The downstream ecological consequences of two controlled "free flow" flushing operations designed to remove sediments accumulated in an alpine reservoir are described. The main objectives of the study were (a) to verify to what extent the suspended solid concentration (SSC) in the receiving water course can be controlled by flushing operations, (b) to determine the biological consequences of flushing operations, and (c) to produce technical guidelines for the future planning and monitoring of these activities. We found that the flushing of large volumes of accumulated sediment had clear effects on the stream ecosystem due to the unpredictability of short duration SSC peaks (70-80 g L(-1)) and the high average SSC (4-5 g L(-1)) within flushing periods. The main impacts were decreased fish densities (up to 73%) and biomass (up to 66%). A greater mortality recorded for juveniles will likely result in long-term impairment of the age-structures of future fish populations. The zoobenthic assemblages, despite exhibiting a drastic reduction in abundance following the first floods, showed substantial recovery within 3 months of the beginning of flushing operations. Regular sediment removal by yearly flushing is recommended in order to avoid SSC peaks and to facilitate the control of scouring effects caused by the water used to wash out sediments. We also recommend maximum allowable SSCs of 10 g L(-1) (daily average) and 5 g L(-1) (overall average) for flushing operations carried out in similar environmental contexts

We report the results of an "open' multicentre study evaluating the use, tolerability and therapeutic efficacy of the sodium salt of 4-hydroxybutyric acid (GHB) for the medium-term treatment of withdrawal symptoms in 179 patients with alcohol dependence followed up as outpatients. The follow-up of patients was 6 and 12 months after drug discontinuation. Following a daily oral administration of 50 mg/kg for approximately 6 months, no serious systemic or single-organ consequences leading to drug discontinuation were reported, and tolerability was fair in all patients. Eleven subjects (10.1%) showed craving for the drug and voluntarily increased their doses (6-7 times the recommended levels). GHB led to complete abstinence during drug administration in 78.0% of the patients. A significant reduction of compulsive desire ("craving') was observed in parallel, as deduced from evaluation of a specific questionnaire, the Alcohol Craving Scale. At follow-up examination, 43 of the treated subjects remained abstinent at 6 months, and 30 subjects were abstinent for 1 year after drug discontinuation.

Sediment flushing may be effective in mitigating loss of reservoir storage due to siltation, but flushing must be controlled to limit the impact on the downstream environment. A reliable prediction of the environmental effects of sediment flushing is hindered by the limited scientific information currently available. Consequently, there may be some controversy as regards to management decisions, planning the work, and monitoring strategies. This paper summarizes the main results of a monitoring campaign on the stream below a small alpine hydropower reservoir subjected to annual flushing between 2006 and 2009. The removed sediment was essentially silt, and the suspended solid concentration (SSC) of the discharged water was controlled to alleviate downstream impact. Control was achieved through hydraulic regulation and mechanical digging, alternating daytime sediment evacuation, and nocturnal clear water release. The four operations lasted about two weeks each and had an average SSC of about 4 g L(-1). Maximum values of SSC were generally kept below 10 g L(-1). Downstream impact was quantified through sampling of fish fauna (brown trout) and macroinvertebrate in the final reach of the effluent stream. The benthic community was severely impaired by the flushing operations, but recovered to pre-flushing values in a few months. As expected, the impact on brown trout was heavier on juveniles. While data biasing due to fish removal and re-stocking cannot be ruled out, the fish community seems to have reached a state of equilibrium characterized by a lower density than was measured before the flushing operations.

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