This article presents the results of analyzing the use of dispersed storage tanks as a low impact development (LID) alternative to mitigate the flash flood risk in consolidated urban watersheds in Barranquilla, Colombia. Fieldwork, rainfall and flow rate monitoring, and numerical modeling were conducted to evaluate different scenarios combining storage tank capacity, two types of storage operations, and different locations by land use and watershed sectoring. These results showed that it is possible to reduce significantly the peak flow with small-capacity tanks distributed in the urban watershed with hydraulic structures that divide the discharge during the peak-flow time interval. By storing 3–17% of the runoff volume, equivalent to a dispersed storage capacity from 4 to 19 mm rainfall, it is possible to reduce the peak flow from 25 to 75%. These results demonstrate the advantages of using low impact development for stormwater management in consolidated cities with limited space, if regulatory policies encourage the massive use of LID in existing buildings.