The Theis equation has been widely used to study the transient movement of groundwater as a result of pumping in a confined aquifer. It is well known that the observed drawdown at early times has an obvious departure from the theoretical drawdown based on the Theis equation. The Theis equation was derived under the assumption that total stress in the aquifer was constant and the mechanical beha...

50 A groundwater investigation including several pumping tests has been carried out by 51 Thames Water Utilities Limited (TWUL) to improve the understanding of the 52 distribution of hydraulic properties of the Chalk in the Swanscombe area of Kent in 53 south-eastern England. The pumping test behaviour is complicated by: the fractured 54 condition of the Chalk, simultaneous pumping from adjacen...

freshwater lens on small islands may easily be overexploited or polluted due to overdrafts of fresh water by pumping which causes drawdown of the water table a rise or up-coning of the saltwater interface. present study is concerned with using a three-dimensional finite-difference numerical model to simulate the groundwater flow and transport model to predict the behavior of groundwater system ...

One of the main concerns to design earth dam is the stability of the upstream slope of the earth dam in phase of rapid drawdown. Confined pore water pressure reduces the effective stress in this mode, so possibility of the instability and slippage will be increased. The main goal of this research is to investigate changes in the pore water pressure by using horizontal drains in upstream slope o...

Abstract. Groundwater table dynamics extensively modify the volume of hyporheic zone and rate exchange processes. Understanding effects daily groundwater fluctuations on tightly coupled flow heat transport within zones is crucial for water resources management. With this aim in mind, a physically based model used to explore responses varying fluctuation scenarios. The different timing amplitude...

The 4-year drawdown of Horsetooth Reservoir, Colorado, for dam maintenance, provides a case study analog of vegetation response on sediment that might be exposed from removal of a tall dam. Early vegetation recovery on the exposed reservoir bottom was a combination of (1) vegetation colonization on bare, moist substrates typical of riparian zones and reservoir sediment of shallow dams and (2) a...

During the last decades there is low flow in the Euphrates River then consequently low flowin Hilla River which is branch of Euphrates River, Iraq. The Tyass Barrage constructed to lift thehydraulic head upstream in Hilla River raised the groundwater table above ground surface.Environmental problems have been occurred in Hashimyia Area, Babylon Governorate, causingflooding an ar...

Rosenfeld and Pindell (2002, 2003) hypothesized that the Gulf of Mexico evaporated to a level below the world ocean for a brief interval during the Paleocene-Eocene. Further study and the results of recent drilling support this idea and suggest that a major change in the interpretation of the Gulf’s history may be warranted. The idea originally arose to explain several major Paleocene-Eocene pa...

The aim of this research was to study the flood pulse influence and the anthropic impact caused by bauxite tailings on the chemical composition of O. glumaepatula in Batata lake (PA, Brazil). Sampling was carried out in stands of O. glumaepatula in the low-water, filling, high-water, and drawdown periods in impacted and natural areas of Batata lake. During the low-water and drawdown periods the...