Drainage Plan

Landscape Drainage Plan

A technical plan designed to manage water runoff, especially critical in the Philippine context due to heavy rainfall and typhoons.

Importance of Drainage

To prevent flooding and erosion, and to protect the usability and structural integrity of the site.

Basic Principle 1 (Gravity)

Water always flows downhill; the drainage design must follow the natural slope of the land.

Basic Principle 2 (Minimum Slope)

Surfaces should have a minimum slope of 1–2% to avoid flat areas and water ponding.

Basic Principle 3 (Redirection)

Directing water flow away from buildings, primary pathways, and main activity areas.

Drainage System Concept

The three-stage process of water management

Step 1

Analyze Site

Step 2

Plan Slopes

Step 3

Catch Basin Spacing

Catch Basin Placement

Strategically locating basins at low points, along road/path edges, and at flow intersections.

Step 4

Drainage Lines

Step 5

Outfall

Common Drainage Mistakes

Using too few basins, lack of sufficient slope, having no final discharge point, or ignoring potential clogging.

Drainage Summary

Maintain a minimum 1–2% slope, space basins every 15–30m, and always prioritize flow continuity.