Site Improvement Catalogue V2
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SITE IMPROVEMENT CATALOGUE Introduction 03 Health and Safety 04 Drainage 06 Strategy 07 Kutapalong-Balukhali Risk Maps 08 Key Principles 10 Guiding Principles 14 Drainage Capacity Estimation 15 Scenarios & Options 17 Indicative Costs 18 Household & Pathway 19 Catch / Ridgeline Drains 22 Cascade / Discharge Drains 24 Stairway Drains 26 Slow &/or Store 27 Drainage 29 Access 32 Access Strategy & Targets 33 Indicative Costs 35 Stairways 36 Pathways 40 CONTENTS Slope Stabilization 45 Contents 46 Small Retaining Wall 47 Mass Retaining Wall 48 Terracing 49 Planting on Slopes 50 Slope Protection 51 INTRODUCTION Objective: This catalogue has been produced to assist site improvement actors in the following ways: 1. To avoid injuries or casualties on site 2. To follow good construction practice and avoid common errors 3. To make informed decisions as to what interventions are appropriate and cost eective 4. To ensure consistency with other SI actors across all camps The guidance contained in this catalogue is applicable in all camps in Cox Bazaar district, including Teknaf camps. Important Note: The sketches/designs in this catalogue are for guidance purposes only; they are not a substitute for engineering design. All site improvement works should be designed and overseen by a qualied engineer. Site Improvement or Site Development? Site Improvement: Small scale, low tech works implemented using casual labour, typically consisting of secondary and tertiary pedestrian access and drainage and low-risk slope stabilization. Site Development: Technically complicated, large scale or high risk works, often involving machinery, such as vehicle roads or concrete retaining walls. Site Development works are generally implemented directly by IOM or SMEP or by UNHCR, WFP or LGED through contractors (not NGO partners). All Site Development works require full engineering design, to be submitted to the relevant Site Management Area Coordinator (i.e. IOM or UNHCR) for approval. This catalogue is provided for Site Improvement works only. Agencies planning to implement Site Development works should coordinate with IOM/UNHCR (as appropriate), who can provide technical assistance. 03 Supervision, Risk Assessments and Safety HEALTH AND SAFETY Inductions: Supervision, Risk Assessments and Safety Avoid overcrowding sites. Only hire as many labourers as required for the task, and provide sucient space for them to work Inductions: Maintain tidy sites: Scattered materials and tools lying around All works should be supervised by a technically qualied present trip hazards construction worker Prevent the public and (and especially children) from entering the Each site to be overseen by a trusted foreman who knows the safety construction area using tape and/or warning signs as appropriate. procedure and has received basic First Aid training and has access to Discuss access and safety issues with the local community prior to a First Aid kit starting work At high risks sites (e.g. where there are machines, deep or fast Never leave deep excavations uncovered overnight owing water, deep excavations or large soil retention activities), Provide shade and drinking water for labourers conduct a Risk Assessment and allocate a dedicated Safety Warden Maintain clear separation of activities and access areas when to monitor the site safety and ensure no public access working alongside machines Provide a safety induction tailored to the activity for all labourers, In the case of soil instability, a qualied technical person should especially when working alongside machines. Explain how to use verify the site safety. Sides of excavations where volunteers / new tools & machines such as a generator or drilling tool workers are exposed to danger from moving ground should be made safe by sloping, shoring or other eective means Protective Equipment: Deep water: All workers should wear hi-visibility vests; Fence o from public Use appropriate Personal Protective Equipment suitable for the Provide rescue rope construction activity (i.e. gloves, goggles) or weather conditions Safety Induction As far as possible, encourage all labourers to wear closed shoes (not sandals); Rain boots should be worn while working in wet areas Use a mask, gloves and boots for clearing drains 04 High Risk Tools Risks Mi�ga�on High Risk Tools Risks Mi�ga�on / Materials / Materials Excava�on Spade, shovel, Cuts & impact injuries Safety induc�on Working at Ladders Falling Extra person to hold ladder hoe, pick, etc. Avoid overcrowding sites Heights Use scaffolding if possible Ensure safe slopes No sarongs for people working at heights None Falling tools or Helmets for staff working Deep Latrine pits & Use warning tape to secure Falling & drowning materials below Excava�ons similar area Grinding Hand grinder Cuts Wear gloves Cover pits over night Works Secure sites at night &/or Eye injuries Wear goggles provide a guard Working on Loose fill Tripping / Falling Avoid overcrowding sites Ankle sprains Portering* Bag, Bucket, Back injuries Max. load = 25 kg Slopes Ensure safe slopes Wheelbarrow Share heavier loads Landslides Working in None Sun stroke & Provide shade, water risk Safe li�ing training High dehydra�on assesment and frequent breaks Unloading Heavy Impact injuries from Safety induc�on Temperatures materials falling materials Working Excavators, Running over feet, Avoid overcrowding sites Sandbag None Back injuries Safety induc�on Alongside bulldozers, etc. crushing against Maintain ‘no go’ areas around Works Machines walls, etc. machines Bamboo Machete, saw, Cuts Clear Safety induc�on Works drill Remove cu�ng tools from Working Unseen Slips and falls Safety induc�on anyone seen using them Close to hazards Cuts from hidden Avoid fast flowing water dangerously Water objects Provide boots and gloves Unstable Falling bamboo Brace temporary structures Deep or fast Drowning Avoid fast flowing water structures flowing water Use labourers who can swim Brick Works None Dropping bricks on feet Avoid overcrowding sites near deep water Wear shoes Provide rescue rope Brick dust in eyes Wet brick chips Clearing Dirty water Slips Use mask, boots & gloves Drains Cuts Concrete Wet concrete Alkali burns Use gloves and boots (if Infec�ons Works standing in concrete) Provide water for people to Waste None Cuts Provide mask, gloves & overalls Management Infections wash hands All Public None Risks to public Segregate works using tape Reinforcem Tie wire & Cuts & scratches Wear gloves Works &/or hazard/informa�on signs ent Works sharp edges Discuss works with local Trip hazards Maintain clean sites avoid community prior to star�ng overcrowding *refer to Protec�on Sector guidance on portering 05 DRAINAGE DRAINAGE: STRATEGY Guiding principles for stormwater management in the camps: 1. Slow down the ow of water and promote inltration in the less densely populated upstream half of the upstream half of the catchment area to reduce ooding in congested downstream areas Only use impermeable canal lining (brick, concrete, tarpaulin, etc.) where necessary, such as for high velocity ows or down steep slopes Maintain a gentle slope in all drains by following contour lines as far as possible Use check dams or steps on steep drains Use silt traps to promote inltration and prevent downstream drains & culverts from blocking. Store water upstream using retention basins or ponds Allow unpopulated valley oors to ood, in order to reduce peak ows downstream 2. Prevent surface erosion to prevent silt washing o exposed slopes and blocking drains downstream Plant grasses on exposed slopes to protect the surface Use jute or geotextile roll to protect exposed soil if there is no time for grass to grow before monsoon Use catch/ridgeline drains connected to discharge drains to prevent water owing over the hill face 3. Use robust brick & concrete drainage in densely populated areas on steep slopes. Brick/concrete drains are easy to clean and provide maximum capacity in congested areas Robust drains prevent scouring and erosion Brick/concrete drains are prone to brittle failure and are dicult to repair 4. Promote durable solutions Use soft/exible infrastructure (not brick and concrete, which cannot accommodate ground movement) where possible, e.g. in open valleys Plant vegetation along embankments to protect from erosion and prevent collapse 5. Ensure networked drainage The drainage network must be considered as a whole, with connected drains from source to outlet Drainage capacity should increase as you move downstream 07 DRAINAGE: MAPS FLOOD MAP POPULATION DENSITY CATCHMENT AREAS Note: Kutapalong-Balukhali Expansion camps shown for illustration purposes only. Detailed ood risk maps for all camps (including Teknaf) are available from ISCG Natural Hazards Task Force 08 FLOODING RISK MAP Camps 4, 4Ext, 17, 18, 20 Camps 1-8: & 20Ext: Medium risk Low risk High population density Low population density Few shelters in ood plains Shelters on hills (not in ood Use natural materials in open valleys plains) Use brick & concrete drains in congested areas Catchment area for major rivers: Reduce ow speed and promote Mudhuchara River (Camps 6, 7 & 8): inltration & retention HIGH RISK Medium population density Use unlined drains & natural High ood level materials Fast owing water Follow natural river curves Use silt traps where possible, Camps 9 & 10: esp. at natural bottlenecks HIGH RISK High discomfort level High population density High water level & shelters in ood plains Slow moving water Camps 11, 12 & 19: Medium risk High population density Camps 10 & 11 River: Few shelters in ood plains VERY HIGH RISK High population density Use natural materials in open valleys Low lying shelters & high ood level Use brick & concrete drains in congested areas Fast owing water 09 3. BRICK & CONCRETE DRAINS IN DRAINAGE: KEY PRINCIPLES SHELTER AREAS, NATURAL DRAINS IN OPEN VALLEYS Robust, easy to clean brick drains in high 1. RETENTION density shelter areas prevent erosion & Slow down & retain water in the sparsely reduce blockages populated upstream half of the camp to reduce peak ows in the rivers Natural drains in open valleys promote downstream inltration and slow down ow Use natural drains (unlined / jute bag / bamboo) to allow inltration 4.