I could be wrong, but I think that he's confusing gutters with storm drains and Houston for a city with actual terrain.
A gutter is, AFAIAC, a
channel dug in the ground fitted around roads, houses, fields etc, to drain off rain water. And it seems it rained on Houston.
I have not mentioned storm drains and I do not know what it is. A storm is violent weather (to avoid at sea) and a drain is a
channel, pipe, trench, etc. but a storm drain? Sorry, I cannot help.