Applications of a GIS Floodplain Mapping Model valley identification, connectivity indexing, and emergency management.

Size: px

Start display at page:

Download "Applications of a GIS Floodplain Mapping Model valley identification, connectivity indexing, and emergency management."

Kimberly Douglas
5 years ago
Views:

1 Applications of a GIS Floodplain Mapping Model valley identification, connectivity indexing, and emergency management. Jude H. Kastens, Debra S. Baker, Donald G. Huggins, and Kevin E. Dobbs University of Kansas March 2010 Missouri Natural Resources Conference, Nebraska City, NE

2 Problem: Extracting the historic floodplain as a map feature. Study Area New method: FLDPLN ( floodplain ) Model 16-m DTF Depth to Flood

3 Topographic Floodplain Model (FLDPLN) Static hydrologic floodplain mapping model, topographic data to estimate floodplain extent as a function of local floodwater depth, stream channel surface elevations provide the reference datum.

4 Topographic Floodplain Model (FLDPLN) Static hydrologic floodplain mapping model, topographic data to estimate floodplain extent as a function of local floodwater depth, stream channel surface elevations provide the reference datum. Based on the pixel-level mechanisms of backfill and spillover flooding.

5 Topographic Floodplain Model (FLDPLN) Static hydrologic floodplain mapping model, topographic data to estimate floodplain extent as a function of local floodwater depth, stream channel surface elevations provide the reference datum. Based on the pixel-level mechanisms of backfill and spillover flooding. Computational model based on hydrologic processes, not a statistical model based on relative elevations.

6 Topographic Floodplain Model (FLDPLN) Static hydrologic floodplain mapping model, topographic data to estimate floodplain extent as a function of local floodwater depth, stream channel surface elevations provide the reference datum. Based on the pixel-level mechanisms of backfill and spillover flooding. Computational model based on hydrologic processes, not a statistical model based on relative elevations. Completely modular - can be applied to a single stream pixel as well as an entire stream network, and everything in between.

7 Topographic Floodplain Model (FLDPLN) Static hydrologic floodplain mapping model, topographic data to estimate floodplain extent as a function of local floodwater depth, stream channel surface elevations provide the reference datum. Based on the pixel-level mechanisms of backfill and spillover flooding. Computational model based on hydrologic processes, not a statistical model based on relative elevations. Completely modular - can be applied to a single stream pixel as well as an entire stream network, and everything in between. Allows for seamless, depth-varying floodplain extent estimates.

8 Topographic Floodplain Model (FLDPLN) Static hydrologic floodplain mapping model, topographic data to estimate floodplain extent as a function of local floodwater depth, stream channel surface elevations provide the reference datum. Based on the pixel-level mechanisms of backfill and spillover flooding. Computational model based on hydrologic processes, not a statistical model based on relative elevations. Completely modular - can be applied to a single stream pixel as well as an entire stream network, and everything in between. Allows for seamless, depth-varying floodplain extent estimates. Dam breach model has been developed that uses output from FLDPLN.

9 Topographic Floodplain Model (FLDPLN) Static hydrologic floodplain mapping model, topographic data to estimate floodplain extent as a function of local floodwater depth, stream channel surface elevations provide the reference datum. Based on the pixel-level mechanisms of backfill and spillover flooding. Computational model based on hydrologic processes, not a statistical model based on relative elevations. Completely modular - can be applied to a single stream pixel as well as an entire stream network, and everything in between. Allows for seamless, depth-varying floodplain extent estimates. Dam breach model has been developed that uses output from FLDPLN.

10 The FLDPLN ( Floodplain ) Model there are two ways that point Q can be flooded by water from point P Backfill Flooding Spillover Flooding Q floodwater surface d P P d { Q Q uphill from P Q downhill from P

11 Backfill Flooding accounts for floodwater expansion due to swelling processes flow divide ground surface FLOODWATER SOURCE PIXEL OVER HERE flow directions PIXEL ON RIDGELINE

12 Backfill Flooding accounts for floodwater expansion due to swelling processes flow divide flood depth ground surface FLOODWATER SOURCE PIXEL OVER HERE flow directions PIXEL ON RIDGELINE

13 Backfill Flooding accounts for floodwater expansion due to swelling processes water surface flow divide flood depth ground surface FLOODWATER SOURCE PIXEL OVER HERE flow directions PIXEL ON RIDGELINE

14 Backfill Flooding accounts for floodwater expansion due to swelling processes water surface flow divide dry flood depth dry dry ground surface FLOODWATER SOURCE PIXEL OVER HERE flow directions PIXEL ON RIDGELINE

15 Spillover Flooding accounts for floodwater rerouting (alternative flow path development) water surface flow divide spillover flood depth flood depth ground surface FLOODWATER SOURCE PIXEL OVER HERE flow directions PIXEL ON RIDGELINE

16 Spillover Flooding accounts for floodwater rerouting (alternative flow path development) water surface flow divide flood depth ground surface FLOODWATER SOURCE PIXEL OVER HERE flow directions PIXEL ON RIDGELINE

17 Spillover Flooding accounts for floodwater rerouting (alternative flow path development) water surface flow divide flood depth ground surface FLOODWATER SOURCE PIXEL OVER HERE flow directions PIXEL ON RIDGELINE

18 PLAN VIEW illustrating backfill and spillover flooding flood source point R tributary channel watershed boundary flood source point

19 PLAN VIEW illustrating backfill and spillover flooding flood source point R tributary channel watershed boundary flood source point

20 Valley Identification

21 River typing and morphology studies valley identification and floor width estimation Valley floor width Valley top width Valley boundary

22 Terrain Processing: Floodplain Mapping FLDPLN can be used as long as you can see the channel in the DEM. No comparable method for doing this using only topographic data. 10-m Floodplain Mud Creek, KS

23 River valley mapping - identifying floodplain wetlands

24 Connectivity Development

25 Wetland Hydrologic Connectivity DTF value extracted for each site. Provides a hydrologic connectivity index. HCI indicates relative frequency of connection (via floodwaters) of a floodplain location to the river. DTF = HCI

26 Levee Effects on Wetland Hydrologic Connectivity Levee data (xyz point files) obtained from KC USACE. Acquired as part of the National Levee Database (NLD) effort. Many levees are absent.

27 Levee Effects on Wetland Hydrologic Connectivity 30-m DEM data backdrop.

28 Without levee data FLDPLN No levee data. DTF = HCI

With levee data DTF values increased more than 4 m, indicating much less frequent reconnection to the river. DTF (no levee): 2.8 m DTF (with levee): 7.2 m DTF (no levee): 2.

29 With levee data DTF values increased more than 4 m, indicating much less frequent reconnection to the river. DTF (no levee): 2.8 m DTF (with levee): 7.2 m DTF (no levee): 2.9 m DTF (with levee): 7.2 m Note: A non-hydrologic connectivity index, such as distance-to-stream, will not pick up levee effects. DTF (no levee): 1.9 m DTF (with levee): 6.3 m

30 Emergency Management

31 Problem: Mapping Floodwater Extent in Real Time Who needs this info: State & Local Disaster Response Personnel

32 Flood Extent Estimation DTF = m Summer 2007 Osage River Missouri flood

33 Cedar River crested 13 June 2008

34 Flooding crested more than 11 ft above the historic record

35 DTF = m

37 Also available as a web mapping service for ArcMap and Google Earth (KML)

38 Frequency Stage or DTF Flood Frequency Next step - convert DTF values back to stage/discharge value and use USGS stream rating curves to convert to a flood frequency. E.g. the 100-year flood at a location can be referenced to a particular local river stage/discharge. Discharge Discharge

39 Contact information Jude Kastens

Rapid Flood Mapping Using Inundation Libraries

Rapid Flood Mapping Using Inundation Libraries Jude Kastens, Kevin Dobbs, James Halgren, Katherine Balster 2017 ASFPM Conference May 3, 2017 5 mi Kansas River Valley between Manhattan and Topeka Email: