The Arizona Department of Water Resources has an excellent program to monitor a somewhat unique geologic hazard – land subsidence. Caused by compaction of valley sediments in areas of declining groundwater table, it can create significant problems for infrastructure such as drainage facilities, flood control works, and gravity flow utilities such as sewer lines. It can also induce a secondary geologic hazard, earth fissures. The ADWR has been using InSAR data supplemented with GPS surveying and other data since 1997 to monitor a number of land subsidence areas in Arizona. This is the first of what I presume will be a series of comprehensive reports on their program. [Source: Read the PDF report from the ADWR. Image: ADWR Land Subsidence Page]
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Earth Fissures on Phoenix PBS Affiliate “Horizon” Show
Phoenix Arizona’s PBS affiliate, KAET-TV, Channel 8 had a segment on Earth Fissures on their May 30th episode of "Horizons". They interviewed one resident of the Chandler Heights area that has problems with earth fissures on her property. They also interviewed Todd Shippman with the AZGS in the field. Todd is the project manager for the AZGS’ earth fissure mapping program. The bulk of the program was an interview with Lee Allison, the head of the AZGS and the Arizona State Geologist. He explains the earth fissure mapping program, and the planning scale maps that were just released this week on the AZGS Website. Click through for embedded video of the segment from the Horizon Website. You can also download it as a podcast if you wish. (Photo courtesy of NCS Consultants, LLC.)
Arizona Geological Survey Publishes Earth Fissure Viewer
Embankment Dams in Fissure Risk Zones
Is it possible to safely rehabilitate dams in earth fissure risk zones to continue to provide economical flood protection to the public, or does the risk of dam failure due to an undetected fissure present too great a threat to the public? Read the article to find out the view of the Arizona Department of Water Resources.