by Peixuan Wu, Associate ASLA
Holding Water, Holding Time
Across California’s Central Valley, small depressions blush with wildflowers each spring before vanishing again under the summer sun. These are vernal pools, ephemeral wetlands formed entirely by rainfall and held in place by dense claypan soils that prevent water from seeping away. For a few brief months each year, they become self-contained worlds: shallow basins that fill, bloom, and dry in rhythmic sequence.
Through winter rains, the pools brim with water and teem with tiny aquatic lives: fairy shrimp, tadpole shrimp, and frog tadpoles which are all racing to mature before the water disappears. As the surface recedes, seedlings rise and burst into color, forming concentric rings of bloom which are yellows, purples, and pinks that ripple outward like a living kaleidoscope. By late summer, the pools lie cracked and still quietly holding within their clay the dormant seeds and cysts of next season’s return.
Vernal pools defy our conventional landscape logic. They are fleeting, enclosed, impermeable and rhythmic worlds that prize timing and pulse over permanence or perfection. Once widespread across central valley in California, more than ninety percent have vanished to agriculture and development, leaving fragile mosaics of rare species and seasonal wonder.
In a profession often obsessed with stability and performance metrics, these short-lived ecosystems ask a radical question:
What if resilience depends not on permanence, but on timing?
“To design with pulse is to accept flux as form.”
