LID-Design Atlas: Mapping Hydrologic Performance and Cost Trade-Offs in Infiltration-Based LID Design

Infiltration-based low-impact development (LID) practices are widely implemented to mitigate urban runoff impacts; however, their design is commonly guided by volumetric water-quality criteria that obscure critical trade-offs among hydrologic performance, geometry, soil properties, and cost. This study introduces the LID-design atlas (LIDA), a physics-based design database that systematically maps hydrologic performance and life cycle cost trade-offs across a broad space of infiltration-based LID configurations. LIDA is populated using thousands of numerical simulations generated with the Darcy–Richards analysis of infiltration in nature-based low-impact development (DRAIN-LID) model, which resolves one-dimensional variably saturated vertical flow through engineered media using a mixed-form Darcy–Richards formulation coupled with synthetic runoff inflow hydrographs. Three numerical design scenarios, spanning residential and roadside retrofit applications, are used to demonstrate how LIDA enables rapid screening of feasible designs based on peak-flow reduction, time-to-peak delay, detention time, ponding depth, and cost constraints. The results reveal strong threshold behavior in system response, with feasible design regions governed by interactions among footprint, media depth, and soil hydraulic conductivity rather than by storage volume alone. In space-constrained settings, increases in media depth are shown to be a more cost-efficient lever than footprint expansion, whereas lower-permeability media substantially restrict feasible design space. By explicitly resolving the temporal redistribution of runoff and exposing cost–performance trade-offs that are not captured by volume-based sizing methods, LIDA provides a transparent and computationally efficient framework for early-stage screening and comparison of infiltration-based LID designs.