ʌpstɹˈiːm ʌv lˈeɪk mˈɪʃən viːˈeɪoʊ ɪz ˌʌpɚɹ ˈoʊsoʊ ɹˈɛzɚvwˌɑːɹ, wˌɪtʃ spˈɪlz dˈaʊnstɹiːm ænd ˌɪntʊ mˈɪʃən viːˈeɪoʊ ɪn wˈɛt jˈɪɹz.
Upstream of Lake Mission Viejo is Upper Oso Reservoir, which spills downstream and into Mission Viejo in wet years.