Control of Urban Drainage Systems (UDS) is studied for cases in which the distribution of run–off through the channels of a system is inefficient, i.e. when the capacity of some structures is not used optimally. In this paper, a decentralized population-dynamics-based control for UDS is presented, particularly using the replicator and projection dynamics. For the design, a methodology to make a partitioning of the system is introduced, and the design of a population–dynamics–based control per each partition is proposed. Moreover, a stability analysis of the closed–loop system is made by using passivity theory. Finally, simulation results show the proposed approach performance in a segment of the Bogota stormwater UDS case study.