61 S in the Gulf of Mexico have documented a large area with seasonally depleted O2 levels (<2 mg L−1). Most aquatic species cannot survive at such low O2 levels. A reduction in NO3–N loading by 30% was initially recommended to reduce hypoxia in the Gulf of Mexico (Mitsch et al., 1999). Following a scientifi c reassessment that recommended a reduction of 45% (USEPA, 2007), the USEPA developed a...

Sand envelopes have often been used in conjunction with conventional subsurface pipes to improve the drainage of soils in the sugar industry. The expense and effort required to implement these are only justified if this practice results in significantly improved drainage, and it was therefore important to establish whether a sand envelope is effective in all soils. Four observation trials were ...

a subsurface drainage network mainly carries unsteady flow and data are not usually available for model parameters calibration in such networks. in the present research, the finite volume method using the time splitting scheme was employed to develop a computer code for solving the one dimensional unsteady flow equations. using corrugated sub drainage pipes, an experimental prototype setup was ...

Land application of animal manure is an important means of utilization of nitrogen and phosphorus. However, the presence of pathogens in manure and their occasional leaching into subsurface water has become a topic of concern during the past few years. This study was undertaken to determine the extent to which Salmonella anatum may leach through tile-drained clay loam soil on which swine manure...