TICKET-UWM is a software application that models metals and organics transport in a well-mixed lake with an underlying sediment layer (Farley et al., 2005; Farley et al., 2011). The name TICKET-UWM comes from a merging of the numerical engine for the model calculations (Tableau Input Coupled Kinetics Equilibrium Transport model) from Farley et al. (2008) and the Unit World Modeling approach that has been previously developed for organic chemicals (Mackay et al., 1996; Mackay and Paterson, 1991) and metals (Diamond et al., 1990). Unlike previous models, however, TICKET-UWM simultaneously considers the effects of chemical speciation on metal partitioning, transport and bioavailability in the lake water column and underlying sediments. The initial version of TICKET-UWM was developed to perform steady-state calculations with a continuous load of metal. Recently, the model was upgraded to perform time-variable simulations as well. The user can now assess the dynamic response of a lake to a continuous or instantaneous load of a metal. The metal source can be specified as a soluble salt subject to instantaneous dissolution or as a powder/massive which dissolves according to a user-specified kinetic expression and rate.