*3.1. Study Area*

The Nile River is one of the longest rivers in the world, traversing 6853 km. It consists of four major water systems, namely the Blue Nile, Tekeze-Atbara, Baro-Sobat, and the White Nile, before forming the main Nile in Sudan and subsequently flowing north through Egypt into the Mediterranean Sea. The Blue Nile, Baro-Sobat, and Tekeze-Atbara originate in the Ethiopian highlands, contributing 86% of annual flow, leaving the White Nile to contribute 14% from the equatorial African lakes region [33]. The basin covers 3.2 million km2, including 11 riparian states, namely Burundi, the Democratic Republic of Congo, Egypt, Eritrea, Ethiopia, Kenya, Rwanda, South Sudan, Sudan, Tanzania, and Uganda (Figure 1). The basin is home for over 257 million people, with the majority near or below the poverty line [33–35].

**Figure 1.** Map of the Nile basin.
