Tandale Flood Inundation Model
Dar es Salaam is the largest city of Tanzania, it has an estimated 5.5 million residents and is also an economic centre for Tanzania and East Africa. Offset with this economic and social importance, Dar es Salaam has a tropical climate, experiencing two rainy seasons in a year (April – May and November – December). These seasons are usually accompanied with high rainfall, with high potential for flooding.
The main reason for the floods to occur in Dar es Salaam is the mismatched pace of the population growth and building infrastructure. The city population is growing so fast that Dar es Salaam has become Africa’s fastest growing city, see here.
Floods in Dar es Salaam
So by using the Ramani Huria experience and code for resilience knowledge and capacity, this project aims to add more efforts and effectiveness in flood resilience building by providing flood inundation models for most flood prone areas in Dar es salaam.
This helps the way the policy decisions are made especially from authorities that are responsible in building flood resilience schemes as they would have in hand one of the important tools (flood models).
The open technologies used in this project are GRASS, Qgis and Python.
Building
First step is to acquire an image for the area to be used for production of a flood map, for our case we used tandale image taken from a Drone.
Tandale elevation image.
Then, the development of a flood map is done by using and combining different hydrological GRASS scripts, if these scripts are executed in a right chronological order for the imported image, a flood map can be created.
GRASS also provide more functions for dealing with hydrological modeling but for now we have focused on creating flood maps and making sure this works and meet the needs for creating a flood map.
Results
MTI map produced from the tandale elevation model
Qgis and InaSAFE Integration
We are integrating this into InaSAFE by implementing a module in the plugin. This will enable one to produce these flood maps without any programming knowledge.
Source code can be found here.
Special Thanks
Tandale Flood Inundation Model
Dar es salaam ni mji unaokua kwa kasi zaidi Tanzania,unakadiriwa kuwa na idadi ya wakazi million 5.5,pia ni kitovu cha uchumi Tanzania na Afrika mashariki,sanjari na umuhimu wa shughuli za kijamii na kiuchumi,Dar es salaam ina hali ya hewa ya kitropiki ambapo hukumbwa na mvua za msimu mara mbili kwa mwaka(Mwezi wa nne -mwezi wa tano na mwezi novemba -Desemba)
Sababu hizi husababishwa na mvua kubwa, ambayo huambatana zaidi na mafuriko.
Sababu mahususi ya mafuriko kutokea Dar es salaam ni kutokulingana kwa ongezeko la watu na miundombinu ya majengo. Idadi ya watu katika jiji linakuwa haraka Dar es salaaam ,hivyo kuwa jiji linalokuwa kwa kasi sana barani afrika, ona hapa
Mradi huu unalenga kuongeza juhudi na ufanisi katika majengo yaliyoathirika na mafuriko kwa kutoa modo za mafuriko kwa maeneo yote yanayokabiliwa na mafuriko Dar es salaam.
Hii inasaidia kufanyika maamuzi ya sera hasa katika mamlaka husika katika kujenga miradi ya kuzuia mafuriko kukiwepo na zana muhimu.
Teckologia wazi inayotumika katika huu mradi ni GRASS,Qgis na Python
Jengo
Hatua ya kwanza ni kuwa na picha ya anga ya eneo husika ambayo ambayo itakusaidia kutengeneza ramani ya mafuriko, mfano wetu tumetumia picha ya anga ya eneo la Tandale iliyopigwa na ndege isiyokuwa na rubani(drone).
Baada ya hapo kutengeneza ramani ya mafuriko hukamilika kwa muunganiko tofauti wa(hydrological Grass Scripts), kama hizi Scripts zinatengenezwa kwa mpangilio na mtiririko ulio sahihi kwa picha ya anga iliyowekwa, kwa hiyo ramani ya mafuriko hutengenezwa.
Grass pia inatoa kazi mbalimbali zinazohusika na model za nishati ya maji lakini kwa sasa tumelenga katika kutengeneza ramani za mafuriko na kuhakikisha zinakidhi mahitaji yakutengeneza ramani za mafuriko.
Matokeo
MTI map produced from the tandale elevation model
Qgis and InaSAFE Integration
Tunaunganisha pamoja na InaSAFE kwa kutekeleza moduli kwenye (plugin) Hii itasaidia kuweza kutoa ramani hizi za mafuriko bila kuwa na ufahamu wa kutumia progarmu.hapa
Shukrani za pekee kwa
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