Create a water map
Observe after meaningful rainfall when safe. Mark standing water, wet edges, flow across pedestrian or traffic paths and the time visible ponding takes to clear.
- Rainfall context
- First visible ponding
- Direction of flow
- Clearing time
Record outlets and constraints
Catch basins, trench drains, curbs, ditches or visible outlets should appear on the site map along with doors, loading bays, ramps and adjacent slabs that constrain grades.
- Drain and catch-basin locations
- Curbs and low edges
- Doors and loading aprons
- Public or neighbouring outlet context
Separate observation from design
A water map can show where problems occur; it cannot establish pipe condition, subsurface grades, design capacity or permitted discharge. Keep those as qualified review questions.
- Hidden system condition unknown
- Survey or design may be required
- Municipal requirements vary
- Utilities can constrain changes
Carry water into the RFP
Ask bidders to state drainage assumptions, grade transitions, catch-basin treatment, excluded design work and how final surface drainage will be reviewed before closeout.
- Assumed flow path
- Drain or utility boundary
- Finished-grade check
- Post-work observation question
Public-road access, drainage, traffic-control and engineered-design requirements depend on the exact property, jurisdiction and project. Verify whether the address is in the Township or City before routing questions. Township of Langley engineering forms and guides ↗