The Rain Garden
This pattern is shaped by
Problem
When stormwater runs off hard surfaces into storm drains and directly into rivers, it carries pollutants, overwhelms infrastructure during heavy rain, and removes water from the local ecosystem. The land gets drier between storms and floods during them.
Evidence and Discussion
Philadelphia's Green City, Clean Waters program has installed over 2,800 "greened" acres of rain gardens, bioswales, and permeable surfaces, keeping billions of gallons of runoff out of the combined sewer system. Copenhagen's Cloudburst Management Plan uses rain gardens, permeable surfaces, and designed depressions that double as public spaces.
Therefore
on every lot, direct roof and driveway runoff to a planted depression — a rain garden — before it reaches the storm drain. Size the garden to absorb a two-year storm event (roughly 25mm of rain). Plant it with deep-rooted native species that tolerate both wet and dry conditions. Position it where it's visible from the house, so its seasonal transformation — from dry meadow to brief pool to lush garden — becomes part of daily life.