This study explores flow regulation controls on daily river discharge variations and trends into Hudson Bay from four highly regulated and 17 moderately regulated/ unregulated systems over 1960-2016. These 21 rivers contribute~70% of the total annual riverine freshwater export to Hudson Bay, with highly regulated and moderately regulated/unregulated rivers accounting for 47% and 53% of the discharge, respectively. Daily observed streamflow data from the Water Survey of Canada, Manitoba Hydro, Ontario Power Generation, and Hydro-Québec are used. Decadal hydrographs of the mean and coefficient of variation of daily river discharge are developed to assess the changing hydrological regimes in both systems. Decadal spectral analyses reveal the dominant controls on daily river discharge input to Hudson Bay from the regulated and unregulated systems. Apart from expected peaks in spectral power on annual timescales arising from the nival regimes in both systems, a strong secondary peak emerges at weekly timescales from flow regulation due to hydropower production. Hydrographs that consider the day of the week reveal distinct weekly cycles in regulated rivers with~10% declines in daily river discharge during weekends and statutory holidays relative to weekday averages, demonstrating the importance of regulation on the timing of freshwater into Hudson Bay.
This study aimed to assess the efficacy of a minimal intervention focusing on hypnotic discontinuation and cognitive-behavioral treatment (CBT) for insomnia. Fifty-three adult chronic users of hypnotics were randomly assigned to an 8-week hypnotic taper program, used alone or combined with a self-help CBT. Weekly hypnotic use decreased in both conditions, from a nearly nightly use at baseline to less than once a week at posttreatment. Nightly dosage (in lorazepam equivalent) decreased from 1.67 mg to 0.12 mg. Participants who received CBT improved their sleep efficiency by 8%, whereas those who did not remained stable. Total wake time decreased by 52 min among CBT participants and increased by 13 min among those receiving the taper schedule alone. Total sleep time remained stable throughout withdrawal in both CBT and taper conditions. The present findings suggest that a systematic withdrawal schedule might be sufficient in helping chronic users stop their hypnotic medication. The addition of a self-help treatment focusing on insomnia, a readily available and cost-effective alternative to individual psychotherapy, produced greater sleep improvement.
Spatial distribution of macrozooplankton was studied during spring in Lake of Geneva to evaluate the influence of abiotic (water temperature and stability, nutrients) and biotic (bacteria, chlorophyll a, fish biomass) factors on macrozooplankton distribution. Mapping and spatial analyses revealed that abiotic factors, as well as crustacean abundances, were structured along a gradient in the great lake basin. Chlorophyll a biomass, bacteria density, cyclopoid abundance, and fish biomass showed more patchy or inshore-offshore distribution patterns. Using canonical analyses, we determined the relative contribution of the spatial and environmental factors to the distribution of macrozooplankton species and of trophic groups based on herbivory and omnivory/carnivory. The distribution of macrozooplankton can be explained by small-scale variations and lake gradients in abiotic and biotic factors, with a dominant contribution of the abiotic factors. Water temperature and stability, as well as ammonium, are the main factors related to macrozooplankton distribution in Lake of Geneva during spring. Chlorophyll a biomass was also related to the distribution of cyclopoids. The canonical models explained 35-72% of the variance in the distribution of total crustaceans, species, and trophic groups. However, 28-65% of the macrozooplankton variance remained unexplained, which may be due to fine-scale variations in other environmental factors.
An assessment of interactions between groundwater and surface water was carried out by applying two different modeling approaches to a small-scale study area in the municipality of Havelock, Quebec. The first approach involved a commonly used sequential procedure that consists in determining the daily recharge rate using a quasi 2D infiltration model (HELP), applied in the next step as an imposed flux to a 3D finite-element groundwater flow model. The flow model was calibrated under steadystate and transient conditions against measured water levels. The second approach was based on a recently developed physically based, 3D fully coupled groundwater-surface water flow model (CATHY) applied to the entire flow domain in an integrated manner. Implementation, calibration, and results of the simulations for both approaches are presented and discussed. For equal annual precipitation (1038 mm/y) and evapotranspiration (556 mm/y), the second approach computed a recharge rate of 233 mm/ y (8.9% higher than the first approach) and a net upward flow from the fractured aquifer (the first approach predicted a net downward flow to the rock). The simulated annual discharge was similar for the two approaches (9.6% difference). Both approaches were found to be useful in understanding the interactions between groundwater and surface water, although limitations are apparent in the sequential procedure's inability to account for surface-subsurface feedbacks, for instance near stream reaches where groundwater discharge is prevalent. The decoupled, two-model approach provides disaggregated surface, vadose, and aquifer flows, and a simple aperçu at the different components of total discharge. The fully coupled model accounts for continuous water exchanges between the land surface, subsurface, and stream channel in a more complex manner, and produces a better match against observed data.
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