Simple Automatic Time‐Stepping for Improved Simulation of Groundwater Hydrographs

Jackson, C. R.

doi:10.1111/j.1745-6584.2011.00898.x

Cited by 8 publications

(6 citation statements)

References 30 publications

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“…This was set to 4000 m day −1 , such that with a fracture porosity of 1 % the bulk saturated hydraulic conductivity of the rock would be 40 m day −1 . This magnitude is consistent with the saturated hydraulic conductivity used in a previous groundwater model developed for the area (discussed in Parker, 2011;Jackson, 2011;Jackson et al, 2011;Jones et al, 2012). …”

Section: Hydraulic Propertiessupporting

confidence: 87%

A critical assessment of simple recharge models: application to the UK Chalk

Ireson

Butler

2013

Hydrol. Earth Syst. Sci.

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Abstract. Quantification of the timing and magnitude of point-scale groundwater recharge is challenging, but possible at specific sites given sufficient high spatial and temporal resolution field observations, and a suitable physically based model. Such models are generally too computationally intensive and have too many unknown parameters to be practically applicable within distributed, larger-scale hydrological or groundwater models. This motivates the need for simpler recharge models, which are widely used within groundwater models. However, it is important that these models are able to capture adequately the unsaturated zone flow processes. We perform an inter-comparison of recharge simulated by a detailed physically based model and a simple recharge model, with both models applied to a field site in the fractured porous Chalk in the UK. Flow processes are simulated convincingly using a dual permeability, equivalent continuum, vertically heterogeneous, Richards' equation model, applied to a 2-D hillslope transect. A simple conventional recharge model was then calibrated to reproduce the water table response simulated by the physically based model. The performance in reproducing the water table was surprisingly good, given the known discrepancies between the actual processes and the model representation. However, comparisons of recharge fluxes simulated by each model highlighted problems with the process representations in the simple model. Specifically, bypass flow events during the summer were compensating for recharge that should have come from slow, continual drainage of the unsaturated zone. Such a model may still be useful for assessment of groundwater resources on a monthly basis, under non-extreme climatic conditions. However, under extreme wet or dry conditions, or under a changed climate the predictive capacity of such models is likely to be inadequate.

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Section: Hydraulic Propertiessupporting

confidence: 87%

A critical assessment of simple recharge models: application to the UK Chalk

Ireson

Butler

2013

Hydrol. Earth Syst. Sci.

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“…Figure 7 illustrates simulated water levels at four selected boreholes for September 2000-August 2001 representing an unusually wet year leading to a groundwater flooding in the area. Similar to the results from Jackson (2012), who considered the same period and boreholes, water levels are mainly overestimated at the Marsh Benham and Bradley Wood boreholes. Moreover, the modelled response at Marsh Benham and Bradley Wood is more attenuated than the observed response.…”

Section: Spatial Redistribution Over the Groundwater And Surface-watesupporting

confidence: 84%

“…1). Groundwater levels at the same observational boreholes were previously examined by Jackson (2012), who used a conceptual model to estimate recharge rates to groundwater.…”

Section: Case Study Data Setsmentioning

confidence: 99%

Diagnosing hydrological limitations of a land surface model: application of JULES to a deep-groundwater chalk basin

Vine

Butler

McIntyre

et al. 2016

Hydrol. Earth Syst. Sci.

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Abstract. Land surface models (LSMs) are prospective starting points to develop a global hyper-resolution model of the terrestrial water, energy, and biogeochemical cycles. However, there are some fundamental limitations of LSMs related to how meaningfully hydrological fluxes and stores are represented. A diagnostic approach to model evaluation and improvement is taken here that exploits hydrological expert knowledge to detect LSM inadequacies through consideration of the major behavioural functions of a hydrological system: overall water balance, vertical water redistribution in the unsaturated zone, temporal water redistribution, and spatial water redistribution over the catchment's groundwater and surface-water systems. Three types of information are utilized to improve the model's hydrology: (a) observations, (b) information about expected response from regionalized data, and (c) information from an independent physics-based model. The study considers the JULES (Joint UK Land Environmental Simulator) LSM applied to a deep-groundwater chalk catchment in the UK. The diagnosed hydrological limitations and the proposed ways to address them are indicative of the challenges faced while transitioning to a global high resolution model of the water cycle.

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“…If there is no convergence in the numerical calculation of the previous incremental step, the ATS method will continue to reduce the size of the incremental step until the iteration convergence. If the convergence is calculated in the previous incremental step, the ATS method will continue to increase the size of the incremental step 36,37 …”

Section: The Numerical Methodsmentioning

confidence: 99%

The mechanism of decrease in bearing capacity and performance evaluation of the yielding bolt in coal mine

Tai

Huang

Xia

et al. 2020

Energy Science & Engineering

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With the increase of the coal mining depth, the surrounding rock shows characteristics of high stress and large deformation. However, the traditional bolt could not adapt to this surrounding rock environment and become invalid due to low elongation. In order to solve the problem, the new type of yielding bolt has been designed. It could release the deformation energy of the surrounding rock through its yielding pipe. However, few studies have been reported on the mechanism in bearing capacity decrease of the yielding pipe. Furthermore, the evaluation of the yielding bolt was not fully understood. Under such a background, a numerical model of the yielding model was established. According to the numerical simulation, the mechanism of the decrease in the bearing capacity of the yielding bolt is that the buckling occurs at different positions of the yielding pipe, making the material stiffness matrix turn negative, and the bearing capacity decreases significantly. Also, the performance of the yielding bolt could be evaluated from the use efficiency of the yielding pipe, the plastic strain characteristics of the components of the yielding bolt, and the energy absorption law. The evaluation results indicated that: (a) the deviation of the yielding pipe's Mises stresses was within the range of 1.0%‐4.0%. The stresses were distributed evenly, and the material use efficiency was high; (b) only the yielding pipe occurred the plastic failure during the yielding process, and other components were at the elastic stages. After the yielding, the yielding bolt was still effective for support. (c) The yielding pipe could absorb energy smoothly, which is helpful for the stability of the yielding bolt.

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Simple Automatic Time‐Stepping for Improved Simulation of Groundwater Hydrographs

Cited by 8 publications

References 30 publications

A critical assessment of simple recharge models: application to the UK Chalk

A critical assessment of simple recharge models: application to the UK Chalk

Diagnosing hydrological limitations of a land surface model: application of JULES to a deep-groundwater chalk basin

The mechanism of decrease in bearing capacity and performance evaluation of the yielding bolt in coal mine

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