Monte Carlo simulations of colloid deposition on a onc-dimensional permeable surface from a uniform flow field are reported. The effects of particle size, fluid velocity, and particle density on the transport of particles to the collector surface by thuid drag, gravity scttling, and Brownian motion are described in terms of a Peclet number, (N_{\mathrm{Pe}}). For (N_{\mathrm{Pe}} \leqslant \mathbf{1 0}^{-1.7}) (small, nearneutrally buoyant particles and low fluid velocities) deposit morphology converges to one of diffusion-limited growth characterized by a fractal dimension, (D), of approximately 1.7 . Thus, small particles ((<0.1 \mu \mathrm{m})) and low fluid velocities favor the formation of loosely packed deposits characterized by small fractal dimensions. Deposit morphology is more compact and approaches the theoretical ballistic limit ((D \rightarrow 2)) for large values of (N_{\mathrm{Pe}}\left(>10^{3}\right)) corresponding to larger particles and higher fluid velocities. However, the theoretical limit is not attained due to constraints imposed on the simulation lattice and deposit restructuring. For intermediate values of (N_{\mathrm{Pe}}\left(10^{-1.7}<N_{\mathrm{Pe}}<10^{3}\right)), an empirical expression is presented for calculating (D) directly from (N_{\mathrm{Pe}}). Intermediate values of (N_{\mathrm{Pe}}) correspond to conditions for particle transport typical of many natural and engincered systems including groundwater aquifers, reverse osmosis modules, and ultrafiltration membranes. Deposits containing particles of two different sizes resemble deposits formed from the smaller of the two particles alone if the transport of one or both of these particles is dominated by Brownian diffusion (small (N_{\mathrm{rc}}) ). In contrast, shadowing profuces fractal dimensions of deposits composed of "ballistic" particles of two different sizes that are smaller than those for deposits of either of the particles alone. (1994 Academic Press, Inc.