5/30/2012

Experimental releases to determine scenarios of optimal Minimum Instream Flow in Aosta Valley river network

Project Final Meeting Aosta, Italy– 24th May 2012 Raffaele Rocco Dipartimento Difesa del Suolo e Risorse Idriche

Annual average flow remaining in a

watercourse as a result of lead

The regional plan for water protection approved in 2006 has required that any derivation of water (new or existing) was released a range of minimum vital flow to be determined on the hydrology criteria or experimentally

The experiment involves the 28 main branches of the CVA group: 10 on Dora Baltea

18 on tributary streams of Baltea

The basins have been grouped into 4 areas chosen on the basis of geographical, climatic, hydro-morphological, human and tourist-recreational special intertessi

CRITERIO SPERIMENTALE DI CALCOLO DEL DMV

The experiment comprises a step of characterization of the area involved and subjected to pressures for decades due to the hydroelectric derivations reference against which to compare and evaluate the responses related to the release ecosystem in the river bed.

With the monitoring activity of 2011 were measured impacts on the water course of three levels of flow (2/3%, 10%, 13% of the annual average flow) in some basins sample taken as representative of the situations present in the region, while for all other lead has worked with a release of around 2% -3% of the annual average flow. The stations are 77 monitoring stations covering nearly 80% of the Aosta Valley.

They are measurements of the following: • 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 the human factors, the current Minimum Instream Flow issued and limiting natural at higher altitudes, we would have about a 75% achievement of the good evaluated with only the chemical and biological indices. With an adjustment of discharges having established production losses is expected that only 5% of the points would not be consistent.

CONCLUSIONI

Hydromorphological indicators seem to be the most responsive to the pressures

of hydropower

The minimum vital flow can not be resolved solely by technical

The role of the programming practices of public admistrators is essential in a

framework of principles of water protection

THANK YOU FOR YOUR ATTENTION