Extreme Precipitation And Runoff Under Changing Climate In Southern Maine

The quantification of extreme precipitation events is vitally important for designing and engineering water and flood sensitive infrastructure. Since this kind of infrastructure is usually built to last much longer than 10, 50, or even 100 years, there is great need for statistically sound estimates of the intensity of 10-, 50-, 100-, and 500-year rainstorms and associated floods. The recent assessment indicated that the intensity of the most extreme precipitation events (or the heaviest 1% of all daily events) have increased in every region of the contiguous states since the 1950s (Melillo et al. 2014). The maximum change in precipitation intensity of extreme events occurred in the northeast region reaching 71%. The precipitation extremes can be characterized using intensity-duration-frequency analysis (IDF). However, the current IDFs in this region were developed around the assumption that climate condition remains stationary over the next 50 or 100 years. To better characterize the potential flood risk, this project will (1) develop precipitation IDFs on the basis of both historical observations and future climate projections from dynamic downscaling with Argonne National Laboratory's (Argonne's) regional climate model and (2) develop runoff IDFs using precipitation IDFs for the Casco Bay Watershed. IDF development also considers non-stationary distribution models and snowmelt effects that are not incorporated in the current IDFs.

Measurement, analysis and modeling of extreme precipitation events linked to floods is vital in understanding changing climate impacts and variability. This book provides methods for assessment of the trends in these events and their impacts. It also provides a basis to develop procedures and guidelines for climate-adaptive hydrologic engineering. Academic researchers in the fields of hydrology, climate change, meteorology, environmental policy and risk assessment, and professionals and policy-makers working in hazard mitigation, water resources engineering and climate adaptation will find this an invaluable resource. This volume is the first in a collection of four books on flood disaster management theory and practice within the context of anthropogenic climate change. The others are: Floods in a Changing Climate: Hydrological Modeling by P. P. Mujumdar and D. Nagesh Kumar, Floods in a Changing Climate: Inundation Modeling by Giuliano Di Baldassarre and Floods in a Changing Climate: Risk Management by Slodoban Simonović.

Hydroclimatic extremes, such as floods and droughts, affect aspects of our lives and the environment including energy, hydropower, agriculture, transportation, urban life, and human health and safety. Climate studies indicate that the risk of increased flooding and/or more severe droughts will be higher in the future than today, causing increased fatalities, environmental degradation, and economic losses. Using a suite of innovative approaches this book quantifies the changes in projected hydroclimatic extremes and illustrates their impacts in several locations in North America, Asia, and Europe.

Extreme climate events like severe precipitation, extreme heat, and drought, have large, negative impacts on society and ecosystems, but are challenging to model and predict due to their complexity. Thus, there remain many unresolved questions about the characteristics of extreme events and their impacts in a changing climate. This dissertation develops new methodological approaches to understand how and why the risks of climate extremes are changing, focusing specifically on two of the most widespread hazards: extreme precipitation and flooding. In Chapter 1, I quantify the impact of long-term changes in precipitation on the cost of flooding in the United States. This research finds that historical changes in precipitation have contributed to around 36% of U.S. flood damages between 1988-2017, providing the first empirical evidence that historical climate changes have already increased the cost of flooding in the U.S. I also analyze precipitation changes simulated by an ensemble of global climate models, finding that pattern of historical change is consistent with human-caused climate change, and that further global warmer will lead to additional increases in extreme precipitation. In Chapter 2, I analyze the changes in flood risk that result from warmer conditions that cause a shift from winter snow to winter rain. Using causal inference regression techniques to analyze data from over 400 watersheds in the western U.S., I show that this shift from snow to rain leads to non-linear increases in flood size due to larger rain-driven floods compared to snowmelt. However, this analysis also indicates some heterogeneity in this response. I find that (i) larger changes in flood risk occur for watersheds with higher average precipitation and (ii) the coldest watersheds may temporarily see decreases in flood risk with initial warming. In Chapter 3, I demonstrate a new application of explainable deep learning to identify the processes that have led to increases in extreme precipitation. Using the U.S. Midwest region as a case study, I find that large-scale atmospheric circulation conditions associated with extreme precipitation have become more frequent over the past 20 years, at a rate of around one additional day per year. These changes in the frequency of atmospheric circulation conditions have co-occurred with increases in atmospheric moisture flux to the Midwest region. As a result, these atmospheric circulation conditions are more likely to result in extreme precipitation now than in the past. Combined, this dissertation (i) provides new empirical evidence quantifying the impacts of climate change, which can inform policy decisions and climate adaptation, and (ii) provides new understanding into the processes that shape extreme precipitation and flooding risks in a warmer climate. Further, this dissertation demonstrates new quantitative approaches to analyze climate hazards and climate impacts that can be extended broadly to study other hazards and regions.

The report also provides a comprehensive assessment of past and future sea level change in a dedicated chapter.

The Intergovernmental Panel on Climate Change (IPCC) is the leading international body for assessing the science related to climate change. It provides policymakers with regular assessments of the scientific basis of human-induced climate change, its impacts and future risks, and options for adaptation and mitigation. This IPCC Special Report on the Ocean and Cryosphere in a Changing Climate is the most comprehensive and up-to-date assessment of the observed and projected changes to the ocean and cryosphere and their associated impacts and risks, with a focus on resilience, risk management response options, and adaptation measures, considering both their potential and limitations. It brings together knowledge on physical and biogeochemical changes, the interplay with ecosystem changes, and the implications for human communities. It serves policymakers, decision makers, stakeholders, and all interested parties with unbiased, up-to-date, policy-relevant information. This title is also available as Open Access on Cambridge Core.

Data on water quality and other environmental issues are being collected at an ever-increasing rate. In the past, however, the techniques used by scientists to interpret this data have not progressed as quickly. This is a book of modern statistical methods for analysis of practical problems in water quality and water resources. The last fifteen years have seen major advances in the fields of exploratory data analysis (EDA) and robust statistical methods. The 'real-life' characteristics of environmental data tend to drive analysis towards the use of these methods. These advances are presented in a practical and relevant format. Alternate methods are compared, highlighting the strengths and weaknesses of each as applied to environmental data. Techniques for trend analysis and dealing with water below the detection limit are topics covered, which are of great interest to consultants in water-quality and hydrology, scientists in state, provincial and federal water resources, and geological survey agencies. The practising water resources scientist will find the worked examples using actual field data from case studies of environmental problems, of real value. Exercises at the end of each chapter enable the mechanics of the methodological process to be fully understood, with data sets included on diskette for easy use. The result is a book that is both up-to-date and immediately relevant to ongoing work in the environmental and water sciences.

Impacts of Climate Change on Rainfall Extremes and Urban Drainage Systems provides a state-of-the-art overview of existing methodologies and relevant results related to the assessment of the climate change impacts on urban rainfall extremes as well as on urban hydrology and hydraulics. This overview focuses mainly on several difficulties and limitations regarding the current methods and discusses various issues and challenges facing the research community in dealing with the climate change impact assessment and adaptation for urban drainage infrastructure design and management. Authors: Patrick Willems, University of Leuven, Hydraulics division; Jonas Olsson, Swedish Meteorological and Hydrological Institute; Karsten Arnbjerg-Nielsen, Technical University of Denmark, Department of Environmental Engineering; Simon Beecham, University of South Australia, School of Natural and Built Environments; Assela Pathirana, UNESCO-IHE Institute for Water Education; Ida Bulow Gregersen, Technical University of Denmark, Department of Environmental Engineering; Henrik Madsen, DHI Water & Environment, Water Resources Department; Van-Thanh-Van Nguyen, McGill University, Department of Civil Engineering and Applied Mechanics