Water in straightened channels also meanders naturally in an attempt to stabilize itself, thus eroding the sides of the channel. The erosion may result in the cave-in of the channel sides, and frequent maintenance is important. Rip-rap is used quite often in graded channels at specific points vulnerable to erosion. Rip-rap is chunks of rocks or concrete which, when held in place by wire mesh, is referred to as gabions. Both rip-rap and gabions work best when vegetation is encouraged.
Plants hold the soil in place and prevent erosion around the rocks and wire mesh.
Another channel treatment involves the use of paving blocks on side slopes with natural vegetation growing between. This method stabilizes the slope and has open space characteristics, but needs irrigation to start vegetation growth and maintenance after high flows. The blocks can also be used with grass, and would then require the same maintenance as many Albuquerque parks. Drop structures are used to stabilize the channels and slow the flow of water. The main problem with this method occurs when falling water carves away the ground at the foot of the structure, either creating pools, or undermining the foundation.