Underneath San Diego streets lies a network of pipes and tunnels that most people never see. But when it rains, that network is busy carrying water out from neighborhoods and into the city’s rivers, bays and beaches. Much of that network is on the verge of collapse, and the city has nowhere near enough money to fix it. A report from the City Auditor’s Office released this month notes a staggering $459 million funding shortfall for stormwater infrastructure.