Beyond Impervious: Urban Land-Cover Pattern Variation and Implications for Watershed Management

Area of Science:

• Environmental Science
• Urban Hydrology
• Landscape Ecology

Background:

• Impervious surfaces significantly impact urban water quality.
• Existing models struggle to explain water quality variations in catchments with similar imperviousness levels.
• Land-cover patterns are hypothesized to be a key factor influencing these variations.

Purpose of the Study:

• To analyze land-cover pattern variability among urban catchments with varying imperviousness.
• To explore the implications of land-cover patterns for urban watershed management.
• To identify how different land-cover types and their spatial arrangements influence water quality.

Main Methods:

• Utilized high-resolution (1 m²) land-cover data for 32 urban catchments.
• Quantified 23 land-cover pattern and stormwater infrastructure metrics.
• Employed hierarchical clustering to group catchments based on distinct landscape patterns.

Main Results:

• Identified four distinct landscape pattern groups among the catchments.
• Land-cover patch connectivity explained 40% of pattern variation; lawn and building size/shape explained 20%.
• Stormwater infrastructure metrics accounted for 8% of the remaining variation, highlighting the importance of landscape configuration.

Conclusions:

• Urban land-cover patterns exhibit significant variability, influencing water quality beyond impervious surface extent.
• Trees and grass (lawns) represent divergent, important cover types in urban landscapes.
• The complex interplay of land-cover patterns necessitates tailored approaches for effective urban watershed management.