Engineering Geology

Engineering Geology

The effects of aquifer and well parameters on Capture Zone and Discharge Zone in alluvial unconfined aquifers

Authors
Amin Ahmadi 1
Manouchehr Chitsazan 1
Seyed Yahya Mirzaee 1
Arash Nadri 2
1 Department of Geology, Earth Sciences Faculty, Shahid Chamran University of Ahvaz
2 Arizona Department of Water Resources, Phoenix, USA
10.22034/JEG.2022.16.2.1019241
Abstract
In order to protect water wells, it is necessary to analyze the zones of influence, capture, recharge and discharge zones. Despite much research, this issue still needs further discussion. The purpose of this research is to analyze the capture and discharge zones of water wells in alluvial unconfined aquifers. For this purpose, a hypothetical aquifer was simulated using the Modflow and Modpath models. The accuracy of the numerical model outputs was confirmed by comparison with the analytical calculations, and then the effect of the independent parameters of the well and the aquifer was investigated. This research showed that, contrary to popular belief, changes in hydraulic conductivity, specific yield, bedrock dip, initial thickness, porosity, and heterogeneity do not cause changes in the surface extent of the well's capture zone in the unconfined aquifer.This research has shown that changes in surface recharge, discharge and well location cause many changes in the surface extent of the well capture zone in unconfined alluvial aquifers. Investigation of the effect of pumping time in a single well system showed that the size of the capture zone initially increases, but after a short period, of time, despite the continued expansion of the drawdown cone, its position stabilises. It was found that the change in all the above parameters causes a change in the size of the well's discharge zone. The stability of the above-mentioned areas is very important for the determination of zones for the protection of the quantity and quality of water wells! It has been found that the relative stability of the water level in the aquifer at an appropriate level is necessary, and this requires the management of the aquifer and the allocation of a limited percentage of the aquifer recharge to discharge through wells.
Keywords
Capture Zone
Discharge Zone
Influence Zone
Protection Zone
Recharge Zone
MODFLOW
Modpath
Ayinippully Nalarajan, N., Govindarajan, S., Nambi, I. 2022. Aquifer heterogeneity on well capture zone and solute transport: numerical investigations with spatial moment analysis. International Journal of Environmental Science and Technology, 19(8), 7261-7274. https://doi.org/10.1007/s13762-021-03573-y
Barlow, P. M., Leake, S. A., Fienen, M. N. 2018. Capture Versus Capture Zones: Clarifying Terminology Related to Sources of Water to Wells. Groundwater, 56(5), 694-704. https://doi.org/http://doi.org/10.1111/gwat.12661
Barrash, W., Dougherty, M. E. 1997. Modeling axially symmetric and nonsymmetric flow to a well with MODFLOW, and application to Goddard2 well test, Boise, Idaho. Groundwater, 35(4), 602-611. https://doi.org/10.1111/j.1745-6584.1997.tb00125.x
Bear, J., Jacobs, M. 1965. On the movement of water bodies injected into aquifers. Journal of Hydrology, 3(1), 37-57.
Dupuit, J. E. 1863. Études théoriques et pratiques sur le mouvement des eaux dans les canaux découverts et à travers les terrains perméables. Dunod, Paris, 352 pp.
Goodarzi, M., Eslamian, S. S. 2019. Evaluation of WhAEM and MODFLOW models to determine the protection zone of drinking wells. Environmental Earth Sciences, 78(6), 195. https://doi.org/10.1007/s12665-019-8204-5
Grubb, S. 1993. Analytical model for estimation of steady‐state capture zones of pumping wells in confined and unconfined aquifers. Groundwater, 31(1), 27-32. https://doi.org/10.1111/j.1745-6584.1993.tb00824.x
IGNSL .2014. Capture-Zone-Delineation-Technical-Report (Institute of Geological and Nuclear Sciences Limited, Issue GNS Science Report 2013/57). www.gns.cri.nz
Javandel, I., Tsang, C. F. 1986. Capture‐zone type curves: A tool for aquifer cleanup. Groundwater, 24(5), 616-625.
Khalilabad, N. M., Mohtashami, A., Akbarpour, A. 2022. Application of random walk algorithm into finite element numerical groundwater model for capture zone depiction. Sustainable Water Resources Management, 8(2), 1-10. https://doi.org/10.1007/s40899-022-00618-z
Langevin, C. D., Hughes, J.D., Banta, E.R., Niswonger, R.G., Panday, Sorab, Provost, A.M. 2017. Documentation for the MODFLOW 6 Groundwater Flow Model: U.S. Geological Survey Techniques and Methods, book 6, chap. A55, 197 p. https://doi.org/10.3133/tm6A55
Liu, Y., Weisbrod, N., Yakirevich, A. 2019. Comparative Study of Methods for Delineating the Wellhead Protection Area in an Unconfined Coastal Aquifer. Water, 11(6), 1168. https://doi.org/doi:10.3390/w11061168
Mahdavi, A. 2019. Transient-state analytical solution for arbitrarily-located multiwells in triangular-shaped unconfined aquifer. Water resources management, 33(10), 3615-3631. https://doi.org/10.1007/s11269-019-02324-6
McDonald, M. G., Harbaugh, A. W. 1988. A modular three-dimensional finite-difference ground-water flow model (Techniques of Water-Resources Investigations of the U.S. Geological Survey Issue book 6, chap. A1). https://doi.org/10.3133/twri06A1
McElwee, C. D. 1991. Capture zones for simple aquifers. Groundwater, 29(4), 587-590. https://doi.org/10.1111/j.1745-6584.1991.tb00551.x
Moench, A. F. 1997. Flow to a well of finite diameter in a homogeneous, anisotropic water table aquifer. Water Resources Research, 33(6), 1397-1407. https://doi.org/10.1029/97WR00651
Muskat, M. 1934. The flow of compressible fluids through porous media and some problems in heat conduction. Physics, 5(3), 71-94. https://doi.org/https://doi.org/10.1063/1.1745233
Nagheli, S., Samani, N., Barry, D. A. 2020. Capture zone models of a multi-well system in aquifers bounded with regular and irregular inflow boundaries. Journal of Hydrology X, 7, 100053. https://doi.org/10.1016/j.hydroa.2020.100053
Neuman, S. P. 1972. Theory of flow in unconfined aquifers considering delayed response of the water table. Water Resources Research, 8(4), 1031-1045. https://doi.org/10.1029/WR008i004p01031
Neuman, S. P. 1974. Effect of partial penetration on flow in unconfined aquifers considering delayed gravity response. Water Resources Research, 10(2), 303-312. https://doi.org/10.1029/WR010i002p00303
Pollock, D. 2016. User Guide for MODPATH Verison 7–a Particle Tracking Model for MODFLOW. Open-file Report 2016–1086. US Geol Surv Washington, DC MODPATH, 7. https://doi.org/10.3133/ofr20161086
Pollock, D. W. 1988. Semianalytical computation of path lines for finite‐difference models. Groundwater, 26(6), 743-750. https://doi.org/10.1111/j.1745-6584.1988.tb00425.x
Rodriguez-Pretelin, A., Nowak, W., Morales-Casique, E. 2022. Optimization-based clustering of random fields for computationally efficient and goal-oriented uncertainty quantification: Concept and demonstration for delineation of wellhead protection areas in transient aquifers. Advances in Water Resources, 162, 104146. https://doi.org/10.1016/j.advwatres.2022.104146
Samani, N., and Zarei-Doudeji, S. 2015. A General Analytical Capture Zone model: A Tool for Groundwater Remediation. IFAC-PapersOnLine, 48(1), 234-239. https://doi.org/https://doi.org/10.1016/j.ifacol.2015.05.065
Shafer, J. M. 1987. Reverse pathline calculation of time‐related capture zones in nonuniform flow. Groundwater, 25(3), 283-289. https://doi.org/10.1111/j.1745-6584.1987.tb02132.x
Shan, C. 1999. An analytical solution for the capture zone of two arbitrarily located wells. Journal of Hydrology, 222(1-4), 123-128. https://doi.org/10.1016/S0022-1694(99)00101-8
Theis, C. V. 1935. The relation between the lowering of the piezometric surface and the rate and duration of discharge of a well using ground‐water storage. Eos, Transactions American Geophysical Union, 16(2), 519-524. https://doi.org/10.1029/TR016i002p00519
Thiem, G. 1906. Hydrologische Methoden: Leipzig, Germany. JM Gebhardt, 56p.
UKEA .2019. Manual for the production of Groundwater Source Protection Zones (U.K.Environment Agency, Issue Report March 2019). www.gov.uk/environment-agency
USEPA .2008. Systematic approach for evaluation of capture zones at pump and treat systems (U.S. Environmental Protection Agency, Issue Report EPA/600/R-08/003). http://www.epa.gov/ada/
USGS .1991. Description and evaluation of selected methods used to delineate wellhead-protection areas around public-supply wells near Mt. Hope, Kansas (U.S. Department of the Interior, U.S. Geological Survey, Issue Report 90-4102). https://books.google.com/books?id=WlGITJCoakUC
Yang, Y. J., Spencer, R. D., Gates, T. M. 1995. Analytical solutions for determination of non‐steady‐state and steady‐state capture zones. Groundwater Monitoring & Remediation, 15(1), 101-106. https://doi.org/10.1111/j.1745-6592.1995.tb00507.x