Sudden or progressive changes in the local environment often adversely affect the lives or living conditions of people. These people may then be forced to leave their homes. When environmental degradation occurs or natural hazards rapidly impact vulnerable areas, People may be forced to move. Relocation areas require proper infrastructure. This requires land clearance and construction activities to be undertaken in a way that does not over compact soil. Poor excavation pollutes the air and watercourses and can spread hazardous substances that may affect the health of humans, flora, and fauna, and can damage sensitive ecosystems and breeding grounds.

Marginalised people are often impacted by construction activities, sometimes forcing them to relocate without any consultation. Vulnerable or minority people should always be consulted and their needs accommodated within the response design.

Air pollution
Soil pollution
Water pollution
Deforestation
Desertification
Loss of biodiversity and ecosystems
Natural Resource depletion
Soil erosion

1. Soil loss

2. Air, water, soil pollution

3. Loss of water resources

4. Damage to fragile ecosystems

5. Health and safety hazards, soil loss, and disease spread from open trenches

6. Soil loss and disease spread from piled excavated soil

1. Soil excavation for shelter sites can cause soil loss through excess removal of vegetation or ground surface reprofiling, both of which can lead to floods, and water or wind erosion of soil and / or degrading of soil quality

2. Excavation activities can pollute air, water or soil by uncovering toxins or pollutants already within a site or importing them in the construction materials used or crisis waste redistributed on a site

3. Excavation activities can block or divert water courses or divert surface water causing excess soil erosion and deposition within water courses. Poorly managed excavation activities can lead to the partial or total loss of water resources if surface water infiltration is reduced or water courses diverted away from the site

4. Fragile ecosystems can easily be damaged by construction activities through removing flora or fauna that other species rely on, interrupting food chains, disrupting water courses or drainage pathways, or introducing pollutants (e.g. diesel spills, cement slurry) or pathogens that spread disease amongst flora and fauna

5. Open trenches create hazards to adults, children, animals and vehicles, who may fall into them. They can also lead to soil loss from water flow and disease spread if they harbour stagnant water

6. Soil loss and disease spread can also ensue from uncovered piled excavated soil that is left on site for excessive periods

1. Minimise soil excavation

2a. Re-use excavated soil on-site wherever possible

2b. Assess crisis or construction waste and imported materials for contaminants

3. Map and protect watercourses

4. Map and protect fragile ecosystems

5. Rebury excavated trenches within 4 days

6. Manage re-use of excavated soil to avoid excessive runoff or hosting disease vectors

1. Minimise soil excavation. This can be done by planning shelter sites within existing ground profiles and contours, noting and avoiding watercourses and natural drainage channels and sensitive ecosystems, and minimising vegetation removal. Alternative construction methods can be used that minimise excavation, such as raft foundations or the use of short piles for buildings.

2a. Always plan to re-use any excavated soil on-site wherever possible, as long as this can be done without harming any fragile ecosystems on the site.

2b. Assess any re-used crisis or construction waste and any imported materials for potential contaminants and ensure contaminants identified are suitably removed and safely disposed of

3. Map watercourses and ensure new structures and infrastructure do not divert them or cause excess surface water run-off to enter them

4. Map the presence of any fragile ecosystems and their specific fragilities and put measures in place to protect them from construction activities

5. Excavated trenches should be reburied quickly (maximum 4 days open) to avoid hosting vectors or accidents within the affected communities

6. Excavated soil must be managed or disposed of to avoid excessive runoff or turning into a potential host for disease vectors. The soil should be re-used locally if possible, or transported to an off-site for another re-use (e.g. construction or landfill cover).

CASE STUDY: ACEH, INDONESIA POST-TSUNAMI HOUSING PROJECT

Houses in Aceh Besar District, Sumatra, Indonesia, were built after the 2004 Indian Ocean tsunami, as well as a newly constructed seawall that was built as a coastal barrier to protect residents from future tsunamis and storms surges. Unfortunately, the site plan and design for the housing project overlooked the fact that a significant quantity of freshwater flows from inland areas toward the ocean during periods of heavy rainfall and becomes trapped by the seawall before it is released into the ocean.

The recurring floods damaged the newly constructed shelter, water and sanitation systems, and roads, and have affected residents’ health and quality of life. As a short-term fix, a costly drainage system was installed. To prevent these types of problems and added costs in the future, project planners need to ensure that there is coordinated planning among a range of stakeholders beyond the immediate project area and must pay particular attention to the broader environmental context.

FROM: https://www.sheltercluster.org/sites/default/files/docs/GRRT%204%20-%20Strategic%20Site%20Selection%20and%20Development.pdf

Percentage decrease in volume of excavated soil

Prevention of environmental damage

Mitigation of environmental damage

Time for assessing ground conditions, and planning construction methods to reduce or avoid excavation