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...

To avoid the generation of air-entraining vortices at a projected outlet structure in an existing reservoir of a pumped-storage plant, large-scale model tests were conducted. The model, with a scale of 1:18, had the considerable dimensions of 30 m in length and 16 m in width. Due to the complex shape of the reservoir, the many inlets and outlets, and numerous operating conditions, very complex ...

The reservoir water level fluctuation is an important factor inducing the reaction of pore-water pressure, seepage and at last resulting in instability failure slope. A typical homogeneous slope conducted as example this paper, stress coupling effect considered, stability calculation analysis are carried out by using finite element method. results demonstrate that safety increases with rises, t...

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 pumping of wells, groundwater level drawdown, as measured in pumped well, is increased by non-linear losses caused water flow velocity through well screens. This undermines adequacy direct use drawdown data for purpose realistic identification effective radius and aquifer parameters. anomaly avoided reshaping function into a specific sw/Q well. simplifies exclusion from sequence at p...

Three diagnostic procedures were tested to determine their potential usefulness in identifying faulty rural wells: (1) monitoring wells were constructed at three depths near each of three rural wells having a history of nitratenitrogen and/or herbicide contamination, and all wells were sampled daily for four weeks and tested for nitrate-nitrogen, atrazine, alachlor, metolachlor, and chloride; (...

semiarid regions with their exceptional weather conditions, low precipitation, and high evapotranspiration pose a great challenge to water resources managers. one possible way to face this challenge is the conjunctive use of both surface water and groundwater resources in these regions. this paper proposes a conjunctive use model which has been implemented in najafabad plain in central iran. th...

An excessive amount of bank erosion along a number of waterways in Illinois and surrounding states exists at the present time. Erosion of stream banks attracts public attention, reduces property values, results in the permanent loss of real estate, increases the turbidity of streams, and accelerates the silting of reservoirs and backwater lakes along stream courses. Among the main causes of ban...