5 3 ▁after ▁the ▁completion ▁of ▁the ▁dam . ▁Part ▁of ▁the ▁Will am ette ▁Valley ▁Project s , ▁the ▁lake ▁was ▁intended ▁primarily ▁for ▁flo od ▁control ▁and ▁power ▁generation ▁but ▁has ▁become ▁one ▁of ▁the ▁major ▁recre ation ▁resources ▁in ▁western ▁Oregon . ▁ ▁Details ▁ ▁The ▁res er voir ▁has ▁a ▁capacity ▁of ▁ ▁of ▁water ▁when ▁full ▁and ▁ ▁in ▁the ▁summer ▁when ▁drawn ▁down . ▁Loc ated ▁in ▁the ▁North ▁Sant iam ▁C any on , ▁the ▁ ▁long ▁lake ▁has ▁sh or eline ▁of ▁ ▁when ▁full . ▁One ▁sw imming ▁opportunity ▁is ▁at ▁the ▁Mong old ▁Day - Use ▁Area ▁( an ▁Oregon ▁State ▁Park ). ▁Detroit ▁Lake ▁is ▁stock ed ▁by ▁the ▁Oregon ▁Department ▁of ▁Fish ▁and ▁Wild life ▁with ▁ 1 2 5 , 0 0 0   catch able ▁rain bow ▁tr out ▁along ▁with ▁finger ling ▁rain bow , ▁k ok ane e ▁and ▁ch ino ok ▁sal mon . ▁ ▁A ▁self - s ust aining ▁population ▁of ▁brown ▁b ull head ▁cat fish ▁res ides ▁in ▁the ▁lake . ▁ ▁Detroit ▁Lake ▁offers ▁year - round ▁fish ing ▁as ▁long ▁as ▁you ▁fish ▁in ▁still ▁water ▁and ▁not ▁in ▁or ▁near ▁the ▁rivers ▁and ▁streams . ▁ ▁It ▁is ▁one ▁of ▁ 3 2 ▁la kes ▁feder ally ▁designated ▁for ▁recre ation , ▁managed ▁by ▁the ▁United ▁States ▁Forest ▁Service . ▁The ▁lake ▁serves ▁many ▁purposes ▁including ▁flo od ▁control , ▁water ▁conservation , ▁and ▁recre ation . ▁ ▁There