Groundwater
Apart from River Malewa, which represents about 3/4 of the basin runoff entering the lake, and the River Gilgil, all other streams that flow to Naivasha are ephemeral, flowing only after heavy rain. This clip shows the bottom of the Marmanet River in the south west of the Naivasha catchment, which disappears underground about 1-2km away from the lake. During recent heavy rains it extended its course for about 300m and created a new swallow hole where it disappeared.
