Sustainable Agriculture satisfies human food and fiber needs, makes the most efficient use of on-farm resources and integrates natural biological cycles, enhances the quality of life for farmers and society as a whole, and sustains the economic viability of farm operations. A farm that is able to produce continuously, yet has negative effects on environmental quality elsewhere, does not support...

The dependency of surfaceor groundwater flows and aquifer hydraulic properties on dewateringinduced layer deformation is not available in the USGS's groundwater model MODFLOW. A new integrated hydrologic model, MODFLOW-OWHM, formulates this dependency by coupling mesh deformation with aquifer transmissivity and storage and by linking land subsidence/uplift with deformationdependent flows that a...

[1] Although there is no evidence of active volcanism on Mars today, ‘‘localized’’ outgassing sources, the hot spots, may not be ruled out. If outgassing does occur somewhere on Mars, water, carbon dioxide, sulfur species, methane, and to a lesser extent, halogens would be the likely molecules of outgassing, based on terrestrial analogs. The sulfur species, methane, and halogens have not been d...

The effective geological storage of liquid CO2 in porous subsurface rock will require the ability to track, and identify the origin of, any CO2 seepage measured at the near-surface. In a study relevant to postemplacement seepage, we examine natural CO2 springs around Green River, on the Colorado Plateau USA, in an attempt to determine the CO2 origins. We use a combination of natural geochemical...

Papers published in Hydrology and Earth System Sciences Discussions are under open-access review for the journal Hydrology and Earth System Sciences Abstract The classical formulation of the coupled hydroelectrical flow in porous media is based on a linear formulation of two coupled constitutive equations for the electrical current density and the seepage velocity of the water phase and obeying...

Water Howellia (Howellia aquatilis) is a rare and endangered wetland plant listed as a threatened species under the Federal Endangered Species Act. 70% of the world population is found in the 1:7 £ 10 ha Swan Valley, Montana, USA in wetlands of usually less than 1-ha. Survival of this aquatic species requires emergence during mid-summer, the drying out of occupied portions of the wetlands, a sl...

Marine hydrocarbon seepage emits oil and gas, including methane ( approximately 30 Tg of CH(4) per year), to the ocean and atmosphere. Sediments from the California margin contain preserved tar, primarily formed through hydrocarbon weathering at the sea surface. We present a record of variation in the abundance of tar in sediments for the past 32,000 years, providing evidence for increases in h...

This paper explored numerical techniques to simulate the movement of an applied tracer plume in a laboratory beach subjected to tide. The MARUN model (Boufadel et al., 1999) was used. The movement of the tracer plume in the beach and the development of a transient seepage on the beach surface were modeled. By calibrating the results of the numerical model against the observed data, the laborato...

it is correct control and monitoring of modern embankment dams that are very vital in the geotechniqual constructions. the improvement of methods of stability control, using the effective stress and the measurement of ganglionic water pressure in embankment dams cause more the safety for this kind of dams. nowedays there is such an idea that in stead of using of being safety factor against coas...

The deposition of the instantaneously released sediment into a gravel matrix and the hydraulic resistance induced by the rapid siltation are investigated herein. The experimental results reveal that the depositional patterns of the sediment are governed by the gravel-sediment size ratio, the amount of sediment released, and the seepage flowrate. The observations also indicate that the stable st...