I have to write a paragraph about the Indus River and how it affected the people living near it, and how they relied on it. What would be a good topic sentence?

The Indus River features a total catchment basin of more than 1,165,000 square km (450,000 sq miles). The approximate yearly discharge of the river figures at approximately 207 cubic kilometers, making it the 21st biggest river in the world in terms of yearly discharge. Starting at the pinnacle of the world with glaciers, the Indus River supplies the flora and fauna of temperate forests, plateaus, and dry rural areas. In conjunction with the rivers Chenab, Jhelum, Sutlej, Ravi, Beas and two tributaries from the Afghanistan and Khyber Pakhtunkhwa, the Indus creates the Sapta Sindhu (Seven Rivers) delta of Pakistan.