ci ation ▁between ▁the ▁villages ▁of ▁Alt gl ash ütt en , ▁F alk au ▁and ▁A ha ▁on ▁the ▁territory ▁of ▁the ▁municipality ▁of ▁L enz kir ch . ▁ ▁The ▁lake ▁lies ▁in ▁a ▁tr ough ▁that ▁runs ▁from ▁the ▁Se eb ach ▁valley ▁in ▁the ▁north west ▁to ▁the ▁Schl uch see ▁in ▁the ▁sout heast ▁and ▁thus ▁cross es ▁the ▁generally ▁n ortheast ward - running ▁streams ▁in ▁the ▁area . ▁This ▁rem nant ▁of ▁a ▁former ▁valley ▁is ▁followed ▁by ▁the ▁Three ▁L akes ▁Railway ▁that ▁was ▁built ▁between ▁ 1 9 2 0 ▁and ▁ 1 9 2 6 ▁and ▁by ▁the ▁transfer ▁channel ▁( Ü ber leitung sk anal ), ▁built ▁in ▁ 1 9 3 2 ▁and ▁belonging ▁to ▁the ▁Schl uch see werk , ▁which ▁takes ▁water ▁from ▁the ▁Se eb ach ▁valley ▁via ▁the ▁Has lach ▁valley ▁to ▁the ▁Schl uch see ▁Bas in . ▁ ▁North ▁of ▁the ▁low - lying ▁waters hed ▁in ▁this ▁tr ough , ▁between ▁the ▁Has lach ▁in ▁the ▁north ▁and ▁the ▁A hab ach ▁in ▁the ▁south , ▁now ▁d rown ed ▁by ▁the ▁imp ounded ▁Schl uch see , ▁the ▁gla cier ▁of ▁the ▁last ▁ice ▁age ▁car ved ▁out ▁a ▁bas in , ▁in ▁which ▁a ▁small ▁bog ▁lake ▁formed , ▁the ▁natural ▁prec ursor ▁to ▁today ' s ▁res er voir . ▁This ▁was ▁en larg ed ▁in ▁ 1 8 9 5 ▁by ▁the ▁former ▁F alk au ▁S cre w ▁Works