File:Flooding in Tanzania (MODIS 2024-05-03).jpg

English: May 2, 2024 May 4, 2023

While southern Africa experienced a prolonged dry spell, heavy rains throughout April 2024 brought severe flooding to eastern African countries, including Tanzania, Kenya, and Somalia. In Tanzania, floods and landslides contributed to hundreds of injuries, more than 150 deaths, and thousands of damaged buildings, according to a report published by ReliefWeb on April 26—and additional rain was in the forecast. Heavy rains in Kenya and Somalia also produced dangerous floods, displacing tens of thousands of people and inundating croplands.

Tanzania’s Rufiji district, about 130 kilometers (80 miles) south of Dar es Salaam, was one particularly hard-hit area. Flooding left tens of thousands of people there in need of food, shelter, clean water, and healthcare. Approximately 34,000 hectares (84,000 acres) of crops were also damaged, the district commissioner said in an April 10 report.

This pair of false-color images, each acquired by the Moderate Resolution Imaging Spectroradiometer (MODIS) MODIS on NASA’s Terra satellite about a year apart (May 2, 2024 an May 4, 2023) provides insight into the widespread flooding in Tanzania’s Rufiji River Basin. This type of false-color image helps separate the presence of water, which appears dark blue, from vegetation, which looks bright green.

Clicking on the dates reveals the relevant image. The 2024 images shows the widespread flooding along the Rufiji River, especially as it approaches the Indian Ocean and in the west upstream of two reservoirs. In the 2023 image, the water levels are more normal, with faint water visible downriver from the dam. Both reservoirs are also notably smaller in 2023.

The largest reservoir is behind the recently completed Julius Nyerere Hydropower Plant. This dam and reservoir are located within the Selous Game Reserve, part of which became Nyerere National Park in 2019. Covering 50,000 square kilometers (19,000 square miles), the area is among the most expansive tracts of wilderness in Africa and is designated a UNESCO World Heritage Site. The dam is expected to alter hydrology downstream and reduce the supply of sediment to floodplains, where farmers cultivate rice, and to the delta, which supports one of the largest mangrove stands in eastern Africa.