Hello, I have seen this in ...

Hello, I have seen this in Guatemala, near our Atlantic coast. To make sure of what you are dealing with, you need to look farther and closer. Measure and have actual flow measurements. Verify if flow speed is increased due to River bedrock changes. Also check other streams nearby. On our case, we were able to find that the stream of interest had constant flow even with similar conditions you describe, but found another spring, coming out of nearby caves on limestone, that one had the changes of flow. We had been paying attention to the wrong springs. Measure and make sure you have data and compare to historical records. Look for tendencies in year to year flow. There's no right answer without actual rain and flow measurements. Best wishes.