Guide on Risk Mitigation Works

Transcription

1 Guide on Risk Mitigation Works Draft Version February 2018 Guide on Risk Mitigation Works v1.0 Shelter & Site Improvements Technical Working Group SHELTER/NFI SECTOR COX S BAZAR SITE MANAGEMENT SECTOR COX S BAZAR

2 FLOODING Unconnected drainage Flooding Drainage channels must be CONNECTED from top of hill to bottom of valley Drainage channels must follow natural slope No drain alongside path Water will run down centre of path Unable to use path after rain (+ erosion) Add drainage channel to side of path Small dams to stop water flowing too fast Add regular diagonal channels across the road to take water off the path and into main drain

3 FLOODING Very narrow channel will create flooding Crossing point is too low Will flood during monsoon Widen channel and add bridge Raise height of crossing point by building an embankment at both ends of the bridge Main drainage channel is not protected erosion & flooding Excavate drainage channel & compact base Reinforce channel walls with bamboo or sandbags Make drainage with geotextile, clay or cement screed

4 FLOODING Relocate shelters to higher ground. Build up base using earth or sandbags Shelters are too low and will be flooded RISKS Bridge is weak and has no hand rail Replace bridge. Build embankment on lower bank and add high & low rails Clear waste from drain. Create community waste disposal scheme Add bamboo fencing Waste in drain will cause blockages and flooding Danger of children falling of edge Danger for children fall in the drain

5 LANDSLIDE Toe of sandbag retaining wall is not secure Add bamboo retaining wall or plant deep rooted grasses (e.g. vetiver) at base of sandbags to prevent from slipping Exposed mud slope will collapse in the rain Grow plants (grass, vetiver, etc.) to protect top soil from erosion Cover exposed slopes with jute netting to protect slopes until vegetation has grown

6 LANDSLIDE Shelter built below steep slope with no retaining wall at base (slope already beginning to collapse) Relocate shelter to safer location Cut back / terrace slope above shelter No drainage channel behind shelter. Water soaking into ground increases chance of landslides Install drains behind building/shelter

7 CYCLONE Shelters that are not tied down and with loose material will blow away in strong winds Stone Tie shelter down securely to anchors buried under the ground Shelters that are not braced will blow down in strong winds Anchor columns into ground and brace structure with rope

8 CYCLONE Poor connections between column and beam and between beam and column roof will fly off in cyclone Tie Rafters down to beam Tie Beams down to columns (N.B. use of dowel) Anchor columns into ground Gable ends (triangular portion) and large roof overhangs attract large uplift forces Avoid large roof overhangs. Use hipped roofs to avoid large uplift at gable ends Separate varandah from main structure so that main structure won t be damaged if porch blows away

9 CYCLONE CGI/tin roofs flying CGI sheet/ debris can rip through Shelters and people Use tarpaulin and grass instead of tin Latrines (with tin roofs and walls, weak structures and weak connections) and loose material become flying debris in high winds Use Hurricane Straps or wire ties to connect Purlin to Rafter (wire), and Rafter to Beam (Hurricane Strap) Bend back nail through purlin to create hook Purlins should be closely spaced Tie down latrines and loose material if cyclone is forecast

10 CYCLONE DO NOT TAKE SHELTER ON HILL TOP BUILDINGS IN EVENT OF CYCLONE Buildings on hill tops will experience highest wind loads No bracing Building will collapse Bamboo footing in tthe ground starts to rot within 6 months ALL COMMUNITY BUILDINGS & SHELTERS MUST HAVE ROPE BRACING IN ALL FOUR SIDES

11 FIRE Maintain minimum spacing between shelters Create exit routes and gathering spaces High density housing + flammable materials Fire spreads widely Community Fire Awareness workshops (min 1/maji) Create Community Fire Response Plans (min 1/maji) Create Fire Wardens & practice Fire Drills Community fire bucket stands with wet sand (1/10 HHs)

12 FIRE Indoor cooking create fire risk Provide outdoor cooking spaces &/or promote community cooking stations Keep cooking area clean and free from flammable materials Store water and sand next to the stove or next to each shelter Candles create large fire risk Ensure all families have min. 1 solar lamp + torch Line walls with earth or CGI sheets, especially behind stoves and between shelters