[gzu]

I wonder much of this is caused by recent installments of agricultural field drainage tile?

Land price increases allow for more farmers to afford to "improve" their farmland by adding underground pipes that quickly wick standing water away into nearby creeks and rivers. What used to be evaporated or absorbed into soils is dumping straight into waterways.

[guerrilla]

You're asking if over 600mm of rain (i.e. more than half a year's worth) in a 24 hour period in Henan was caused by recent installments of agricultural field drainage? Or if that caused the jet stream to hold the storm over NRW to drop months worth in a 24 hour period?

1. https://weatherspark.com/y/127378/Average-Weather-in-Zhengzh...

2. https://weatherspark.com/y/58162/Average-Weather-in-Wupperta...