Judson W Harvey (Former Employee)

Sediment macropores (with effective diameters larger than 100 ??m) comprise 11% of the bulk sediment volume in a tidal freshwater wetland vegetated with Peltandra virginica. In order to determine effects of macroporous sediment structure on solute transport, we conducted a solute tracer experiment in the sediment. The effective transport volume (??eff, the volume of sediment through...

Upward discharge of fresh groundwater into a mid-Atlantic intertidal wetland contributed 62% of the water needed to replace evapotranspiration losses from the sediment during an 11 day period in September. Infiltration during flooding by tides provided most of the balance; thus there was a net advection of salt into the sediment. The amount of groundwater discharge was estimated from...

Chloride was highly concentrated relative to seawater in matrix porewater but was comparatively dilute in macropores. Concentration differences in pore-size classes declined with depth until indistinguishable below 10 cm. The segregated chloride distribution can be explained if recharge to the sediment occurred by downward infiltration in macropores and discharge occurred by an upward...

Solute transport concepts in soil are based on speculation that solutes are distributed nonuniformly within large and small pores. Solute concentrations have not previously been measured across a range of pore sizes and examined in relation to soil hydrological properties. For this study, modified pressure cells were used to measure variation in concentration of a solute tracer across a...

No abstract available.

A numerical hydrological simulation suggested that water exchange between stream channels and adjacent aquifers is enhanced by convexities and concavities in streambed topography. At St. Kevin Gulch, an effluent stream in the Rocky Mountains of Colorado, subsurface hydraulic gradients and movement of ionic tracers indicated that stream water was locally recharged into well-defined flow...