The transport of electrical charges in the shallow subsurface occurs mostly through the displacement of ions in aqueous solutions occupying part of the porous space of the medium. That displacement occurs by solute transport, i. e. by molecular diffusion and advection by the tortuous pore scale flow, of the charged species, by displacement under the effect of an externally applied electrical field, or by electro osmotic flow in the vicinity of mineral surfaces. This charge displacement results in an electrical current. We investigate numerically the coupled flow and transport of ions in geological fractures. Fracture wall roughness is responsible for flow channeling within the fracture plane, which impacts the fracture’s transmissivitty. To compute the distribution of local fluxes in (and transmissivitty of a) rough fracture without resorting to a full 3D flow simulation, one can use the lubrication approximation, which leads to a simple linear equation for pressure: the Reynolds equation. However, the presence of a structural surface charge on geological fractures’ walls leads to the formation of electrical double layers (EDLs) at the fluid-solid interface. Consequently, the occurrence of externally-imposed or naturally-occurring gradients in electrical potential and/or ionic concentration leads to significant changes in the fluid flow and solute transport as compared to flows driven primarily by hydraulic head differences. We study this phenomenon in geological fractures with a realistic aperture field and explore the flow dynamics resulting from such coupled electro-hydrodynamic processes. To this end, we generalize the standard lubrication theory for flow to obtain a description of the coupled transport of fluid mass, solutes, and electrical current under the application of fixed differences in hydraulic head (or pressure), electrical potential and concentration across the fracture. We observe interesting flow behaviors in the fractures, in particular depending on the surface charge density of the fracture walls, and investigate how these behaviors impact the dependence of the hydraulic and electrical apertures of the fractures on their closure.