Environmental Management (2010) 46:378–390 Table 2 Difference between photo-interpreted and NLCD 2001 derived impervious cover values by generalized NLCD land cover classes within each mapping zone Zone Developed land cover Forest land cover Agriculture–grassland land cover Other land cover n PI SE NLCD Diff n PI SE NLCD Diff n NLCD Diff n PI SE NLCD Diff 1 2 3 4 5 6 7 8 9 10 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 63 23.8 5.4 29.4 93 28.0 4.7 26.8 41 9.8 4.6 14.9 166 40.4 3.8 35.9 93 25.8 4.5 29.6 25 32.0 9.3 24.1 20 15.0 8.0 17.4 43 32.6 7.1 16.6 21 4.8 4.6 13.6 20 25.0 9.7 26.7 20 15.0 8.0 15.7 20 35.0 10.7 33.7 43 46.5 7.6 32.0 26 15.4 7.1 19.2 21 23.8 9.3 14.8 27 44.4 9.6 34.7 20 30.0 10.2 14.3 20 0.0 4.9a 19.7 20 15.0 8.0 12.5 20 25.0 9.7 12.3 20 10.0 6.7 18.1 20 35.0 10.7 20.9 21 9.5 6.4 16.7 21 52.4 10.9 23.4 20 25.0 9.7 14.2 20 10.0 6.7 14.4 20 45.0 11.1 18.4 20 25.0 9.7 19.4 21 9.5 6.4 9.4 24 20.8 8.3 13.9 102 28.4 4.5 22.6 36 41.7 8.2 15.1 34 23.5 7.3 11.2 39 17.9 6.1 20.5 75 24.0 4.9 26.4 64 12.5 4.1 26.1 49 18.4 5.5 16.1 59 27.1 5.8 10.6 46 15.2 5.3 11.0 59 37.3 6.3 22.4 86 19.8 4.3 14.3 64 25.0 5.4 20.0 56 26.8 5.9 18.7 54 25.9 6.0 10.7 75 22.7 4.8 17.1 67 23.9 5.2 18.0 -5.6 799 1.3 0.4 0.0 1.2 695 0.6 0.3 0.0 -5.1 838 0.0 0.1a 0.0 4.5 508 0.6 0.3 0.0 -3.8 53 1.9 1.9 0.0 7.9 811 0.4 0.2 0.1 -2.4 810 0.4 0.2 0.1 15.9* 468 0.2 0.2 0.1 -8.8 787 0.3 0.2 0.1 -1.7 859 0.8 0.3 0.1 -0.7 896 0.2 0.2 0.1 1.3 879 0.6 0.3 0.1 14.6 856 1.1 0.3 0.1 -3.8 945 0.2 0.1 0.1 9.0 918 0.2 0.2 0.0 9.7 757 0.5 0.3 0.2 15.7 599 0.8 0.4 0.1 -19.7** 664 0.8 0.3 0.1 2.5 158 1.3 0.9 0.1 12.7 785 0.0 0.1a 0.0 -8.1 800 0.6 0.3 0.2 14.1 812 0.4 0.2 0.1 -7.2 779 0.6 0.3 0.2 29.0* 817 0.6 0.3 0.1 10.8 878 0.6 0.3 0.1 -4.4 266 0.8 0.5 0.1 26.6* 749 0.9 0.4 0.1 5.6 448 0.4 0.3 0.1 0.2 52 0.0 1.9a 0.0 6.9 34 0.0 2.9a 0.0 5.8 213 1.4 0.8 0.0 26.5** 26 0.0 3.8a 0.0 12.3 300 1.0 0.6 0.1 -2.5 654 1.7 0.5 0.1 -2.4 419 0.7 0.4 0.0 -13.6** 667 1.6 0.5 0.0 2.2 26 0.0 3.8a 0.0 16.5** 24 0.0 4.1a 0.0 4.2 32 3.1 3.1 0.0 14.9* 587 0.9 0.4 0.1 5.4 74 1.4 1.3 0.0 5.0 143 0.7 0.7 0.0 8.1 622 1.1 0.4 0.0 15.2* 232 0.4 0.4 0.0 5.5 715 1.4 0.4 0.0 5.9 487 1.0 0.5 0.0 1.2** 84 0.6* 179 0.0 118 0.6 280 1.9 815 0.2 122 0.2 133 0.2 464 0.1 101 0.7* 124 0.1 58 0.5 22 1.0** 72 0.1 35 0.2 41 0.3 103 0.7* 359 0.7* 305 1.1 818 0.0 187 0.4 165 0.2 116 0.5 188 0.5 132 0.4 99 0.7 711 0.8* 199 0.3 528 0.0 916 0.0 919 1.4 676 0.0 940 0.9 659 1.5** 295 0.7 464 1.6** 202 0.0 922 0.0 890 3.1 863 0.8* 264 1.3 831 0.7 787 1.1** 322 0.4 710 1.4** 201 1.0* 441 PI 2.4 2.8 1.7 2.9 1.5 0.0 0.8 0.6 0.0 0.8 0.0 0.0 2.8 2.9 2.4 3.9 1.4 0.7 0.4 0.0 0.6 0.0 0.5 0.8 1.0 0.8 2.0 0.2 0.7 0.7 1.0 0.7 0.8 1.4 0.6 2.0 1.4 0.9 0.6 3.0 1.3 1.4 2.8 2.5 4.0 2.5 SE 1.7 1.2 1.2 1.0 0.4 0.8a 0.7 0.4 1.0a 0.8 1.7a 4.4a 1.9 2.8 2.4 1.9 0.6 0.5 0.2 0.0 0.6 0.9a 0.5 0.8 1.0 0.3 1.0 0.2 0.3 0.3 0.4 0.3 0.3 0.7 0.4 1.0 0.4 0.3 0.3 1.1 0.4 0.4 0.9 0.6 1.4 0.7 0.1 0.0 0.0 0.0 0.0 0.2 0.1 0.0 0.1 0.2 0.1 0.1 0.0 0.1 0.0 0.2 0.0 0.2 0.2 0.1 0.2 0.1 0.1 0.1 0.1 0.1 0.2 0.2 0.1 0.1 0.0 0.0 0.1 0.1 0.0 0.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 2.3 2.7* 1.7 2.8** 1.5** -0.2 0.6 0.6 -0.1 0.6 -0.1 -0.1 2.7 2.7 2.4 3.7 1.4* 0.5 0.2 -0.1 0.4 -0.1 0.4 0.7 1.0 0.8* 1.8 0.0 0.6* 0.6* 1.0** 0.7** 0.7* 1.3 0.6 1.9 1.4** 0.9** 0.6* 3.0** 1.3** 1.4** 2.8** 2.5** 4.0** 2.5** 46 2.2 2.2 0.0 29 0.0 3.4a 0.0 113 0.9 0.9 0.0 46 0.0 2.2a 0.0 39 0.0 2.5a 0.1 37 0.0 2.7a 0.0 36 0.0 2.7a 0.1 23 0.0 4.3a 0.1 21 0.0 4.6a 0.1 20 0.0 4.9a 0.2 39 0.0 3.5a 0.1 81 3.7 2.1 0.3 29 3.4 3.4 0.0 25 0.0 3.9a 0.1 23 0.0 4.3a 0.0 113 0.0 0.9a 0.1 29 0.0 3.4a 0.0 20 0.0 4.9a 0.0 20 0.0 4.9a 0.2 20 0.0 4.9a 0.0 26 0.0 3.8a 0.2 65 0.0 1.5a 0.0 27 0.0 3.6a 0.1 29 3.4 3.4 0.1 21 0.0 4.6a 0.3 20 5.0 4.9 0.1 36 0.0 2.7a 0.0 20 0.0 4.9a 0.4 21 0.0 4.6a 0.0 31 0.0 3.2a 0.1 20 0.0 4.9a 0.1 22 4.5 4.4 0.0 20 5.0 4.9 0.2 20 5.0 4.9 0.4 42 0.0 2.4a 0.0 65 1.5 1.5 0.0 21 0.0 4.6a 0.0 35 0.0 2.8a 0.0 56 1.8 1.8 0.0 86 1.2 1.2 0.0 26 3.8 3.8 0.0 20 5.0 4.9 0.1 20 10.0 6.7 0.1 20 0.0 4.9a 0.0 22 4.5 4.4 0.0 22 0.0 4.4a 3.6 383 2.1 0.0 0.8 0.0 -0.1 0.0 -0.1 -0.1 -0.1 -0.2 -0.1 3.4 3.4 -0.1 0.0 -0.1 0.0 0.0 -0.2 0.0 -0.2 0.0 -0.1 3.4 -0.3 4.9 0.0 -0.4 0.0 -0.1 -0.1 4.5 4.8 4.6 0.0 1.5 0.0 0.0 1.8 1.1 3.8 4.9 9.9 0.0 4.5 -3.6 123