Simon Hoggart

Urban river wall habitat and vegetation: observations from the River Thames through central London

Along heavily engineered urban rivers, river walls and embankments represent the most common habitat available to riparian vegetation. This paper presents the first study into river wall vegetation and the influence of wall surface materials on plant diversity. We were concerned with investigating the plant diversity of such wall habitats, assessing relationships between different wall surface materials and plant diversity, and determining whether river wall and embankment habitats along the River Thames through central London could support native riparian species alongside more typical urban wall flora. Fifteen sites along the River Thames through central London were surveyed to describe wall flora and establish relationships between plant diversity and wall materials. Walls were not species rich, but contained a mix of terrestrial and riparian species. Stone walls with surface fractures and heterogeneous wall surfaces were conducive to plant diversity at the local scale, while wall surface heterogeneity was also important at the landscape scale. Some stratification of vegetation was observed based on wall position relative to flow disturbance. The potential exists for walls to act as sites for habitat improvement and reconciliation ecology within urban rivers.

Innovative Engineering Solutions and Best Practices to Mitigate Coastal Risk

Engineering solutions are widely used for the mitigation of flood and erosion risks and have new challenges because of the expected effects induced by climate change in particular sea level rise and increase of storminess. This chapter describes both active methods of mitigation based on the reduction of the incident wave energy, such as the use of wave energy converters, floating breakwaters and artificial reefs, and passive methods, consisting of increase in overtopping resistance of dikes, improvement of resilience of breakwaters against failures, and the use of beach nourishment as well as tailored dredging operations.Existing coastal management and defense approaches are not well suited to meet the challenges of climate change and related uncertanities. Professionals in this field need a more dynamic, systematic and multidisciplinary approach. Written by an international group of experts, Coastal Risk Management in a Changing Climate provides innovative, multidisciplinary best practices for mitigating the effects of climate change on coastal structures. Based on the Theseus program, the book includes eight study sites across Europe, with specific attention to the most vulnerable coastal environments such as deltas, estuaries and wetlands, where many large cities and industrial areas are located. * Integrated risk assessment tools for considering the effects of climate change and related uncertainties* Presents latest insights on coastal engineering defenses* Provides integrated guidelines for setting up optimal mitigation measures* Provides directly applicable tools for the design of mitigation measures* Highlights socio-economic perspectives in coastal mitigation

Chapter 3 – Innovative Engineering Solutions and Best Practices to Mitigate Coastal Risk

Engineering solutions are widely used for the mitigation of flood and erosion risks and have new challenges because of the expected effects induced by climate change in particular sea level rise and increase of storminess. This chapter describes both active methods of mitigation based on the reduction of the incident wave energy, such as the use of wave energy converters, floating breakwaters and artificial reefs, and passive methods, consisting of increase in overtopping resistance of dikes, improvement of resilience of breakwaters against failures, and the use of beach nourishment as well as tailored dredging operations.Existing coastal management and defense approaches are not well suited to meet the challenges of climate change and related uncertanities. Professionals in this field need a more dynamic, systematic and multidisciplinary approach. Written by an international group of experts, Coastal Risk Management in a Changing Climate provides innovative, multidisciplinary best practices for mitigating the effects of climate change on coastal structures. Based on the Theseus program, the book includes eight study sites across Europe, with specific attention to the most vulnerable coastal environments such as deltas, estuaries and wetlands, where many large cities and industrial areas are located. * Integrated risk assessment tools for considering the effects of climate change and related uncertainties* Presents latest insights on coastal engineering defenses* Provides integrated guidelines for setting up optimal mitigation measures* Provides directly applicable tools for the design of mitigation measures* Highlights socio-economic perspectives in coastal mitigation

Ecological approaches to coastal risk mitigation

Natural coastal habitats play an important role in protecting coastal areas from sea water flooding caused by storm surge events. Many of these habitats, however, have been lost completely or degraded, reducing their ability to function as a natural flood defense. Once degraded, natural habitats can potently be destroyed by storm events, further threatening these systems. Much of the loss of coastal habitats is caused by increased human activity in coastal areas and through land claimed for urban, industrial, or agricultural use. As a result, some coastal habitats have become rare and threatened across much of Europe and the world. An associated problem is that of sea level rise, which has the combined impact of both increasing the risk of flooding in coastal ecosystems and increasing the severity of storm surge events. This chapter addresses two key topics: (1) the use of natural habitats as a form of coastal defense focusing on the required management and how to restore and/or create them and (2) ecological considerations in the design of hard coastal defense structures. The habitats that play a role in coastal deface and considered here are: (1) saltmarshes, (2) sand dunes, (3) seagrass meadows, and (4) biogenic reefs, including Sabellaria reefs, oyster beds, and mussel beds. As part of coastal habitat restoration and management, the process of saltmarsh creation, either through seaward extension or managed realignment is discussed focusing on potential benefits. Finally, key cumulative stressors that can hinder ecological approaches to coastal risk mitigation are reviewed.

Coastal Risk Management in a Changing Climate

Engineering solutions are widely used for the mitigation of flood and erosion risks and have new challenges because of the expected effects induced by climate change in particular sea level rise and increase of storminess. This chapter describes both active methods of mitigation based on the reduction of the incident wave energy, such as the use of wave energy converters, floating breakwaters and artificial reefs, and passive methods, consisting of increase in overtopping resistance of dikes, improvement of resilience of breakwaters against failures, and the use of beach nourishment as well as tailored dredging operations.Existing coastal management and defense approaches are not well suited to meet the challenges of climate change and related uncertanities. Professionals in this field need a more dynamic, systematic and multidisciplinary approach. Written by an international group of experts, Coastal Risk Management in a Changing Climate provides innovative, multidisciplinary best practices for mitigating the effects of climate change on coastal structures. Based on the Theseus program, the book includes eight study sites across Europe, with specific attention to the most vulnerable coastal environments such as deltas, estuaries and wetlands, where many large cities and industrial areas are located. * Integrated risk assessment tools for considering the effects of climate change and related uncertainties* Presents latest insights on coastal engineering defenses* Provides integrated guidelines for setting up optimal mitigation measures* Provides directly applicable tools for the design of mitigation measures* Highlights socio-economic perspectives in coastal mitigation

Developing a holistic approach to assessing and managing coastal flood risk

It is increasingly recognized that a comprehensive understanding of the existing flood system is necessary to effectively manage coastal flood risk. This involves consideration of the social and ecological dimensions in addition to the hydrological aspects that have been the traditional focus of flood analysis. Social aspects are important, as they represent both the reason for flood management and the growth in exposure, as well as providing the context within which any decision will be made. Coastal species and habitats are inherently important for the flood management ecosystem services that they provide for flood management. The flood flow, depth, and extent determine the potential for flood damage. The conceptual model adopted here for coastal risk assessment is based on the Source-Pathway-Receptor-Consequence model, which is a simple linear conceptual model for representing flood systems and processes that lead to a particular flooding consequence. This approach is being used to evaluate how the Sources (waves, tides, storm surge, mean sea level, river discharge, run-off), through the Pathways (including coastal defenses), affect the Receptors (inland system), generating economic, social, and environmental Consequences. Collectively, this more holistic analysis of the flood system can identify likely trends in flood risk and the wide range of potential mitigation options embracing engineering, ecological, or socioeconomic measures, including hybrid combined approaches.

Chapter 6 – Toward Sustainable Decision Making

In this chapter, the issue of sustainable decision making for successful coastal flood management is examined. In this setting, a key concept is sustainable development, defined as a pattern of resource use that aims to meet human needs while preserving the environment so that these needs can be met not only today, but also for future generations. Sustainability for a given coastal system requires: (1) efficient protection to life and goods, and preserving socioeconomic development and opportunities of coastal areas; (2) maintenance of the environmental assets; and (3) short-, medium-, and long-term scenarios accounting for climate change effects. Different tools for sustainable decision making are presented. Design should be aimed at providing “continuity of daily life”—before, during, and after a flood, to avoid the detrimental social and economic impact that would otherwise result. A development that intrinsically provides flood resilience, through an adequate defense planning strategy, should give insurers and financiers the confidence to offer affordable, long-term policies, and investments. While planning coastal risk management strategies, coastal managers need to assess risk across a range of spatial and temporal scales. geographic information systems–based tools are one efficient way to support them in the decision-making process through a scenarios analysis starting from social, economic, and environmental information integrated into a common platform.