Permeable surfaces within a city provide benefits such as effective stormwater management, pollutant filtration, water conservation, and reduction in urban heat island effects. A permeable surface is defined as a surface that allows water to pass through it and into the ground.

Section C1 of City Plan: Nanaimo ReImagined supports landscapes that absorb and mimic natural systems, including stormwater detention and absorbent landscapes. City Plan policy C1.4.2 encourages incorporating best management practices for new and existing developments to support watershed health. Examples include pervious paving, rain gardens, bioswales, deep absorbent soils, green/blue roofs, rainwater capture or detention systems, or other best practices and emerging techniques.

To measure surface permeability within the City boundaries, the GIS department completed a Land Cover Classification project using 2024 high‑resolution orthophotos and LiDAR data collected in summer 2025. This data was used to categorize land into a series of classes, which were then grouped into permeable and impermeable surfaces to produce an overall surface‑permeability percentage in the City. 

The surface permeability indicator data is from the Land Cover Classification project. Explore this topic further through the Land Cover Classification Dashboard.