Kevin Byrne's Study of Flash Flood Vulnernability of Raingardens in Rochester (Minnesota)


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Kevin Byrne's Study of Flash Flood Vulnernability of Raingardens in Rochester (Minnesota)

  1. 1. Flash Flood Vulnerability of Rain Garden Homeowners in Rochester, MN for Week 6 of St. Mary U’s Advanced Modeling __________________________________________ Kevin Byrne October 13, 2009  
  2. 2. Goal Analyze and map the flash flood vulnerability of homeowners on Rochester (MN) parcels who have – or are now installing – rain gardens on their property.  
  3. 3. Context Rochester Public Works launched a program titled Realize Raingardens Rochester recently that funded partial subsidy for installation by residents. Four were approved this year. As a future rain garden owner I felt it would be useful to ponder how flash floods might impact such a garden, say 5 or 10 inch rainfalls.  
  4. 4. Method 1. Ponder all the variables that might pertain to raingarden flash flood issues. 2. Contact Rochester Public Works for what they might have on the topic. 3. Gather, inspect, and organize all the assets. 4. Construct a basic layered ArcMap file as a base map. 5. Get well acquainted with Spatial Analyst, ArcToolBox’s Spatial Analyst Tools’ Hydrology, and Xtools for data analysis. Then do it all! 6. Export lots of micro-maps to PDF since no one big map will tell the story. 7. Create a well-structured and clean custom .xls table that holds keys data. 8. Aggregate the three most significant criteria into a “summary” attribute column to portray flash flood vulnerability for four lots with rain gardens. 9. Prepare a report and slide presentation.  
  5. 5. Image credit: University of Wisconsin Extension
  6. 6. Image credit: University of Wisconsin Extension
  7. 7. Variables • Groundwater height • Bedrock height • Sun aspect • Slope • Soil type and properties • Surface runoff • Saturated hydraulic conductivity • Urbanity, i.e. porosity and proximity of neighborhood surfaces  
  8. 8. 31st St NW Realize Raingardens Rochester 31st St NW NW US St 2009 Sites Basemap th 29th St NW Hw 30 t NW hS 29t y 52 28th St NW 31st Ave NW 28th St NW 2915 27th St NW EU 12th Ave NW Va 26th St NW SH NW lle t hS 4th Ave NW y 26t wy hig 25 26th St NW h 52 th Rd S tN W Fro W 25th St NW W NW N 24th St NW 21 eN e nta 24th St NW Av st A 18 r NW ge NW h 17th Av 11th Ave NW NW 5t 1/2 ve ve NW 23r R hA dS d US ve ills D 22nd S NW t NW t NW Ave 0t Va hA lky 14th Ave 3 21s rie nH t St NW 15t 32nd A La Hw NW N W Elto y5 20t 20th Ave NW hS 26th Ave NW 2 tN 19th Ave NW NW ve 20th St W NW 19th St NW 16th Ave NW 1865 18th St NW Legend W US Hwy 52 Front age Rd 17 1/2 St NW 25 Op 17th St NW th parcels po Av rtu 16 1/2 St NW e 11 nit In soil microregion NW th du 16th St NW yR Av st 15 1/2 15 1/2 Ave NW 16 1/2 Ave NW e St d streams NW ria 16th Ave NW 15th St NW NW 15th Ave NW NW lD rN NW other water 15th St W 10th Ave NW 7th S 14th St NW t streets 6th Ave NW 9th Ave NW NW 5th Ave NW 7th Ave NW 18th Ave NW elevation 17th Ave NW 12th St NW US H wy 1 Frontag 4 Lakeridge Dr NW US H 10th St NW High : 1260 wy 1 4 9th S t NW e Rd 9th St NW Unkn Low : 958 35th Ave NW o wn or N o Stre etna me 6th Ave NW 6th St NW W N Civic Center Dr NW 13th A St 4th St NW ke 35th Ave NW La ve 3rd St NW NW 13th Ave NW 2nd St NW 18 1/2 Ave NW 17th Ave NW 1st St NW 1st St NW 1st St NW 36th Ave NW Cou W Center St 5th Ave SW 5th Ave SW 7th Ave SW nty C lub R dW 1st St SW 1st St SW l 2nd St SW nP pe 3rd St SW 3rd St SW As 16th Ave SW 17th Ave SW Eagle La SW 18 1/2 Ave SW 18th Ave SW 19th Ave SW 20th Ave SW 9th Ave SW h St SW 4th St SW 425 4t 4th St SW 15th Ave SW 10th Ave SW 5th St SW SW 6th St SW SW e Av 7th Ave SW 19th Ave SW ill West C e 7th St SW 8th S 23rd Av H US 6th Ave SW t SW 8th St SW 8th St SW Hw ir le Dr y1 10th St S Cl W ov Fox 4 17 La SW 8th Ave SW Walden er We st C La roft a yL irle W th La S Skyline La SW 1005 SW Cir c Dr ell ne Av Folw 0.5 Au hit e da W SW Fox Va z SW lley Dr La SW 11th St SW mile Fox V alley Dr SW Mem orial P kwy
  9. 9. 425
  10. 10. 425
  11. 11. 1005
  12. 12. 1005
  13. 13. 425 Legend parcels PCFFVULN 91% 64% 55% 45% streams other water 350 Feet
  14. 14. 1005 Legend parcels PCFFVULN 91% 64% 55% 45% streams other water 490 Feet
  15. 15. Legend parcels PCFFVULN 1865 91% 64% 55% 45% streams other water 400 Feet
  16. 16. Legend parcels PCFFVULN 91% 64% 55% 45% 2915 streams other water 370 Feet
  17. 17. What I learned • Soil classifications and theory • Definition – and kinds of – floods and rainfalls • Criteria for above: surface runoff, hydraulic conductivity, etc. • Criteria for rain garden planning • Slope derivation from a DEM • Directional flow derived from above • “Kindness of strangers” • Aggregating multiple criteria into a “summary” attribute column to portray flash flood vulnerability  
  18. 18. What’s still left to acknowledge and pursue • It’s complicated • It’s like art: there is lots of subjectivity • Your custom Excel table needs to be assembled perfectly or table joins just don’t work • Directional Accum. is a good next step after Directional Flow • Buffering is trickier than I thought, need to work on that • I need to get better skilled at grid analysis and reclassification • I think GIS analysis of the “landscape architecture of rain gardens” just might be a profitable endeavor or specialty  
  19. 19. Software and References • ESRI ArcGIS (ArcMap) • ESRI and second party extensions o Spatial Analyst o ArcToolBox: Spatial Analyst Tools: Hydrology o Xtools • Documents from Allison Plume, Rochester Public Works • Files from Prof. John Ebert • Minnesota DEM • Literature: J. Dobur, 2000, “Analysis of Geographical Distribution of Flash Flood Events,” NOAA/NWS, and others!