Facilities & Capabilities

In the Lab

Tempe cells
	Soil Water Characteristic curves show the relationship between the matric potential and volumetric water content of a soil. As water content decreases, matric potential becomes very negative. The shape of a SWC curve depends on pore size distribution and specific surface of the soil, and is therefore, unique to a particular soil. To produce a water characteristic curve, the volumetric water content at different known tensions must be determined. One way to do this is to saturate an intact soil core, and then drive water out of the core by applying a regulated air pressure using a tempe cell. The tempe cell is designed to hold a soil core which is seated against a ceramic plate. The ceramic plate is porous and rated for different air pressures. The typical matric potential for a SWC curve ranges from 0 to -15 bars.
Pressure plates
	Pressure plates are often used to measure the volumetric content of a soil at wilting point (-15 bar). Saturated, sieved soil samples are placed in a small ring on the pressure plate. Air pressure is then applied to the soil for several days to drive off water and the final volumetric water content is determined.
Water Filtration
	Total Suspended Solids (TSS) are measured using a 250ml aliquot of a stream water sample that is filtered through a 0.45 micron glass fiber filter. The filter is pre-weighed and then dried and weighed after filtration to calculate TSS in mg/L.

In the Field

ISCO Automated 6712 Water Sampler
	ISCO 6712 automated water samplers are located at each of our stream research locations. A pressure transducer sensor from the ISCO is placed in the stream to measure stage height (m), flow (cfs), and velocity (m/s). Samples are taken based on increase in stage height, flow, uniform time event or non uniform time event. Samples are retrieved using suction tubing and placed into 1L bottles. Field personnel then obtain the samples after desired conditions have occurred and brought back to the lab for analysis.
Compact Constant Head Permeameter

TDR

Tensiometer