(a) This section applies only to a county that:
(1) has a population of 190,000 or more, is adjacent to a county with a population of 3.3 million or more, and borders the Gulf of Mexico; and
(2) operates a road department system under Subchapter D, Chapter 252, Transportation Code.
(b) The commissioners court may require the county road engineer to prepare and coordinate a county master drainage plan. The commissioners court by order may adopt regulations to implement the county master drainage plan.