SCIENTIFIC AND MANAGEMENT RECOMMENDATIONS INFORMATION GAPS
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and Silversands Hotels and at the Boathouse of the Kunduchi Fisheries Institute. However, at the southern end of the Kunduchi Beach Hotel, there was an erosion of 30 cm depth along the first 10 metres of the profile. But in
August and especially during high tides, the beach lines receded 1.5 metres at the American Club; 10 metres near the southern end of Bahari Beach Hotel; 2 metres at the Boathouse of the Kunduchi Fisheries Institute and 2 metres at the
southern end of the Kunduchi Beach Hotel. However, at the Africana Hotel the situation was different from what happened on other profiles. The high tides of August resulted in an accretion of sand of about 30 cm depth along the
entire profile. At Msasani Beach, there was a steady accretion of sand along the profile until mid-June when erosion started. The August high tides affected mainly the crest and 20 cm depth of sand was washed away.
On assessing aerial photos, Mushala 1978 found that over a 20-year period there was a recession of the shorelines of more than 50 metres at both the Siversands and Kunduchi Baech Hotels. Mushala 1978 observed seasonal changes
in profiles at fixed points along Kunduchi Beach from October 1977 to April 1978. He found that erosion, accretion and sediment transport were taking place simultaneously at varying rates. The maximum rate of erosion was a 4-metre
loss in thickness between two consecutive profiles over one month. The minimum rate of erosion was 0.2 metre. The maximum rate of accretion was a vertical increase of 2.2 metres in a month while the minimum rate was 0.1 metre.
These rates had a direct relationship with changes in the monsoon winds. Severe erosion was observed during the SE monsoons, while accretion took place at time of transition of wind direction of the monsoons.
Mwandosya et al. 1998 conducted a study on the impacts of sea level rise on the coastline of Tanzania. The analytical approach topographic maps showed that in Tanga region, Moa was the most vulnerable coastal unit
area while Kigombe was the least vulnerable. In Lindi and Mtwara, Nangurukuru was most vulnerable followed by Mnazi Bay while Lindi was the least vulnerable. In Dar es Salaam and coast regions, Salale was the most
vulnerable followed by Mbwera while Kawe was the least vulnerable. On the whole of the Tanzanian coastline, mangroves were the most vulnerable coastal resources and Dar es Salaamcoast area was the most vulnerable
while Tanga was the least vulnerable.
Mwandosya et al. 1998 also examined two sea level rise scenarios of 0.5 m and 1.0 m. The study suggests that a 1.0 m – rise in sea level would permanently flood about 500 km
2
of land, most of which is wetlands. Inundation would claim about 250 km
2
for 0.5 m of sea level rise and about 490 km
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for 1 m rise of sea level. Future erosion rates were projected using the Bruun Rule for Dar es Salaam in response to global warming and accelerated sea
level rise of 1 m to about 9 km
2
. Aerial videotape-assisted Vulnerability Analysis AVVA together with ground truthing exercise for Dar es Salaam suggested an area of about 12 km
2
of land would be lost for the same rise in sea level. This land loss would claim buildings and other structures valued at about Tsh. 50 billion and Tsh. 86
billion for 0.5m and 1.0m of sea level rise respectively. Expected storm surges of 5m would bring a damage of over Tsh. 200 billion for Dar es Salaam.