For regional models, the shallow water table surface is often used as a source/sink boundary condition, as model grid scale precludes simulation of the water table aquifer. This approach is appropriate when the water table surface is relatively stationary. Since water table surface maps are not readily available, the elevation of the water table used in model cells is estimated via a two-step p...

Carbon (C) modeling and carbon dioxide (CO2) flux measurements in peatlands are dependent on the distribution and productivity of vegetation in a system with a high degree of spatial variability, often linked to the position of the water table. We tested the hypothesis that at a fine-scale (tens of metres) water table position exerts a strong control on species abundance, plant biomass, particu...

field experiments were conducted on an existing subsurface drainage system in roodasht region of esfahan, ian, to test the performance of drain spacing equations for transient flow. the water table profiles recorded from a series of observation wells indicated an essentially flat water surface. the effective hydraulic conductivity and the degree of anisotropy were calculated as 19.2 cm h-1 and ...

This study aims to investigate and optimize the effects of the main parameters including the particle size, gravity and magnetic separation combination, high gradient magnetic separation, magnetic field intensity, shaking table slope, washing water flow, and electrostatic separation upon the rare earth element (REE) recoveries from iron mine waste. The electron microprobe showed that high amoun...

The effects of land use and land use change on stream nitrate are poorly understood. While case studies have been presented, most process work has been done in areas with one land use (minimally disturbed or agricultural) and areas with substantial atmospheric deposition. In this paper we present results from three neighboring headwater catchments in western Oregon with similar (low) atmospheri...

An algorithm is presented for generating ®nite element grids that can be used to calculate the position of a ̄uctuating water table and the formation of seepage faces within a heterogeneous uncon®ned aquifer. Our approach overcomes limitations with existing techniques by allowing the water table to rise or decline through hydrostratigraphic boundaries yet maintains numerical and conceptual accur...

this research was conducted at torogh agricultural research station in khorasan-e razavi province to determine the impact of irrigation cutoff at different growth stages and percentage of water use on the yield and water use efficiency (wue) of wheat cultivars using sprinkler irrigation. the study was done from 2006-2008. the experimental design was a randomized complete block design with a str...

1. Discoloration of polyvinyl chloride (PVC) tape has been used in peatland ecological and hydrological studies as an inexpensive way to monitor changes in water-table depth and reducing conditions. 2. We investigated the relationship between depth of PVC tape discoloration and measured water-table depth at monthly time steps during the growing season within nine kettle peatlands of northern Wi...