Understanding drivers of trophic cascades, whereby the addition of a top predator causes reciprocal changes in the relative abundance of lower trophic level species, is critical for anticipating how communities respond to environmental change. However, the occurrence and strength of trophic cascades in empirical systems are hard to predict. One important possible driver of the observed variation in trophic cascades is environmental disturbance, such as river floods. Typically, disturbance is thought to provide pulses of biotic resources to communities, however, equally likely is that disturbance acts to remove biotic resources. Rivers may be particularly sensitive to trophic cascades given their propensity for disturbance and the widespread prevalence of non-native top predators, such as trout. Thus, disentangling the importance of these drivers is particularly critical for understanding these dynamic communities. Here, we apply a standard multi-species consumer-resource model to explore how the timing of disturbance and the resultant timing of the biotic resource pulse interact to impact trophic cascades in a two-patch riverine system. We reveal that downstream patches are actually more sensitive to the timing of the pulse of biotic resources rather than the effect of the disturbance itself. This is a particularly intriguing result given the large body of empirical work exploring the impact of disturbance on river communities. Moreover, the strength of trophic cascades in downstream communities are strongly influenced by a de-synchronization in the timing of disturbance and resulting resource pulse; providing a mechanistic explanation for why the occurrence and strength of trophic cascades in these riverine communities may be hard to predict. In particular, our work helps to deconstruct the drivers of trophic cascades and offer insight into appropriate management actions under changing climatic regimes.