Experimental releases to determinescenarios of optimal Minimum InstreamFlow in Aosta Valley river networkProject Final MeetingAosta, Italy– 24th May 2012Raffaele RoccoDipartimento Difesa del Suolo e Risorse Idriche 5/30/2012
Annual average flow remaining in a watercourse as a result of lead
The regional plan forwater protectionapproved in 2006 hasrequired that anyderivation of water(new or existing) wasreleased a range ofminimum vital flow tobe determined on thehydrology criteria orexperimentally
The experiment involves the 28 main branches of the CVA group: 10 on Dora Baltea
CRITERIO SPERIMENTALE DI CALCOLO DEL DMVThe basins have been grouped into 4 areas chosen on thebasis of geographical, climatic, hydro-morphological,human and tourist-recreational special intertessi
The experiment comprises a step ofcharacterization of the area involvedand subjected to pressures for decadesdue to the hydroelectric derivationsreference against which to compare andevaluate the responses related to therelease ecosystem in the river bed.
With the monitoring activity of 2011were measured impacts on the watercourse of three levels of flow (2/3%,10%, 13% of the annual average flow)in some basins sample taken asrepresentative of the situations presentin the region, while for all other leadhas worked with a release of around2% -3% of the annual average flow.The stations are 77 monitoring stationscovering nearly 80% of the AostaValley.
They are measurements of thefollowing:• LIM, IBE, pH, flow, turbidity, temperature and IFF (all sections);• The detail information of the hydromorphology of significant parts of the river system under consideration;• As regards the fishes are carried out in 22 sampling stations
At present, taking into account thehuman factors, the current MinimumInstream Flow issued and limitingnatural at higher altitudes, we wouldhave about a 75% achievement of thegood evaluated with only the chemicaland biological indices.With an adjustment of dischargeshaving established production losses isexpected that only 5% of the pointswould not be consistent.
CONCLUSIONIHydromorphological indicators seem tobe the most responsive to the pressures of hydropower The minimum vital flow can not be resolved solely by technicalThe role of the programming practicesof public admistrators is essential in a framework of principles of water protection