Modeling hydrological responses of karst spring to storm events: example of the Shuifang spring (Jinfo Mt., Chongqing, China)

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Publication Date

November 2007

Abstract

Reproduction of hydrographs at karst springs has been an approach of understanding the karst aquifer, which normally acts as drains for the groundwater flow. However, its numerical modeling is difficult since factors for the internal geometry and connectedness are unknown and hard to quantify. Hydrographs of the karst aquifer with well-developed conduits in Shuifang spring catchment were obtained from the automatic gauging station at the spring orifice. Data as to the conduit system were also obtained based on results and analyses of tracer tests. With these data, the hydrological responses of Shuifang spring to storm events were simulated by storm water management model (SWMM) developed by USA EPA (Environmental Protection Agency). Nash–Sutcliffe efficiencies are used to compare the computed flow to the observed, which are 0.95 and 0.92 for calibration and validation. SWMM was verified and applicable in karst conduit drainage system. The model illustrated correctly quick recharge through conduits and slow and low inflow from the fissured aquifer matrix. The SCS-CN (soil conservation service-curve number) infiltration method was used for computation of losses and runoff. Field tests indicated that permeability was extremely high but different in karst area, which was less sensitive to the computed runoff when exceeded the common value provided by SWMM. Therefore, an improved quantitative infiltration model for karst area will make SWMM possible to be a useful tool for assessing and reproducing spring hydrographs. Karst modeling and hydrological forecasts have always been difficult due to heterogeneity and anisotropy of the aquifer system, incongruity of surface and subsurface watershed boundaries, and very wide range of infiltration rates in karst areas compared with non-karst areas. Great progresses have been made in numerical modeling since 1960s of last century. A number of models applied in non-karst areas have been developed to simulate surface runoff, underground dynamics and transfers between them. Karst

Keywords

Karst Spring, Modeling, Swmm, Conduit Flow, Tracer Tests

Document Type

Article

Notes

Environmental Geology, Vol. 55, no. 7 (2007-11-08).

Identifier

SFS0055829_00001

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