However, in drier years, the Shebelle River diminishes and transforms into a series of wetlands and sandy plains to the northeast of the confluence with the Jubba.
[7] Through their control of the region's wells, the Garen rulers effectively held a monopoly over their nomadic subjects as they were the only hydraulic empire in Africa during their reign.
The centralized regulations of the wells made it easier for the nomads to settle disputes by taking their queries to government officials who would act as mediators.
Today, numerous ruined and abandoned towns throughout the interior of Somalia and the Horn of Africa are evidence of a once-booming inland trade network dating from the medieval period.
The urban centers of Mogadishu, Merca, Barawa, Kismayo and Hobyo and other respective ports became profitable trade outlets for commodities originating from the interior of the state.
The Somali farming communities of the hinterland from Jubba and Shebelle rivers brought their crops to the Somali coastal cities, where they were sold to local merchants who maintained a lucrative foreign commerce with ships sailing to and coming from Arabia, Persia, India, Venice, Egypt, Portugal, and as far away as Java and China.
[11] In 1989, with the help of Soviet engineers, the Melka Wakena dam was built on the upper reaches of the Shebelle River in the Bale Mountains.