Abstract:

Considering the condition of nonhorizontal initial surfaces, a transient flow model for semi-infinite aquifer seepage subjected to river boundary is constructed. The simple calculation methods of initial non-horizontal surfaces and their associated parameters (a, t_N) are proposed. The applicable conditions of the model are also explored. The result shows that the method is suitable for the seepage calculation when there are insufficient observation groundwater level data near the river, especially in the case that groundwater level variation is smaller campared to the thickness of unconfined aquifer and that the observation well is close to the river. Case analysis show that the calculated values of parameters a and t_N are different using the lookup table method and wiring method. Calculation error of the water level is within 0.02 m. The free surface calculation results are much better than the existed formulas. An easy method for calculating water seepage of the initial conditions of nonhorizontal surfaces is provided.

Key words: river, semi-infinite aquifer, phreatic water, transient flow, non-horizontal initial water table