Observational evidence suggests that a substantial fraction of the subtidal volume exchange in the Delaware estuary is associated with the exchange through the Chesapeake and Delaware Canal, which connects the upper reach of Delaware estuary to the head of Chesapeake Bay. An analytical model is developed to examine the effect of the combined forcing from Chesapeake Bay and the ocean on the barotropic volume exchange within the Delaware estuary. The relative importance of these two forcing mechanisms depends strongly on the time scales involved. At the semidiurnal tidal frequency, remote forcing from Chesapeake Bay is not important to the exchange process in the Delaware estuary, and the response of the estuary is predominantly driven by forcing from the ocean. At subtidal frequencies, however, forcing from Chesapeake Bay via the canal is just as effective as forcing from the ocean in producing volume exchange within part of the Delaware estuary. Furthermore, the presence of the canal significantly modifies the way in which the Delaware estuary responds to forcing from the ocean.