Safety, Grading & Drainage
Site grading, surface drainage, French drains, catch basins, equipment operation, WHMIS, and utility locating.
- Calculate proper grading slopes for surface drainage away from buildings
- Describe French drain, catch basin, and soakaway pit construction
- Identify safe equipment operation procedures and PPE requirements
- Explain WHMIS, utility locating, and safe digging practices
Leçon 1
Site Grading, Slopes & Surface Drainage
The Purpose of Grading
Proper site grading directs surface water away from buildings, prevents ponding, and ensures healthy plant growth. Every landscape project must account for positive drainage - water flowing away from structures, not toward them.
The minimum slope required for proper surface drainage on a lawn is 1-2% (1:100 to 1:50). This means the ground drops 1-2 cm for every 100 cm (1 m) of horizontal distance. A 1% slope is barely perceptible to the eye but is sufficient to move water across the surface.
Reading a Landscape Plan
When reading a landscape plan, north is typically at the top and the scale is indicated in the legend or title block. Contour lines show elevation changes - closely spaced lines indicate steep slopes, widely spaced lines indicate gentle slopes. Spot elevations are shown as numbers with a plus sign or "X" marker.
Grading Tools
- Laser level - projects a horizontal plane of light for setting grade stakes
- Transit or builder's level - optical instrument for reading elevations at distance
- String line and level - simple method for short distances
- Grade stakes - wooden stakes marked with cut/fill amounts
Exam Tip
The minimum slope for lawn drainage is 1-2%. On landscape plans, north is typically at the top and the scale is indicated.
The minimum slope for proper surface drainage on a lawn is 1-2% (1:100 to 1:50). On landscape plans, north is typically at the top with the scale indicated. Always grade away from buildings.