Maui has experienced significant loss of beachfront in the last few decades and the problem is getting worse. The causes are not fully understood. But there is agreement that beach nourishment by sand replenishment is the best way to slow the loss of sand from our beaches. Shoreline armoring just shifts the erosion to the neighboring beaches and shoreline.
The two local sources for replacement sand are, mining sand from inland sites, or dredging off-shore areas and pumping a wet slurry of sand-laden seawater back onto the beach. Inland sand mining is cheaper than dredging sand from the seafloor. I have heard that the sand from dunes near Wailuku is mined at a rate of more than 300,000 tons a year, and is mostly shipped to Honolulu to be used in the manufacture of concrete. It is estimated that at the current rate of extraction that Maui’s supplies of inland sand will run out in 5-7 years. Maui needs to keep all of its own supply of replenishment sand. Sooner or later Maui will need this local supply of sand for its own uses including, replenishing the beaches here. When we run out of local sand stocks, we will have to start importing sand from elsewhere at a much higher price. We need our beaches for recreation and to stabilize the shorefront homes and other buildings that would otherwise be consumed by the sea. Please spare a thought for the plight of our beautiful beaches and save our sand before it is too late.
Sand Export is Accelerating: The rate of sand export is accelerating and now at least 96 of these barges per year take Maui sand to Oahu, that is about two of these barge fulls per week. *look closely and you can see the back end of a semi-truck on the barge unloading a full load of sand. It is estimated that Maui is losing over 2 million tons of sand that are being shipped out to Oahu each year.
Sand Removal and Sand Mining: The main reason we have beach loss today is the fact that too much sand was taken off the beaches for commercial use. Beach Sand was used in the construction industry, but mostly for sugar cane production, and agriculture. Sand was removed from the beaches and nearshore systems for decades. Beach Sand was used as aggregate for construction, and also turned into lime. Lime is used to make concrete, used as a fertilizer, and is used an additive in the sugar cane production process. The coral sand was burned in a rotary kiln to produce lime.
Lime Kiln at Paia: HC&S ran a Lime Kiln in Paia for over 70 years harvesting sand from the adjacent beach at Baldwin Beach. The Paia Lime kiln was the only lime kiln operation in the nation to be using coral sand as a feed stock for their facility. The huge amount of sand removed from the beaches in that time has caused tremendous environmental damage, and has long lasting consequences that we are still experiencing today.
Here are some quotes from the 1961 Mineral Year Book:
and this one,
Sand removed from Kaa Beach: Sand was also harvested from Kaa Beach which has never been replaced. The sandy beaches at Kanaha Littoral cell were historically much wider and the degradation we see today is a result was from over-exploitation of the finite sand resource by the Sugar Industry.
Beach Sand Mining is now illegal: In the mid to late 70’s the State of Hawaii passed laws that outlaw the removal of beach sand. However the damage to the beach environment has already been done. We are still seeing the effects of this damage decades later.
Beach restoration is possible: There has already been a lot of studies by State and Maui County that say that Kanaha Beach and other Maui beaches could (and should) be restored by replenishing sand stocks, from either land-based or offshore sand sources. But sadly there is no plans to do a beach replenishment project at Kanaha Beach. A sand supplementation, “beach nourishment” project would be a great assist to Kanaha Beach.
There have been several beach restoration projects around Maui: Restoration projects include inside the Kahului harbor on the eastern beach in front of the Maui Coast Hotel, Sugar Cove beach on north Shore, Stable Road beach 1/2 mile east of Kanaha Beach, The beach west of the KWWTP 1/4 mile west of Kanaha Beach, and several beaches in Kihei. But it is a very long time-consuming process to get the studies and all the permits, and the financing. Currently Kahana Beach on the upper west side of Maui (not to be confused with “Kanaha”) has been waiting for 11 years to get its badly needed restoration project going, and it is still going through the red tape.