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Loads, Trends, and Indicators for Selected Non-tidal Sites, Chesapeake Bay Watershed, 1985-2010

Loads, Trends, and Indicators for Selected Non-tidal Sites, Chesapeake Bay Watershed, 1985-2010. Nontidal Workgroup 9/8/10. Project staff – Mike Langland –USGS, PA Joel Blomquist – USGS, MD Ken Hyer – USGS, VA Doug Moyer – USGS, VA. Nontidal Workgroup 9/8/10. Topics –

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Loads, Trends, and Indicators for Selected Non-tidal Sites, Chesapeake Bay Watershed, 1985-2010

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  1. Loads, Trends, and Indicators for Selected Non-tidal Sites, Chesapeake Bay Watershed, 1985-2010

  2. Nontidal Workgroup 9/8/10 Project staff – Mike Langland –USGS, PA Joel Blomquist – USGS, MD Ken Hyer – USGS, VA Doug Moyer – USGS, VA

  3. Nontidal Workgroup 9/8/10 Topics – Discussion of sites and site selection Presentation of load and trend results Indicators Summary

  4. Discussion of sites and site selection Loads and trends over multiple time periods • WHY? • - Align with current NTN Monitoring list (10 yr trend/5 yr load) • Examine changes over shorter time frames • Interest in change since 2000 agreement • Development of new indicators and measure of change

  5. Currently (2010) USGS updating loads and trends at 31 long-term (1985) stations in Bay Watershed 9 River Input Stations 22 Upstream Stations

  6. Currently (2010) USGS updating loads and trends at 64 stations in Bay Watershed 2 sites added with +10 years (green) 11 sites with 6-9 years (2009-purple) 20 new sites with 5 year (yellow)

  7. Streamflow – Total Flow to the Bay • For WY2010 79,900 cfs (normal year) (+23% vs 2009) • 2% above long-term mean (78,300 cfs) • 5 of last 6 years annual “normal” flow 25th and 75th percentiles

  8. Streamflow – Site Results Produce Annual and Seasonal Streamflows for all Sites For 2010 – no significant trends in streamflow for the 31 sites 28 of the 31 sites had increase in flow vs. 2009

  9. LOADS

  10. ESTIMATOR MODEL where: c is measured concentration, in milligrams per liter; q is measured daily-mean streamflow, in cubic feet per second; t is time, in decimal years; are centering variables (orthogonal) for streamflow and time; are coefficients estimated by ordinary least squares (non-censored observations, for censored observations implements AMLE procedure) sin and cos are seasonal components  residual error

  11. Regression Diagnostics

  12. Additional Diagnostics

  13. TN Loads and Streamflow TN – 33% increase in combined RIM loads First increase in TN loads since 2004 All 9 RIM sites loads increased vs 2009

  14. TP Loads and Streamflow TP – 120% increase in combined RIM loads First increase in TP loads since 2003 All 9 RIM sites increased vs 2009

  15. SED Loads and Streamflow SED – 330% increase in combined RIM loads All 9 RIM sites increased vs 2009

  16. FA - TRENDS Flow-adjusted concentration • Useful for examining effects of management actions • Helps to adjust for the “effects” of hydrology and season • Flow adjustment from ESTIMATOR model • Uses the slope coefficient (b), time (t), and time (t2) for non-linearity trend • Many significant FAC trends

  17. FAC - TN For 1985-2010 19 of 31 sites (~65%) down, 2 sites up 4 of 9 RIM sites downward All 8 sites in SUS down 2009 - 22 DN, 2 UP 2008 - 22 DN, 2 UP 2007 – 22 DN, 2 UP 2006 – 25 DN, 4 UP

  18. FAC - TP For 1985-2010 21 of 31 sites (~70%) down, 4 sites up 2 of 9 RIM sites downward, 3 upward 13 down sites exceed 50% reduction 2009 - 21 DN, 4 UP 2008 - 22 DN, 3 UP 2007 – 22 DN, 3 UP 2006 – 23 DN, 4 UP

  19. FAC - SED For 1985-2010 10 sites down, 7 sites up 5 > 50% up 17 of 31 sites ns (55%) 4 of 9 RIM sites downward, 2 upward 2009 – 12 DN, 4 UP 2008 – 15 DN, 2 UP 2007 – 15 DN, 2 UP 2006 – 11 DN, 2UP

  20. FAC – 10 year trends • Comparison of trends (POR to 10-yr) • Number of significant trends is less in the latter time period • The sites with the significantly upwards trends are rarely the same between the 2 time periods

  21. Time period effect 1985-2010 2001-2010

  22. Time period effect 2001-2010

  23. TN Indicator 10 yr trend (33 sites) 5-yr TN Yields (tons/mi2) at 64 sites 14 of 31 sites indicate improving trends Spatially, higher yield distribution in middle of Bay watershed, lower yields in lower Bay watershed

  24. TP Indicator 10 yr trend (33 sites) 5-yr TN Yields (tons/mi2) at 64 sites 12 of 31 sites indicate improving trends No geographic yield distribution, except for western Potomac basin

  25. SED Indicator 10 yr trend (33 sites) 5-yr TN Yields (tons/mi2) at 64 sites 3 of 31 sites indicate improving trends, 9 degrading trends No geographic yield distribution is indicated

  26. Indicator Summary Table can be used to identify “best and worst” conditions

  27. Summary • Refined site selection – loads/trends on multiple time periods • RIM flow to the Bay was 23% above normal in 2009 • No significant trends in streamflow • FAC trends - the majority of the 31 sites were downward for TN (19) and TP (21), less (10) for SED • Less improving trends as time period is shortened • More “best than worst” scenarios for TN and TP, SED is reversed

  28. Future Directions • Continuing to improve trends and loads techniques (WRTDS) • Continue to examine POR and shorter term trends (base of 2000 and 10 yrs) and loads (5 yrs) • Greater interaction with several new web sites (USGS, CBP), new indicators (Katie/NTWG), and new site selection (NTWG) • Involved in new effort to streamline data acquisition though CIMS

  29. Thank You

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