The dam, in simple concrete, is a double-curved vault non-overflowing, set on a reinforced concrete pier cap. Maximum retained height 41,60m, Crowning quote 181,00masl, Crowning development 137,70m, Maximum reservoir heigth 180,00masl, Liquid mirror surface (at maximum reservoir heigth ) 3,702km2, Reservoir total volume (pursuant to D.M. n° 44 of 24/03/82) 38,40x106m3, catchment area surface directly subtended 136,0km2.
The methodological approach was divided into phases:
I Phase - Re-evaluation of the dam and ancillary works seismic safety - The activities and operations concerning the verifications are: recognition and verification of existing documentation, supplementary surveys and reconstruction of any consistency drawings, definition of the investigation plan, execution of investigations and laboratory tests, construction supervision, supervision and control during the execution of the investigations, drafting of the geological study, drafting of the geotechnical study, seismotectonic study, execution of seismic checks, overall judgment on seismic safety, definition of the interventions to improve/adapt the stability conditions of the dam, examination of the alternatives of seismic improvement/adaptation of ancillary works.
II Phase - Dam hydrological-hydraulic study - Reassessment of the hydrological-hydraulic safety of the restraint system, re-elaborating the study already prepared by the pro tempore Operator, updating it to the current legislation and to the observations of the Hydraulic Office of the General Direction of the Dams, in order to identify the maximum regulation heigth that can be reached by the dam and the contextual verification of the dam's net heigth difference.
III Phase - Technical and economic feasibility design - Definition of the extraordinary maintenance interventions of the Arancio dam discharges, in the light of the results of the previous seismic safety reassessment studies and of the hydrological-hydraulic study carried out in the dam.