Abstract Based on summarizing all kinds of methods used to calculate karst groundwater seepage，aiming at the seepage characteristics in karst region，two methods considering Darcy and non-Darcy fluid simultaneously are put forward：(1) improved converting permeability coefficient method. In this method，a formula suitable for solving the stream wise head loss coefficient l of three turbulence zones is deduced from Colebrook C. F. formula，which can integrate flows in karst conduits with voids as well as cracks；and (2) variable permeability coefficient method. It expresses the permeability coefficient of karst conduits as the function of water head to be solved and the exponent of flow regime，which can integrate the non-Darcy flow in karst conduits with the Darcy flow in other media. To overcome the disadvantage of converting permeability coefficients method，the formulas to calculate tensor of karst conduit in global coordinate system are deduced. According to the basic differential equation for karst seepage，the finite element method(FEM) equations applied for calculating karst seepage are developed on the basis of Galerkin FEM. Verified by examples，the two methods are reasonable and feasible.
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Received: 23 June 2003
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