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Espa P.,University of Insubria | Castelli E.,ARPA Lombardia Regional Agency for Environmental Protection | Crosa G.,University of Insubria | Gentili G.,GRAIA Srl
Environmental Management | Year: 2013

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. © 2013 Springer Science+Business Media New York. Source

Colombi C.,ARPA Lombardia Regional Agency for Environmental Protection | Gianelle V.L.,ARPA Lombardia Regional Agency for Environmental Protection | Belis C.A.,European Commission - Joint Research Center Ispra | Larsen B.R.,European Commission - Joint Research Center Ispra
Chemical Engineering Transactions | Year: 2010

Knowledge on the main emission sources and their relative importance is essential for policy makers to define effective pollution reduction strategies. Such knowledge can be gained by receptor modeling using e.g. the chemical mass balance model (CMB). For a successful application of CMB all important sources must be known and information must be available on representative emission profiles. Speciation profiles of emission sources can be found in literature and extensive databases are available (U.S. E.P.A., 2002). However, it is preferable to use profiles representing the actual sources present in the area whenever is possible. For the Lombardy region, previous studies have demonstrated the importance of soil and fugitive dust, biomass burning and brake lining dust (Regione Lombardia, ARPA Lombardia, Fondazione Lombardia per l'Ambiente, 2008; AA.VV., 2006). The goal of this work is to report our methodology used to determine 'local' source profiles of soil dust, domestic wood burning and brake lining dust, to be used for example in the CMB applications. To investigate the model sensitivity, simulations were carried out for several sites with different local and no-local profiles. Copyright © 2010, AIDIC Servizi S.r.l. Source

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