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ForewordCreating Value by Engineering With NatureWe rely on natural processes and landscapes to sustain human life and well-being. Our energy, water, infrastructure, and agricultural systems use these processes and landscapes to satisfy our most basic human needs. One motivation, therefore, for protecting the environment is to sustain the ecosystem goods and services upon which we depend. As we emerge from the sixth decade of modern environmentalism, there is a growing international awareness of opportunities to efficiently and effectively integrate natural and engineered systems to create even more value.I hope you enjoy learning from the projects in this book while considering future ways that you can contribute to Engineering With Nature.Working with natural processes to manage flood and coastal erosion risks is an important theme in the UK Government's new national 25-year plan for the environment. Engineering With Nature, or "Natural Flood Management" as we often refer to it, is an important tool in flood risk toolbox and can bring fabulous environmental benefits too.Approaching flood risk with softer engineered solutions is not new to our engineers. For years, many of our beaches have been managed to take the energy out of stormy seas to protect our coasts, and in the northeast of England, flood water has been stored in catchments on the "Ings"-and old Norse word for flood meadows-for generations.What is new is a better understanding of how we can work collaboratively to provide the most effective blend of solutions. Too often, the conversation has been about a false choice between hard or soft engineering-as if there were conflict or competition between them.We're proud to have been able to contribute nine case studies to the Engineering With Nature Atlas. I hope you'll be inspired by the projects in the Atlas from across the world and use it to continue to build our capacity to collaborate with each other and with nature to protect people from environmental hazards and to enhance the environment for wildlife.

Sediments collected at various field locations may have chemical and physical constituents that influence test results and may contain organisms that cannot be readily removed. Thus, reference sediments are needed that can be formulated to match diverse freshwater and estuarine sediments encountered in comprehensive testing programs. This research evaluated formulated reference sediments in terms of (a) their ability to match field-collected sediments both chemically and physically; (b) their suitability as habitat (survival and reproduction) for typical invertebrate toxicity testing species (Hyalella azteca Saussure, Chironomus tentans Fabricius, and Daphnia magna Straus) during chronic exposures; and (c) their suitability as a substrate for HyalelIa azteca, Chironomus tentans, Daphnia magna, Ceriodaphnia dubia Richard, and Pimephales promelas Rafinesque in 14-d whole-sediment exposures. Formulated reference sediments were prepared to match naturally occurring sediments with respect to particle-size distribution, organic matter, organic carbon, pH, solids, CEC, but not redox potential. After preparation, a conditioning period of at least 7 d was required for pH stabilization of formulated reference sediments. In culture experiments, formulated reference sediment was suitable for Hyalella azteca, Chironomus tentans, and Daphnia magna survival and reproduction for 56,40, and 28 d, respectively. Hyalella azteca, Chironomus tentans, Daphnia magna, Ceriodaphnia dubia and Pirnephalesprornelas survival was 288% in 14-d exposures to formulated reference sediment. Formulated reference sediments may reduce some unexplained physical, chemical, or biological "toxicity" of field-collected sediments (e.g., organic matter) that may influence toxicity testing results. I

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