Laboratory equipment (homemade)
Integrated soil column system
This integrated soil column can be used to measure common electrical and hydraulic properties of soils, including hydraulic conductivity, electrical resistivity, and streaming potential coupling coefficient. In saturated conditions, the measurement is similar to the traditional constant head tests. This system can also be arranged to perform a drainage test, during which the soil water pressure (matric suction) and electrical potential at different levels along the sample can also be measured. Using these transient measurements, a stochastic inversion can be performed to estimate the soil's unsaturated properties, including soil water retention curve and unsaturated electrical/hydraulic conductivity.
Hydrogeophysical probe
This probe integrates the non-polarizing electrode into a traditional tensiometer. The ceramic cup in the probe will prevent air in the soil from entering into the probe when soil suction is lower than the air entry value of the ceramic cup. Water, on the other hand, can move quickly between the probe and soil sample, and a pressure transducer inserted into the probe can measure the pore water pressure in the sample. A non-polarizing Ag/AgCl electrode is also inserted into the probe and sealed by a rubber stopper. Due to the presence of the ceramic cup, the probe will always be full of water, ensuring that the electrode is immersed in water even the sample under test is in unsaturated condition. Such an integrated design allows the pore water pressure and electrical potential in soils can be measured in both saturated and unsaturated conditions
Lysimeter
This lysimeter is designed to conduct hydrological tests that involve evaporation and evapotranspiration (ET). One special feature of this lysimeter is that electrodes can be installed at different levels for geoelectrical monitoring during the experiments. A mini-well is also installed such that the "groundwater" chemistry can be monitored. Available electrical measurements include resistivity, induced polarization, and self-potential. This lysimeter can be used to study various hydrological processes in the root zone of soils.
Laboratory equipment (commercial)
HYPROP 2
HYPROP 2 can automatically determine unsaturated hydraulic conductivity and water retention curve on undisturbed soil samples. Compared to the traditional method (e.g., pressure plate extractor), it saves a lot of time and generates more data points.
Pressure plate extractor
The pressure plate extractor measures the water retention curve of soils using a traditional technique (axis translation), which takes much longer than HYPROP 2. We are in the process of adding geoelectrical monitoring sensors in the sample for acquiring additional data.
Bender element system
The bender element system can generate and pick up mechanical waves signals traveling in geological materials. Based on the generated and measured waveform, the elastic wave velocity of the sample can be determined. The measured velocity can be used for interpreting field seismic refraction tests.
Portable spectral induced polarization (PSIP) system
The PSIP system measures the complex electrical conductivity of geological materials in the frequency range between 0.001 Hz and 10 kHz. The complex conductivity (real conductivity and induced polarization) of geological materials is correlated some hydrological properties such as permeability and moisture content.
Field equipment
Resistivity meter
We have SYSCAL Pro 72 and Limman 4point light. They are used in the field mostly for electrical resistivity tomography (ERT) or time-lapse ERT.
Geometrics Geode system
The department also has the Geode system, which can be used in the field to conduct seismic refraction tests.
SIP Compact S
The SIP COMPACT S can be used in the field for monitoring the complex conductivity in a wide frequency range (0.001 Hz to 10 kHz).
Nearby field site
Boise Hydrogeophysical Research Site (BHRS)
Researchers in our department have developed the Boise Hydrogeophysical Research Site for applying geophysical tools to aquifer characterizations. For more details, refer to https://www.boisestate.edu/earth-bhrs/
Dry Creek Experimental Watershed
The Dry Creek Experimental Watershed is ~10 miles from the campus. It was developed to study runoff generation, ecohydrology, and snow in semi-arid regions. More information can be found at https://www.boisestate.edu/drycreek/