Application of Spatially Referenced Regression Modeling for the Evaluation of Total Nitrogen Loading in the Chesapeake Bay Watershed
by Stephen D. Preston and John W. Brakebill
Figures
Figure 1. Location of the Chesapeake Bay watershed. -- 409 kilobyte file
Figure 2. Land cover in the Chesapeake Bay watershed (Gutierrez-Magness and others, 1997). -- 68 kilobyte file
Figure 3. Hydrogeomorphic regions of the Chesapeake Bay watershed (Bachman and others, 1998). -- 75 kilobyte file
Figure 4. Mathematical form of the SPARROW model. -- 17.3 kilobyte file
Figure 5. River Reach File 1 stream network (DeWald and others, 1985) and stream nutrient-load data-collection site locations (indicated by red triangles). (Area in white represents the coastal margin area that is not described by the current version of the Chesapeake Bay SPARROW model) -- 124.5 kilobyte file
Figure 6. Relation of predicted and observed total-nitrogen load values from calibration of the Chesapeake Bay SPARROW model. (Observed loads are those calculated from measured stream-discharge and concentration data using the ESTIMATOR program, Cohn and others, 1992). - 18 kilobyte file
Figure 7. Total-nitrogen load predictions of the Chesapeake Bay SPARROW model in relation to those of the Chesapeake Bay Program Hydrologic Simulation Program-FORTRAN (CBP HSPF) model. -- 15.2 kilobyte file
Figure 8. Incremental yield of total nitrogen in the Chesapeake Bay watershed during 1987. (Incremental yield is the amount of total nitrogen that is generated locally and contributed to each stream reach.) -- 109 kilobyte file
Figure 9. Delivered yield of total nitrogen in the Chesapeake Bay watershed during 1987. (Delivered yield is the amount of total nitrogen that is generated locally for each stream reach weighted by the amount of instream loss that would occur with transport from the reach to the Bay.) -- 110 kilobyte file
Figure 10. Potential delivery of total nitrogen in the Chesapeake Bay watershed during 1987. (Values represent the percentage of stream load that may reach the Bay after accounting for instream losses.) -- 106.4 kilobyte file
Figure 11. Incremental yield of total nitrogen due to point sources in the Chesapeake Bay watershed during 1987. (Incremental yield due to point sources is the amount of total nitrogen generated locally and contributed to each stream reach by point sources.) -- 102.5 kilobyte file
Figure 12. Incremental yield of total nitrogen due to agricultural sources in the Chesapeake Bay watershed during 1987. (Incremental yield due to agricultural sources is the amount of total nitrogen generated locally and contributed to each stream reach by fertilizer and manure.) -- 111 kilobyte file
Table 1. Parameter estimates, probability levels, and regression results for the Chesapeake Bay total nitrogen SPARROW model - 34 kilobyte file
