main water conveyance tunnel of Dahuofang reservoir is 85.4Km long and threads through Archaeozoic compositing gneiss, Paleozoic quartzite and marble, Mesozoic volcano,lava,volcanic breccia,tuff , sand-shale stone and Yanshan period orthophyre.

• 大伙房水库输水工程隧道主洞线长85.；4km；穿越的地层有太古界混合片麻岩; 元古界石英岩、大理岩;