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Revisiting the Fully Automated Double-Ring Infiltrometer Using Open-Source Electronics
Ong, J., D. Werkema, AND J. Lane. Revisiting the Fully Automated Double-Ring Infiltrometer Using Open-Source Electronics. Presented at American Geophysical Union Fall Meeting, San Francisco, CA, December 03 - 07, 2012.
Here we use an inexpensive combination of pressure transducers, microcontroller, and open-source electronics that eliminate the need for Mariotte tubes. The system automates DRI water delivery and data recording for both constant- and falling-head infiltration tests. The user has the option of choosing water supplied to the DRI through a pressurized water system, pump, or gravity fed. An LCD screen enables user interface and observation of data for quality analysis in the field. The digital data is stored on a micro-SD card in standard column format for future retrieval and easy importing into conventional processing and plotting software. We show the results of infiltrometer tests using the automated system and a conventional Mariotte tube system conducted over test beds of uniform soils.
The double-ring infiltrometer (DRI) is commonly used for measuring soil hydraulic conductivity. However, constant-head DRI tests typically involve the use of Mariotte tubes, which can be problematic to set-up, and time-consuming to maintain and monitor during infiltration tests. Maheshwari (1996, Australian Journal of Soil Research, v. 34, p. 709-714) developed a method for eliminating Mariotte tubes for constant-head tests using a computer-controlled combination of water-level indicators and solenoids to maintain a near-constant head in the DRI. A pressure transducer mounted on a depth-to-volume calibrated tank measures the water delivery rates during the test and data are saved on a hard drive or floppy disk.