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Modeling Subcommittee Meeting January 8, 2003

Use of surface and tracer analysis to estimate nutrient and sediment load allocation to Chesapeake Bay. Modeling Subcommittee Meeting January 8, 2003. Application of Surface analysis.

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Modeling Subcommittee Meeting January 8, 2003

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  1. Use of surface and tracer analysis to estimate nutrient and sediment load allocation to Chesapeake Bay Modeling Subcommittee Meeting January 8, 2003

  2. Application of Surface analysis • To understand the interactions among water quality indices and load constituents: Thomann, Collier, Butt, Casman and Linker (1994); Wang, Linker and Batiuk (2001) Proceedings of 7th International Conference in Estuarine and Coastal Modeling, St. Pete Beach, FL. Dec, 2001, pp27. • To provide info for load allocation • Load allocation practice 1: using the info from traceranalysis -- Linker (2001) A presentation to the Modeling Subcommittee; Wang and Linker (2002) Proceedings of Watershed 2002 (Feb. 26, 2002, Ft Lauderdale, FL) pp28. • Load allocation practice 2: without tracer analysis

  3. 1.0 ! 0.7 ! 1.0 ! ! ! 0.7 0.4 0.4 Chl = f (N, P) 1.0 ! 0.7 ! 1.0 ! 0.7 0.4 0.4

  4. 1.0 0.7 0.4 1.0 0.7 0.4

  5. 1.0 ! 0.7 ! 1.0 ! 0.7 0.4 0.4 Chl = f (N, P) 1.0 ! 0.7 ! 1.0 ! 0.7 0.4 0.4

  6. CB4MH Violation DO TN TP

  7. * DO = f (N, P) = a N2 + b P2 + c NP + d N + e P + f * Each scenario has DO and percentage of violation (V). * Use regression to get: DO = g(V); project for equivalent DO at 0% violation, or minimum attainment (A): ** A = F (N, P)

  8. n40s40 n40s70 n40 Load P100 n70s40 n70s70 n70 s70 NSP s40 n40p70s70 n40p70 n40p70s40 N100 n70p70 n70p70s70 n70p70s40 p70s40 p70 p70s70 S100 n40p40s70 n40p40 n40p40s40 n70p40s40 n70p40s70 n70p40 P40s40 p40 p40s70

  9. N40 Percent of Pr2000 load NS40 NP40 S100 P100 NPS100 NPS100 S40 N100 P40 N100 S40 P40 PS40 N40 S100 P100 PS40 NP40 NS40

  10. n40s40 n40s70 n40 P100 n70s40 n70s70 n70 s70 NSP s40 N100 n40p70s70 n40p70 n40p70s40 n70p70 n70p70s70 n70p70s40 p70s40 p70 p70s70 S100 n40p40s70 n40p40 n40p40s40 n70p40s40 n70p40s70 n70p40 p40s40 p40 p40s70

  11. n40s40 n40s70 n40 P100 n70s40 n70s70 n70 s70 NSP s40 n40p70s70 n40p70 n40p70s40 n70p70 n70p70s70 n70p70s40 p70s40 p70 p70s70 N100 S100 n40p40s70 n40p40 n40p40s40 n70p40s40 n70p40s70 n70p40 p40s40 p40 p40s70

  12. * DO = f (N, P, S) = a N2 + b P2 + c S2 + d NP + e NS + f PS + g N + h P + i S + j * Each scenario has DO and percentage of violation (V). * Use regression to get: DO = g(V); project for equivalent DO at 0% violation, or minimum attainment (A): ** A = F (N, P, S)

  13. Application of Surface analysis • To understand the interactions among water quality indices and load constituents: Thomann, Collier, Butt, Casman and Linker (1994); Wang, Linker and Batiuk (2001) Proceedings of 7th International Conference in Estuarine and Coastal Modeling, St. Pete Beach, FL. Dec, 2001, pp27. • To provide info for load allocation • Load allocation practice 1: using the info from tracer analysis -- Linker (2001) A presentation to the Modeling Subcommittee; Wang and Linker (2002) Proceedings of Watershed 2002 (Feb. 26, 2002, Ft Lauderdale, FL) pp28. • Load allocation practice 2: without tracer analysis

  14. Load Reduction Allocation • Equal reduction: • Most responsive allocation: allocate more reduction to the source contributing more load to the water body. • Cost effective allocation: considering the lowest total cost in load reduction from all sources. • Detailed cost effective and acceptable allocation: that’s what we will do.

  15. Use of Surface Analysis for Load Reduction Allocation • Info useful for allocation from the surface analysis: Water quality as a function of TN, TP and/or TSS loads. The minimum TN, TP and/or TSS load to achieve criteria attainment. • Errors : . .

  16. Assumption 1: The transport of conservative tracer represents the transport of non-conservative materials, and the long term average of mass in a model segment represents the intensity of a source to the segment. Assumption 2: A reduction of load from a source causes the same percentage reduction of the effective load from that source to model segments.

  17. Conceptual load: We use average daily mass of tracer in a segment to indicate the relative influence by the source, called the “conceptual load” from a source to a segment. -- No meaning in absolute value. “Transport load” from a source to a segment: conceptual load to a segment Load to Bay * ---------------------------------------- conceptual load to whole Bay The ratio is called the transport factor from the source to the segment.

  18. Firstly, get transport load to a segment from its all sources. Five major sources (kg/day): 10 + 20 + 40 + 50 + 80 = 200 5%, 10%, 20%, 25%, 40%. 50% reduction from source 5: 10 + 20 + 40 + 50 + 40 = 160 6.25%, 12.5%, 25%, 31.25%, 25%.

  19. Load Reduction Allocation • Equal reduction • Most responsive allocation: allocate more reduction to the source contributing more load to the water body. • Cost effective allocation: considering the lowest total cost in load reduction from all sources.

  20. Most responsive allocation: A) Not lower than a limit, e.g., LOT, or 60% reduction, or all controllable load. B) Not lower than the next responsive party. S1: 700 - 420 = 280 ….. 60% reduction cause lower than S2. 700 - 400 = 300, (- 185/2), over -420: - 420 = 280 S2: 300 (- 185/2), [- 165], -145 = 155 - 20/2; - 155 = 145 S3: 155 - 20/2; - 10 = 145 S4: 10 - 0 = 10 S5: 5 - 0 = 5 sum: 1170 - 585 (.e.g. 50% reduc) = Target final total load: 585. * -400 from S1(left 185); -185 from S1+S2 (but S1 < 280). * -420 from S1 (left 165); -165 from S2 (but S2 = 135 < S3); -145 from S2 (left 20); - 20 from S2+S3.

  21. A B C D E F G H =B/C*D B/Bsum =F/D * G/Gsum Target: 3.10E+7 * 0.55=1.7E+7

  22. Most cost effective allocation: The required information: 1) Total goal of final load -- through surface + tracer analysis. 2) Cost per mass reduction from each source. The costs in reduction of load to a segment are different for different sources and in different levels of reduction from a source.We need to assign reductions to sources step by step with a certain amount of reduction. In each step, from the reduction of transport load to a segment we calculate the required load reduction from each source as if the reduction is assigned to only one source. Comparing to the costs among the sources, the source with least cost will be allocated for reduction in this step.

  23. Suggested loading in tracer runs • Different sources rq. different tracer runs. • Loading rate: the same as that in WQM input (varying daily) for that component. • If loading rates for two components or one component in two scenarios in WQM runs are changed proportionally, separate tracer may be avoided by using calculations under the two assumptions.

  24. Assumption 1: The transport of conservative tracer represents the transport of non-conservative materials, and the long term average of mass in a model segment represents the intensity of a source to the segment. Assumption 2: A reduction of load from a source causes the same percentage reduction of the effective load from that source to model segments.

  25. n60s60 n60s30 n60 Reduction P0 n30s60 n30s30 n30 s30 NSP s60 n60p30s30 n60p30 n60p30s60 n30p30 n30p30s30 n30p30s60 p30s60 p30 p30s30 S0 n60p60s30 n60p60 n60p60s60 n30p60s60 n30p60s30 n30p60 N0 p60s60 p60 p60s30

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