The drainage from the ponds will be into natural ditches cut into the pond area fill and the natural ground. These ditches will be 20 to 30 cm deep and have 3:1 side slopes. For 1 m on either side of the pond water outlet monks, the drainage ditches will be lined with unreinforced concrete about 5 cm thick. It is assumed that a high percentage of the effluent from the ponds will be absorbed into the ground before reaching the end of the ditch. If the amount of effluent sinking into the ground creates an undesirable situation, the drainage ditches will be lined with polythylene until the final drainage system is designed and funded in the Pilot Project (Phase I). For that phase it is envisioned that a drainage lagoon may be constructed to act as a settling basin and perhaps a culture pond for tilapia, mussels and other experimental or feed species. The lagoon would be gravity drained in part at low tide, with low-head pumps completing the drainage cycle as required.
The final grades and direction of the drainage ditches will have to be laid out in the field with the aid of surveyors, as the existing topographical survey does not give enough detail for this purpose. Dredging pipelines and stockpiles just outside the project fence facing the Gulf currently make final planning difficult. This is a temporary situation, however.
