77 research outputs found

    Model-based design for restoration of a small urban river

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    A model-based design is presented for restoring the small urban river Panke located in Berlin, Germany. This new design process combines high resolution 2D hydraulic modeling with habitat modeling and river-ecological expert knowledge in a highly iterative way. Advances have been made for the habitat modeling: habitat suitability maps have been developed for fish and the habitat suitability for benthos has been assessed by including groups with different hydraulic preferences. Using the model-based design we have developed preference variants for the Panke which include structures such as pools, riffles, river banks, dead wood as well as aquatic vegetation. To account for the very detailed geometry of some structures such as dead wood, high resolution grids with edge length up to one decimeter have been generated. Furthermore flood protection has been assured. The variants should be constructed in the Panke in 2015. We expect that the ecological conditions for fish and benthos will improve, however this has to be evaluated by further measurements. The model-based approach for the design of enhancement measures delivered valuable hints on current shortcomings in the river morphology, priorities for the creation of new habitats and quantitative information on the increase of suitable areas to be expected. In addition, relating the habitat changes to different flow rates helped to estimate the temporal availability of high quality habitats after the implementation of the measures

    First-Hand Experience and Second-Hand Information: Changing Trust across Three Levels of Government

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    Little is known about how different sources of information drive citizen trust in government. To address that gap this article compares disaster evacuees to observers, noting how trust differs as attention to media coverage increases. First-hand experience supplies information to update trust through biological and personal processes and performance assessments, while secondary sources provide information about other people's experiences, filtered through lenses that take an active role in crafting information. These two types of information have varying effects depending on the level of government being trusted. Using surveys administered a year after Hurricane Katrina, I find that Katrina evacuees have the highest trust in federal government, until they start paying attention to media coverage, and that attention to coverage has the most dramatic effect on these evacuees compared to all other groups. I also find that increasing attention to second-hand information corresponds with higher trust in local officials, and that this effect decreases as the level of government increases. It appears media coverage creates a comparison in the mind of hurricane evacuees, causing them to update their performance assessments based on comparing their own experience to that which they observe, thereby updating their political trust
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