Pesticide transport through the unsaturated zone is a function of chemical and soil characteristics, application, and water recharge rate. The fate and transport of 82 pesticides and degradates were investigated at five different agricultural sites. Atrazine and metolachlor, as well as several of the degradates of atrazine, metolachlor, acetochlor, and alachlor, were frequently detected in soil...

Short-term management of groundwater resources, especially during droughts, can be assisted by forecasts of groundwater levels. Such forecasts need to account for the natural dynamic behaviour of the aquifer, likely recharge scenarios, and recent but unknown abstractions. These requirements mean that forecasts, at say monthly intervals, need to be updated with current observations on a real-tim...

The aim of this study is to present a linked simulation-optimisation model to estimate the groundwater recharge rates, their associated zone structures, and hydraulic conductivity values for regional, steady-state groundwater flow models. For the zone structure estimation problem the fuzzy c-means clustering (FCM) method was used. According to our current knowledge, this is the first time that ...

A simple, practical model for estimating daily recharge as hydrologically effective rainfall (HER) to the Chalk outcrop of southern England is presented. Daily meteorological observations are the only data requirements. The model was calibrated for a Chalk river, the Wey, in south Dorset. Six different root constant thresholds were used to estimate daily actual evapotranspiration (AET) rates fo...

In semiarid climates, a significant component of recharge to basin aquifers occurs along the mountain front. Traditionally called “mountain-front recharge” (MFR), this process has been treated by modelers of basins as a boundary condition. In general, mountain-front recharge estimates are based on the general precipitation characteristics of the mountain (as estimated, e.g., by the chloride mas...

We optimize groundwater management in the presence of marine consequences of submarine groundwater discharge (SGD). Concern for marine biota increases the optimal steady-state head level of the aquifer. The model is discussed in general terms for any coastal groundwater resource where SGD has a positive impact on valuable near-shore resources. Our application focuses of the Kona Coast of Hawai’...

An Essential Hormone Testosterone, estrogen, cortisol, DHEA, and pregnenolone are members of a family of natural hormones that are essential for human survival. All of these hormones contain four carbon-ring structures attached to each other, and appear very similar.1Small differences in structure, however, produce dramatic changes in function. Testosterone, the “male” hormone, is only slightly...

The vulnerability of public supply wells to chlorinated ethene (CE) contamination in part depends on the availability of naturally occurring organic carbon to consume dissolved oxygen (DO) and initiate reductive dechlorination. This was quantified by building a mass balance model of the Kirkwood-Cohansey aquifer, which is widely used for public water supply in New Jersey. This model was built b...

Citation: Potter KE, Shervais JW, Christiansen EH and Vetter SK (2018) Evidence for Cyclical Fractional Crystallization, Recharge, and Assimilation in Basalts of the Kimama Drill Core, Central Snake River Plain, Idaho: 5.5-Million-Years of Petrogenesis in a Mid-crustal Sill Complex. Front. Earth Sci. 6:10. doi: 10.3389/feart.2018.00010 Evidence for Cyclical Fractional Crystallization, Recharge,...