Comparison of pumping at constant head and at a constant rate for determining the sustainable yield of a well

Baiocchi, Antonella; Lotti, Francesca; Piacentini, Simone Maria; Piscopo, Vincenzo

doi:10.1007/s12665-013-3016-5

Cited by 5 publications

(3 citation statements)

References 21 publications

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“…Their estimated yield (0.94 × 10 −3 m 3 /s) was a fraction of the production (2-5 × 10 −3 m 3 /s), which reflected the result of seasonal variations during the year-long test. The higher yields were confirmed by a follow-on numerical model developed by Baiocchi et al (2014).…”

Section: Introductionmentioning

confidence: 75%

Reliable yields of public water-supply wells in the fractured-rock aquifers of central Maryland, USA

Hammond¹

2017

Hydrogeol J

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Most studies of fractured-rock aquifers are about analytical models used for evaluating aquifer tests or numerical methods for describing groundwater flow, but there have been few investigations on how to estimate the reliable long-term drought yields of individual hard-rock wells. During the drought period of 1998 to 2002, many municipal water suppliers in the Piedmont/Blue Ridge areas of central Maryland (USA) had to institute water restrictions due to declining well yields. Previous estimates of the yields of those wells were commonly based on extrapolating drawdowns, measured during short-term singlewell hydraulic pumping tests, to the first primary water-bearing fracture in a well. The extrapolations were often made from pseudo-equilibrium phases, frequently resulting in substantially over-estimated well yields. The methods developed in the present study to predict yields consist of extrapolating drawdown data from infinite acting radial flow periods or by fitting type curves of other conceptual models to the data, using diagnostic plots, inverse analysis and derivative analysis. Available drawdowns were determined by the positions of transition zones in crystalline rocks or thin-bedded consolidated sandstone/limestone layers (reservoir rocks). Aquifer dewatering effects were detected by type-curve matching of step-test data or by breaks in the drawdown curves constructed from hydraulic tests. Operational data were then used to confirm the predicted yields and compared to regional groundwater levels to determine seasonal variations in well yields. Such well yield estimates are needed by hydrogeologists and water engineers for the engineering design of water systems, but should be verified by the collection of longterm monitoring data.

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Section: Introductionmentioning

confidence: 75%

Reliable yields of public water-supply wells in the fractured-rock aquifers of central Maryland, USA

Hammond¹

2017

Hydrogeol J

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“…Moreover, the water volume extracted did not exceed the recharge [40]. Subsequently, constant head model was compared with a constant flow rate model by Baiocchi et al Based on numerical modelling, the authors concluded that constant flow rate model could be particularly useful when the problem is one of determining the sustainable yield of a single well from aquifers with low hydraulic diffusivity and when an extensive monitoring of the aquifer is not economically viable [41]. Unfortunately, the researchers did not evaluate whether both models had an impact on the well efficiency at the end of the research period.…”

Section: Methodsmentioning

confidence: 99%

The Dynamics of Water Wells Efficiency Reduction and Ageing Process Compensation

Polak

Górecki²,

Kaznowska-Opala

2019

Water

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Water wells play an increasingly important role in providing water for the civilian population all over the world. Like other engineering structures, wells are subject to ageing processes resulting in degradation, which is observed as a reduction in hydraulic efficiency throughout their lifespan. To date, it has been found that the ageing process of a well is determined by a number of factors. The mathematical description of this process can be simplified. Drawing on Jacob’s equation, this paper presents the course of the degradation process as a variable depending on operation time, well loss and flow rate. To apply the determined relationships in practice, simplifying assumptions were adopted, which make it possible to determine the moment of ageing compensations of the degradation processes. It was also demonstrated that the degradation process may be slowed down by the appropriate selection of initial operating parameters. The presented discussion highlights the significance of parameters α, δ and exponent β. The relation between hydraulic resistances in an aquifer and in the engineering structure is closely connected with these values. The presented arguments indicate that step drawdown tests provide the necessary information which allows tracking changes in the ageing processes occurring in the engineering structure. The analysis of the drawdown test results makes it possible to determine the moment when the necessary adjustments in the operating parameters of a water well should be performed. Eventually, it allows maintaining the high hydraulic efficiency of the intake and extending the lifespan of the well in accordance with the principle of sustainability.

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“…Other studies on fractured aquifers show that drawdown extrapolated from pumping tests, when interpreted considering the operational data of the well during seasonal variations, forms the basis for predicting the well yield according to the definition of reliable yield or sustainable yield of a well [6]. Pumping at constant drawdown was also tested to determine a variable sustainable yield, which is useful in specific cases such as when it is necessary to maintain a constant quality over time of water extracted from the well [7,8].…”

Section: Introductionmentioning

confidence: 99%

Practical Approach for Defining the Sustainable Yield of Wells in Low-Permeability Fractured Rocks

Piscopo,

Sbarbati,

Dinagde

et al. 2023

Sustainability

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Groundwater sustainability is still an open question. Theoretical and practical approaches to the definition of groundwater sustainability were mainly developed on large scales, while few studies are available for its definition at a single well scale, especially in fractured aquifers. This study examines how much the sustainable yield of a well in fractured aquifers depends on the trend of drawdown over time. For this aim, pumping tests conducted in fractured rocks were considered and analytical models were applied to examine the long-term response of groundwater levels in some wells. To define the operational pumping flow of a well in these aquifers, results show that long constant flow rate pumping tests are preferred to step-drawdown tests. The late drawdown–time curve and residual drawdown segment-curves during the recovery, approximated by power, exponential or polynomial equations, represent the first step to extrapolating the long-term drawdown in the well. This prediction combined with the assessment of a drawdown limit in the well (as a function of the saturated thickness of the aquifer) are essential to plan the first operation of the well (flow rate and time of pumping). Subsequently, through the monitoring of this first operation step, the following operation phases can be updated and improved.

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Comparison of pumping at constant head and at a constant rate for determining the sustainable yield of a well

Cited by 5 publications

References 21 publications

Reliable yields of public water-supply wells in the fractured-rock aquifers of central Maryland, USA

Reliable yields of public water-supply wells in the fractured-rock aquifers of central Maryland, USA

The Dynamics of Water Wells Efficiency Reduction and Ageing Process Compensation

Practical Approach for Defining the Sustainable Yield of Wells in Low-Permeability Fractured Rocks

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