A decades-old stormwater solution that helps recharge groundwater in Modesto is also a major contributor to yearly street flooding and a potential source of contamination. Modesto’s stormwater system is different from most other cities of its size in California. Instead of a traditional system using pipes that flow into rivers or out into the ocean, it heavily relies on thousands of rock wells — gravel-filled holes that drain untreated rainwater directly into the ground. … Rock wells work as a source of groundwater recharge, replenishing aquifers below. But they also are easily clogged by debris like leaves and trash, leading to major street flooding during heavy storms.

Other stormwater infrastructure news:

• Enterprise-Record (Chico, Calif.): Five-Mile flood prevention project remains in early stages