I chose Po'ipu Beach Park, on the Island of Kaua'i for my field trip report because I was born and raised on the south side of Kaua'i. Po'ipu Beach is my old stomping grounds as I lived just 3 miles away from it. As a little girl, my Dad took my brother and sister to Po'ipu Beach to swim. This was our favorite spot, for swimming, and picnicking. This beach is the south shore's most popular beach. In fact, Po'ipu Beach was rated as the #1 beach in the world. Tourists and locals come to sunbathe, snorkel, swim, bodysurf, bodyboard, and surf. When the trade winds are blowing this is the place for windsurfing.

Po'ipu has beautiful cream colored (light tan) sand. Po'ipu Beach is a pocket beach that lies in a small bay between two rocky points. Next to it is the Po'ipu Beach Park. Po'ipu Beach Park is also a pocket of sand, its shallow nearshore waters are protected by a short breakwater to the east and by Nukumoi Point to the west.

Tombolos are sandbars that build across the ocean bottom from one island to another, or from shore to an island. Just such a sand bar, built between the shoreline of the park and a shallow rock islet offshore made Nukumoi Point. There are only three

tombolos in the state and all are located on the Island of Kauai.Po'ipu Beach Park is an attraction for families with young children, as

rocks were placed to barricade a section for the little children and the open part of the bay for the older children and adults. At times, when there is high surf, the lifeguards will post up warning signs as there are rip currents.

I have given information on Po'ipu Beach Park as it was before. Now to my disappointment, Po'ipu Beach Park has suffered a lot of changes due to Hurricane Iniki that hit the south shore of Kauai in 1992; and just two years ago, the south shore also got hit with a southeast swell that changed the whole topography of the Park. The past two years, the beach has not had its wide sandy berm but instead, the beach face is eroding and the berm is smaller because it is now winter. Much of the sand is gone leaving black basalt rocks along the shoreline.

In doing my research, I had an opportunity to talk to one of the lifeguards who has been at the Po'ipu Beach Park for several years. He told me that part of the erosion problem was because of Hurricane Iniki. Most of the sand was washed up on the grassy land area and across the road (Po'ipu Beach Park is close to the road). Instead of pushing the sand back, various companies came in and took the washed up sand and sold it off-island. This lack of sand was never replaced and the process of the natural sand coming back will take many years and to add to the problem the sand will keep depleting because there is no tombolo keeping the sand in the bay. When the southeast swell hit Po'ipu Beach, more sand was washed with the current and now, the tombolo is completely covered with water causing it to become a channel between the two bays, connecting Po'ipu Beach Park with Po'ipu Beach.

Po'ipu Beach Park during the 1980's was covered with sand, and it had a full wide berm. Today, Po'ipu Beach Park has a smaller berm, with basalt rocks washed ashore. The shore banks are eroding from the waves of the water, and lack of sand. (Picture below is how Po'ipu Beach Park looks today).

The swimming areas at the Po'ipu Beach Park were all laden with sand bottoms, but because of the depletion of the sand, the swimming area now is just coral reefs and basalt rocks.

There were interesting findings of the content of the sand at the Po'ipu Beach Park. I took sand that was taken from the shoreline just at the breaking of the water wave. It was very coarse and the grains were larger particles of black basalt rock, on the shoreline with coral and shells worn out by the waves.

Sand observed from the berm area had a texture of medium grain consisting of calcareous sand. These are from off-shore corals, algae, and shells

Sand that was taken on the grassy land area away from the shoreline was very soft and talc like. I was told by the lifeguard that the sand that was on the grassy area was quartz that was brought in to make up the lack of sand. He did not like the quartz because of its fine soft-like talc texture and when the wind blows, it is easily blown away. The difference that he pointed out with quartz and beach sand is that the beach sand, when poured into the water, will settle quickly to the bottom of the ocean, and the water will clear quickly. When quartz is poured into the water, the water gets very cloudy and does not settle quickly

In closing, I hope that our once beautiful beach can be restored. The County of Kaua'i has designated Po'ipu as a resort area. They are looking into ways to restore the beach as it was. One of the ways they are looking into, is to rebuild the tombolo as this is

very important as it serves as a dam to keep the sand from going downstream. As it is now, the sand that is coming into the bay, is just being swept away by the waves and currents over the tombolo into the other side of the bay. To restore the tombolo they are looking into using biodegradable sandbags and placing it down during the low tide, so the sand can rebuild again restoring back the tombolo. This is very important because of the erosion problem. This will help in rebuilding the sand back at Po'ipu Beach. If this works, the lifeguard I was talking to, said that it would take another 5 years for it to be restored. I am hoping to see Po'ipu Beach as the # 1 Beach in the world again!

I also found out something very interesting. Besides the coral, reefs, and algae that erode to form sand, the U'u (Parrotfish) also contributes to the making of sand on the beach. This fish eats off of the coral reefs and when it excretes, it releases fine grain sand that is washed up to our shores. When I went to observe the beach waves, they were coming in parallel to the shoreline.

BIBLIOGRAPHY

Clark, John R.K. Beaches of Kaua'i and Ni'ihau . University of Hawaii Press. C 1990.

 

Source: http://www.honolulu.hawaii.edu



Updated on : Aug 09, 2016   View : 134