WaterSubject

Although it is well documented that ground water extraction (i.e., pump and treat) has limited potential for restoring aquifers to pristine conditions at most sites, it is still the most widely used technology for controlling plume migration and protecting potential receptors. Much of the early work in remediation hydrogeology focused on ground water capture problems, and various methods using analytical solutions and numerical models have been developed for capture design and assessment. One of the most common approaches for capture analysis is ... Read More

Hydraulic tomography has been developed as an alternative to traditional geostatistical methods to delineate heterogeneity patterns in parameters such as hydraulic conductivity (K) and specific storage (Ss). During hydraulic tomography surveys, a large number of hydraulic head data are collected from a series of cross-hole tests in the subsurface. These head data are then used to interpret the spatial distribution of K and Ss using inverse modeling. Here, we use the Sequential Successive Linear Estimator (SSLE) of to interpret synthetic pumping test ... Read More

In conventional geosciences such as hydrogeology, ground water flow, and geotechnical engineering, the bulk permeability of a geomaterial is generally considered to be a sessile property. Permeability of geomaterials can evolve due to external actions such as mechanical and thermal loading. Pore fabric alterations by dissolution and precipitation of minerals during advective transport of reactive chemicals within the pore space and molecular diffusion within the impervious grain structure can also lead to permeability alterations. These phenomena are important for the deep geological ... Read More

We considered small-scale measurement of permeability in pebbly sands having coarser grains supported in a finer grained matrix (fine packing). Our central question was whether air-based measurements are representative if made with a permeameter tip seal pressed in the sand matrix. We created pebbly sands and variably sorted sands, with systematic variation in aspects of their fine packing. We made permeability measurements by inserting the tip seal of an air permeameter in the matrix of these samples and compared them to the ... Read More

Many places in the world are experiencing a water crisis. This water crisis is attributed to a governance crisis, whereas often fragmented institutional and physical water structures are used to explain a policy of overexploitation. The Israeli water system, which adopted integrated water resource management (IWRM), is often cited as a model for other countries struggling with fragmented water systems. Yet, despite the exceptional degree of integration, Israel in the past two decades has adopted an unsustainable water policy. The aim of ... Read More

In arid regions, human activities like agriculture and industry often require large ground water extractions. Under these circumstances, appropriate ground water management policies are essential for preventing aquifer overdraft, and thereby protecting critical ecologic and economic objectives. Identification of such policies requires accurate simulation capability of the ground water system in response to hydrological, meteorological, and human factors. In this research, artificial neural networks (ANNs) were developed and applied to investigate the effects of these factors on ground water levels in the ... Read More

Saline water from a storm surge can flow down storm-damaged submerged water supply wells and contaminate boreholes and surrounding aquifers. Using data from conventional purging techniques, aquifer test response analysis, chemical analysis, and regression analysis of chloride/silica (Cl/Si) ratio, equations were derived to estimate the volume of saline water intrusion into a well and a porous media aquifer, the volume of water needed to purge a well shortly following an intrusion event, and the volume of water needed after delay of several ... Read More

Solute and colloid transport in karst aquifers under low and high flows was investigated by tracer tests using fluorescent dyes (uranine) and microspheres of the size of pathogenic bacteria (1 ?m) and Cryptosporidium cysts (5 ?m), which were injected into a cave stream and sampled at a spring 2.5 km away. The two types of microspheres were analyzed using an epifluorescence microscope or a novel fluorescence particle counter, respectively. Uranine breakthrough curves (BTCs) were regular shaped and recovery approached 100%. Microsphere recoveries ... Read More

The mobility of phosphorus (P) in septic system plumes remains a topic of debate because of the considerable reactivity of this constituent. In this study, a septic system plume in Ontario was monitored over a 16-year period with detail that clearly shows the advancing frontal portion of the P plume. This monitoring record provides insight into the extent of secondary P attenuation in the ground water zone beyond that available from previous studies. A P plume 16 m in length developed over ... Read More

The leakage of pollutants from agricultural lands to aquifers has increased greatly, driven by increasing fertilizer and pesticide use. Because this increase is recent, ground water pollutant concentrations, loads, and exports may also be increasing as pollutants penetrate more deeply into aquifers. We established in an aquifer profile a ground water recharge and pollutant leakage chronology in an agricultural landscape where 30 m of till blankets a 57-m thick sandstone aquifer. Pollutant concentrations increased from older ground water (1963) at the aquifer ... Read More