Old Spillway
"In the summer of 1905, Fredrick R. Lyman, Edward Leo Lyman, Peter Anderson (Bishop of the Oak City Ward), E. L. Lyman Jr. and Callis Lyman made a trip from Oak City in a white top to look over the ground and see if it would be feasible to take water out of the river and run it to the land they desired to irrigate. (The farm ground around Delta.) 
They looked over the land and were pleased with it, then followed up the river to where the present diverting works are located, deciding that every thing was favorable for taking out the water at that place and running it in a canal to the land. (Taken from my Grandfather's writings in 1926.)
In 1910 and 1911 the diversion dam was built here after the Burtner dam washed out twice. The DMAD was built in 1960 and the spillway was no longer needed. The old spillway was used to "de-energize" the water coming from the DMAD.
In the Flood of 1983 the Old Spillway went out first. The river start making a gorge as it washed out working it's way back up the river to the spillway on the DMAD dam. When the gorge reach the DMAD spillway, the spillway "fell" in to the gorge the DMAD dam washed out and flooded everything down stream.
Walk about a 100 yards to the south and over the edge of the river and you can see the wings that are left from the old spillway after it washed out. (See photos included)