The world according to me....

At the end of a beach nourishment project, the finishing touch consists of tilling (essentially dragging a big rake back and forth across the beach). The logic behind this is that tilling will ensure that the new material placed on the beach is not too compact for the succesful digging of sea turtle nests. However, is tilling always necessary? In general, the less manipulation done to the beach, the better. Guidelines for post-nourishment project tilling do exist, but they are antiquated and it invariably has been easier for the engineering firm hired to complete the nourishment project to always till afterwards. In the case of the current project on Atlantic Beach, the Fish and Wildlife Service, the NC Wildlife Resources Commission and the US Army Corps of Engineers agreed to withhold automatic tilling until we could check out the compaction using a penetrometer.

This is Kristin Holloman, a biologist working on sea turtles in Atlantic Beach, using the penetrometer to test the compaction on the beach. As it turned out, some parts of the beach were highly compact while others were not. Specifically, in those areas where the nourished material had high levels of organic content (i.e. mud), we couldn't get the penetrometer deeper than 3-4 inches from the surface. We recommended tilling in these compact zones. For the areas with less organic content (see picture at the top), the compaction was similar to beach areas that have not been nourished. We recommended that no tilling take place in these zones. One concern has been the extensive use of vehicles on the beach, both as a result of the nourishment project and by the public (see tire tracks in photo at the top). For now, the compaction of the material did not seem to be negatively affected, but we will keep an eye on it. Of course, the best indicator of the suitability of the material will be whether the turtles use these zones for nesting, starting in May 2005.