The groundwater flow pattern is examined in an idealized situation, which is an approximation for situations as found at the confluence of rivers or where streams flow into or out of a lake or at peninsulas or bays. Two isopotential lines meet at an angle α; it is assumed that the aquifer is well connected to all surface water bodies. Moreover, groundwater flow is determined by a base flow component and recharge or pumping wells. The flow field is constructed using superposition of analytical solutions and conformal mapping. Classical results for α = π concerning the onset of bank filtration and the length of the infiltration zone are extended for the general case. Finally, an outlook is given on general problem setups, for which the proposed methodology can be applied too.