Cost issues   Blackwater Wetland, Tres Rios, TX   The construction cost at the Tres Rios in Texas is estimated at $ 80 million, including both initial cost and predictions for expansion to reach the full-scale operation. In comparison, the estimate for the expansion of the local existing facility to achieve the same result would be more than $ 625 million. This is largely due to the fact that the constructed wetland system only requires periodic on-site labor, rather than continuous full-time attention, as required for the operation of the conventional treatment plant. The scale of he Tres Rios project is 800 acres. Put in another way by Mike Ogden, the estimated operating cost for this technology may be 10 to 15 cents per thousand gallons compared to average treatment cost of $2.50 to $3.00 per thousand gallons at conventional treatment plants.