1. GIS Analysis in Land Management
Presented by:
Jimmy West, The Schneider Corporation

2. Presentation Overview:
Creating Computer Generated Watersheds
Use of Drainage Calculation Software to Assess Drainage with Parcels, Watersheds & Soils Layers

3. Accuracy… Fancy software does not equal accurate data
Additional data layers will only be as accurate as basemap
Parcels must be maintained and up to date through a known date – almost all GIS layers will refer back to ownership information

4. Watersheds of the Past?

5. Software Used to Create Computer Generated Watersheds
ESRI – ArcInfo
ESRI – Spatial Analyst Tools
What is needed?

6. Data Layer Sources Needed for Computer Generated Watersheds
2’ contours – seamless
Linear stream features – seamless and topologically correct
2’ contours – seamless
Linear stream features – seamless and topologically correct

7. Computer Generated Watershed Raster Processes
Elevation Raster
Flow Direction Raster
Flow Accumulation Raster
Raster Streams Layer
Make grid 2x bigger

8. Assumptions and Obstacles: …and 3 things to know about drainage
Water runs downhill
Water drains into streams
Obstacles
“Sinks” and “Peaks”
Culverts

9. “Fill” Process for Sinks and Peaks

10. Streams at Culverts

11. Zoomed Stream Elevation Raster

12. “Burning” in the Streams

13. Creation of Computer Generated Watersheds
Hydrology Modeling extension is used to “burn in streams” and build watersheds using raster images created from contour data
Computer generated watersheds are merged/attributed to match County’s existing tiered administrative watershed system

14. Computer Generated Watersheds Threshold = 500 Watersheds

15. Tiered Watershed Layer

16. Drain Calc Overview Preparing Data For Use in Drain Calc
Multiple assessment methodologies
One rate per acre assessments
Proportional assessments

17. Tiered Watershed Layer

18. Watershed/Parcel Overlay

19. Watershed/Parcel Intersect - Lower

20. Watershed/Parcel Intersect - Upper

21. Watershed/Parcel/Soil Intersect

22. Range of Watershed Assessment Options
Flat rate per benefited acre
Setting minimum assessment amount(s)
Additional assessment options
Soils
Parcel class/landuse
Distance from hydrological features
other

23. Individual Watershed Projects

24. Defined Watershed Project

25. Apply Assessment Rule Selections

26. Soil Type Rule Example

27. Import Parcel Data

28. Define Hearing/Notice Report Info

29. Generate Reports/Notices

30. Print Assessment Schedule