Aquifer Imaging with Oscillatory Hydraulic Tomography: Application at the Field Scale.

Modeling and laboratory experiments have demonstrated the ability of oscillatory hydraulic tomography (OHT) to characterize heterogeneity in aquifer hydraulic properties. In OHT, a location is stressed via periodic pumping/injection at a set frequency, and the resulting head signal is measured at a number of monitoring locations. The source of oscillations is repeatedly moved, allowing tomographic imaging of aquifer properties.

Oscillatory hydraulic testing as a strategy for NAPL source zone monitoring: Laboratory experiments.

Non-aqueous phase liquids (NAPLs) have a complex mode of transport in heterogeneous aquifers, which can result in pools and lenses of NAPLs (the "source zone") that are difficult to detect and can cause long-term contamination via slow dissolution into groundwater (the "dissolved plume"). Characterizing the extent and evolution of NAPL contamination within the source zone is a useful strategy for designing and adapting appropriate remedial actions at many contaminated sites. As a NAPL flows into a given aquifer volume, the effective hydraulic conductivity (K) and specific storage (S) of the volume changes associated with the viscosity and compressibility of the impinging fluid, meaning that NAPL movement may be detectable with hydraulic testing.

The influence of streambed heterogeneity on hyporheic flow in gravelly rivers.

Deposits of open-framework gravel occurring in gravelly streambeds can exert a significant influence on hyporheic flow. The influence was quantified using a numerical model of the hyporheic zone. The model included open-framework gravel stratasets represented with commonly observed characteristics including a volume fraction of about one-third of the streambed sediment, a hydraulic conductivity two orders of magnitude greater than other strata present, and a spatial connectivity forming preferential-flow pathways.

Surgical treatment of cardiac pheochromocytoma: a case report.

Primary cardiac pheochromocytoma is an extremely rare neoplasm. We report a 15-year-old girl who was presented with paroxysmal hypertension. An iodine-131 metaiodobenzylguanidine scintigraphy scanning showed a pheochromocytoma in her right atrial and ventricular wall.