the system dynamics technique is an object-oriented approach that studies and manages complex feedback systems. its merits include the friendly and easy development and improvement of a model. it is also used as a decision tool for engineering problems. in this paper, the system dynamics technique was used to simulate the performance of a subsurface drainage system in an unsteady state. the mod...

There are human and animal health concerns related to drainage systems because nutrients, especially nitrogen and phosphorus, can contaminate water supplies. A field study was conducted on consolidated paddy fields of Sari Agricultural Sciences and Natural Resources University, Northern Iran (36.3°N, 53.04°E), to determine the effect of subsurface drain depth and spacing on nitrogen (N) and pho...

Subsurface drainage involves both intensity and capacity attributes. Intensity of subsurface drainage refers to how rapidly a root zone drains. Capacity, on the other hand, refers to the extent of excess (gravitational) water removal from the root zone. Consequently, discussions of putting green drainage often become confused since the expression improved drainage can imply improved drainage ca...

Benchmarking coupled surface-subsurface flow models becomes more important as they are increasingly used for operational purposes (e.g. in water management) and long-term analysis (e.g. in climate change research). For this reason we inter-compare the hydrogeological models HydroGeoSphere and OpenGeoSys and present results with emphasis on the parametrization of the surface-soil water coupling ...

All research projects making conclusions or recommendations based on environmentally related measurements and funded by the Environmental Protection Agency are required to participate in the Agency Quality Assurance Program. This project did not involve environmentally related measurements and did not involve a Quality Assurance Project Plan. Mention of trade names or commercial products does n...

During the last two decades the multiple functions and values of wetlands have been recognized not only by the scientists and managers working with wetlands, but also by the public. The ability of wetlands to transform and store organic matter has been exploited in constructed wetlands. This paper summarizes the state-of-the-art of the uses of constructed wetlands in water pollution control by ...

Using the coupled climate model of intermediate complexity, CLIMBER-3 , changes in the vertical thermal structure associated with a shutdown of the Atlantic meridional overturning circulation (AMOC) are investigated. When North Atlantic Deep Water formation is inhibited by anomalous freshwater forcing, intermediate depth ventilation can remain active and cool the subsurface water masses (i.e., ...

An understanding of microbial transport and survival in the subsurface is needed for public health, environmental applications, and industrial processes. Much research has therefore been directed to quantify mechanisms influencing microbial fate, and the results demonstrate a complex coupling among many physical, chemical, and biological factors. Mathematical models can be used to help understa...

3D hydrological modeling was performed, using CATHY (acronym for CATchment HYdrology model), with the basic objective of checking whether the model could reproduce the effects of subsurface agricultural drainage on stream flows and soil water storage. The model was also used to further our understanding of the impact of soil hydrodynamic properties on watershed hydrology. Flows simulated by CAT...