most u.s. beaches are shrinking or encroaching on the land rather than growing or moving seaward, so the land of the u.s. is getting smaller, not bigger. which of the following is a likely cause for loss of at least some of our beaches: group of answer choices sea-level rise as the last ice age drained river valleys to get rid of bays, and sediment now is transported to the coast rather than being trapped in bays. dams have greatly increased the sediment supply to deltas that feed longshore drift to grow beaches. land is sinking in some places as it recovers from being bulged up beyond the edge of the ice-age ice sheets. water, oil and gas are being pumped into the ground in some places, causing the land to rise.