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Q: What is sand and gravel mining?
A: The industry of aggregate production, or sand and gravel mining, involves excavating loose alluvial material from the river bed or its banks, sorting and grading the material, and hauling it in trucks away from the site. The Flood Control District of Maricopa County is primarily concerned with regulating the aggregate extraction activities within delineated floodplains and floodways.
Q: Who do I contact about dust, noise or traffic impacts from a sand and gravel activity?
A: We only regulate the impacts on stormwater conveyance of sand and gravel mining. Dust is regulated by the Maricopa County Air Quality Department. Noise and traffic complaints can be sent to the Maricopa County Department of Transportation. Potential zoning conflicts arising as a result of sand and gravel mining should be referred to the Maricopa County Department of Planning and Development.
Q: What are the major impacts of sand and gravel mining within floodplains?
A: The impact of a sand and gravel operation depends primarily upon where the pit is located within a floodplain, and the depth and area of excavation. If not excavated properly, sand and gravel pits can change the depth, velocity or path of floodwater in a river bed, endangering lives and property.
Q: How do sand and gravel pits cause impacts that can endanger lives and property?
A: When floodwater enters a pit, erosion occurs on the upstream lip of the pit. The erosion cuts away at the lip, moving it upstream in a process known as headcutting. Floodwater in natural streams in Maricopa County contains huge quantities of sand and gravel in motion. When these sediment-rich waters enter a large pit, the solids settle out, and the water leaving the pit is relatively clean. This cleaner water tends to pick up more sediment after leaving the pit and causes downstream erosion, or tailcutting. The inadequate embankment stabilization of deep pits causes the steep slopes to collapse into the pits as floodwater passes, causing lateral migration of the pit.
Q: How does the District prevent adverse impacts from sand and gravel pits?
A: The District requires that a Floodplain Use Permit be issued for each sand and gravel operation. Permit applicants are required to submit an engineered plan that addresses concerns about bank stability and erosion of the site activities and how they will affect the river morphology when floods occur.
Q: Why is a permit required from the District for sand and gravel mining?
A: A permit ensures that sand and gravel mining operations do not have any adverse impacts on adjacent properties, such as diverting floodwater or causing river bed changes which alone or cumulatively can put other properties at risk of flooding or erosion hazards.
Q: Under what authority does the District permit sand and gravel operations?
A: The District permits sand and gravel operations in floodways under the authority of the Floodplain Regulations, Section 801(B). Operations within the floodway fringe are permitted under the authority of Section 802.
Q: What permits are required for sand and gravel mining?
A: In addition to the Floodplain Use Permit from the District, permits are required from the Maricopa County Air Quality Department for dust control and construction, and from Arizona Department of Environmental Quality for water quality. If the excavation disturbs the vegetation of a wildlife habitat or enters into an area designated as "waters of the United States" by the U.S. Army Corps of Engineers, the operation must obtain a 404 permit as well. See links to other permits.
Q: What are the penalties for violation of the regulations for sand and gravel permits?
A: Violation of the Floodplain Regulations is a class 2 misdemeanor, punishable by a fine of $10,000. The Enforcement Rules for the Floodplain Regulations have been adopted for Maricopa County, which provides an administrative hearing officer process for correcting violations and ensuring compliance with the Floodplain Regulations.
Q: Where are the locations of major sand and gravel operations in Maricopa County?
A: Sand and gravel mining occurs on the Salt River, Gila River, Agua Fria River and Hassayampa River. You may view the following map to find the area you are interested in: Index Map
Q: Where can I learn more about sand and gravel mining?
A: The Arizona Rock Products Association maintains a Web site to promote the interests of the aggregate extraction industry in Arizona.
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