Test taking is a humiliating experience for many students, with no perceived direct educational benefit. That need not be so. When circumstances allow, I use a two-pen method of collaborative testing. Students have told me that they leave the exam having figured out what they didn’t understand, filled in the...
Vineyard managers must decide on the timing and amount of irrigation. In Oregon the need for irrigation differs greatly year to year and field to field based on micro climate, soil, root development, plant health, and root stock. We suggest the use of leaf water potential as a useful management...
Spatial resolution fiber-optic cables allow for detailed observation of thermally complex heterogeneous hydrologic systems. A commercially produced high spatial resolution helically wound optic fiber sensing cable is employed in the Dead Sea, in order to study the dynamics of thermal stratification of the hypersaline lake. Structured spatial artifacts were found...
Sloping interfaces of fine over coarse porous material have been considered for use as barriers to infiltration for many years. Previous literature has developed analytical solutions for flow over such interfaces, numerical simulation of such flow, and the effects of anisotropy on the diversion capacity of such a system. In...
The Walla Walla basin lies in an arid region on the border of Eastern Washington and Oregon. A large portion of the area is devoted to agricultural production, relying on irrigation water diverted from the Walla Walla River and underlying aquifers occurring within Quaternary gravel and Mio-pliocene basalt formations. Heavy...
Over the past five years, Distributed Temperature Sensing (DTS) along fiber optic cables using Raman backscattering has become an important tool in the environmental sciences. Many environmental applications of DTS demand very accurate temperature measurements, with typical RMSE < 0.1 K. The aim of this paper is to describe and...
A new approach to monitoring surface waters using distributed fiber optic temperature sensing is presented, allowing resolutions of temperature of 0.01°C every meter along a fiber optic cable of up to 10,000 m in length. We illustrate the potential of this approach by quantifying both stream temperature dynamics and groundwater...
Directly below commercial mint fields, percolation in excess of 10 ppm of nitrogen as nitrate (NO3 --N), the EPA drinking water standard, occurs for much of the year (Figure 1, page 2). Concentrations rise rapidly after irrigation starts in June, indicating that this nitrogen is being pushed through by irrigation...
We present a novel technique to simultaneously measure wind speed (U) at thousands of locations continuously in time based on measurement of velocity-dependent heat transfer from a heated surface. Measuring temperature differences between paired passive and actively heated fiber-optic (AHFO) cables with a distributed temperature sensing system allowed estimation of...