Watershed development and drainage assessments

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Watershed development and drainage assessments

  1. 1. GIS for Drainage Assessment Andrew Harrison, GISP Business Development Manager The Schneider Corporation (317) 826-7393 [email_address]
  2. 2. Overview <ul><li>Generating watershed from GIS data </li></ul><ul><li>Use of calculation software to assess drainage districts with Parcel, Watershed & Soils Layers </li></ul>
  3. 3. Accuracy… <ul><li>Fancy software does not equal accurate data </li></ul><ul><li>Additional data layers will only be as accurate as basemap </li></ul><ul><li>Parcels must be maintained and up-to-date through a known date </li></ul><ul><ul><li>almost all GIS layers will refer back to ownership information (in local government) </li></ul></ul>
  4. 4. Watersheds of the Past?
  5. 5. Software <ul><li>ESRI </li></ul><ul><ul><li>ArcGIS/ArcInfo </li></ul></ul><ul><ul><li>Spatial Analyst </li></ul></ul><ul><ul><li>Hydrology Modeling Extension </li></ul></ul>
  6. 6. Contours – 2’ Seamless
  7. 7. Linear Stream Features
  8. 8. Elevation Raster
  9. 9. Flow Direction Raster
  10. 10. Flow Accumulation Raster
  11. 11. Raster Streams Layer
  12. 12. Watershed Rasters
  13. 13. Assumptions and Obstacles: <ul><li>3 things to know about drainage (assumptions) </li></ul><ul><ul><li>Water runs downhill </li></ul></ul><ul><ul><ul><li>Water drains into streams </li></ul></ul></ul><ul><ul><li>Payday is Friday </li></ul></ul><ul><ul><li>The boss is a jerk! </li></ul></ul><ul><li>Obstacles </li></ul><ul><ul><li>“ Sinks” and “Peaks” </li></ul></ul><ul><ul><li>Culverts </li></ul></ul>
  14. 14. “ Fill” Process for Sinks and Peaks
  15. 15. Streams at Culverts
  16. 16. Zoomed Stream Elevation Raster
  17. 17. “ Burning” in the Streams
  18. 18. Watershed Generation Process <ul><li>Hydrology Modeling extension is used to “burn in streams” and build watersheds using raster images created from contour data </li></ul><ul><li>Computer generated watersheds are merged/attributed to match County’s existing tiered administrative watershed system </li></ul>
  19. 19. Threshold = 500 Watersheds
  20. 20. Threshold = 5000 Watersheds
  21. 21. Remember these?
  22. 22. Tiered Watersheds Watersheds
  23. 23. Tiered Watersheds Sub Watersheds
  24. 24. Tiered Watersheds Subs of Sub Watersheds
  25. 25. Tiered Watersheds Subs of Subs of Sub Watersheds
  26. 26. Tiered Watersheds Subs of Subs of Subs of Subs Watersheds
  27. 27. What can I do with this watershed data? <ul><li>Provide greater accuracy to what was originally a poor data source </li></ul><ul><ul><li>Hand drawn maps </li></ul></ul><ul><ul><li>On-screen digitized </li></ul></ul><ul><li>More equitable assessment for drainage </li></ul><ul><ul><li>Geogear draincalc </li></ul></ul>
  28. 28. Draincalc Overview <ul><li>A tool to utilize watershed data </li></ul><ul><li>Allows drainage officials to quickly, accurately create the assessment </li></ul><ul><li>Utilizes the geoprocessing functionality of ArcGIS </li></ul><ul><ul><li>Meant to allow non-GIS people to benefit from GIS </li></ul></ul>
  29. 29. Tiered Watershed Layer
  30. 30. Watershed/Parcel Overlay
  31. 31. Watershed/Parcel Intersect - Lower
  32. 32. Watershed/Parcel Intersect - Upper
  33. 33. Watershed/Parcel/Soil Intersect
  34. 34. Range of Watershed Assessment Options <ul><li>Flat rate per benefited acre </li></ul><ul><li>Percent of total (benefited acres) </li></ul><ul><li>Setting minimum assessment amount(s) </li></ul><ul><li>Additional assessment options </li></ul><ul><ul><li>Soils </li></ul></ul><ul><ul><li>Parcel class/landuse </li></ul></ul><ul><ul><li>Distance from hydrological features </li></ul></ul><ul><ul><li>Any customization you come up with </li></ul></ul>
  35. 35. Individual Watershed Projects
  36. 36. Defined Watershed Project
  37. 37. Proportion of total - values
  38. 38. Create Assessment Methods
  39. 39. Apply Assessment Rule Selections
  40. 40. Reports
  41. 41. Hearing Notice
  42. 42. Print Assessment Schedule
  43. 43. Summary <ul><li>How is this useful in the local government office? </li></ul><ul><ul><li>Using GIS we were able to work from only contours and parcels </li></ul></ul><ul><ul><li>Generate watersheds </li></ul></ul><ul><ul><li>Calculate assessments for those watersheds </li></ul></ul><ul><ul><li>Print hearing notices </li></ul></ul><ul><ul><li>Mail merge to labels (by watershed) </li></ul></ul>
  44. 44. Customizable Assessment Methodology
  45. 45. Customizable Assessment Methodology
  46. 46. Benefits <ul><li>What benefits are gained from using GIS for these tasks? </li></ul><ul><ul><li>More accurate watersheds </li></ul></ul><ul><ul><li>More equitable assessment </li></ul></ul><ul><ul><li>Speed and efficiency </li></ul></ul>
  47. 47. Thank you! Presenter: Andrew Harrison, GISP Business Development Manager The Schneider Corporation (317) 826-7393 [email_address]

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