The trial court filed findings of fact and conclusions of law. In order to provide a background, we first summarize the trial court's findings and other facts as to which there is no dispute. At the location in question, the Brazos runs from east to west. Defendant Garcia, who owns the land adjacent to and immediately east of plaintiffs, entered into a ten-year lease with defendants Standley, Kegel and Campos (SKC) in July, 1964, which authorized the mining and removal of sand and gravel from Garcia's land bordering the north bank of the Brazos. Shortly after the execution of that lease, SKC entered into a sublease with Everist to carry out the mining activities contemplated in and during the term of the base lease. Both leases provided for royalty payments to the lessor, with the sublease containing a slightly higher percentage. Everist conducted mining operation from August, 1964 through October, 1970. Plaintiffs were aware of the mining operations when they acquired their property in 1966. The active channel of the Brazos at the time the mining operations commenced and when plaintiffs acquired their property was in the southern-most channel, and remained in that channel until the river flooded in May, 1973. After that flood, it formed a new channel to the north. The Brazos River valley floor, which includes the properties in question, lies within an historical flood plain periodically subject to "inundation at various places." As a result of the May, 1973 flood, the river breached its bank in two or more places and flowed over and across plaintiffs' properties. The trial court found that the acts and omissions of defendants did not cause or contribute to plaintiffs' damages and that plaintiffs had failed to establish such. The trial court also found or concluded that plaintiffs failed to establish any breach of duty owed by defendants to plaintiffs, and that substantial evidence satisfied the court that defendants were not negligent.