ARTIFICIAL RESERVOIRS

The applicable national legislation (DPR 1363/59 and subsequent provisions issued to supplement the Regulation, including: Ministry of Public Works Circular 28 August 1986, No. 1125; Ministry of Public Works Circular 4 December 1987, No. 352; Law No. 584 of October 21, 1994; P.C.M. Circular 13 December 1995, No. DSTN/2/22806; Ministry of Public Works Decree 24/3/82; Law 183/89; DL 507/94, converted into Law 584/94; Law 139/04; Legislative Decree 152/06; Ministry of Public Works Decree 14 January 2008; Ministry of Infrastructure and Transport Decree 26 June 2014) regulates the technical standards for the design and construction of dam structures, defines management regulations , provides implementing provisions, and outlines responsibilities regarding Large and small dams. It also identifies urgent safety measures for large dams, following  changes in national legislation on seismic risk (Law 64/74, Law 139/04, OPCM 3519 of April 28, 2006) and establishes operational guidelines for managing geo-hydrological and hydraulic critical conditions (DPCM 27/02/2004, P.C.M. Directive 8 July 2014).

Reservoirs, underground thanks, or suspended tanks are not subject to dam regulations because they do not involve dam structures. Also excluded are all dam works that create reservoirs solely for the storage, decanting, or washing industrial residues, which, according to Law 584/94, fall under the jurisdiction of the Ministry of Enterprises and Made in Italy (MIMIT).

Several circulars on seismic safety have been issued (DG Dighe Circular 27 September 2017, No. 21530; DG Dighe Circular No. 25157 of 8 November 2017; DG Dighe Circular 18 March 2019 No. 6.660; DG Dighe Circular 3 July 2019 No. 16790). These documents provide guidance on methodologies and requirements for assessing seismic hazard at dam sites and update procedures for extraordinary inspections following seismic events.

Regarding small dams, Article 1 of Law 584/94 (and subsequent Legislative Decree 112/98) establishes that responsibilities outlined in D.P.R. No. 1363/59  fall under the ordinary and special status regions and the autonomous provinces of Trento and Bolzano. These regulations apply to dams not exceeding 15 meters in height or to reservoirs with a capacity of 1,000,000 cubic meters or less. Law No. 584/1994, in Article 2, paragraph 2-bis, required regions to adopt their own regulations within six months of the issuance of the national regulation to govern administrative functions regarding the dams under their responsibility. Until the regulation takes effect, the provisions of the 59/1363 approved by Presidential Decree remain in force. Despite the absence of a national regulation framework, several regions and provinces have independently introduced regulations for small reservoirs, providing implementing provisions to regulate project approval procedures and the supervision of retaining dams and related storage basins (Basilicata, Sardinia, Veneto, Piedmont, Aosta Valley, Tuscany, Abruzzo, Campania, Molise, Umbria, Emilia-Romagna, Lombardy, autonomous provinces of Trento and Bolzano, Civil Engineering of Catania). Some regional regulations also define reservoir risk categories (Tuscany Regional Law 28/07/2014, No. 43; Piedmont Regional Law 6/10/2003, No. 25 and related regional regulations: No. 12/R of 9/11/2004, and No. 1/R of 29/01/2008; Abruzzo Regional Law 27/06/2013, No. 18; Aosta Valley Regional Law 29/03/2010, No. 13, and DGR 2073 of 30/7/2010; Sardinia Regional Law 31/10/2007, No. 12). These are based on the Presidency of the Council of Ministers, Civil Protection Department, Forecasting and Prevention Service,  31 July 1991 (No. prev. 2554 gen. 804).

The European Parliament and Council Directive 2000/60/EC, of October 23, 2000, establishes a framework for community action in water policy, introducing the obligation to prepare river basin management plans for all hydrographic districts  to achieve a good ecological and chemical status of waters. Regarding the protection of surface waters, Article 74(2)(g) of Legislative Decree 152/06 defines an "artificial water body" as "a surface water body created by human activity," and "heavily modified water body" (HMWB) as "a surface water body whose nature, following physical alterations due to human activity, is substantially changed, as determined by the competent authority based on the provisions of Articles 118 and 120." Physical alteration refers to any modification whose effects result in hydromorphological changes that substantially alter the natural characteristics of the water body. Heavily modified water bodies (HMWBs) are artificially created by dams (or weirs) built on rivers or streams to store large volumes of water for civil  (drinking water production), industrial (e.g., hydropower generation), and agricultural uses.