Table 2. Cross-tabulation of current land-use maps and groundwater travel-time maps categorized by land-change submodel. Values are expressed as (A) percent of total groundwatershed and (B) percentage of land-use/cover class in a groundwater travel-time class in which each class represents a backcast land-change submodel. A. Cross-tabulation of GWTT maps with submodel classes and current land use/cover maps GWTT class   Urban   Agriculture   Shrub   Forest   Wetlands   Totals 2006 (0-age)   2.82   5.32   3.44   11.59   3.05   26.23 1998–2005   1.45   0.06   1.07   3.57   0.03   6.19 1978–1998   1.30   1.48   2.01   9.37   0.32   14.49 1978–1939   0.76   3.12   2.26   9.90   0.57   16.61 1900–1939   0.42   2.68   1.58   4.56   0.36   9.60 Pre-1900   1.15   11.72   4.24   8.74   1.04   26.89 Column totals   7.92   24.38   14.59   47.74   5.37   100.0 % of 0-age in cover class [(1)*100/(RT)]   10.76   20.28   13.12   44.21   11.63     B. Percentage of column totals GWTT Class   Urban   Agriculture   Shrub   Forest   Wetlands 2006 (0-age)   35.63   21.82   23.58   24.29   56.80 1998–2005   18.37   0.25   7.33   7.48   0.57 1978–1998   16.44   6.07   13.79   19.63   5.98 1978–1939   9.65   12.78   15.46   20.74   10.63 1900–1939   5.35   11.00   10.80   9.55   6.69 Pre-1900   14.56   48.08   29.05   18.30   19.32 Column totals   100.0   100.0   100.0   100.0   100.0