The standard formulation of a block-centered finite-difference model, such as MODFLOW, uses the center of the cell as the location of a cell node. Simulations of a dynamic water table can be improved if the node of a cell containing the water table is located at the water table rather than at the center of the cell. The LPF package of MOD-FLOW-2000 was changed to position a cell's node at the w...

evaluating drainage systems, exploring their strengths and weaknesses, provides a comprehensive perspective to designers and organizers for optimum design and implementation of guidelines for the future. this study was conducted at an experimental site consisting of three plots on a subsurface drainage network under operation in behshahr, a coastal region in northern iran. to evaluate system pe...

in tunisia, kalâat el andalous irrigated district is one of the most affected areas by salinization. the objective of this study was to predict the root zone salinity (over 10 years) in this area using the saltmod simulation model for subsurface drainage system. saltmod is based on water balance, salt balance model, and seasonal agronomic aspects. in the pilot area, irrigated vegetables crops s...

Floristic studies indicate the abundance of microalgae in northern boreal peatlands, but we know relatively little about their ecology or how they will respond to changes in environmental conditions expected in this region as climate changes. We examined changes in algal community structure at sites exposed to a long-term water-table manipulation, including drought (lowered water-table treatmen...

playas are low-lands which is considered to be the locations of accumulation of superficial and ground waters fromhigher elevations and these waters have different types of salts and various salinity level. therefore, because of lack ofrainfall and fresh-water both for human and animal useage or even for plants, it is needed to apply proper methods toharvest fresh water from these saline-waters...

[1] Areas with a relatively shallow water table are environments where the groundwater plays a key role on the ecosystem function, and important interactions exist between hydrology and ecosystem processes. We propose here an analytical model to study the interactions between rainfall, water table, and vegetation in groundwater-dependent ecosystems. The water table dynamics are studied as a ran...

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...

the impact of meteorological and hydrological drought on groundwater resources in coastal deserts in the south of iran was investigated during 1991-2011, using standardized precipitation index (spi), standardized runoff index (sri), and groundwater resources index (gri). the results indicated that wet and drought spells governed the area in the first and second decades, respectively, which was ...

An analytical one-dimensional model for vertical transmission of barometric pressure in soil unsaturated zone has been developed to examine the effect of free boundary caused by water table. The model is applicable to a special case in which the water table moves in according to the pressure with high barometric efficiency. Ambient sinusoidal pressure fluctuation is assumed at the soil surface....