2026 WA GIS Conference: Full Schedule

1:30pm PDT

New ArcHydro tools to facilitate connecting data to hydrography through linear referencing

Thursday May 21, 2026 1:30pm - 2:00pm PDT

Linear referencing in hydrography is a way to locate information along rivers and streams using distance measured along the waterway, rather than using map coordinates. This makes it easier to link data—such as sampling points, monitoring stations, or stream segments—to their exact position on a stream network. These linked datasets are commonly referred to as “events” and support analysis of relationships among different hydrologic observations.
Linear referencing and dynamic segmentation are widely used in water resources to connect attribute data to specific parts of water features. This is critically important to make hydrography data useful for modelling, policy, conservation and a better understanding of our surface waters. Historically, this process has relied on the National Hydrography Dataset (NHD) and reach codes. However, a modernized approach is needed since reach codes are no longer maintained and are not part of the 3D Hydrography Program (3DHP).
Washington Department of Ecology has been working with Esri’s Arc Hydro team to develop simplified data models and tools that can be used with ArcGIS Pro, to provide a foundation for developing an updated linear referencing system. This presentation introduces new Arc Hydro tools and workflows for managing events, explains the development of a linear referencing system based on elevation derived hydrography (including 3DHP), outlines methods for transitioning existing events from NHD to 3DHP, and demonstrates techniques for analyzing and visualizing events using dynamic segmentation.

Speakers

Joshua Greenberg

Hydrography Steward, WA Department of Ecology

Joshua Greenberg works for the Washington Department of Ecology and is the hydrography steward for the State. He has been the hydro-steward five years, but has over 20 years’ experience working for local government. His background offers both ecological and technical guidance and... Read More →

Thursday May 21, 2026 1:30pm - 2:00pm PDT
401-402

Technology, ArcHydro

2026 WA GIS Conference

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2026 WA GIS Conference

1:30pm PDT

Joshua Greenberg

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