Norcross Trees to Offset Stormwater

This project, called Trees to Offset Water, is a study of Norcross, Georgia’s forest canopy and the role that trees play in up taking, storing and releasing water. This study was undertaken to assist Norcross in evaluating how to better integrate trees into their stormwater management programs. More specifically, the study covers the role that trees play in stormwater management and shows ways in which the city can benefit from tree conservation and replanting. It also evaluated ways for the city to improve forest management as the city develops.

The goal of this study was to identify ways in which water entering the city’s municipal separate storm sewer system (MS4) could be reduced by using trees to intercept and soak up runoff. Tree canopy serves as ‘green infrastructure’ that can provide more capacity for the city’s grey infrastructure (i.e. stormwater drainage systems) by absorbing or evaporating excess water before it runs off. The model created in this study also shows how the Norcross can reduce potential pollution of its surface waters.

This report includes those findings and recommendations that are based on tree canopy cover mapping and analysis, the modeling of stormwater uptake by trees, a review of relevant city codes and ordinances, and citizen input and recommendations for the future of Wilmington. More specifically, the following deliverables were included in the pilot study:
• Analysis of the current extent of the urban forest through high resolution tree canopy mapping,
• Possible Planting Area analysis to determine where additional trees could be planted,
• A method to calculate stormwater uptake by the city’s tree canopy,
• A review of existing codes, ordinances, guidance documents, programs and staff capabilities related to trees and stormwater management, and recommendations for improvement,
• Two community meetings to provide outreach and education.

This is one of 12 case study reports produced by GIC for the Trees to Offset Stormwater Project.
You can view the Summary Report here.
You can learn more about this project on our Trees and Stormwater page here.