- gener ators ▁re - fill ▁the ▁res er voir s ▁and ▁the ▁process ▁repe ats ▁as ▁needed . ▁The ▁Chi ot as ' ▁upper ▁res er voir , ▁L ago ▁del ▁Chi ot as , ▁is ▁located ▁much ▁higher ▁in ▁the ▁valley ▁and ▁larger ▁than ▁R ov ina ' s ▁L ago ▁della ▁R ov ina ▁which ▁aff ords ▁it ▁the ▁ability ▁to ▁produce ▁more ▁electric ity . ▁The ▁installed ▁capacity ▁of ▁Chi ot as ▁is ▁ ▁with ▁a ▁hyd ra ul ic ▁head ▁( water ▁drop ▁in ▁elev ation ) ▁of ▁ ▁while ▁R ov ina ▁has ▁an ▁installed ▁capacity ▁of ▁ ▁and ▁a ▁head ▁of ▁. ▁Const ruction ▁on ▁the ▁plant ▁began ▁in ▁ 1 9 6 2 ▁and ▁operations ▁started ▁in ▁ 1 9 8 2 . ▁It ▁is ▁owned ▁and ▁operated ▁by ▁En el . ▁ ▁Design ▁and ▁operation ▁ ▁The ▁Ent rac que ▁Power ▁Plant ▁is ▁supported ▁by ▁a ▁scheme ▁that ▁also ▁primarily ▁consists ▁of ▁three ▁res er voir s . ▁The ▁lower ▁res er voir ▁used ▁by ▁both ▁the ▁Chi ot as ▁and ▁R ov ina ▁is ▁L ago ▁della ▁Pi ast ra . ▁The ▁res er voir ▁is ▁located ▁at ▁the ▁base ▁of ▁the ▁valley ▁and ▁was ▁formed ▁by ▁the ▁construction ▁of ▁an ▁ ▁tall ▁gravity ▁dam . ▁Its ▁water ▁level ▁has ▁a ▁normal ▁operating ▁elev ation ▁of ▁ ▁and ▁ ▁of ▁its ▁total ▁ ▁storage ▁capacity ▁can ▁be ▁p ump ed ▁up ▁to ▁the ▁upper ▁res er voir s . ▁The ▁p ump ing