Articles | Volume 372
https://doi.org/10.5194/piahs-372-437-2015
https://doi.org/10.5194/piahs-372-437-2015
12 Nov 2015
 | 12 Nov 2015

3-D land subsidence simulation using the NDIS package for MODFLOW

D. H. Kang and J. Li

Abstract. The standard subsidence package for MODFLOW, MODFLOW-SUB simulates aquifer-system compaction and subsidence assuming that only 1-D-vertical displacement of the aquifer system occurs in response to applied stresses such as drawdowns accompanying groundwater extraction. In the present paper, 3-D movement of an aquifer system in responses to one or more pumping wells is considered using the new aquifer-system deformation package for MODFLOW, NDIS. The simulation of aquifer- system 3-D movement using NDIS was conducted with a stress or hydraulic head dependent specific storage coefficient to simulate nonlinear deformation behavior of aquifer-system sedimentary materials. NDIS's numerical simulation for aquifer horizontal movement is consistent with an analytic solution for horizontal motion in response to pumping from a leaky confined aquifer (Li, 2007). For purposes of comparison, vertical subsidence of the aquifer system in response to groundwater pumping is simulated by the both the NDIS and MODFLOW-SUB models. The results of the simulations show that land subsidence simulated by MODFLOW-SUB is significantly larger and less sensitive to pumping rate and time than that simulated by NDIS. The NDIS simulations also suggest that if the total pumpage is the same, pumping from a single well may induce more land subsidence than pumping from multiple wells.

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Short summary
3D movement of an aquifer system with stress-dependent storage in response to one or more pumping wells is simulated using a new package for MODFLOW, NDIS. Results indicate horizontal movement is consistent with the analytic solution, and vertical movement is smaller and more sensitive to pumping rates and time than that simulated by MODFLOW-SUB. The simulation shows that if the total pumpage is the same, pumping from a single well may induce more land subsidence than pumping from multiple well.