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 ...

Dissolved noble gases in groundwater are used to reconstruct paleotemperature, but also yield information about "excess air", a component of dissolved gases in excess of solubility equilibrium, derived from dissolution of trapped air in the ground. A good characterization of the excess air component is necessary not only to obtain reliable noble gas temperatures, but also to investigate the pot...

Shales are among the most considered geomaterials in current energy-related geomechanical investigations; they are involved in engineering applications such as the unconventional extraction of natural gas, CO2 sequestration and nuclear waste geological storage. A deep understanding of their behaviour with regard to variations in the degree of saturation is of primary significance for such appli...

Most field-based approaches that address runoff generation questions have been conducted in steep landscapes with shallow soils. Runoff generation processes in low relief landscapes with deep soils remain less understood. We addressed this by characterizing dominant runoff generating flow paths by monitoring the timing and magnitude of precipitation, runoff, shallow soil moisture, and shallow a...

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....

many mathematical models have been applied and developed for simulation of water and solute transport in irrigated agriculture. using a model, it should be first calibrated and validated for different regions. swap is a field scale model that simulates water, solute and heat movement in the soil profile. in this study, the swap model was evaluated for two years (2001 and 2002) on wheat in a sem...

Table 1. June water chemistry values for Nine Pipe and Ovando Valley wetland study sites. Data from Borth (1998). Table 2. July water chemistry values for Nine Pipe and Ovando Valley wetland study sites. Data from Borth (1998). Table 3. August water chemistry values for Nine Pipe and Ovando Valley wetland study sites. Data from Borth (1998). Table 4. June, July and August average water chemistr...