BEST PRACTICES IN THE USE OF LIDAR FOR HYDROGRAPHIC NETWORK AND HYDROLOGIC BOUNDARY EXTRACTION

2012 NHD/WBD Stewardhsip Conference – 3/29/2012

GOALS

Provide framework for appropriate levels of rigor, consistency and cooperation

Report by Stewards and collaborators on their experiences

Consolidate these into a set of best practices for lidar based delineations

Establish a set of recommendations for the resulting update of the NHD and WBD

Inform analysis of the benefit cost ratio for developing 3-dimentional hydrography network and hydrologic boundaries from lidar sources

SCOPE

The project carried out a nation-wide critical inventory of practices in:

1. Lidar collection and processing2. Hydrography extraction3. Standardization of the extracted dataWorkgroup members provided copious

information about their home entity practices. Member contributions available thru MyUSGS collaboration platform, NHD/LIDAR/ workspace.

WORKGROUP MEMBER AWRA PRESENTATIONS

A Workflow for NHD Update from Lidar, Craig DuceyBuilding High-Resolution DEM and WBD Coverages From

Overlapping LiDAR Point Clouds of Varying Resolutions in New Jersey, Jeffrey Hoffman

Lessons From the Development of New York City’s Water Supply Watershed Hydrography Model, Ricardo Lopez-Torrijos

A Community Approach for Hydrologic Enforcement of Topography Data, Brian Quinn

Find at AWRA’s www.awra.org/proceedings/Spring2012/ , or ask the author for a copy.

OTHER AWRA PRESENTATIONS OF INTEREST

Enhancing LiDAR for Improved Watershed Modeling, Mark Ellard

Wetlands Correction Factors for LiDAR Digital Elevation Models, Sandra Fox

Automated Hydrologic Enforcement of High Resolution Topography, Brian Gelder

Creating Local Resolution NHD: An Examination of Similarities and Differences in Three State Projects, Susan Phelps.

Hydrographic Feature Extraction and Hydrological Modeling Based on LiDAR Point Cloud, Ping Yang

Find at AWRA’s www.awra.org/proceedings/Spring2012/, or ask the author for a copy.

RECOMMENDATIONS

If not working directly with the lidar point cloud, refer to the bare-earth surface as lidar-derived

RECOMMENDATIONS

Conclusions are valid for any high resolution bare earth surface, irrespective of the technology used to measure the elevations.

RECOMMENDATIONS

Produce a summary report of the workgroup’s findings.

In project design, evaluate carefully the project area boundary to ensure complete elevation data coverage.

RECOMMENDATIONS

Develop metrics to measure relative level of effort, and then a blue book guide for project costing and design, providing project costs according to each set of recommended specifications.

Improve the tools for conflation of attributes to newly compiled vector data.

Clarify expectations for submissions of NHD updates based on lidar.

Clarify guidelines for WBD delineation.

RECOMMENDATIONS

Provide recommendations on storage of information used to incorporate storm water features into the stream network, and on update and hosting of other linear event information

RECOMMENDATIONS – VERTICAL INTEGRATION

The vertical integration of elevation and NHD/WBD needs to resolve issues with:

Collection of underground infrastructure. Flow routing determination in flat areas. Determination of threshold source

contributing area for stream initiation. Review process and feedback loops.

RECOMMENDATIONS – VERTICAL INTEGRATION

Resolve issues with: Vertical matching of vectors meeting

existing streams at the project’s edge. Integration with non Z-enabled stream

data in the NHD repository.

QUESTIONS?

Ricardo Lopez-Torrijos

Ricardo.Lopez.inAlbany@gmail.com Jeff Simley

jsimley@usgs.gov