VelProbePE: An automated spreadsheet program for interpreting point velocity probe breakthrough curves

A benchtop sandbox constructed from nested storage tanks (NeSTs), was assembled for studying flow and transport in porous media. Molded plastic storage containers, purchased at a department store, were modified to fashion the tanks. The remaining construction materials were also inexpensive and the NeST design made it virtually leak‐proof. The uniformity of flow in the NeST was evaluated with three independent tracer tests. Estimated velocities were within about ±20% including all test results, indicating a high degree of predictability and uniformity in the flow. The NeST is a simple and robust tool suitable for research and teaching purposes, particularly for the testing of flow measurement sensors like the point velocity probes.

Section: Methodsmentioning

confidence: 99%

Design and Testing of a Convenient Benchtop Sandbox for Controlled Flow Experiments

Bowen¹,

Devlin²,

Schillig³

2012

“…Data collection was accomplished using a Campbell Scientific CR1000 datalogger set up to collect data at 2 s intervals. Data were processed using the software package VelProbePE (Schillig ).…”

Section: Methodsmentioning

confidence: 99%

A Comparison of Tools and Methods for Estimating Groundwater‐Surface Water Exchange

Cremeans¹,

Devlin²,

Osorno³

et al. 2020

A comparison of tools for measuring discharge rates in a sandy streambed was conducted along a transect near the north bank of the Grindsted Å (stream), Denmark. Four tools were evaluated at six locations spaced 3 m apart in the stream: mini‐piezometers, streambed point velocity probes (SBPVPs), temperature profilers, and seepage meters. Comparison of the methods showed that all identified a similar trend of low to high groundwater discharges moving westward along the transect. Furthermore, it was found that the differences between discharges estimated from Darcy calculations (using the mini‐pizometers), and SBPVPs were not statistically different from zero, at the 90% confidence level. Seepage meter estimates were consistently lower than those of the other two methods, but compared more reasonably with the application of a correction factor of 1.7, taken from the literature. In contrast, discharges estimated from temperature profiling (to a depth of 40 cm) were found to be about an order of magnitude less than those determined with the other methods, possibly due to interferences from horizontal hyporheic flow. Where the various methods produced statistically different discharge estimations at the same location, it is hypothesized that the differences arose from method‐specific sources of bias, including installation depths. On the basis of this work, practitioners interested in measuring flow across the groundwater‐surface water interface achieve the least variability with seepage meters and the SBPVP. However the accuracy of the seepage meter depended on a calibrated correction factor while that of the SBPVP did not.

“…The signals recorded by the datalogger took the form of breakthrough curves of the tracer at the detectors. Tracer breakthrough curves were analyzed with VelprobePE by fitting the curves with a solution of the advection‐dispersion equation (Schillig ) (Figure ), and with an analysis by the method of moments (Cremeans and Devlin ). The method of moments (MM) (Freyberg ) provides an estimate of seepage velocity ( v ) based on the progress of the center of mass of the tracer pulse.…”

Section: Methodsmentioning

confidence: 99%

Assessment of Bed Hydraulics and Metal Loadings in a Passive Vertical Flow Bioreactor in Commerce, Oklahoma

Cremeans¹,

Devlin²,

Osorno³

et al. 2019

A treatment pond, with an engineered bed that served as a passive vertical flow bioreactor (VFBR), was operated as part of a passive sequenced treatment system for the removal of metals from groundwater at the Mayer Ranch in Commerce, Oklahoma. The groundwater was contaminated by mining activities in west Commerce and discharges at this location occurred as artesian springs through improperly abandoned, over‐drilled, and cased legacy boreholes. The VFBR operated by establishing reducing conditions in the organic bed of a pond to promote metal sorption and precipitation as sulfides. In order to verify that operations were unhindered by nonuniform flow in the VFBR, an assessment of the flow uniformity in the pond was undertaken using the streambed point velocity probe (SBPVP). The velocity data were independently validated with a water balance. The outflow calculated from the SBPVP data came within 30% of the value suggested by measured inflow rates to the pond, supporting the conclusion that the SBPVP measurements were representative of flow in the VFBR, and that flow through the bed was occurring with a satisfactory level of uniformity. Water flow rates through the reactive bed were found to be up to an order of magnitude greater than those employed in the prior column testing, contributing to metal loading rates (of Cd, Pb, Zn, Ni) estimated to be two orders of magnitude greater than those tested in the columns (4.2 × 104 and 3.2 × 102 mg/m3/d, respectively). However, apparently rapid chemical reactions that likely occurred close to the pond water‐sediment interface contributed to the treatment system achieving its design objectives.