Maricopa County Drainage Analysis & Water Flow Map

Address
Overview

Where does rainwater drain in Maricopa County? This interactive map shows surface drainage patterns across Phoenix, Scottsdale, Mesa, and surrounding areas based on terrain shape - where gravity directs rainwater based on elevation and slope. For official flood risk information, see the FEMA flood zone layer on the Hazards tab.

Maricopa County's desert terrain creates extreme flash flood risk during monsoon season. Hard-packed caliche soil and sparse vegetation offer almost zero infiltration, converting intense rainfall directly into fast-moving sheet flow through dry washes. The Salt River, Indian Bend Wash, and Cave Creek are normally dry but can become raging torrents within minutes during summer thunderstorms. Enter any address to see parcel-level surface drainage analysis and water flow direction based on terrain shape.

Interpretation

Select a location on the map or enter an address to see terrain analysis.

3D Terrain Visualization
Where does rainwater flow based on terrain shape? Blue areas show where water collects and drains downhill.
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