The details of the 1700 Cascadia Subdction Zone earthquake and tsunami can be better constrained using data from tsunami sand sheets, provided knowledge of the waveform, estuary geometry and bed roughness controls on the deposition pattern of the sand sheet. In this study, we use the hydrodynamic and sediment transport model, Delft3D, to investigate the effects of each of these parameters on tsunami sand sheet inland extent and deposition pattern. Different waves produce different sand sheet patterns, as do different estuary geometries and bed roughness. The key finding is that estuary geometry has the greatest impact on deposition and erosion. With accurate reconstruction of the estuary parameters at the time of the event, a relatively limited range of waveforms can be inferred from the sand sheet, therefore informing details of the associated rupture. Inversion of rupture characteristics from tsunami deposits can be applied to estuaries along the coast of Oregon. With this information, new constrains of the details of the 1700 event and older events allows for improved estimates of a future Cascadia Subduction Zone event.