▁to ▁supply ▁Pan ama ▁City ' s ▁fresh ▁water . ▁ ▁G at un ▁Dam ▁and ▁G at un ▁Lake ▁ ▁At ▁ ▁from ▁the ▁river ' s ▁mouth ▁lies ▁the ▁G at un ▁Dam , ▁which ▁created ▁G at un ▁Lake ▁and ▁provides ▁hydro elect ric ity . ▁Cre ated ▁in ▁ 1 9 1 3 ▁by ▁the ▁dam ming ▁of ▁the ▁Ch ag res ▁River , ▁G at un ▁Lake ▁is ▁an ▁essential ▁part ▁of ▁the ▁Pan ama ▁Canal , ▁which ▁forms ▁a ▁water ▁passage ▁between ▁the ▁Atlantic ▁Ocean ▁and ▁the ▁Pacific ▁Ocean , ▁perm itting ▁ship ▁trans it ▁in ▁both ▁directions . ▁The ▁lake ▁is ▁essential ▁to ▁the ▁canal ' s ▁water ▁supply , ▁as ▁it ▁provides ▁the ▁millions ▁of ▁gall ons ▁of ▁water ▁at ▁the ▁high ▁level ▁needed ▁for ▁the ▁lo cks ▁to ▁function ▁correctly . ▁The ▁lake ▁is ▁also ▁part ▁of ▁the ▁navig ational ▁canal ▁and ▁provides ▁drink ing ▁water ▁for ▁Pan ama ▁City ▁and ▁Col on . ▁ ▁At ▁the ▁time ▁it ▁was ▁formed , ▁G at un ▁Lake ▁was ▁the ▁largest ▁man - made ▁lake ▁in ▁the ▁world . ▁The ▁imp ass able ▁rain for est ▁around ▁G at un ▁Lake ▁has ▁been ▁the ▁best ▁defense ▁of ▁the ▁Pan ama ▁Canal . ▁Today , ▁these ▁areas ▁have ▁end ured ▁pract ically ▁un sc athed ▁by ▁human ▁inter ference ▁and ▁are ▁among ▁the ▁one ▁the ▁few ▁accessible ▁areas ▁where ▁various ▁native ▁Central ▁American ▁animal ▁and ▁plant ▁species ▁can ▁be ▁observed ▁und ist urbed ▁in ▁their ▁natural ▁habitat