2025 Big Sky GeoCon - Mapping the Future: Innovations in Geospatial Technology

Stormwater management is increasingly becoming a challenge for towns and cities that contend with population growth, aging stormwater infrastructure, and the increasing frequency and cost of storm events. Municipalities can leverage impervious surface mapping and analysis to help fund stormwater maintenance by providing an avenue to equitably assess stormwater utility fees based on the amount of impervious surface on a property contributing surface water runoff to a municipality's stormwater system.

In 2024, the City of Cheyenne, Wyoming, partnered with Pickett and Associates to advance its stormwater management program by conducting a GIS-based impervious surface mapping project. Pickett leveraged AI-based image classification using high-resolution aerial imagery to map impervious surfaces across 47.5 square miles and over 29,000 parcels within the City of Cheyenne. Pickett leveraged GIS tools, together with GIS data from the City and County, including Parcels, Address Points, Zoning, and Jurisdictional boundaries, to associate each parcel with a total impervious surface area and tie that impervious surface area to address points and, ultimately, utility billing accounts. Throughout this project, Pickett relied on web mapping applications to enhance communication and stakeholder engagement with the city engineers and city council members. This impervious surface analysis gave the city insight into each parcel’s surface water runoff potential based on its impervious surface area, which directly enabled Cheyenne to equitably assess a new stormwater utility fee based on parcel-level surface runoff potential. The city council passed the new stormwater ordinance in November 2024.

This presentation discusses the GIS-based approach and analysis that Pickett conducted for the City of Cheyenne, highlighting some of the challenges we faced and the impact that this analysis has made for the city’s stormwater program. The impervious surface mapping project not only supports Cheyenne’s Surface Water Management Program, but also provides actionable insights for future urban planning and stormwater mitigation, enabling the City to make informed, data-driven decisions to reduce flooding risks, improve water quality and better manage its stormwater infrastructure, ultimately benefiting the community’s sustainability and resilience.