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Professor: EPD study flawed
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Editor’s note: Dr. Jack Blanton is professor emeritus at the Skidaway Island Institute of Oceanography in Savannah. He has researched physical oceanography for more  than 40 years. For that reason, we invited him to answer questions regarding the Liberty County Development Authority’s proposed wastewater treatment facility. Here are our questions and his replies.

Q. The Georgia EPD recently announced that the impact of a proposed Liberty County Wastewater treatment facility would be ‘de minimis’, apparently meaning it would have minimal or no impact on the environment. Opponents of the plant are skeptical, and there’s been suggestion that the EPD study is flawed. What is your professional view of the EPD finding?
A. The model being used is not really applicable to judging water-quality impacts to estuaries and tidal channels common to Georgia. The Georgia EPD is underfunded to take on studies that are required for such areas.

Q. If this study is flawed, what sort of study should be done? What is it about the Laurel View River and the model used by EPD to conduct their study that makes a different study necessary?
A. A model relevant to Georgia coastal areas needs to be 3-dimensional and include the marshes and small creeks surrounding the main channel. Due to the shallow nature of the channels, the large tidal range and large expanses of marshes, the simple one channel model is not applicable. It is the residence time and flushing of the marshes which should be assessed. Models to judge impacts in such coastal areas need to
1. Allow for overtopping of tidal channels, which leads to inundation of marshes;
2. Account for the fact that average flow in tidal channels is NOT uniformly seaward;
3. Include wind effects on circulation. Even winds on the continental shelf can alter water levels and effect circulation varies dramatically in time.

Q. Did SKIO offer to do the study?
A. No.

Q. If the study used by EPD to come up with its finding serves as the basis for operation of the plant, what could that mean for the coastal ecosystem?
A. There would be very little effective management of the rapid development underway in Georgia.

Q. Do you believe the plant should be built?
No, not based on the present EPD evaluation. The EPD study doesn’t properly address any of the processes that are important when ascertaining the likely long-term impact of the Liberty County Wastewater plant. For example, specific regions of the marshes surrounding the plant effluents will have longer residence times, which are not taken into account in judging the plant’s impact. In fact, the present study cannot reliably assess residence times within specific regions of the marsh, nor the average overall residence times of waters within the marsh. So even if concentrations of pollutants introduced to the creeks are low, chronic doses could lead to eventual degradation of surrounding intertidal areas.

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