Modeling the Spatial and Seasonal Variations of Groundwater Head in an Urbanized Area under Low Impact Development

Abstract

Increasing impervious land cover has great impacts on groundwater regimes in urbanized areas. Low impact development (LID) is generally regarded as a sustainable solution for groundwater conservation. However, the effects of LID on the spatial-temporal distribution of groundwater are not yet fully understood. In this case study, a coupled Storm Water Management Model (SWMM) and Finite Element Subsurface FLOW system (FEFLOW) model was used to simulate surface and groundwater flow in an urbanized area in Shenzhen, China. After verification, the model was used to analyze the spatial-seasonal variations of groundwater head and hydrological processes under different LID scenarios. The results indicate that if the runoff from 7.5% and 15% of impervious area is treated by LID facilities, the annual surface runoff decreases by 5% and 9%, respectively, and the spatial average groundwater head relative to sea level pressure increases by 0.9 m and 1.7 m in the study area, respectively. The rise in groundwater head generally decreases from the recharge zones to the discharge zones surrounded by the streams and coastal waters. However, the groundwater head change is determined not only by the location in the catchment, but also by the hydraulic conductivity of underlying aquifer and LID infiltration intensity. Moreover, LID significantly enhances groundwater recharge and aquifer storage in the wet seasons; in turn it increases aquifer release and groundwater discharge in the dry seasons. However, LID has the potential to increase the risk of groundwater flooding during wet seasons in areas with poor aquifer drainage capacity and shallow groundwater depth. The findings from this study provide the basis for further assessing the benefit and risk of LID infiltration for groundwater supplementation in the urbanized areas.

Groundwater Rise and Associated Flooding in Coastal Settlements Due To Sea‐Level Rise: A Review of Processes and Methods

“…However, comprehensive and sufficient datasets of long duration to capture shallow groundwater variability are available only in specific locations to allow the numerical approach and modeling performance evaluation, and certainly not at a global scale. Simulation of groundwater and infrastructure interactions use mostly open-source groundwater numerical codes (i.e., MODFLOW-based), to simulate infiltration into sewer pipes network, drainage systems, pumps and roads (Habel et al, 2019;Karpf & Krebs, 2013;Knott et al, 2017;Su et al, 2020), other computer models (i.e., composite mesh simulator by Székely (1998Székely ( , 1999Székely ( , 2008 or commercial integrated tools (i.e., MIKE SHE and MOUSE pipe flow by DHI Group, FEFLOW also by DHI Group) (Thorndahl et al, 2016;Zheng et al, 2018). Simulations of shallow groundwater's influence on urban surface and subsurface infrastructure (e.g., wastewater networks, building basements) was recently developed with modules within the URBS model (Pophillat et al, 2021).…”

Multifactor analysis of specific storage estimates and implications for transient groundwater modelling

“…Four of the models reviewed were assigned with uniform and fixed S S values for all layers despite differences in subsurface materials (Ackerman et al 2010; CDM-Smith 2016; Jacobs 2018; SKM-NSW 2010). Five of the models reviewed assigned different S S values across each layer, while the values were uniform within each layer (Geofirma 2011;GHD 2013;HydroSimulations-Hume 2018;Mackie 2013;Zheng et al 2018). In these models, S S values range from 1.6 × 10 -3 to 2.0 × 10 -7 m -1 with most of the values in order of 10 -5 and 10 -6 m -1 .…”

Development and Evaluation of a Saturated Zone Module in an Integrated Urban Hydrological Model

“…Main Objectives and Functionalities SWMM-FEFLOW [26] Evaluation of the LID designs effects on groundwater SWMM-MODFLOW [29] Simulation of fine temporal scale interactions between Green infrastructures and groundwater Mike Urban-Mike SHE [4] Estimation of the extent of the groundwater rise due to urbanization WEAP-MODFLOW [27] Simulation of urbanization and irrigation impacts on the groundwater levels, in a semi-arid periurban catchment For these reasons, the stormwater management in cities and urban hydrology is moving towards integrated approaches, aiming to find solutions to specific problems in the highly complex urban system. From the modelling point of view, the term "integrated" can be interpreted in multiple ways.…”

“…Dynamic coupling has been successfully implemented in various urban studies to better reproduce interactions between surface runoff and subsurface/groundwater flow processes (Table 1). However, these coupling approaches may have some limitations due to the way in which the hydrological variables are transferred from the groundwater model to the surface model [26], or due to the large amount of data needed [27]. The improvement of the vadose zone's representation within a groundwater flow model may be another option, as is suggested within the MODFLOW code [28].…”