Abstract
Low impact development (LID) practices are effective in restoring natural hydrological processes, but they may be affected by groundwater and pose additional risk to groundwater dynamics and contamination in shallow groundwater conditions. Their performance in shallow groundwater is not well understood due to monitoring difficulty and the deficiency of modeling tools. The Storm Water Management Model (SWMM) is an urban hydrology-hydraulic model that has been widely used to evaluate the performance of LID practices. However, it cannot accurately simulate the hydrological processes of LID practices in shallow groundwater. This study presents the development, calibration, validation, and testing of a modified SWMM (SWMM-LID-GW) that incorporates groundwater feedbacks into LID simulations. The hydrological performance of LID practices under different environmental conditions was simulated, based on which the impacts of initial groundwater table depth, rainfall type, and in-situ soil type were evaluated, and a number of general nonlinear multivariate formulas were proposed to predict the hydrologic performance of LID practices in shallow groundwater environment and support the feasibility analysis of LID practices before project implementation. The reduction of exfiltration and increase of groundwater drainage in shallow groundwater accounted for a significant proportion of the water budget of LID practices. The influence of shallow groundwater was greater for shallower groundwater tables, in less permeable in-situ soils, and for events of higher intensities and longer durations. However, due to the dominant role of shallow groundwater, the impacts of both rainfall type and in-situ soil type on the hydrological performance of LID practices in shallow groundwater were minimal in general, in contrast to the impacts on deep groundwater tables. The SWMM-LID-GW outperformed the current SWMM for a wide range of groundwater conditions, particularly for locations in which the groundwater table frequently rises to 1.0 m or less below ground.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 313-331 |
| Number of pages | 19 |
| Journal | Journal of Hydrology |
| Volume | 566 |
| DOIs | |
| State | Published - Nov 2018 |
| Externally published | Yes |
Bibliographical note
Funding Information:The CKCC site is about 2.63 ha in size. There are nine bioretention cells at the site, and about 35% of the site (mostly located at the western part of the site and 0.93 ha in size) is covered by porous pavement in the form of parking lots. The porous pavement can be roughly separated into 10 parcels based on location and topography. The location of the site and the layout of the LID practices are shown in Fig. 3 . These LID practices were constructed as the result of the LID demonstration project conducted in autumn 2010, which was funded by Ecology’s Stormwater Implementation Grant Program ( Herrera, 2013 ).
Funding Information:
This work was funded by the Seed Funding Programme for Basic Research of The University of Hong Kong (Project code: 201611159011). The authors are grateful to the Stormwater Division of the Kitsap County Department of Public Words (Washington, U.S.A.) for providing the monitoring data used in model calibration.
Publisher Copyright:
© 2018 Elsevier B.V.
Keywords
- Green infrastructure
- Low impact development
- Shallow groundwater
- Sponge city
- Stormwater management
- SWMM
