The presentation of the preliminary results for the vegetated roof model created in the fall of 2009.

1. A Preliminary study of the Water RetentionPerformance of an ExtensiveVegetated Roof Using a Scaled Model at Lafayette College

2. How did this get started? Spring 2008: Kney! can we have a roof garden?? Pleasee?? Summer 2008:Excel research to identify possible roofs. Attend GRHC workshop “Green Roofs 101” Fall 2008: Select Acopian roof for the project, bring Spillman Farmer Architects into the project. Spring 2009: Select vegetated roof material based on architects recommendation. Preliminary design for the model in CE 351. Summer 2009: WOOT! We have a vegetated roof! Fall 2009: Preliminary data collection

3. Why Vegetated Roof? Filters water/air Retain water (reduce sewage system loads) Act as a rain water buffer Extend the life of the roof: UV and acid rain protection Lowers heating and cooling cost (acts as an insulator) Increased property value Stores carbon Creates a habitat Helps maintain healthy ecosystem commitment to sustainability/reducing footprint A pilot for future vegetated roofs new route for research which could combine different discipline: geo, bio, eng, econ. Easton has combined sanitary and storm water system, green roofs reduce run off into the system Increases the life of the roof Energy cost reduction due to better insulation Increased property value In General: For Lafayette:

4. Vegetative Roof System Vegetation Growing Medium Slab/Sheet rock Retention Fleece Waterproofing membrane Drainage Mat Insulation The roof garden system used is a pre-vegetated mat from XeroFlor. The vegetation is primarily sedum and moss, which are both low lying durable plants. This is an ultra lightweight system, weighing approximately 12 lb/SF and only 3” thick. The waterproofing membrane will be a modified bitumen membrane. The system costs approximately $37/per square foot.

5. Preliminary Study Goals Get model up and running properly Gather data from at least 3 storm events Determine whether data seems reasonable Estimate retention for large roof based off data or other vegetated roof studies

7. Percent retained in the 25%-75% range

10. Model is sloped towards the 2 inch PVC drainage pipe

11. PVC pipe penetrates just above the waterproofing layer

13. Data Summary Weather.com precipitation is on the same order as the rain gauge, the difference might be accounted for in the distanced between the gauges. Vegetated roof runoff is consistently lower than the precipitation

14. Data Summary: STORM 1 10/24/09

15. Data Summary: STORM 1 10/24/09

16. Data Summary

17. Data Summary: Storm 3

18. Comparing Our Results Lawerence Technological University: 1,000 SF green roof. retained an average of 68.24%over the course of 21 storm events. 9 were small, 8 were medium sized and 3 were large. Penn State University: detention and retention abilities of green roofs between July and October of 2002. 100% of storms less than 4mm(~.157in) were completely retained by the green roof. 20-25% of runoff is retained for storms around 25mm (~.984 in.) North Carolina State University: two different sites 2003-2004. The Goldsboro site had a 63% retention rate, while Raleigh had a 55% retention rate.

20. Percent retained WAS NOT in the 25%-75% range

21. The difference in Lafayette’s results most likely due to the size of the storms being observed. It may also be possible that water is leaking.

22. Runoff Peak would require further study to determined if it is delayed slightly from precipitation peakDue to issues setting up a procedure and constant adjustment to the model runoff collection system, not much data was taken. It is difficult to draw any conclusions with statistical confidence without further study. Is the roof reducing runoff? If the vegetated roof retained 58% of the total rainfall, I estimate it could hold 106 gallons for small (.5in) storms and up to 200 gallons for medium storms (1in).

24. Water quality analysis

25. Temperature data collection Lessons Learned: Drainage mechanisms should pierce the waterproofing layer Don’t assume things have been installed correctly

27. George Xiques,

28. Salvatore Verrastro,

29. Prof. Anne Raich,

30. Prof. Arthur D. Kney,

31. Prof. Steve Mylon,

32. Prof. John Greenleaf,

33. Anthony Belgiovine ‘12,

34. Joshua Sadlock ’12,

35. Jeffrey Shoemaker ‘10,

36. Diana Hasegan ‘10,

37. Tomas Concepcion ‘11,

38. Lindsey Getches ‘11,

39. Dan Miller ’11

40. Dan Moran ‘11