Using enhanced urban drainage modeling to prioritize green infrastructure efficiencies

The objective of this study to discuss how enhanced urban drainage modeling provides an indicator to prioritize LID efficiencies through:

• High Resolution Urban Stormwater Planning Model
• Green Infrastructure (GI) Siting Tool
• GI Placement and Sizing Optimization

Advancement in digital elevation data and processing application tools are used to achieve a high resolution urban stormwater planning model. In the enhanced modeling approach, the pipe network, the overland flow paths, and the interaction between the two, are modeled to accurately represent the dynamics of urban storm drainage. The streets are modeled as open channels and overland flows running on streets before going to storm inlets or GI units. The enhanced approaches improve the stormwater modeling reliability and provides accurate estimation of flows that goes to GI units.

At the same time, GI Siting Tool was developed to get the best sites for potential GIs. This tool takes into consideration of 1) vacant parcels 2) utilities features like sanitary line, hydrants, phone/light poles, etc. 3) available spaces like parking, trees, building setbacks 4) Conditions like sidewalk, street slopes, etc. The tool identifies potential GI sites with minimal field work by spatially overlay multiple layers for a scoring coverage for preferable locations.

The selected GI sites are added to the enhanced model to interact with the overland flow. The performance for these units is evaluated in terms of inflows, total and unit captured volume, % captured, etc. This information is essential to prioritize GI sites placement and to size the units correctly. The optimizing GI planning will meet water quality, water quantity, and stormwater drainage compliance at a reduced cost.

A GI Siting Tool was developed to locate large number of sites suitable for GI units which takes into consideration several impacts, like surface structures, subsurface infrastructure, Trees, roads and traffic, topology, etc. Integrating these factors to identify best through automated process that identify continuum of potential suitable sites.