3D Hydrography (3DHP) Interest Group

Since my "second retirement from NSGIC" last year, I've continued to work with the Hamilton County, Indiana GIS Department (the county where I live) on the first county-level 3D Hydrography Program (3DHP) Elevation-Derived Hydrography (EDH) project in our state-and I wanted to share our results with you.

This work was completed as part of Hamilton County's 2024 Basemap Update Project and was fully aligned with both the USGS 3DEP and 3DHP programs and the County's hydrography mapping requirements. For the 3DHP component, Dewberry Engineers produced EDH from the county's new QL1 3DEP lidar and prepared it for contribution to the USGS national 3DHP database. To meet our county requirements, they also integrated the new EDH data with our local government storm sewer networks, regulated drains, and developed new AI/ML-based wetlands predictive modeling/mapping layers. When the project wraps up next month, the county will also share these datasets with the Indiana Geographic Information Council (IGIC) Waters Workgroup and the Indiana Geographic Information Office (IGIO) to help inform their development of a statewide 3DHP plan.

Earlier this week Hamilton County hosted a 3DHP – EDH 101 technical workshop for local and state partners who will begin seeing and using this new data next month on the County's GeoHUB.  Presentation materials are available below:

• Slides (PDF): [LINK]
• Recording: [LINK]

I'm very excited about our results and hope you find this information timely and useful!

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Philip Worrall
Retired
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Nice job Phil,

We had a similar experience in Alabama with our North Central Alabama DCA 26 submission. We had local champions that were the spearhead of the DCA and were directly involved in getting the estimate and providing specifications. At the State level I provided support and coordinated additional funding. When submitted, we had 6 local gov, 5 state gov, 2 states, and 1 fed partner for 100% cost and coverage of the HUC 8 project.

Local champions and buy-in are critical to our acquisition, funding effort, continued lifecycle.

I'll look at your presentation materials for more information. We'd also be interested in use cases. Would you be ok if we shared your experience with our state on 3DHP.alabama.gov?

We want to capture more information on local use and opportunity. Our recent presentation on GIS day will be posted soon.

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Mike Vanhook
IT Business Solutions Manager
Alabama Department of Economic and Community Affairs
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Mike,

Yes, please share our presentation as needed!  We have another session on December 17th where we are looking at applications for both data creation, maintenance, and local government end-user applications.  We are in early days for these, but we also hope to learn from others how these data can be leveraged.  For example, in Indiana there appears to be a lot of county-level interest in conducting new "water studies" of both ground and surface water resources within political boundaries and how to better control and manage these local water resources as new (internal and external) economic and environmental forces emerge.

I'd love to see this conversation expand to learn how other local governments across the US are participating or leading EDH development.  I believe Ohio has had some County funded EDH initiatives that Woolpert has helped with.  Would love to learn more!  

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Philip Worrall
Retired
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Original Message:
Sent: 11-22-2025 08:54
From: Mike Vanhook
Subject: Results of Hamilton County, Indiana's 3D Hydrography EDH Data Development:

Nice job Phil,

We had a similar experience in Alabama with our North Central Alabama DCA 26 submission. We had local champions that were the spearhead of the DCA and were directly involved in getting the estimate and providing specifications. At the State level I provided support and coordinated additional funding. When submitted, we had 6 local gov, 5 state gov, 2 states, and 1 fed partner for 100% cost and coverage of the HUC 8 project.

Local champions and buy-in are critical to our acquisition, funding effort, continued lifecycle.

I'll look at your presentation materials for more information. We'd also be interested in use cases. Would you be ok if we shared your experience with our state on 3DHP.alabama.gov?

We want to capture more information on local use and opportunity. Our recent presentation on GIS day will be posted soon.

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Mike Vanhook
IT Business Solutions Manager
Alabama Department of Economic and Community Affairs
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Subject: Update on Hamilton County, Indiana's 3DEP & 3DHP-Aligned Data Modernization

Hi everyone,

I want to share a brief clarification and update following my recent post about Hamilton County's new lidar and Elevation-Derived Hydrography (EDH) work. Several colleagues reached out with questions, and I thought it would be helpful to provide a bit more context for the full group.

Hamilton County's 2024 QL1 lidar and EDH development were part of the County's internal basemap, lidar, and hydrology modernization effort. These datasets directly support local integration with our stormwater systems, regulated drains, and wetlands mapping. While the work follows the 3DEP and 3DHP technical specifications, it was completed on a local timeline to meet immediate operational needs-not as DCA acquisition projects with USGS.

To ensure future alignment with national programs, the County has submitted coordinated FY25 3DEP and FY26 3DHP DCA proposals.

• The FY25 award supports USGS validation of the County-funded QL1 lidar for use as updated 3DEP elevation data.

• The FY26 proposal builds on that foundation and includes formal guarantees for EDH corrections by our contractor (Dewberry) so the hydrography will fully align with the final validated DEM and the 3DHP EDH specifications when USGS is able to review it.

Hamilton County remains committed to sharing our new elevation and hydrography data with state and federal partners and ensuring they can both support Indiana's statewide 3DHP planning and future national integration through the 3DEP and 3DHP programs.

Thanks to everyone who has reached out with questions-happy to continue the discussion as more counties and states begin exploring similar workflows.

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Philip Worrall
Retired
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Philip Worrall
Retired
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Thanks Phil

Lots of good information in that presentation!

Best

Josh

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Joshua Greenberg
WA State NHD Steward
WA Department of Ecology
Lacey WA
360-742-6992
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Original Message:
Sent: 12-23-2025 12:02
From: Philip Worrall
Subject: Results of Hamilton County, Indiana's 3D Hydrography EDH Data Development:

Last week Hamilton County GIS hosted a second technical workshop on EDH & 3DHP Applications for our partners who will begin using the County's new hydrography data.  Presentation materials for this session are available below:

     Presentation Slides: [.PDF]

     Presentation Recording: [LINK]

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Philip Worrall
Retired
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