When Your Process Model Assumes Steady Flow but Your Rain Data Shows Pulses: How to Tune the Integration Logic
You spent weeks building a process model. It handles steady-state flows like a dream. But the first real rain event hits, and your tank overflows before the pump even wakes up. Sound familiar? The problem isn't your model—it's the assumption that rain comes in a smooth, predictable stream. Real rainfall is lumpy: 15 minutes of torrent, then nothing. Your integration logic needs to handle pulses, not averages. Here's what to fix. Why This Mismatch Costs You Money The steady-flow fallacy in sizing Most commercial rainwater models treat rainfall like a faucet—turn it on, let it run at a constant rate, turn it off. That fiction makes the math easy. It also makes your tank wrong. I have watched engineers size a 12,000-gallon cistern using average daily rainfall for Austin, only to have the system overflow twice in the first March storm and run dry by June.