Wednesday, 9 April 2014

RIVER KISSIMMEE

SOFT ENGINEERING IN A MORE DEVELOPED COUNTRY






WHAT IS THS BACKGROUND TO THIS PROJECT?
·        The river Kissimmee once meandered for 103 miles through central Florida.
·        Its floodplain, which reached up to 3 miles wide, was regularly inundated with heavy seasonal rain for long periods of time creating a unique and highest diverse ecosystem in North America.
·        In the 1940’s, the River Kissimmee endured prolonged flooding after a series of hurricanes which had severe impacts on the people in the region. So drastic measures were taken by the Central and Southern Florida Project and the Kissimmee was cut and dredged and channelized (from 1960-1971) into a 30 feet deep straightway: the C-38 canal.
·        Although flood control benefits were achieved, it was soon considered to be an ‘ecological disaster as waterfowl numbers fells by 90% and Bald Eagle nesting fell by 75%.
·        In response a restoration project was authorised in 1992, which aims to be completed by 2019.          







HOW IS THE RIVER BEING RESTORED?
·        One aim of this project was to return the river back to its meandering self and thus restore its ecological integrity but another aim of the restoration was to maintain flood protection.
·        The meanders were formed by cutting out the original meander scars into oxbow lakes and then connecting them to the river. The sediment was then used to backfill the canal so the original meandering river could flow naturally.
·        The upper and lower portions of Canal 38 will remain channelized to maintain flood protection benefits, while the middle 22 miles of canal are being replaced with 40 miles of meandering river.
·        The total cost of the project is estimated to be around $500m including the acquisition of 102k acres of floodplain that was previously used for farming/human habitation.







WHAT IMPACTS HAS THIS PROJECT HAD?
·        Dissolved oxygen levels have increased and sand bars have reformed on the river bed providing new habitats to support greater biodiversity.
·        Flora and fauna such as the Black-Bellied Whistling Duck, that disappeared when the system was channelized have returned in great numbers and are now thriving in the newly restored system.
·        The wider Kissimee basin is now protected from flooding by both soft and hard engineering methods. The restored floodplain will store water and decrease lag time naturally whilst the remaining canal & dams allow discharge to be regulated artificially.
·        The river is now important for tourism and education. For example the Riverwoods Field Laboratory hosts ecologists carrying out research and runs eco-tours of the river.

·        The newly restored the floodplain is now open for public recreation such as horse-riding and camping, bird-watching and fishing. 










Discussion point: Was the restoration a good idea for flood protection?


With thanks to Yasmin Karabasic

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