case study: the opportunities presented by a river, the hazards associated with it and their management

•opportunities, hazards and management of Bangladesh (River Ganges)

•opportunities at the River Ganges:

          •fertile land - annual deposits of alluvium from flooding 

                     •agriculture of rice and jute

                     •irrigation when the climate is unsuitable 

          •water supply

                    •cleaning, bathing, drinking 

                    •irrigation 

                    •enough for dense population of 1101 per km2

          •fish supply

                    •trade, boosting economy

                    •food can feed the dense population

                    •provides lots of jobs for locals

          •building

                    •flat land means high density can be supported 

          •economy

                    •fourth largest producer of rice and the largest producer of jute 

                    

•causes of flooding in Bangladesh 

          •human causes of flooding:

                    •1101 people per km2 means high density, causing some to live on floodplains

                    •deforestation: building; cooking; farmland; more flooding

                    •farming creates silts, silting up the river - shallow river means lower capacity 

                    •urbanisation: decreases infiltration, increasing overland flow

                              •poor live next to the river

                              •global warming means glacier melting means sea levels rise 

             

          •physical causes of flooding:

                    •lies in the belt of onshore winds from monsoons from the Indian ocean

                              •May - September 1 metre of rain a day (a major flood every 5 years) 

                    •tropical cyclones cause torrential rain, high winds and flooding 

                    •1.7 million km2 of drainage basin means large area affected by rainfall flooding

                              •exacerbated by meltwater from the Himalayas 

                                       •very flat land - 50% of the country is less than 12 metres above sea level

•the impacts of river flooding in Bangladesh in 1998 

•physical impacts

          •670,000 hectares if crops destroyed

          •2 million tonnes of rice destroyed 

•social impacts

          •1000 killed; 30 million refugees; 50 million without resources; damaged hospitals;   

          •water mixed with sewage, creating cholera   

          • 2 million tonnes of rice destroyed 

•economic impacts

          •land washed away; can’t invest in infrastructure; chars (poor housing) washed away   

          •$1 billion of damage

          •400 factories closed; 20% decrease in production 

          •higher food prices due to major loss

•management of the River Ganges (aided by Oxfam and Practical Action)

          •1. Dhaka Flood Protection Project 

                    •embankment along the western side in response to 1998, increasing water capacity 

                    •pump stations and drainage systems in Dhaka to move water back into the river 

                              •problems: $100 million project; expensive to build and maintain 

          •2. Flood Preparedness Programme 

                    •cluster villages: raised land with houses and facilities for 30 families in each

                    •food shelters: 2 hectares of raised land with livestock and facilities for 100 families

                    •rescue boats: located at flood points and new flood shelters

                    •raised homestead: home raised 2 metres; grass planted to prevent erosion 

                    •radios: flood warnings, given to the ‘preparedness committee’