Metropolitan New York in the Greenhouse: Air Quality and Health Effects

A variety of potential effects on human health resulting from climate change have been identified in several assessments. According to an international panel{sup 1} they include direct effects of extreme temperatures on cardiovascular deaths, secondary effects due to vector-borne diseases or crop yields, and tertiary effects such as those that might arise from conflicts over freshwater supplies. To this fist we add the secondary effects of increased air pollution, which may result either directly from climate change or indirectly from increased air conditioning loads and the corresponding pollutant emissions from electric utilities. Higher ozone concentrations have been linked to increased ambient temperatures by both theory and observations of monitoring data. A similar association with particulate matter has been limited to observations, thus far. The pollution-heat linkage has been recognized before` but health effects have not been evaluated in terms of predictions of the joint effects of both agents. This paper has been prepared in two sections. First, we discuss the ozone situation with special reference to the Northeast Corridor and New York. In the second section, we present estimates of the health effects of climate change on New York and discuss some mitigation options

Geomorphic effects of wood quantity and characteristics in three Italian gravel-bed rivers

In-channel wood is a fundamental component of the riverine system. Its nature, abundance, and distribution as well as the role of wood in trapping sediment have been reported by many authors. However, a lack of knowledge still exists on how the geomorphic effects, quantity, and characteristics of in-channel wood may be altered by different human pressures. For this reason, in-channel wood was surveyed in the Brenta, Piave, and Tagliamento gravel-bed rivers (northeastern Italy), which are altered by different degrees of human pressures. Both single pieces of wood (>. 0.1. m diameter, and/or >. 1. m long) and accumulations of large wood were measured on cross sectional transects within the active channels. Overall, 3430 (8.4, 13.9 and 10.7 elements/ha in the Brenta, Piave, and Tagliamento rivers, respectively) of isolated pieces and 591 (9.8, 15.0, and 11.0 wood accumulations/ha in the Brenta, Piave, and Tagliamento rivers, respectively) accumulations were surveyed in the study sites. In the Brenta and Piave rivers, which feature the greater human pressures, logs appear in a worse state of conservation. In the less disturbed Tagliamento River, the logs appear to be smaller and in a better state of conservation with higher capacity for resprouting. In addition, higher geomorphic interactions were found between wood and sediments in the Tagliamento River. Because of its ability to create geomorphic effects, in-channel wood represents an important source of complexity that can increase habitat diversity in river systems. A better knowledge of the role of human disturbances on the characteristics and abundance of large wood in river systems could help in developing better river management and the practical application of river ecology. © 2015 Elsevier B.V

River widening in mountain and foothill areas during floods: Insights from a meta-analysis of 51 European Rivers

River widening, defined as a lateral expansion of the channel, is a critical process that maintains fluvial ecosystems and is part of the regular functioning of rivers. However, in areas with high population density, channel widening can cause damage during floods. Therefore, for effective flood risk management it is essential to identify river reaches where abrupt channel widening may occur. Despite numerous efforts to predict channel widening, most studies have been limited to single rivers and single flood events, which may not be representative of other conditions. Moreover, a multi-catchment scale approach that covers various settings and flood magnitudes has been lacking. In this study, we fill this gap by compiling a large database comprising 1564 river reaches in several mountain regions in Europe affected by floods of varying magnitudes in the last six decades. By applying a meta-analysis, we aimed to identify the types of floods responsible for more extensive widening, the river reach types where intense widening is more likely to occur, and the hydraulic and morphological variables that explain widening and can aid in predicting widening. Our analysis revealed seven groups of reaches with significantly different responses to floods regarding width ratios (i.e., the ratio between channel width after and before a flood). Among these groups, the river reaches located in the Mediterranean region and affected by extreme floods triggered by short and intense precipitation events showed significantly larger widening than other river reaches in other regions. Additionally, the meta-analysis confirmed valley confinement as a critical morphological variable that controls channel widening but showed that it is not the only controlling factor. We proposed new statistical models to identify river reaches prone to widening, estimate potential channel width after a flood, and compute upper bound width ratios. These findings can inform flood hazard evaluations and the design of mitigation measures

Spatial and temporal variability in sedimentation rates associated with cut-off channel infill deposits: Ain River, France

International audienceFloodplain development is associated with lateral accretion along stable channel geometry. Along shifting rivers, the floodplain sedimentation is more complex because of changes in channel position but also cutoff channel presence, which exhibit specific overflow patterns. In this contribution, the spatial and temporal variability of sedimentation rates in cutoff channel infill deposits is related to channel changes of a shifting gravel bed river (Ain River, France). The sedimentation rates estimated from dendrogeomorphic analysis are compared between and within 14 cutoff channel infills.Detailed analyses along a single channel infill are performed to assess changes in the sedimentation rates through time by analyzing activity profiles of the fallout radionuclides 137Cs and unsupported 210Pb. Sedimentation rates are also compared within the channel infills with rates in other plots located in the adjacent floodplain. Sedimentation rates range between 0.65 and 2.4 cm a1 over a period of 10 to 40 years. The data provide additional information on the role of distance from the bank, overbank flow frequency, and channel geometry in controlling the sedimentation rate. Channel infills, lower than adjacent floodplains, exhibit higher sedimentation rates and convey overbanksediment farther away within the floodplain. Additionally, channel degradation, aggradation, and bank erosion, which reduce or increase the distance between themain channel and the cutoff channel aquatic zone, affect local overbank flow magnitude and frequency and therefore sedimentation rates, thereby creating a complex mosaic of sedimentation zones within the floodplain and along the cutoff channel infills. Last, thedendrogeomorphic and 137Cs approaches are cross validated for estimating the sedimentation rate within a channel infil