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Operations & maintenance has three maintenance branches: North, East and Central. These branches are responsible for maintaining the District's dams, channels, roadways and other structural features. An Ecology maintenance group is responsible for the installation and care of vegetation for erosion control, landscaping aesthetics, annual herbicide spraying projects on District structures and animal mitigation projects. The Work Control Center, Shop and Administration branches provide support services to the maintenance groups. The District has a satellite maintenance office in the North Valley of the Phoenix metropolitan area and another in east Mesa.
The maintenance of flood control structures involves several different processes, including inspections, vegetation management and animal management. Together, these maintenance procedures keep flood control structures functioning properly and safely.
Inspections
The Flood Control District delivers on the promise of safety first. The operations & maintenance inspection personnel have nearly 100 years of combined experience. They conduct quarterly and annual inspections of dams, and annual inspections of non-dam flood control structures.
The quarterly inspections for the dams occur in January, April, July and October of each calendar year. These are visual inspections conducted to ensure the operational function of each dam.
Annual dam inspections are coordinated with the District dam safety engineers and the Arizona Department of Water Resources. These inspections involve evaluating the 22 dams for their structural integrity. All other non-dam type structures are also inspected annually for structure integrity by the operations & maintenance personnel.
Vegetation Management
The dams constructed in Maricopa County are predominantly earthen structures composed of materials like compacted soil, gravel and rock. In addition, many flood control channels are unlined, compacted earth. Trees, bushes, shrubs and grasses may grow in, on and around these structures, and this vegetation poses a threat to the structural integrity of the structure. Tree roots loosen the soils of dam embankments and create seepage paths for water. Bushes and shrubs may divert water flows away from a structure, thereby defeating the structure’s designed purpose. Grasses can easily cover the surface of a dam or channel, obscuring defects in the structure that would otherwise be seen in during a safety inspection. To reduce these problems, the District follows a maintenance program that includes mowing grass and removing deep rooted vegetation in and around flood control structures.
Animal Management
Small animals can cause big problems for earthen flood control structures like dams. Wildlife that burrows into the ground to make their homes, such as ground squirrels and mice, can cause a multitude of structural and erosion issues. Over time, the holes and trenches made by burrows can cause sections of a dam to collapse. Erosion can also occur if water infiltrates a dam structure through a burrow hole.
The District mitigates burrowing animal populations when they pose a threat to a flood control structure. Even so, when the wildlife in question is an endangered or protected species or a species of concern (one that warrants special attention), the District fully complies with all federal regulations that protect such animals. In the case of the western burrowing owl, a species of concern, the District has gone to great lengths to carefully remove owls from flood control structure construction and maintenance sites, and then return them to a site near their original home, even constructing artificial burrows for the owls to use that protect the flood control structure from future damage. To learn more about the western burrowing owl relocation program, go to the Environmental page of this Web site.
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