Leveraging LiDAR for Statewide NHD Hydrography Projects. Susan Phelps, CFM, GISP

Transcription

1 Leveraging LiDAR for Statewide NHD Hydrography Projects Susan Phelps, CFM, GISP Mon, July 11 th, 2016

2 National Hydrography Dataset (NHD) Background

3 Why Local-Res NHD? Drivers Include: Availability of accurate framework layers Enhanced quality, content Uniform mapping Local-Res NHD HRBS Results 24K NHD Page 3

4 NHD Data Model 5 Hydro feature classes NHDFlowline NHDWaterbody NHDArea NHDPoint NHDLine Watershed Boundary Dataset (WBD) HUC levels 2-12 Attribute tables Metadata Reach Cross Reference Flowline Value-Added Attributes Event tables

5 Local-Res NHD from LiDAR-Based Sources AECOM Approach

6 Elevation-Based Local-Res NHD Workflow 1. Pilot study to establish project scope, specs 2. Base data collection and prep LiDAR, Imagery, 24K NHD, local hydro, stormwater data, dams, etc. Page 7

7 Elevation-Based Local-Res NHD Workflow 3. Generate Terrain Reference Files A. Import elevation data into AECOM s WISE software program, hydro-correct (hydro-enforce) B. Create DEMs, hillshades for reference, as well as 6 acre or 18 acre basins and streams (*specs vary from state to state) o Provides guideline for upstream limits, general stream location, stream/basin coverage Page 8

8 Elevation-Based Local-Res NHD Workflow 4. Digitize Local-Res NHD Linework Using Reference Files Imagery, DEMs and hillshades are primary data sources for horizontal stream location LiDAR-based guide streams and 24K indicate where streams should be digitized and how far up into the basin Page 9

9 Elevation-Based Local-Res NHD Workflow 4. Digitize Local-Res NHD Linework (cont d) Features digitized using USGS NHD schema, FTypes Edge-matched to adjacent NHD at state borders, sub-basin boundaries Topology, flow directions QC d 5. Conflation / Attribution 24K NHD info conflated to new linework using USGS Conflation, Update tools, utilities Final product loaded into USGS The National Map (TNM) database Page 10

10 Local-Resolution NHD Projects Indiana & Mississippi

11 Indiana Local-Res NHD Project Stakeholders NHD Project Stewards: IN Office of Technology (IOT): Jim Sparks Indiana Geographic Information Council (IGIC) Executive Director: Phil Worrall IGIC Waters Workgroup Chair: Mike Martin USGS POC Region 3: Joel Skalet USGS Geospatial Liaison: Dave Nail Contractor: AECOM Key Agencies in IGIC Waters Workgroup IGIC Indiana DNR Indiana DEM USGS NRCS Page 12

12 Indiana Local-Res NHD Project Background Completed statewide by HUC 8 sub-basin (39 total) Work area priorities based on: Availability of new LiDAR Workgroup requests based on agency priorities Special circumstances requiring additional analysis o Karst, canal/ditches, urban, coast Check-in/check-out for conflation, edge-matching Page 13

13 Indiana Local-Res NHD Project Background Started with 2005 ISTAR elevation data, transitioned to LiDAR ISTAR > 5 ft DEMs produced from ADS40 and ISTAR processing; approx 2 m post spacing LiDAR > 5 ft DEMs generated from 1.5 m post spacing LiDAR data LiDAR collection in 3 phases; NHD work areas followed same pattern Streams up to 6 acre drainage limit included in NHD Waterbodies ¼ acre or larger digitized Page 14

14 Indiana Local-Res NHD Project Award AECOM, key Waters workgroup members awarded IGIC s 2016 Special Achievement in GIS award Largest local-res NHD project in TNM Leveraged statewide lidar Engagement with community, USGS Overcoming challenges High quality Pioneering work Page 16

15 Indiana Local-Res NHD Project Current Status and What s Next All sub-basins conflated and successfully loaded by USGS Last 4 basins not yet available on TNM, but will be posted soon Data also available on IndianaMAP here: IGIC Waters Workgroup starting maintenance activities QC linework at basin boundaries for edgematching conflicts Identify WBD conflicts, updates needed Test automated method for perennial / intermittent / ephemeral breakpoints Page 17

16 Indiana Local-Res NHD Swipe Map pid= dd8485a9bde427361ee1394# Page 18

17 Mississippi Local-Res NHD Project Stakeholders Managed by Mississippi Department of Environmental Quality (MDEQ) NHD developed by AECOM and Waggoner Engineering under Mississippi Geographic Information (MGI) JV NHD Project Stewards: MDEQ: Steve Champlain MS NHD Steward: Jim Steil, Mississippi Automated Resource Information System (MARIS) o AECOM serving as MS NHD sub-steward, assist with NHD data check outs, conflation QC, and data submittals to USGS USGS POC Region 4: TBD USGS Geospatial Liaison: George Heleine Page 19

18 Mississippi Local-Res NHD Project Background Phase I (Fall 10 Spring 11) Blue hatched areas 4 full HUC 8 sub-basins all available on TNM Phase II (Fall 15 Ongoing) Work areas shown in pastel (eastern central MS) Includes 2 full HUC 8 sub-basins, 3 partial HUC 8 sub-basins o 2 (partial) sub-basins available in TNM o 3 sub-basins with draft linework completed Phase III coming soon Likely includes 3 coastal basins

19 Mississippi Local-Res NHD Project Background Work areas prioritized by LIDAR availability Coastal areas recently completed Most of LiDAR collection by county NHD project areas by HUC 12 where new LiDAR not yet available Partial conflation process Goal is full HUC 8 conflation once better elevation data available in remaining areas

20 Mississippi Local-Res NHD Project Background Streams up to 18 acre upstream drainage limit included Waterbodies 1 acre or larger digitized MDEQ Dams, USACE Vicksburg and FEMA levees incorporated

21 Local-Res NHD and LiDAR- Based Hydrography Lessons Learned

22 LiDAR-Based Local-Res NHD Challenges Determining stream flow in extremely flat areas and along basin boundaries Guide streams typically not as accurate Rely more on imagery, terrain, local sources Page 25

23 LiDAR-Based Local-Res NHD Challenges Incorporating local stormwater data in urban areas Can have significant impacts on WBD boundaries Agricultural areas Page 27

24 LiDAR-Based Local-Res NHD Challenges Differing base data between HUC 8 basins Karst areas ISTAR LiDAR Page 28

25 LiDAR-Based Local-Res NHD and Ele-Hydro Moving Forward

26 Considerations for Future Local-Res NHD and Ele- Hydro Efforts 1. Plan NHD, WBD projects in conjunction with LiDAR collection LiDAR acquisition presents challenges when HUC/WBD only have partial coverage 2. Investigate, improve on auto-feature extraction and processing techniques Syncing of elevation, hydro, WBD Resulting hydro data that s accurate, cartographically acceptable Manual manipulation still required - Ftypes, Fcodes; stream periodicity; incorporation of local data Page 31

27 Considerations for Future Local-Res NHD and Ele- Hydro Efforts 3. Develop / Update Mapping Standards for Local- Resolution NHD Use GIS-based rules to classify periodicity for LiDAR/imagerygenerated drainage? New classification[s] for Headwaters in NHD database? Document business rules and decisions via standards doc, metadata, issue papers, etc. 4. Relevance to USGS Hydro Requirements and Benefits Study (HRBS) Suggested activities relevant to HRBS, NHD stakeholders? One size does not fit all! Page 32

28 Questions? Comments? For more info, contact Susan susan.phelps@aecom.com Mon, July 11 th, 2016