There is a river passing down Garissa county. It's called River Tana. It produces electricity and irrigation to the people and is one of the longest rivers in Kenya. It's mouth/sources is from Mt. KenyaBelieve it or not but parts of NFD is blessed with fertile lowlands and rivers.
There are many massive Somali farms on the Dawa river produced by the Garre clan in Mandera region.
There is also another massive Somali farms found on the Tana river in Garissa region by the Ogaden clan.