QUICK2 / QUICK2AF Ingredients List and BFE Recipe

REFERENCES

• MANAGING FLOODPLAIN DEVELOPMENT IN APPROXIMATE ZONE A AREAS 
• Guidance for Flood Risk Analysis and Mapping: Alluvial Fans
• REST Service to NFIP mapped Alluvial Fan Areas
• CAUTIONS: Backwater Conditions and Alluvial Fans

DOWNLOADS

• Quick2af (download)
• Quick2af BFE Worksheet (download)
• Statewide/County SFHA Database (download)
• Stateplane Zones (download)
• DEM for request area (State/USGS/NRCS)
• StreamStats stream grid (download)
• Landcover for request area (download)
• Landcover Mannings N reference (download)
• QGIS (if needed) (QGIS.ORG) (long-term release recommended)
• QGIS Plugins: Lat Lon Tools, Profile Tool and QuickMapServices (w/contribution pack)

CREATE AND MEASURE IN GIS

1. Create a BFE project in GIS and locate the project by coordinates
2. Use the state plane CRS of the project location in feet (Stateplane Zones)
3. DEM(s) is/are merged and converted to vertical feet if needed (DEM for request area)
4. One foot contours are created from DEM
5. Cross-section layer is created using H&H common practice and assigned the project CRS
6. Measurements are then taken from attached layers (using workbook working down and right through tabs).
7. Backwater test from nearest downstream Zone AE elevation (State SFHA Database).
8. Place a cross sections are placed from left to right looking downstream with a state plane projection in feet, one at home/site and one upstream a minimum 100 feet with a positive slope value and a change in elevation minimum of a foot.
9. StreamStats report is generated from Cross Section intersection with NSS stream grid (fill in basin sq mi, region, 1% AEP discharge).
10. Mannings N is determined from XS, aerial, landcover, and Mannings N reference. Stream is always 0.04.
11. Profile is created from 40 points at the downstream XS of location (copied) and pasted into the worksheet Downstream XS tab. Copy and past from resulting QGIS attribute table by creating SHP file, points along line spaced length divided by 39, and extract elevations from DEM.
12. Left and right banks are identified in Downstream XS tab Notes field
13. The Quick2 Worksheet tab fields: Number of Stations, Left Bank Station, and Right Bank Station - column A is text file input for Quick2.