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The impact of dam removal on the ice regime of northern rivers has largely been ignored in the recent push for removal of dams to restore or improve aquatic habitat. However, dam removal may have significant impacts on the ice regime and has resulted in increased frequency and severity of downstream jams. Lowering of water levels in impoundments containing sediment deposits may result in more frequent or longer duration ice-induced scour and erosion of bed and bank material. Ice-related adverse impacts associated with dam removal can be mitigated through ice control measures. This paper presents a brief overview of the evolution of the typical ice regime, followed by a discussion of potential impacts resulting from dam removal. Examples of the impact of dam removal on riverine ice regime are presented, including two case studies in which dam removal has required the later construction of ice control structures. Recommendations are made for supplemental studies, when dam removal is considered in ice-affected rivers. CE Database keywords: Dams; Ice; Cold regions; Rivers.

The use of explosives in blasting and clearing ice jams has been widely used in Germany since 1758. However, blasting operations are dangerous and could lead to serious injury or death. Furthermore, they can also cause damage to properties and the environment. Nevertheless, blasting of ice jams can be an effective mitigation strategy as long as the operation is properly planned. Preparing an effective blasting plan in advance can also prevent costly delays.

In areas where damaging spring breakup ice jams are recurring events, advance mitigation measures should be considered. One mitigation measure that might be used in advance of ice breakup is aerial dusting of the ice, which enhances the natural weakening process. Because there may be limited time in which to organize and implement advance measures for ice jams, dusting operations should be planned beforehand. This paper provides a brief overview of the physical processes involved in ice dusting and discusses important aspects of a dusting plan. Experiences from two dusting programs in Nebraska were used as the basis for developing a set of guidelines for planning dusting operations. A spreadsheet for estimating dusting costs was also developed, and is presented with actual data from a 1994 dusting operation.

Breakup ice jams form suddenly and with little warning. The lack of forewarning hinders emergency response and ice jam mitigation efforts. Present knowledge of breakup jam processes does not allow for the development of a deterministic ice jam prediction model. Probabilistically based prediction models include linear regression, discriminant function analysis, and empirical cluster-type analyses. In this paper, the use of logistic regression to predict breakup ice jam occurrence is presented, with an example application for the Platte River at North Bend, Nebraska.

Evaluation of alternatives to reduce the severity of ice-jam flooding requires the development of probability distributions for ice-affected stage at non-gauged locations along a river reach. Difficulties arise as the ice-affected peak stage is not only a function of discharge and channel hydraulic properties, as is the case for the open water period, but is also influenced by the location, extent, thickness, and roughness of ice jams. This paper presents a new method for estimating winter peak stage along a river reach by dividing the record of winter peak discharges into distinct ice-jam and no-ice-jam populations. Rating curves may then be developed for each population using gradually varied-flow analysis and existing equilibrium ice-jam theory. Stage-probability distributions for the ice jam and no-ice-jam populations may then be combined into a single stage-frequency relationship representing the entire winter period. A case study is presented, in which the method is used to develop probability distributions for the annual maximum stage along the Winooski River at Montpelier, Vt. Viewed in the context of the historical record, the method yields reasonable results.

Describes some of the problems in communicating educational research findings to a general audience and provides helpful information on how researchers can best present data on educational practices that work and those that don't. The needs of the audience should be the primary focus in such reports. (SLD)

For many climate change impacts such as drought and heat waves, global and national frameworks for climate services are providing ever more critical support to adaptation activities. Coastal zones are especially in need of climate services for adaptation, as they are increasingly threatened by sea level rise and its impacts, such as submergence, flooding, shoreline erosion, salinization and wetland change. In this paper, we examine how annual to multi-decadal sea level projections can be used within coastal climate services (CCS). To this end, we review the current state-of-the art of coastal climate services in the US, Australia and France, and identify lessons learned. More broadly, we also review current barriers in the development of CCS, and identify research and development efforts for overcoming barriers and facilitating their continued growth. The latter includes: (1) research in the field of sea level, coastal and adaptation science and (2) cross-cutting research in the area of user interactions, decision making, propagation of uncertainties and overall service architecture design. We suggest that standard approaches are required to translate relative sea level information into the forms required to inform the wide range of relevant decisions across coastal management, including coastal adaptation. [ABSTRACT FROM AUTHOR]

Recent events in the USA have highlighted a lack of resilience in the coastal population to coastal flooding, especially amongst disadvantaged and isolated communities. Some low income countries, such as Cuba and Bangladesh, have made significant progress towards transformed societies that are more resilient to the impacts of cyclones and coastal flooding. To understand how this has come about a systematic review of the peer-reviewed and grey literature related to resilience of communities to coastal flooding was undertaken in both countries. In both Cuba and Bangladesh the trust between national and local authorities, community leaders and civil society is high. As a consequence evacuation warnings are generally followed and communities are well prepared. As a result over the past 25 years in Bangladesh the number of deaths directly related to cyclones and coastal flooding has decreased, despite an increase of almost 50% in the number of people exposed to these hazards. In Cuba, over the course of eight hurricanes between 2003 and 2011, the normalised number of deaths related to cyclones and coastal floods was an order of magnitude less than in the USA. In low-income countries, warning systems and effective shelter/evacuation systems, combined with high levels of disaster risk reduction education and social cohesion, coupled with trust between government authorities and vulnerable communities can help to increase resilience to coastal hazards and tropical cyclones. In the USA, transferable lessons include improving communication and the awareness of the risk posed by coastal surges, mainstreaming disaster risk reduction into the education system and building trusted community networks to help isolated and disadvantaged communities, and improve community's resilience. [ABSTRACT FROM AUTHOR]