… coming soon to a stream near you

The Ministries responsible for Jamaica’s roads and public works have told us recently that some of the damage from Tropical Storm Nicole will not be fixed until some basic support work is done.  Their argument is that it makes no sense to patch roads if the next storm – almost in the yard as we went to press – is just going to wash them out again.  This is sound reasoning, as long as it doesn’t turn into an excuse for doing nothing.

The basic support work is designed to prevent future damage and protect important public works like sewage plants, water pipes and reservoirs as well as roads.  It includes rebuilding road beds for greater stability and better drainage, clearing and repairing drains, culverts and gullies, building or fixing retaining walls and a lot of “river training”.

What is “river training”, and why should we care about it?  River training is changing the beds and banks of rivers to suit some human purpose.  These purposes range from controlling floods and preventing erosion to improving water supplies and creating shipping channels.  In most cases, the effort and expense of river training is downstream punishment now for the upstream sins of the past.

Some of the best examples of river training are in Switzerland and Germany, where engineering is being used to restore old rivers.  One of the worst is in the U.S., where the mouth of the Mississippi River was deepened and straightened.  The increased outflow ate away the barrier islands that should have protected New Orleans from Hurricane Katrina, and is still causing the slow death of coastal wetlands.

River training on a modest scale has been going on in Jamaica for some time.  In fact, after Nicole the CEO of the National Works Agency stated that work done on the Rio Cobre had saved both the Soapberry sewage plant and the Mandela Highway from the worst effects of the storm.  Similar works are now planned for St. Thomas (five projects) and Portland (three projects).

The Jamaican version of river training is simple.  Metal mesh bags of rocks are placed against river banks, especially where the banks have been undercut.  The mesh structures, shaped like mattresses, teardrops or sausages according to the holes to be filled, are covered with rubble and soil (possibly including material from the river bed) and seeded with fast-growing plants like wild cane to hold the fill in place.

This is an expensive fix, not a long-term solution.  Water can’t really be trained – hold it here and it pops out there.  As long as we continue to strip hillsides, build on flood plains, mine riverbanks, dump garbage into the gullies and drain roads into the rivers, there will be destructive floods.

For his part, NWA head Patrick Wong states "We have to work towards an overall drainage plan for areas that are being flooded”, noting that Montego Bay did not have a drainage system.  A drainage plan is a step in the right direction, but better land use planning, that looks at whole watersheds from mountain top to sea floor and corrects some past mistakes, is the only way to keep deadly floods and landslides from being annual events.

PHOTO CREDIT - Minister of Transport and Works, Hon. Mike Henry (left), and Flood Control Officer, National Works Agency, Mr. Leslie White (right), observe river training work being carried out along the Rio Cobre in the vicinity of the Soapberry Sewage Treatment Plant. Source: Kingston Chronicle