Walnut Creek Public Library

Walnut Creek Downtown Public Library, 1644 N. Broadway Map

Rain Garden at Walnut Creek LibraryWalnut Creek’s downtown public library, at the south end of creek-edged Civic Park, treats runoff from its roof with flow-through planters and a rain garden.
Detail of how moisture from building reaches rain gardenInlets and drain in bioretention area, Walnut Creek LibraryLeft, drain to rain garden.
Right, rain-garden plumbing: inlets in background, raised drain to prevent flooding during storms in foreground.
Click images to enlarge them.
Raised flow-through planters edge much of Walnut Creek Library Swale-like planter with raised drain for for high flows
Narrow planters edging the building also play a role. Above left and below, flow-through planters use growing media engineered to filter pollutants but drain quickly. J-drains prevent overflows. Above right, basin-like planting bed retains some runoff, but raised drain prevents overflows.

Dramatic Flow-Through Planter at Walnut Creek Library