Waimea was originally an ahupua'a (land division) of Ko'olauloa, and it wasn't until 1886 that government officials re-designated the valley in the district of Waialua. This move may have been related to water and forest resources that would benefit the Waialua sugar industry. Regardless, by the time of the illegal overthrow of the monarchy in 1893, Waimea and its mountain tributaries had been stripped of their forests and cleared on the plains for sugar production.
Industrial efforts had a devastating effect on the valley in 1894 when heavy rains caused a massive flood that deposited thousands of tons of silt on the wide valley floor. The flood destroyed the entire village and buried most of the kalo (taro) terraces and agricultural endeavors in the valley. Incidentally, that deposited silt created a firm bank upon which the sands of Waimea Bay began to collect and stabilize. Prior to the flood, canoes could paddle some distance up the river for trade and safe harbor.
Since the flood, the valley was abandoned by inhabitants, until quarrying began in the late 1920s for the construction of Kamehameha Highway. That most famous of church towers at Saint Peter and Paul's Cathedral was originally built by the quarry as a silo for crushed rubble, later purchased by the church when the highway was completed and the quarry abandoned. The nearby haunted house was also related to the quarry, whose owners built it atop an old heiau (temple). The sand that built up caused the bay to close out on bigger swells and it blocked off the river mouth for much of the year. But it allowed fishermen to camp in the cave that now lies underwater beneath the jump rock.
That all changed again when industrial sand mining began in Waimea for the purpose of creating beaches in WaikI-kI-, and constructing Ala Moana and Magic Island, which began in the mid-1950s, continuing until the early 1960s. Over 200,000 tons of sand was removed, deepening the bay considerably. Fred Van Dyke once mentioned that he felt there was a correlation between the removal of sand and the momentous pioneering morning in 1957 on which he and his friends decided to challenge the Waimea surf.
Further sand removal occurred during the large winter surf created by the El Nio conditions in 1969 and 1983. Waimea Tuberider James Jones describes early 1983 as having 20 days of rideable surf over 15 feet and two closed out days of 30 to 40 feet--and it was only the first day of March! He describes the scene:
"At Waimea the wave erosion threatened to undermine the road on the north side. The sidewalk that runs along the west side of the beach park collapsed and fell into the ocean. Where once had been a wide sand dune, was now a 20-foot cliff dropping down to the pounding surf. The treasure hunters scurried up and down the beach at Waimea finding coins dating back to the early 1900s. Then one of them picked up a coin minted when Hawai'i was still a kingdom, dated 1883, and bearing the name of Kamehameha III. The strangest thing of all though was the human skull found in the former beach, now cliff, next to the lifeguard stand. An archaeologist estimated that it had been there for eighty years. At Ke Waena, a previously unknown Hawaiian petroglyph was exposed on the rock shelf below the beach there. Perhaps a message in time that the ancient Hawaiians had seen this strange phenomenon of nature before". Jones, 1983