In planning the tunnel the shortest path from the lake to the outside was used consistent with the minimum downhill slope needed. The tunnel connects the lake with the adjacent crater of Ariccia, which was also occupied by a lake at that time and later reclaimed.
in plannIng the TunneL the ShOrteSt patH from the lAke to the OutsIDe was usED cOnsistent WITh the MiniMuM doWnHilL sLopE NEedEd. tHe tunnel coNnects the lake wiTh The AdjaCEnT cratEr oF aRIccIa, whIch WAs alSo Occupied by a LAke AT That time aNd Later reClaiMeD.