The two sand replenishment projects completed over the past three years have restored most of our seawall beaches. Sadly, our new beaches will slowly erode away.
Sand replenishment projects will have to be repeated periodically to keep our new beaches intact. This is about our only option.
Sea level rise and past land subsidence (Galveston Island and local coastal mainland subsidence had effectively been stopped since the 1990s by limiting the pumping and use of underground water sources) have contributed to the disappearing beach problem in Galveston. However, the following answers the question: Can “nature” ever be expected to maintain our beaches?
Some simple facts:
• On a natural barrier island, beaches move, osculating seaward and landward over time.
• A natural Galveston beach would continually receive sand from rivers east of Galveston — Trinity, San Jacinto, Neches, Sabine and Mississippi. This sand would flow unimpeded into the Gulf through undredged river deltas and would then be carried by our natural northeast to southwest shore current and deposited along Galveston beaches.
• A natural Galveston beach stores a large amount of the sand it receives in a healthy dune system behind the high tide line.
• Large storm surges periodically take sand from the beach system by destroying the beach dunes. During a large surge, the dune sand is either pushed onto the land or lost to the open ocean. The beach and dunes after a surge naturally try to retreat landward then slowly build seaward, aided by river sand, etc.
Conclusion: Natural healthy Galveston beaches must be free to move around with respect to the Gulf and must have a continual source of new sand.
I had the opportunity to visit a near-natural barrier island at Cape Lookout, N.C. This area gives one a vision of Galveston minus most of the human construction.
Over the past 150 years we have turned Galveston into an “Unnatural Barrier Island.” We have built dams on all Texas Rivers east of Galveston. We dredged the ship channel, which required long seaward jetties. Also, we built a thriving city on the island, which eventually required a seawall.
The dams trap river sand, thus much of the sand which once fed our beaches never gets to the Gulf. The ship channel jetties interfere with the natural northeast to southwest movement of river sand along the Texas Gulf Coast. Lastly, the seawall does not allow the dune line and beach to move over time.
River dams, channel jetties and seawalls all have good justifications for their existence. However, these justifications are to help people, not barrier island beaches. We all know there is no way we are going to remove any of these and we can do very little about sea level changes. Therefore, large periodic sand replenishment projects are our only option if we want sandy beaches along our seawall.