Why was it so important to the South's Civil War effort that Texas maintain control of its ports

Answer: Because through the port, they were supplying their troops.

Explanation:

Texas was one of the critical areas of the Confederate troops. A supply of armaments and horses ran through Texas through Confederate soldiers. Until mid-1863. Texas had an essential function in those above. Namely, soon the boats of the Union would control the river, which was a critical moment in the war.