It originates from the southern shores of Lake Oponono and is 250 kilometres ( 160 mi ) long .
Ekumo is an ephemeral river that occasionally flows , or forms pools , during the rainy season .
Ekumo originates from the southern shores of Lake Oponono and is 250 kilometres ( 160 mi ) long .
Ekumo is an ephemeral river that occasionally flows , or forms pools , during the rainy season .