Project title development and testing of a borehole tool to measure high frequency three dimensional groundwater flow direction and velocity during long term deploymentproject period 08 01 2023…

Project title development and testing of a borehole tool to measure high frequency three dimensional groundwater flow direction and velocity during long term deploymentproject period 08 01 2023 through 07 31 2025AWARD purpose given increasing demands on water for agriculture, industry, and drinking water, inventory and assessment of groundwater supplies has never been morecritical. Yet, sensors that can be used to track flow direction and velocity of groundwater inthree dimensions (3D) that can operate in the extensive network of USGS groundwatermonitoring wells do not exist. A network of low cost borehole tools to measure groundwatervectors in three dimensions would enable a number of critical applications including inventoriesof groundwater quantity and contaminant tracking and modeling. Miniaturization of digitalmicrocontroller and thermistor technology now enables the production of sensors that can useplumes of heat to determine groundwater flow vectors in three dimensions. This project will use anexisting open source microcontroller known as rriv (river restoration information andverification) as a platform to develop this sensor.activities to be performed the objectives for the project are as follows 1) develop a boreholetool for high frequency measurements of three dimensional (3D) groundwater vectors duringlong term deployment, functional in a range of environmental settings, easily calibrated andintegrated with existing equipment and data transmission systems 2) develop or modify existingsoftware to collect data necessary to compute 3D vectors onsite and in real time and 3) evaluatethe accuracy of the tool in mutually agreed upon laboratory and field tests. A device will be builtto measure groundwater flow vectors in three dimensions using water temperature. A centralheating element will add a known amount of heat to the groundwater environment. Arrays ofminiaturized thermistors will be placed around the heating element and will detect the directionand speed of the plume of heated water. Engineers at rriv will assist with the design andmanufacture of microcontroller components required for the construction of this device.as described above, the devices will be tested under both laboratory and field conditions.laboratory testing will focus on assessing the following characteristics 1) characterization ofsensitivity the sensitivity and measurement error of the sensor will be tested under a variety ofrealistic groundwater flow conditions. These tests will be used to develop a limit of detectionminimum groundwater flow rateunder which the sensor can operate. 2)sensitivity ofmeasurements to groundwater media the sensor will be tested with simulated groundwatermedia that varies in size to assess the influence of nominal grain size on flow rate measurements.deliverables and expected outcomes as a deliverable, a minimum of four working prototypes will be developed as well as associated data and schematics. Findings from this research will be reported to scientific conferences and submitted to peer reviewed journals. Intended beneficiaries the 3D groundwater flow devices that will be created will allow collection of far more data about groundwater flows than are currently available, at a reduced cost. Thus, any users of USGS generated groundwater data will benefit from enhanced data about groundwater fluxes and processes. Further, designs produced during this project will be released with an open source license, meaning that any users in need of 3D groundwater flow data will have access to this newly designed instrument.