1. Stormwater Asset Management Using GIS Vithal V. Deshpande, Environmental Coordinator, City of Somerville, Massachusetts, and Britta Roden, M.S. Economics Candidate Tufts University May 4, 2005 Environmental Expo & Conference Seaport World Trade Center Boston, MA

4. Where is Somerville?

13. GIS – Storm Drains

14. GIS - Catch Basins

15. GIS – Combined Sewer Overflows (CSOs)

16. GIS - Stormtreat

17. GIS – Street Cleaning

20. Impact of Trees on Stormwater Runoff Runoff Volume Time less trees more trees HYDROGRAPH

24. Satellite Imagery

25. CITYGreen Landcover Classification

26. Tufts University Area False Color Image, red represents trees, grass, lawn

27. Tufts University Area Landcover Classification

28. Somerville Neighborhoods

31. City Green Report for Air Pollution and Carbon Sequestration T

32. City Green Report for Stormwater

33. City Green Analysis Neighborhoods Summary 2.8 % 18.0 % 6.6 % 72.7 14.3 % 22.5 % 35.9 % Somerville 0.2 % 18.8 % 7.3 % 73.8 15.4 % 22.1 % 36.3 % Winter Hill 0.3 % 25.3 % 8.2 % 66.4 15.4 % 20.3 % 30.7 % West Somerville 0 % 9.6 % 4.5 % 85.7 11.7 % 28.0 % 46.0 % Ward2/CobbleHill 0 % 30.5 % 9.2 % 55.0 17.0 % 18.2 % 25.1 % Tufts 3.5 % 19.7 % 7.5 % 69.3 13.5 % 21.6 % 34.2 % Ten Hills 0.1 % 23.7 % 8.2 % 68.0 16.5 % 20.4 % 31.1 % Spring Hill 0.1 % 21.9 % 7.5 % 70.4 15.5 % 21.3 % 33.6 % Prospect Hill 0 % 23.6 % 9.1 % 67.4 16.0 % 19.4 % 32.0 % Powderhouse 0.7 % 21.3 % 6.9 % 71.1 14.2 % 20.7 % 36.2 % Magoun / Albion 13.3 % 10.6 % 4.7 % 71.4 12.9 % 22.6 % 35.9 % East Somerville 0.1 % 22.1 % 7.5 % 70.3 17.3 % 20.1 % 32.9 % Davis Square 0.1 % 25.6 % 8.3 % 66.1 15.3 % 20.6 % 30.2 % Central Hill Water Area Trees Open Space: Grass Impervious Total Impervious Surfaces: Unpaved Impervious Surfaces: Paved Impervious Surfaces: Buildings Somerville Neighborhood

34. CITYGreen Neighborhoods Stormwater Analysis $8,630,078 4,315,039 4.09 3.68 -39.47 39.21 -19.56 Somerville $584,374 292,187 4.09 3.76 -30.83 27.93 -15.67 Winter Hill $735,965 367,983 4.26 3.76 -38.95 44.95 -21.88 West Somerville $1,581,130 790,565 3.84 3.61 -33.49 22.60 -13.24 Ward2/CobbleH $525,687 262,843 4.44 3.76 -44.78 62.57 -27.32 Tufts $734,613 367,307 4.09 3.68 -39.47 36.42 -19.56 Ten Hills $739,524 369,762 4.26 3.76 -38.95 44.60 -21.88 Spring Hill $377,437 188,718 4.17 3.76 -35.25 34.35 -18.89 Prospect Hill $388,322 194,161 4.26 3.76 -38.95 44.51 -21.88 Powderhouse $485,224 242,612 4.17 3.68 -43.34 44.27 -22.63 Magoun/Albion $1,305,089 652,545 3.84 3.61 -33.49 22.35 -13.24 East Somerville $615,832 307,916 4.17 3.76 -35.25 37.74 -18.89 Davis Square $190,339 95,170 4.26 3.76 -38.95 39.88 -21.88 Central Hill Total Stormwater Savings Storage volume needed cu.ft Runoff in inches w/out trees Runoff in inches w/ trees Infiltration % change Peak Flow % change Time of Concentration % change Somerville Neighborhood

35. CITYGreen – Neighborhoods Summary Chart

36. CITYGreen Neighborhoods Air Pollution Removal 124580 50689 4143 5521 28824 14052 32379 10539 58591 19071 643 1506 Somerville 8686 2338 289 385 2010 980 2257 735 4085 133 45 105 Winter Hill 12689 5163 422 562 2936 1431 3298 1074 5968 1943 65 153 West Som. 12400 5045 412 549 2869 1399 3223 1049 5832 1898 64 150 Ward2 CobbleH 9713 3952 323 430 2247 1096 2525 822 4568 1487 50 117 Tufts 11877 3627 395 526 2748 134 3087 1005 5586 1818 61 144 Ten Hills 11897 4840 396 527 2753 1342 3092 1006 5595 1821 61 144 Spring Hill 6003 2443 200 266 1389 677 1560 508 2823 919 31 73 Prospect Hill 6198 2522 206 275 1434 699 1611 524 2915 949 32 75 Powderhouse 6966 2834 232 309 1612 786 1810 589 3276 1066 36 84 Magoun, Albion 24998 10172 831 1108 5784 2820 6497 2115 11757 3827 129 302 East Somerville 9854 4009 328 437 2280 1111 2561 834 4634 1508 51 119 Davis Square 3305 1345 110 146 765 373 859 280 1554 506 17 40 Central Hill Value lbs/yr Value lbs/yr Value lbs/yr Value lbs/yr Value lbs/yr Value lbs/yr Total SO 2 Particulate Matter NO 2 Ozone CO Somerville Neighborhood

37. CITYGreen Analysis Carbon Storage & Sequestration 18.0 % 488.1 188.61 24,227.09 Somerville 18.8 % 38.8 13.15 1,689.05 Winter Hill 25.3 % 56.8 19.21 2,467.84 West Somerville 9.6 % 54.7 18.77 2,411.33 Ward2/CobbleHill 30.5 % 43.9 14.71 1,888.98 Tufts 19.7 % 45.7 17.98 2,309.95 Ten Hills 23.7 % 53.5 18.01 2,313.62 Spring Hill 21.9 % 27.0 9.09 1,167.26 Prospect Hill 23.6 % 28.0 9.38 1,205.23 Powderhouse 21.3 % 30.5 10.55 1,354.55 Magoun / Albion 9.6 % 50.1 37.85 4,861.33 East Somerville 22.1 % 44.3 14.92 1,916.12 Davis Square 25.6 % 14.9 5.00 642.66 Central Hill Percent Tree Cover Tree Cover in acres Total Tons Sequestered (annually Total Tons Stored Somerville Neighborhood