Storage Coefficient and Transmissivity from Residual Drawdowns

Singh, Sushil K.

doi:10.1061/(asce)0733-9429(2003)129:8(637)

Cited by 13 publications

(10 citation statements)

References 11 publications

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“…The same set of data has been analysed by other authors including Ballukaraya and Sharma (1991), Singh (1999), Chenaf and Chapuis (2002), Singh (2003), Zheng et al (2005) and Singh (2006). The residual drawdowns were measured in an observation well located 30 .…”

Section: Case Studymentioning

confidence: 99%

Estimation of aquifer parameters from residual drawdowns

Kambhammettu¹,

King²

2010

Proceedings of the Institution of Civil Engineers - Water Manag

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Reliable and accurate estimation of aquifer parameters is a key process in efficiently managing the groundwater resources of a region. Today, a number of stochastic optimisation tools are available to solve the non-linear aquifer parameters using gradient-based techniques. However, these tools use conventional stabilisation techniques in estimating the non-linear parameters. In the present study, an attempt was made to accelerate and stabilise the conventional Levenberg-Marquardt algorithm. A generalised Matlab code was developed to estimate the transmissivity and storage coefficient of the confined aquifer by considering the residual drawdowns measured in a single observation well. The applicability of the present method was illustrated by considering two datasets from different sources and the results were compared with previous research. Statistical analysis on the estimated parameters demonstrated that the present method can estimate the confined aquifer parameters accurately with a more rapid convergence in comparison with the conventional algorithms. NOTATION i index for residual drawdown N number of observed residual drawdowns Q constant flow rate from pumping well (m 3 /s) r radial distance to observation well from pumping well (m) S storage coefficient of the confined aquifer s9 obs measured residual drawdown in observation well (m) s9 th theoretical residual drawdown at observation well (m) T transmissivity of the confined aquifer (m 2 /s) t time since beginning of pumping (s) t9time since shutdown of pumping (s) t p duration of pumping (s) W(u) well function during pumping phase W(u9) well function during recovery phase º non-negative damping factor

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Section: Case Studymentioning

confidence: 99%

Estimation of aquifer parameters from residual drawdowns

Kambhammettu¹,

King²

2010

Proceedings of the Institution of Civil Engineers - Water Manag

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“…The storage coefficient cannot be estimated using only residual drawdowns for which the arguments of well function during both pumping and recovery are small, i.e. <0.01 (see Singh, 2003). A method to estimate T and S from only residual drawdowns observed at a single observation well was probably first proposed by Case et al (1974).…”

Section: Introductionmentioning

confidence: 99%

“…Also, Bardsley et al (1985) provided a least-squares method to estimate T and S using only residual drawdowns. These methods cannot identify a changed storage coefficient during recovery; also, it can be ascertained using Singh's (2003) method that the data used by the authors for the application of these methods do not pertain to confined aquifers, hence are inconsistent with the methods used. Banton & Bangoy (1996) proposed a method to estimate S from recovery data by taking the first three terms of the series expansion of the well function; their method requires more than one observation well (at least two) when no degree of freedom is allowed.…”

Section: Introductionmentioning

confidence: 99%

“…Banton & Bangoy (1996) proposed a method to estimate S from recovery data by taking the first three terms of the series expansion of the well function; their method requires more than one observation well (at least two) when no degree of freedom is allowed. Singh (1999) has optimized the aquifer parameters from residual drawdowns and Singh (2003) proposed a simple method to identify S and T from only residual drawdowns.…”

Section: Introductionmentioning

confidence: 99%

“…In the present context, the aquifer is the system, its excitation is through pumping and relaxation is through recovery. If the aquifer behaviour is affected by hysteresis, a changed value of S is expected during the recovery phase (see also Singh, 2003). Therefore, the estimates of S during pumping and recovery phases are needed to assess the extent of the difference, which would be of great value in theoretical and modelling studies on groundwater flow.…”

Section: Introductionmentioning

confidence: 99%

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Identification of aquifer parameters from residual drawdowns: an optimization approach

Singh

2006

Hydrological Sciences Journal

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An optimization method based on nonlinear least squares is proposed for the identification of aquifer transmissivity and two storage coefficients, one for the pumping phase and the other for the recovery phase, using only residual drawdowns at an observation well. The method is applicable irrespective of whether pumping and recovery storage coefficients are the same or are different and the argument of well function during recovery is less than or greater than 0.01. The method can check for the changed value of storage coefficient during the recovery phase and can quantify this change. Use of the method is illustrated through examples, which show that the parameters are estimated reliably.Key words aquifer; drawdown; pumping test; optimization; parameter estimation; storage coefficient; transmissivity Identification de paramètres d'aquifère à partir de rabattements résiduels: une approche d'optimisationRésumé Une méthode d'optimisation basée sur les moindres carrés non-linéaires est proposée pour identifier la transmissivité de l'aquifère ainsi que deux coefficients de stockage, l'un pour la phase de pompage et l'autre pour la phase de relaxation, en n'utilisant que les rabattements résiduels au niveau d'un puits d'observation. La méthode est applicable que les coefficients de stockage en phases de pompage et de relaxation soient identiques ou différents, et que l'argument de la fonction de puits pendant la relaxation soit inférieur ou supérieur à 0.01. La méthode peut tenir compte de la modification de la valeur du coefficient de stockage lors de la phase de relaxation et peut quantifier cette modification. L'utilisation de cette méthode est illustrée par des exemples qui montrent que les paramètres sont estimés de manière satisfaisante. [-] u′ argument of well function during recovery [-] u i argument of well function during pumping for ith residual drawdown [-] u i ′ argument of well function during recovery for ith residual drawdown [-] α S′/S [-] Mots clefs

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Hydrological Processes

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Storage Coefficient and Transmissivity from Residual Drawdowns

Cited by 13 publications

References 11 publications

Estimation of aquifer parameters from residual drawdowns

Estimation of aquifer parameters from residual drawdowns

Identification of aquifer parameters from residual drawdowns: an optimization approach

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