Page 26 - GRIHA Manual Volume II - Introduction to National Rating System
P. 26
18 GrIha Manual: Volume 2
Figure 4 Topsoil protection at a GRIHA project site in Kanpur, where the adjoining areas were barricaded to prevent
construction activities damaging the surrounding areas
At a micro level, during construction, the soil becomes loose due to the removal of stabilizing
material such as vegetation and disturbance of stabilized existing grade, resulting in loss of topsoil
and its deposition in undesirable places. Measures for preservation of topsoil are given below.
# Collection, storage and reapplication of topsoil
• This should be done from areas likely to be disturbed by construction activities (especially
in cases where the site area is larger than 10 000 m ), topsoil should be stripped to a depth
2
of 20 cm from the areas proposed for buildings, roads, paved areas, and external services.
• It should be stockpiled to a height of 40 cm in designated areas and reapplied during
plantation of the proposed vegetation. The topsoil should be separated from the subsoil
debris and stones larger than 50 mm in diameter.
# Sedimentation basin
• Sedimentation basin, a temporary dam or basin at the lowest convenient point of the site
should be constructed for collecting, trapping, and storing sediment produced by the
construction activities.
• A low-detention facility must also be constructed for reducing peak run-of rates. This would
allow most of the sediments to settle before the run-off is directed towards the outfall.
# Contour trenching
• Contour trenching is an earth embankment or ridge-and-channel arrangement constructed
parallel to the contours, along the face of the slope, at regular intervals on the lengths and
slopes greater than 10% (1:10).
Figure 4 Topsoil protection at a GRIHA project site in Kanpur, where the adjoining areas were barricaded to prevent
construction activities damaging the surrounding areas
At a micro level, during construction, the soil becomes loose due to the removal of stabilizing
material such as vegetation and disturbance of stabilized existing grade, resulting in loss of topsoil
and its deposition in undesirable places. Measures for preservation of topsoil are given below.
# Collection, storage and reapplication of topsoil
• This should be done from areas likely to be disturbed by construction activities (especially
in cases where the site area is larger than 10 000 m ), topsoil should be stripped to a depth
2
of 20 cm from the areas proposed for buildings, roads, paved areas, and external services.
• It should be stockpiled to a height of 40 cm in designated areas and reapplied during
plantation of the proposed vegetation. The topsoil should be separated from the subsoil
debris and stones larger than 50 mm in diameter.
# Sedimentation basin
• Sedimentation basin, a temporary dam or basin at the lowest convenient point of the site
should be constructed for collecting, trapping, and storing sediment produced by the
construction activities.
• A low-detention facility must also be constructed for reducing peak run-of rates. This would
allow most of the sediments to settle before the run-off is directed towards the outfall.
# Contour trenching
• Contour trenching is an earth embankment or ridge-and-channel arrangement constructed
parallel to the contours, along the face of the slope, at regular intervals on the lengths and
slopes greater than 10% (1:10).
