登入選單
返回Google圖書搜尋
Environmental Effects of Hydraulic Dredging for Clam Shells in Lake Pontchartrain, Louisiana
註釋The approach taken in the present study was to select two sites in proximity that would also be representative of the area subjected to the perturbation cause by dredging operations. One site would serve as the control site and not be dredged; the second would be the experimental site and would be dredged in a manner approximating normal operations. Each site would be sampled in a quantitative manner both before and after dredging on a logarithmic time scale for the first year and on a quarterly basis thereafter. Ideally, the two sites would be located somewhere in the mid-lake region and would not ever have been dredged. Unfortunately, because dredging operations have occurred pretty much at random over the past 45 years with few, if any, records having been kept, it was virtually impossible to ascertain that any particular area had never been dredged. The next best alternative was to select an area that had not been dredged recently and that would be protected from being dredged again before the completion of the study. Such an area that had not been dredged recently and that would be protected from being dredged again before the completion of the study. Such an area exists along a two-mile wide swath, one mile on each side of the Lake Pontchartrain Causeway, which was first open in 1956.