"I needed to explain that Louisiana's coast accepts the drainage from two-thirds of the United States and, while the necessary levees constructed upstream have prevented floods, they have also contributed to problems downstream"

John Breaux's quote is describing the environmental effect of the levees constructed along the Mississippi River. These levees were constructed to safeguard the states upstream from flooding, but they have had a negative impact on the states downstream. Louisiana's coast is especially affected, as it gets the drainage from two-thirds of the United States. The levees have actually avoided floods, but they have actually also caused problems downstream, such as increased sedimentation, decreased water quality, and reduced water flow. This has had an unfavorable influence on the environment, as well as the economy and incomes of those residing in the affected areas. The quote is a reminder of the importance of considering the long-lasting effects of our actions, and the need to find solutions that are beneficial for all.