Search

In this article, we quantify the effects of a standing ice cover on the hydrodynamics of a mesotidal estuary. The Portneuf Estuary, Quebec, is 5.9 km in length and has a 3-m-deep thalweg. According to our numerical model simulations (using an adapted version of Environment Canada's ONE-D model) and field measurements, the midwinter 50-cm-thick ice cover produced an attenuation of the neap tidal range (1.9 m) and spring tidal range (4.0 m) of 17 and 37%, respectively, near the upstream end of the estuary. The arrival of low water was also delayed by about 90 min at this location. At the mouth, the cover attenuation peak ebb tide flow (200 [m.sup.3]/s) and flood tide flow (500 [m.sup.3]/s) by approximately 18 and 13%, respectively. Here the peak flood flow was normally delayed by 41 min, while the ebb tide was usually advanced by 8 min. In general, the ice cover attenuated peak velocities by 12 to 20%, although at certain times and locations the ice cover could induce higher velocities than would be present under open water conditions. The ice cover also retarded and diminished the salt wedge intrusion and is expected to dramatically reduce the sediment transport processes, although its presence could cause some sporadic local increases in erosion. DOI: 10.1061/(ASCE)0887-381X(2006)20:3(95) CE Database subject headings: Estuaries; Ice cover; Finite element method; Dimensional analysis.

This paper presents a new vertical 1D finite-element model to simulate the growth and decay of an ice cover (columnar ice, snow ice, slush, and snow cover consolidation) over a winter season in a partially mixed mesotidal estuary. In this study, we present, discuss, and validate boundary conditions as well as test and optimize the numerical model. Predictions from the model were assessed against field observations of ice thicknesses and internal temperatures taken over 3 years. This paper explains why ice in the estuary is almost completely composed of freshwater. We demonstrate how a columnar ice sheet grows over the first half of the winter season and is then melted from underneath during the second half of winter, especially where currents are strong. We also demonstrate that significant snow ice may form over the second half of winter if the ice cover survives long enough by resisting mechanical breakup of spring tides in March. DOI: 10.1061/(ASCE)0887-381X(2006)20:3(70) CE Database subject headings: Estuaries; Models; Salt water intrusion; Ice; Velocity; Hydrodynamics.

Environmental and social mitigation measures, are implemented by the practitioners of the hydropower industry. A study, based on a survey of nine international hydropower producers, regarding the effectiveness of such measures is described.

Objective Background Methods Results Conclusion The objective of this pilot study was to assess physical therapists’ (PTs) knowledge and needs regarding headache diagnosis and management.While there is significant research on physical therapy and cervicogenic headache, studies suggest that migraine is often under‐recognized, misdiagnosed, and inadequately treated across society despite its high prevalence and burden. Because migraine commonly includes concurrent neck pain and/or vestibular symptoms, patients with migraine may present to PTs for treatment. Very little is known about PTs' headache and migraine education, knowledge, and clinical practices.A team of headache specialists and PTs adapted a previously used headache knowledge and needs assessment survey to help ascertain PTs' knowledge and needs regarding headache treatment. The cross‐sectional survey was distributed online via Research Electronic Data Capture (REDCap) to PTs within a large healthcare system in Connecticut.An estimated 50.5% (101/200) of PTs invited to complete the survey did so. Only 37.6% (38/101) of respondents reported receiving any formal headache or migraine education in their professional training, leading to knowledge gaps in differentiating and responding to headache subtypes. Only 45.5% (46/101) were able to identify that migraine is characterized by greater pain intensity than tension‐type headache, and 22.8% (23/101) reported not knowing the duration of untreated migraine. When asked about the aspects of care they believe their patients with headache would like to see improved, PTs reported education around prevention and appropriate medication use (61/100 [61.0%]), provider awareness of the degree of disability associated with migraine (51/100 [51.0%]), and diagnostics (47/100 [47.0%]).This sample of PTs from one healthcare system demonstrates knowledge gaps and variations in clinical practice for managing their patients with headache. Future research on integrating additional opportunities for headache education for physical therapists, including evidence‐based behavioral therapies, is needed to ascertain whether it is likely to improve patient care. [ABSTRACT FROM AUTHOR]

Construction of the La Grande Complex in Eastern Canada called for complete or partial diversion of six rivers, the mean annual discharge of which varied from 60 to 1600 m3 s−1, and the transfer of water from two adjoining watersheds (1586m3 s−1) into La Grande Rivière. Three of these rivers with reduced flow, Eastmain (from 700 to 95m3 s−1), Opinaca (from 260 to 35m3 s−1), and Caniapiscau (from 1708 to 960m3 s−1) and the waterways with increased flows, Boyd-Sakami (from 1 to 811m3 s−1) and La Grande Rivière (from 1760 to 3400m3 s−1) were intensively monitored from 1978 to 1988, while the others were surveyed sporadically. Very few modifications were observed, compared to previous conditions, in banks stability, water quality, and aquatic fauna of the affected rivers: those which appeared can be explained by the water level fluctuations, the water quality of the tributaries of the residual drainage basin, and/or by the direct influence of the reservoirs. In James Bay, the areal extent of the Eastmain River and La Grand Rivière plumes varied with discharge in an exponential relation, mostly under ice cover; resources from the coastal environment had not yet undergone any major changes. Because of the very small population dwelling in the area, less than 3000 inhabitants, modifications in the hydrological regime of these rivers did cause relatively few impacts, the main being greater banks instability in specific locations, reduction of the thickness and ice cover on La Grande Rivière, enhancement of navigation constraints on Eastmain River, and higher mercury levels in fish related to operation of the reservoirs. [ABSTRACT FROM AUTHOR]