Beach Profiling

Introduction:

Beach profiling is a great way to study beach erosion. If you take multiple beach profiles, you can very effectively compare the size and shape of sand dunes over time. The results of beach profiling can be affected by many factors. For example, if there are ditches or cliffs in the dunes, they will show in the final profile. Over time, beaches can be shaped by a variety of factors, including wind, waves, and tide. Rain often erodes beaches, changing their shape. Other things affecting the beach's sand levels are human activity such as walking or driving along the beach. The very successful dune restoration project at our specific beach will also undoubtedly affect profiles as well; if we had taken these profiles before the restoration project was initiated, the beaches would have been much flatter.

Procedure:

1. Collect materials (Rise tool, run tool, compass, GPS, data sheet, transect line, writing utensil) and go to beach.

2. Find a point on a sand dune a little ways inland, and take the latitude/longitude coordinates of that point using the GPS (This will be Point A). Record data.

3. Starting at Point A on the dune, lay the transect line exactly perpendicular to the shoreline, going towards the water. BE AS PRECISE AS POSSIBLE.

4. Using the compass, take a reading from Point A telling which exact direction/degree the transect line is running. Record data.

5. Place the run tool firmly on the ground at Point A, pointing down the transect line. Use the level to make it exactly even.

6. Brace the rise tool on the ground at the other end of the run tool (this is Point B), and use the level to even it out.

7. Look where the run tool points to on the rise tool. The number it touches is the rise from point A to point B. If the dune slopes upward, it should be a negative number. Record the rise as well as any notable features included between the two points.

8. Move the foot of the run tool to the foot of the rise tool and switch them carefully, making sure to use the exact same point. Make sure the run tool is still even and pointing along the transect line. Move the rise tool to the other end of the run tool and, using the same method as step 7, collect data.

9. Repeat step 8 until you reach the waters edge, then repeat the same data-collecting process into the water. Continue until you reach the “foot” of the beach, a small dip in the sand just offshore (almost all beaches have them).

Pictures:

Here we are taking the GPS coordinates of our starting point (step 2).

Here we are taking the actual data (step 7). We're getting closer to the foot of the beach with every step!

Results:

Beach Profile

Here we have the slope of the beach at transect 2. This should be pretty close to the actual shape of the dune, although if we were to be perfectly precise, this graph would be stretched dramatically length-wise. Overall though, it's a good representation of the beach . . .

Current Map:

. . .here we have a current map of south Kalepolepo. We carefully tossed a special scientific floating tool (a rotten guava) into the ocean and recorded its progress through the water, noting the shape and speed of the current. It took us a few times to do this correctly; we kept losing sight of our guavas and having to start over. This is the final result.