Political Memes

I can't speak for the modeling regarding the amount of rain, but I'm was published in college for watershed analysis and now work in municipal development and review drainage plans.

When use LIDAR to update watershed maps and can estimate the amount of water rise that will occur at a specific location with a specific amount of rainfall. One thing that makes predictions in central Texas is the heavy development and vast difference in development standards.

Some municipalities are very strict, and only allow 15%-25% impervious cover, while others don't care. And with tree coverage it's hard to tell from serials if the ground is sod, mud, gravel, or concrete.

More importantly, many local jurisdictions don't require rainwater detention, and counties typically don't have the resources to inspect stuff installed without their knowledge outdlside of cities, so as development increases runoff into the watershed increases, as there's less pervious cover and what cover remains is more quickly saturated. Also, the grading of land and removal of vegetation leads to less friction, speeding up runoff. If upstream water is flowing faster, then the water rises higher and faster.