Houston is practically a swamp, why would they need water from Colorado?
I think he is confusing the rivers. There is a Colorado River that originates in Colorado and drains into the Gulf of California.
But, there is also a Colorado River that originates in Lubbock, and drains into Matagorda Bay. However, that's south of Houston, about halfway to Corpus Christi.
The Rio Grande originates in Colorado and drains into the Gulf of Mexico, but that's the border between Texas and Mexico.