Sediment Concentrations and Loads t L k E i 1975 2009to Lake Erie, 1975-2009
R. Peter RichardsNational Center for Water Quality Research
Heidelberg CollegeTiffin, Ohio 44883
Cleveland, OH Managing and Understanding Sediments January 12, 2011
TopicsSediment levels in contextSediment trends over 30+ yearsyProgress report on Lake Erie CREP2007: The perfect storm (year)2007: The perfect storm (year)
The rivers: Maumee, Sandusky, and Cuyahoga
Background: NCWQR MonitoringRaisin Lake Erie
Background: NCWQR Monitoring
GrandVermilion
Sandusky CuyahogaMichigan New York
Ontario
LakeErie
Maumee
N
PennsylvaniaOhioIndiana
Erie
EW
S
0 40 80 Kilometers120
A t l t USGS t ti 3 l dAutosamplers at USGS stations, 3 samples per daySediment, nutrients, major ions1974 to present 15 000 samples per station1974 to present, ~15,000 samples per station
I S di i d l dI. Sediment concentrations and loads
I. Sediment concentrations and loads: how much is lots?
Gross erosion rates for these watersheds are not particularly highBut the Maumee and Sandusky, at least, get
very muddy when it rains!Fine-grained sediment stays in suspension a
long time!
I. Sediment conc’s: how much is lots?Annual flow-weighted mean concentrations (1982 2007):
500
Annual flow-weighted mean concentrations (1982-2007):
What’s a FWMC?But what do we compare
See next slide…300
400
mg/
L
pthese numbers to? (No standards).
200
FWM
C, m
0
100
Maumee Sandusky CuyahogaMaumee Sandusky Cuyahoga
I. Sediment conc’s: how much is lots?
•In comparison with the true Midwest and much of the west the Great Lakesthe west, the Great Lakes watersheds have low concentrations.•But in comparison with ut co pa so w tother Great Lakes watersheds, these Lake Erie watersheds have above average concentrations.
http://co.water.usgs.gov/sediment/conc.frame.html#HDR1
I. Sediment loads: how much is lots?S di i ld i l i l l id i
80
90
median
Sediment yields in 277 mostly agricultural Midwestern rivers
50
60
70
of ri
vers
M (96 f 278 65th til )
30
40
Num
ber o Maumee (96 of 278, 65th percentile)
Sandusky (51 of 278, 82nd percentile)
0
10
20 Cuyahoga (14 of 278, 95th percentile)
0150
300450
600750
9001050
12001350
15001650
18001950
21002250
24002550
27002850
0Yield, kg/ha
I. ConclusionWhether you consider concentrations or loads,
these Lake Erie tributaries rank relatively high in comparison with other Great Lakes tributariescomparison with other Great Lakes tributaries.
However, at least in terms of concentrations, rivers elsewhere are often much higher.rivers elsewhere are often much higher.
II S di t t d tiII. Sediment trends over time
II. Sediment trends: loads or concs?For many (but not all) management issues,
especially for receiving waters, loads are what’s importantimportant Inputs to Lake Erie or a reservoir Dredging issues
However, loads are affected by flow as well as concentration, and changes in flow are largely beyond our managerial controlg
Therefore it is useful to look at trends in both concentration and loads
Sediment trendsSediment trends
2250
ion
1500
Con
cent
rat
750
Sed
imen
t C
0
1975 1980 1985 1990 1995 2000
Sediment trends: Maumee4000 75
90 Concentration
Sediment trends: MaumeeFlow
1000
2000
3000
30
45
60
0
1000
1975 1980 1985 1990 1995 2000
0
15
1975 1980 1985 1990 1995 2000
60
80
100
60
80
100Seasonal Concentration
800
1000
1200 Load
0
20
40
60
0
20
40
60
0
200
400
600
1975 1980 1985 1990 1995 20001975 1980 1985 1990 1995 20001975 1980 1985 1990 1995 2000
Sediment trends: Sandusky
600
800
60
80 Concentration
Sediment trends: SanduskyFlow
200
400
600
20
40
60
0
1975 1980 1985 1990 1995 2000
0
1975 1980 1985 1990 1995 2000
40
6060
80
Seasonal Concentration
160
200
240Load
0
20
40
0
20
40
0
40
80
120
1975 1980 1985 1990 1995 20001975 1980 1985 1990 1995 20001975 1980 1985 1990 1995 2000
Sediment trends: Cuyahoga40
Sediment trends: CuyahogaFlow 100 Concentration
10
20
30
40
60
80
01975 1980 1985 1990 1995 2000 2005
0
20
1975 1980 1985 1990 1995 2000 2005
60
80
100
300
400 Seasonal ConcentrationLoad
0
20
40
0
100
200
01975 1980 1985 1990 1995 2000 2005
01975 1980 1985 1990 1995 2000 2005
Sediment trends: How much change
Regression analysis of log(ss) as function of time, log(flow), and seasonality
In spite of wiggles, reported is total estimated change, 1985-2009, as percent of 1985 load.
River Maumee Sandusky Cuyahoga
% Change -46% -23% +40%
Sediment trends: Chance or Management?
Maybe the observed trends are just “good (or bad) luck”.( )Maybe they just reflect random fluctuations
in the weather as seen mainly in changesin the weather… as seen mainly in changes in flow
Importance of weather as a causeImportance of weather as a cause of trends can be questioned…
Not much historical change in flowFlow adjustment does not change SS trend
slope much, just lowers MSEp j…but it would be nice to have a more
quantitative evaluationquantitative evaluation
Weather Effects and Trends
2 0
3.0 overallLog(SS) 1990
2000
19701975198019851995
1.0
2.0 2000
ANCOVA
0.0
ANCOVAYear as categorical variabley=mx+b+bdifyearSum of bdif is 0
-1.0
1 0 2 0 3 0 4 0
Sum of bdifyear is 0Look at bdif vs year
1.0 2.0 3.0 4.0
Log(Flow)
Analysis of Variance ForNo Selector
LogSS
Weather Effects and TrendsNo Selector9102 total cases of which 62 are missing
SourceConst
df1
Sums of Squares 26198.9
Mean Square26198.9
F-ratio234182
Prob Š 0.0001
LgQWYErrorTotal
12690129039
565.480105.821
1008.211745.43
565.4804.070030.111874
5054.636.380
Š 0.0001 Š 0.0001
Level of WY Coefficient1975 0.28311976 0.1533
Level of WY Coefficient1985 0.10211986 0.1036
Level of WY Coefficient1995 -0.02321996 -0.0708
1977 0.06161978 -0.13541979 no data1980 no data1981 no data
1987 -0.00891988 0.09311989 0.07341990 0.15691991 0 1086
1997 0.03531998 -0.02811999 -0.09312000 -0.10492001 -0 18531981 no data
1982 0.02021983 0.06201984 -0.0565
1991 0.10861992 -0.01931993 -0.01491994 -0.0767
2001 -0.18532002 -0.08222003 -0.17742004 -0.1766
Weather Effects and Trends
0.2
0.3
Intercept
bdif=-.009*Yr + 17.9r2=45.9 p=.0001
0 0
0.1
Difference(bdif)
-0.1
0.0
1975 1980 1985 1990 1995 2000
Year
Conclusion: highly significant decrease in sediment concentration as a function of flow over 30 years!
Weather Effects and Trends
Further analysis shows: Most of this change is associated with theMost of this change is associated with the
“summer” months (May-October) The Sandusky shows the same changes, though y g , g
not as strongly The Cuyahoga is going the other way…y g g g y
Weather Effects and Trends:Weather Effects and Trends:Results for all three rivers
River Slope of bdifYR
vs. Time
Statistical significanc
e
Summer slope
Statistical significance
Winter slope
Statistical significance
Maumee -0.0207 0.0001 -0.0295 ≤0.0001 -0.0063 0.3213
Sandusky -0.0157 0.0008 -0.0254 ≤0.0001 -0.0071 0.2848
Cuyahoga 0.0217 0.0044 0.0301 0.0020 0.0159 0.0941
ConclusionsSediment concentrations and loads are decreasing overall in
the Maumee and Sandusky, but increasing in the Cuyahoga. Increases in last 5 years of the analysis (2000-2005) are Increases in last 5 years of the analysis (2000-2005) are
partly (mostly?) due to increased flow.Decreasing relationships between SS concentration and
fl i M d S d k fl t tflow in Maumee and Sandusky reflect management success, not weather effects.
Increasing trends in Cuyahoga: suburbanization, deforestation? Any other ideas?
III. Lake Erie CREP and Sediment Control
III. Lake Erie CREP
Derivation of WQ GoalApproach to evaluationApproach to evaluationWhere do we stand with meeting the goal?
S tti th t lit lSetting the water quality goal
One Index of Lake Erie Quality is tributary sedimentQuality is tributary sediment loads.
For 1991-1996, the average annual sediment load from the Maumee, Sandusky, and Cuyahoga Rivers isCuyahoga Rivers is 1,500,000 metric tons
Reduce this by 67%(!)
L k E i CREP P j t ALake Erie CREP Project Area
S tti th t lit lSetting the water quality goal
Lake Erie CREP Implementation Goal: Protect 10% of farmed riparian acresp Protect 10% of riparian corridor => reduce
loads by 10% or by 150,000 metric tons llannually
Gradual implementation, assumed uniform over 10 years10 years
Thus save 15,000 metric tons the first year, 30,000 the second year, etc., y ,
Th t lit lThe water quality goal
Year Sediment load reduction in this year
Total sediment saved to date
2001 15,000 15,000 2002 30,000 45,000 2003 45,000 90,000 2004 60,000 150,000 2005 75 000 225 0002005 75,000 225,0002006 90,000 315,000 2007 105,000 420,000 2008 120 000 540 0002008 120,000 540,0002009 135,000 675,000 2010 150,000 825,000
…plus 10 more years of loads reduced by 150,000 m.t./yr
for a total of 2,325,000 tons saved over 20 years.
201080
Results to date2005
2006
2007
20082009
2010
40
60ObservedDischarge
201012
14
16
ObservedOver the goal-BAD!
20002001
20022003
20042005
0
20
20042005
2006
2007
20082009
2010
6
8
10
12ObservedSediment
LoadBAD!
16
0 20 40 60 80
Predicted Discharge
200020012002
20032004
0
2
4
0 2 4 6 8 10 12 14 16
Target Sediment Load
Under the goal-GOOD!
20072008
20092010
8
10
12
14
ObservedSediment
Load
Target Sediment Load
Note: these are cumulative 20002001
20022003
20042005
2006
0
2
4
6
loads and discharges.Units: million metric tons, million cubic meters
00 2 4 6 8 10 12 14 16
Target Sediment Load
ConclusionsLooking good (in spite of under enrollment)!Looking good (in spite of under-enrollment)!More than 3.2 million metric tons of sediment saved
(after adjustment for discharge)!(after adjustment for discharge)!This exceeds the target for the full 20-year program!Practices may be more effective than we assumedPractices may be more effective than we assumed.
IV 2007 Th “P f t St ”IV. 2007: The “Perfect Storm”
IV. 2007: The “Perfect Storm”
Largest loads for many parameters in 35 yearsFall and winter weather and interaction
with farming practices
Discharge
2,500
Sandusky River data
1,000
1,500
2,000
Chloride load
40,000
45,000
50,000
Sandusky River data
0
500
0 31 61 92 122 153 183 214 244 275 305 336 366
Day of Water Year 15,000
20,000
25,000
30,000
35,000
40,000
0
5,000
10,000
0 31 61 92 122 153 183 214 244 275 305 336 366
Day of Water Year
Dissolved Reactive Phosphorus load
250
300
100
150
200 Suspended Solids load
600,000
700,000
0
50
0 31 61 92 122 153 183 214 244 275 305 336 366
Day of Water Year 200,000
300,000
400,000
500,000
0
100,000
0 31 61 92 122 153 183 214 244 275 305 336 366
Day of Water Year
Loads 2007 compared with averageRainfall
Loads 2007 compared with averageHighest load observed
Discharge
SS load
TP load
in 33 years
PP load
DRP load
NO3 loadNO3 load
TKN load
Chloride load
0% 50% 100% 150% 200% 250% 300% 350%Percent of Average Annual Load
ConclusionsMany parameters had record loads in 2007, due to the
interaction of unusually wet weather with farming practicesTh f h h di l d d iThe fact that the sediment load was not record-setting reflects success in controlling (reducing) sediment losses
Summary (Concluding Conclusions) Sediment concentrations and loads in Ohio’s Lake Erie tributaries are
higher than average for the Great Lakes region, but not compared to some other regions
Sediment concentrations and loads are decreasing overall in the Maumee and Sandusky, but increasing in the Cuyahoga
Increase in Sandusky and Cuyahoga loads (2000-2005) mostly due to increased discharge, but longer-term trends not weather-related
Lake Erie CREP well ahead of schedule in meeting sediment control goal
Record 2007 loads reflect the influence of weather in determining loads, but modest sediment load further indicates success in controlling sediment losses
Sediment Control Grade
B/B+B/BComment to parents:Comment to parents: Good progress, but more commitment to goals would yield greater improvements. Cuyahoga needs work.
The End
Rock Creek 6/25/06
