Waikiki

1) The volume of sand that was once abundant on Waikiki Beach has  now become almost completely eroded as a result of industrialization in the 1800s when it became a popular tourist destination. Because the beach is mostly ma-made, it faces many complications that have to do with the fact that concrete-control structures such as sea walls having manipulated and changed the natural flow of water on the beach. As sea levels respond to human impact, sand is moved around differently and in this case, is gradually being covered and pulled away from the beach
2) Since 1939 there have been sand-replenishment programs there have bean over 10 replenishment attempts in which at over 300,000 cubic yards of sand were added to the beach. These attempts have served as very temporary solutions to the overall problem and have not come close to being a long-term solution. A few years, 2.2 million was spent to spread new sand over the span of 1730 feet. Less than a year afterwards, the beach continued to erode. The current plan is for the government to receive 7 cents for every 1000 dollars worth of a businesses property value and use it towards replenishment. In addition, there is a plan to float a barge over large masses of sand and transferring it via pipeline to the shore. I think that a gradual upkeep plan like this would be more effective than one large depositing of sand, however neither is a long term solution. There needs to be another strategy that can make the shoreline exist farther out. 
3)Economically, the taxes of residents are used on replenishing the beach. People in the tourist industry on beaches will have a more difficult time working as less-and less- beach exists. There will be less vacation tourism in Waikiki if it's signature beaches are not there anymore.  On the social side, tourists will no longer be able to enjoy the beach and resident/tourist surfers face safety hazards with the uncovering of dangerous concrete. Native Hawaiians are losing their valued area of historical significance. Tourists will not be able to have an aesthetically pleasing beach experience as the shore is full of chains, concrete, and sandbags. Environmentally, the constant replenishing and addition of sand from humans could affect ecosystems close to shore that are bombarded with foreign sand and the biomass on other beaches where the sand is extracted from may be corrupted.