Restoring Rivers and Floodplains for Habitat and Flood Risk Reduction: Experiences in Multi-Benefit Floodplain Management From California and Germany

Conventional flood control has emphasized structural measures such as levees, reservoirs, and engineered channels—measures that typically simplify river channels and cut them off from their floodplain, both with adverse environmental consequences. Structural measures tend to be rigid and not easily adapted to increased flooding regimes resulting from environmental change. Such actions also limit the natural hydrologic benefits of floodplains such as storing floodwaters, improving water quality, providing habitat for invertebrates and fish during periods of inundation, and supporting a multitude of cultural services. As these benefits are more widely recognized, policies are being adopted to encourage projects that reduce flood risks and restore floodplain ecosystems, while acknowledging the social-ecological context. The number of such projects, however, remains small. We assessed four multi-benefit floodplain projects (two in California, United States, and two in Germany) and characterized their drivers, history, and measures implemented. In both United States cases, the dominant driver behind the project was flood risk reduction, and ecosystem restoration followed, in one case inadvertently, in the other as a requirement to receive a subsidy for a flood risk reduction project. One German case was motivated by ecosystem restoration, but it was more widely accepted because it also offered flood management benefits. The fourth case was conceived in terms of balanced goals of flood risk reduction, ecosystem restoration, and recreation. We conclude that projects that both reduce flood risk and restore ecosystems are clearly possible and often cost-effective, and that they could be more widely implemented. The principal barriers are often institutional and regulatory, rather than technical

Living Labs—A Concept for Co-Designing Nature-Base Solutions

Living Labs are recognized as a progressive form to foster innovation and the strengthening of collaborative planning. The concept has received strong attention by the European Union (EU) research and innovation agendas recently. This contribution investigates how a Living Lab approach could be used for the design and implementation of Nature-Based Solutions (NBS). NBS are gaining acceptance as a more sustainable solution for reducing the exposure to natural hazards and vulnerability to events, such as increased flooding in changing climate. However, a lack of collaborative approaches hinders their broader implementation. A literature review on the theoretical aspects of the Living Labs concept in the context of NBS is conducted, and we compare the theoretical findings with practices that were observed by case studies implementing NBS in a collaborative manner. The Isar-Plan River Restoration in Munich, Germany, and the Mountain Forest Initiative (Bergwaldoffensive). Both of the case studies have already started well before the concept of Living Labs gained wider popularity. Both award-winning cases are recognized good practice for their exemplary in-depth stakeholder involvement. The paper discusses the concepts and approaches of Living Labs and reflects on how it can serve and support in-depth participatory stakeholder involvement.publishedVersio

Stamp forming of carbon fibre/PA12 composites - a comparison of a reactive impregnation process and a commingled yarn system

Two forms of carbon fibre reinforced polyamide 12 (PA12) were compared during non-isothermal stamp forming. The first was a stretch broken commingled yarn woven into a fabric, studied at three initial preconsolidation levels. The second was produced by in situ anionic polymerisation of lactam 12 (APLC12) in a carbon fibre textile, using a thermoplastic resin transfer moulding (TP-RTM) process. A processing window was defined for TP-RTM based upon non-isothermal polymerisation kinetics. For each material form, the effects of stamping parameters on flat plaque properties were examined. For commingled materials, the influence of preheat temperature and the initial preconsolidation level dominated, with preconsolidated materials deconsolidating strongly during the preheat cycle. For CF/APLC12 materials, the effect of material temperature and tool temperature dominated and reduced deconsolidation occurred. Hemisphere forming was enabled by stretch-broken yarn but was possible for both material classes. Over-injection moulding of recompounded CF/APLC12 composite onto stamped CF/APLC12 plate was performed, demonstrating a closed-loop recycling process

Living Labs—A Concept for Co-Designing Nature-Base Solutions

Living Labs are recognized as a progressive form to foster innovation and the strengthening of collaborative planning. The concept has received strong attention by the European Union (EU) research and innovation agendas recently. This contribution investigates how a Living Lab approach could be used for the design and implementation of Nature-Based Solutions (NBS). NBS are gaining acceptance as a more sustainable solution for reducing the exposure to natural hazards and vulnerability to events, such as increased flooding in changing climate. However, a lack of collaborative approaches hinders their broader implementation. A literature review on the theoretical aspects of the Living Labs concept in the context of NBS is conducted, and we compare the theoretical findings with practices that were observed by case studies implementing NBS in a collaborative manner. The Isar-Plan River Restoration in Munich, Germany, and the Mountain Forest Initiative (Bergwaldoffensive). Both of the case studies have already started well before the concept of Living Labs gained wider popularity. Both award-winning cases are recognized good practice for their exemplary in-depth stakeholder involvement. The paper discusses the concepts and approaches of Living Labs and reflects on how it can serve and support in-depth participatory stakeholder involvement

Model-Based Evaluation of the Effects of River Discharge Modulations on Physical Fish Habitat Quality

The increase in minimum flows has rarely been considered to mitigate the ecological impact of hydroelectric power plants because it requires a site-specific design and expensive long-term monitoring procedure to identify the most beneficial scenario. This study presents a model-based method to estimate, within the model constraints, the most sustainable scenario of water resource sharing between nature and human needs. We studied physical habitat suitability of the Isar River in Munich (Germany) for three protected fish species: Thymallus thymallus L., Hucho hucho L., and Chondostroma nasus L. The analysis combined a high-resolution two-dimensional (2D) hydromorphological model with expert-based procedures using Computer Aided Simulation Model for Instream Flow Requirements (CASiMIR). We simulated a range of minimum discharges from 5 to 68.5 m³/s and four scenarios: (A) maximum use of the resource for humans; (B) slight increase in the minimum water flow; (C) medium increase in the minimum water flow; and, (D) without diversion for hydroelectric production. Under the current hydromorphological conditions, model outputs showed that different life stages of the fish species showed preferences for different scenarios, and that none of the four scenarios provided permanently suitable habitat conditions for the three species. We suggest that discharge management should be combined with hydromorphological restoration actions to re-establish parts of the modified channel slope and/or parts of the previously lost floodplain habitat in order to implement a solution that favors all species at the same time. The modeling procedure that is presented may be helpful to identify the discharge scenario that is most efficient for maintaining target fish species under realistic usage conditions