dam period is estimated about 11969 m3s−1 (reduction of 37.06 percent from the pre-dam 100-year flood flow) which has only 1 percent chance of occurrence in one of given year (i.e. 1 in 100 years). The 2-year flood (50 percent probability of occurrence) is estimated about 3234 m3s−1 (reduction of 58.44 percent from the pre-dam 2-year flood flow).
Flood hazards in urban environment
Published in Georisk: Assessment and Management of Risk for Engineered Systems and Geohazards, 2023
Liang Gao, Limin Zhang, Yang Hong, Hong-Xin Chen, Shi-Jin Feng
A flood event can be statistically measured using return period, which is also known as a recurrence interval. The return period is the inverse of the average frequency of occurrence. That is, a 100-year flood has a 0.01 chance of being exceeded in any one year. The return period of a flood or storm surge can be estimated using statistical method based on the historical record. For an extreme event like a 1000-year event, which exceeds the historical return interval records, a statistical model could be adopted to predict the magnitude of such an extreme event. Probabilistic models including the Poisson distribution and the Binomial distribution could be used to determine the return period. The return period is also an important indicator for analyzing risks. Typically, a flood event can be measured in terms of discharge or water level, a storm surge event can be quantified in terms of surge height.
An integrated approach to evaluating inland waterway disruptions using economic interdependence, agent-based, and Bayesian models
Published in The Engineering Economist, 2023
Paul M. Johnson, Hiba Baroud, Craig Philip, Mark Abkowitz
However, it should be noted that our current flood scenarios likely over-estimate the impacts of more-frequent, lower-severity floods because we only have seven years worth of data on which to ground our models, and one of those years includes a 100-year event. The USACE will continue to collect and provide river gauge data, so the accuracy of our forecasts will improve with time. Additionally, it is worth noting that climate change is expected to increase the frequency and severity of extreme weather events, so return periods of floods may be vastly different going forward (e.g. a previously deemed 100-year flood may now occur every 20 years) (Camp et al., 2013; Pregnolato et al., 2017).