This paper analyzes the effects of different hydrological mechanisms on the solute response in watershed stream networks. Important processes are due to the hydraulic and chemical retention of reactive solutes in transient storage zones and the cumulative consequences of these processes from a single transport pathway as well as from the network of transport pathways. Temporal moments are derived for a distributed stream network and for a compartment-in-series model. The temporal moments are evaluated and are utilized to derive formal expressions for translating the network parameters into compartmental model parameters. The analysis reveals that in addition to the hydraulic and chemical retention processes, the morphological and topological properties of a watershed have a distinct impact on the central temporal moments in terms of averaging of the solute load weighted distances as well as the transport parameters over the network. Kinetic (rate-limited) transient storage affects second-order and higher central temporal moments and thus has a secondary effect on the parameterization of compartmental models. Additional considerable contributions to all temporal moments are introduced when parameter variability along transport pathways is considered. The paper demonstrates an improved model outcome for phosphorus transport in a small Swedish watershed by accounting for the overall network effects when parameterizing a compartment-in-series model.