A mixed numerical and analytical technique is presented to investigate orbital angular momentum (OAM) beam scattering in turbid water for underwater lidar applications. Electromagnetic simulations are used to generate single-scattering phase functions (SSPFs) that predict the angular scattering distribution for a single particle illuminated by either a Gaussian beam or an OAM beam. These SSPFs are used in array theory and radiative transfer calculations to predict the net volumetric scattering functions (VSFs) and transmittance for multiparticle scattering in a three-dimensional space for both Gaussian and OAM beams. Simulation results show that the VSFs (and therefore the transmittance) of Gaussian and OAM beams are nearly identical, with a slight dependence on OAM charge. Laboratory water tank transmission experiments are performed to verify the simulated predictions. The experimental results are in excellent agreement with the simulation predictions.