Nitratenitrogen and Oxygen Isotope Characterization of the Shiraz Aquifer (Iran)

Amiri, Haleh; Zare, Mohammad; Wîdory, David

doi:10.1016/j.proeps.2015.07.012

Cited by 3 publications

(1 citation statement)

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“…The groundwater flow direction in Shiraz's aquifer is generally NW-SE. This aquifer is unconfined in northern and central regions but convert to the confined type in south and southeastern regions due to the presence of some interbedded clay layers [31]. The thickness of the alluvial aquifer varies from 10 to 500 m over the study area, resulting in a spatially-averaged thickness of 115 m [32].…”

Section: Resultsmentioning

confidence: 99%

Estimating confined aquifer parameters using a simple derivative-based method

Naderi

2019

Heliyon

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The confined aquifer parameters, transmissivity and storage coefficient, are commonly determined using the pumping tests. Several methods have been developed to estimate confined aquifer parameters using pumping tests, but different methods suffer from different drawbacks. Those methods that use the truncated Theis well functionwtrue(utrue), apply just early or late drawdowns, depending on the case, to estimate the aquifer parameters. Those methods, such as Theis (1935), that use non-truncated well functionwtrue(utrue), can apply all drawdown data for aquifer parameter estimation but may still suffer from subjectivities such as personsal judgment in curve matching, time-consuming procedure and requiring values for Theis well function, wtrue(utrue), and its argument utrue(u=r2S4Tttrue). The aim of this study is to present a new method to overcome the aforementioned drawbacks and subjectivities involved in available published methods. In this paper, a simple derivative-based method is presented to estimate confined aquifer parameters applicable for entire drawdowns during the pumping period. The time derivative of drawdowns relate non-linearly with pumping timet, and therefore, aquifer parameters are estimated using developed equations based on the least squares optimization approach. The method is applied to three sets of synthetic, published and field data and results show that the estimation accuracy is acceptable. The drawdown time interval measurement has a marginal effect on parameters estimation due to the analytical basis of derivative calculations. The method does not require construction of graphs, and numerical calculations may be performed on a calculator to determine the aquifer parameters on site. It does not require curve matching, initial guess of the parameters and values of wtrue(utrue) and u.

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Section: Resultsmentioning

confidence: 99%