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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 – - PowerPoint PPT Presentation
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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 –
Discussion of sites and site selection
Presentation of load and trend results
Indicators
Summary
Discussion of sites and site selectionLoads and trends over multiple time periods
Time period
Length of Record
Type Number of sites
1985-2010
25 yrs Load/tend 31
2001-2010
10 yrs Load/tend 33
2006-2010
5 yrs Loads only
64WHY?- 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
Currently (2010) USGS updating loads and trends at 31 long-term (1985) stations in Bay Watershed
9 River Input Stations
22 Upstream Stations
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)
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
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
LOADS
2 2
0 1 2 3 4 5 6ˆ ˆ ˆ ˆ ˆ ˆ ˆln ln ln sin 2 cos 2c c c cc q q q q t t t t t t
ESTIMATOR MODEL
where:
i are coefficients estimated by ordinary least squares (non-censored observations, for censored observations implements AMLE procedure)
sin and cos are seasonal components
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;cq ct
are centering variables (orthogonal) for streamflow and time;
residual error
Regression Diagnostics
Additional Diagnostics
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
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
SED Loads and Streamflow
SED – 330% increase in combined RIM loads
All 9 RIM sites increased vs 2009
• 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
Flow-adjusted concentration
FA - TRENDS
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
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
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
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
1985-2010 2001-2010 Change
TN 19 DN 2 UP 14 DN 2 UP5 less improving sites
TP 21 DN 4 UP 12 DN 4 UP9 less improving sites
SED 9 DN 7 UP 3 DN 9 UP6 less improving sites
Time period effect
2001-20101985-2010
Time period effect
2001-2010
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
TN 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
TP 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
SED Indicator
Indicator Summary 10-year flow-adjusted trend (2001-2010)
Total Nitrogen
5-year Yields (2005-2010)
Yield Degrading (upward)
Not significantImproving
(downward)Trends not available
high 2 4 2 13
medium 0 6 7 10
low 0 4 8 8
Total Phosphorus
5-year Yields (2005-2010)
Yield Degrading (upward)
Not significantImproving
(downward)Trends not available
high 2 2 6 14
medium 1 7 5 7
low 1 3 6 10
Sediment
5-year Yields (2005-2010)
Yield Degrading (upward)
Not significantImproving
(downward)Trends not available
high 5 6 1 11
medium 1 10 0 8
low 3 5 2 13
Table can be used to identify “best and worst” conditions
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
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
Thank You