By Felix Mwakyembe, Alertnet (January 17, 2012)
Pius Yanda, one of the authors of a recent report on extreme weather by the Intergovernmental Panel for Climate Change (IPCC), has a knowledge of his subject that goes beyond the academic.
Yanda, a professor at the University of Dar es Salaam, was forced from his home last month by flooding in the nation’s largest city following the heaviest recorded rains in Tanzania’s modern history. He and five family members sought temporary refuge at a hotel in the city.
The Tanzania Meteorological Agency reported that 260 mm (10 inches) of rain fell during a continuous downpour that began on December 20 and ended two days later. On December 21 alone, Dar es Salaam received 156 mm (6 inches) of rain, the highest daily amount since 1954.
Agnes Kijazi, director general of the agency, said that while rains are expected in the last quarter of the year, these were unusually heavy.
The torrential rains affected regions across the east African nation, including Mwanza in the northwest and Kilimanjaro in the northeast, where there were landslides, as well as Dodoma in the country’s centre, and Mbeya to the south.
The flooding left around 40 people dead and thousands homeless.
Policy makers are now faced with the challenge of planning to mitigate flood damage in a country that is more used to grappling with ongoing drought.
Yanda, who was a contributor to the IPCC’s recent “Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation” report, characterized the floods as a consequence of increasing extreme weather events linked to climate change.
He explained that the number of days of rain received annually by Dar es Salaam has been declining, but rainfall is becoming heavier when it does occur.
DEVELOPMENT WORSENING PROBLEMS
At the same time, urban development has contributed to problems from extreme rainfall as people clear trees and vegetation to make way for the construction of houses.
“When you clear trees you create more surface run-off” of water, said Yanda.
The director of the government’s Environment Division, Julius Ningu, criticised land use officials for allowing unplanned settlements and letting people build homes in valleys, where the homes block natural water courses.
“People have built houses in canals, valleys and swamps. Other countries leave those areas,” Ningu said. Such areas should be set aside as buffer zones, and more trees should be planted to help hold water and soil, he said.
Rural inhabitants tell a similar story of a changed environment. Nelson Mahena, of Ikuti village in Mbeya region, about 860 km (540 miles) from Dar es Salaam, says that before 1975 there were few houses in the region. Most of the area was covered by natural forest and was uncultivated.
“The weather was very cold throughout the year and (even) in July we experienced frost. There were springs everywhere here, (but) we had no floods like this year,” said the 63-year-old.
By contrast, Mahena said it is now much warmer during the summer months, and the springs and streams have dried up. However, he was not affected by the December floods because he lives in the uplands.
Ulimboka Mwakilili of the Red Cross said that the clearing of trees and natural vegetation in the area around Dar es Salaam contributed to the floods by increasing the flow of water from the uplands and depriving it of natural run-off channels.
Deodatus Mfugale, chairman of the Journalists Environmental Association of Tanzania, blamed poor city adaptation plans for the floods, citing the construction of bridges and canals without consideration of the impacts of climate change.
“Adaptation is not only about money, (but) the planning of our cities,” Mfugale said.
Climate change experts recommend revisiting the development plans of all Tanzania’s cities and have urged rapid measures to establish new plans where needed – plans that are adapted to the growing possibility of extreme weather events.
“The design of our infrastructure should take into account anticipated extremes. Canals should be able to carry a lot of water,” Yanda said.
In response to the recent floods, President Jakaya Kikwete issued a directive to those living in valleys to move to specially allocated upland areas.
The Dar es Salaam regional authority has set aside 200 hectares (about 500 acres) with 2,800 plots that will be allocated to flood victims and others living in valleys.