Statistical Analysis Phase 1
Statistical Analysis Phase 1 July, 2009 John W. Green, Ph.D, Ph.D DuPont Applied Statistics
Data Considered • Water Samples – 42,336 measurements on 5581 samples
• Sediment Samples – 10,800 measurements on 1788 samples
• Floodplain – 11,280 measurements on 627 samples
• Riverbank – 184 samples or predictions
• Loading – 40,032 measurements on 2224 samples
• Flow (Discharge) – Daily averages at three locations since 1926
Data Considered • Storm Data – 10,062 measurements on 559 samples • Included in Loading dataset
• Samples have – GPS coordinates • Translated to NAD83 coordinates and RRM
– Date collected – Many also have time of sample – Other identifying info
Data to be Included Later • Biota – Approximately 35,000 measurements on 5000 samples
• Storm – 70 samples have not yet been identified as to time collected relative to storm beginning • Will be done by comparing flow at collection time against daily flow values
Treatment of Data • Where replicates were collected, the values across reps of each measurement (chemical) were examined for consistency. • A few unbelievable extremes (hi or low) were discarded • Replicate means (or geometric means) were used for analysis • Distributions were fit to each response
Sampling Points
Sampling Points Reach 1
Sampling Points Reach 2
Sampling Points Reach 3
Sampling Points Reach 4
Sampling Points Reach 5
Sampling Points Reach 6
SW THg vs. Others
Total Suspended Solids • Previous plot indicates a positive correlation of THg and TSS • Expect a correlation of TSS and flow rate, especially storm related • Next plot explores this idea
TSS vs. Storm Flow Rate
THg vs. Storm Flow rate
MeHg vs. FLOWRATE
THg, MeHg vs. Flow rate • Baseline negative correlation consistent with dilution of MeHg with higher flow volume. • Storm plots suggests increased flow of MeHg into river during storms, but plots “noisy” • THg positively correlated with flow rate at baseline and during storm day
SW THg vs. Others
SW THg vs. Others
SW THg vs. Others
Annual THg Load From Bank
Mercury Entering South River Surface Water from Eroding Banks (ng/L) Year 2001 2002 2003 2004 2005 2006 2007 2008 2009
meanHg 142.224 210.388 36.723 64.615 73.860 65.558 106.381 139.395 105.790
mdHg 229.361 333.982 55.180 85.559 101.260 115.375 186.637 203.604 137.949
minHg 10.1260 28.7134 1.5230 4.6774 3.1106 4.7005 13.0390 24.5638 16.2709
maxHg 432.658 543.913 218.816 260.780 292.876 307.048 328.223 432.658 209.197
Annualized rate is approximately 17 kg/Yr. Table based on Mean, median, minimum and maximum measured flow volumes.
Table: Mercury Observed in South River (ng/L) YEAR 2001 2002 2003 2004 2005 2006 2007 2008
mdHg 1.50000 7.85000 3.04000 3.78460 5.43000 7.92000 6.43000 8.73737
minHg 1.500 1.500 1.500 0.690 0.150 0.280 0.100 0.265
maxHg 38 449 415 2887 739 4656 3430 642
Table based on median, minimum, and maximum flow volumes and sample THg values. This works out to between 0.18 and 2 kg/Yr. Values from riverbank thus exceed measured SW THg levels, possibly due to deposition of THg from banks into sediment and floodplain. This, in turn suggests possibility of relationships between sediment chemicals and SW THg and MeHg. Next plots compare sediment THg to other chemicals
SED THg vs. Others
SED MeHg vs. Others
MeHg as Percent of THg Year Stream %(MeHg/THg) 2004 2005 2006 2007 2008
SR SR SR SR SR
2.99 5.54 3.07 2.81 3.46
Q1
1.17 2.09 1.08 0.93 1.25
Q3
n
THg
MeHg
6.34 11.37 6.81 7.03 6.15
38 303 754 417 152
3.79 5.43 7.92 6.43 8.74
0.4975 0.2650 0.3925 0.3157 0.3477
Thus, MeHg is only a small fraction of THg in the South River. Similar calculations hold for sediment, floodplain, Tribs, reference streams. High correlation of THg and MeHg suggests similar models may apply
SW MeHg vs. Others
SW MeHg vs. Others
SW MeHg vs. Others
THg vs. RRM
In baseline plot one can discern the “hump” between RRMs 4.5 and 12 (Ln(RRM)=1.5 to 2.5). Storm plots may suggest greater flow of THg downriver during storms.
MeHg vs. RRM
No “hump” observed in the baseline plot between RRMs 4.5 and 12 (Ln(RRM)=1.5 to 2.5). Storm plots may suggest greater flow of MeHg downriver during storms.
Principal Component Analysis • PCA can identify relationships among a large number of chemicals that simple correlation analysis misses. • PCA was done separately on – All SW chemicals and water quality criteria – All sediment chemicals
• This potentially provides useful associations to explain THg or MeHg – In fact, little useful info found in this way
SW PCA, Excl Ref Samples Factor1 ALKALINITY AMMONIA BOD5DAY CALCIUM CARBON_ORG CHLORIDE COD DOC F_COLIFORM HARDNESS MAGNESIUM
75 14 -10 39 23 48 17 33 8 77 39
MEHG MERCURY
12 8
NITRATE NITRITE NITRITE_P_NITRATE NITROGEN_KJELD OPHOSPHATE ORTHOPHOSPHATE PHOSPHORUS POTASSIUM RESIDUE_VOLNONFIL SILICA SODIUM SPECIFIC_CONDUC SULFATE TOTFIX_SOLIDS_NONFIL TOT_SUSP_SOLIDS TURBIDITY
50 11 40 36 62 46 51 72 18 47 46 48 37 -6 23 20
*
* * * * *
* * * * * * * * * * *
Factor2 -30 * 23 9 -10 20 -29 * 16 -8 11 -12 -9
Factor3
*
-18 17 46 39 29 19 54 26 -6 -19 38
15 11
-29 * -1
-2 -9
-7 27 -20 54 4 24 61 -36 78 13 -32 -12 -9 30 74 3
12 7 30 17 16 -38 17 20 6 -39 41 -18 8 -15 10 28
-17 7 -10 3 -13 -3 -9 4 -7 -38 * 41 * -13 1 65 * -14 14
*
* * * *
* *
15 29 39 -65 13 42 6 -38 -12 -18 -65
Factor4
* * * * *
*
*
* *
* * * *
*
Factor5 -20 28 * 1 10 33 * -41 * 20 -11 8 5 10
-19 -10 44 45 25 29 47 -26 2 -8 -36 -4 -34 -4 -15 -10 -40 -27
Factor6 7 -42 -10 -38 36 -14 57 -13 19 7 -38
* * * *
*
8 1 * * * *
* *
*
9 -11 3 -32 * 8 12 -11 -4 -9 36 * -7 21 -2 46 * -9 12
Factor7 5 33 * 19 -18 -23 5 -13 7 19 1 -18
Factor8 -3 -15 -2 5 16 -7 4 12 -9 -4 4
46 * 26 -21 40 -35 20 8 15 -15 4 -32 22 -5 -1 13 9 -26 30
* *
*
*
52 * 76 * 18 -7 18 -11 5 -29 * -5 6 -1 -24 1 -11 -4 -9 17 -7
THg appears uncorrelated with other chemicals and water quality criteria in PCA. MeHg mildly associated with low magnesium and calcium and high sodium
SED PCA, Excl Ref Samples ACENAPHTHENE ACENAPHTHYLENE ACETOPHENONE ALUMINUM ANILINE ANTHRACENE ANTIMONY ARSENIC BENZO_A BENZO_APYRENE BENZO_B BENZO_GHI BENZO_K BERYLLIUM CADMIUM CHROMIUM CHRYSENE COPPER DIBENZ_AHA DRY_FRACTION FLUORANTHENE FLUORENE INDENO_PYRENE IRON LEAD LOI MANGANESE
Factor1 80 * 80 * 70 * -6 52 * 93 * -7 -7 93 * 95 * 95 * 96 * 96 * 1 37 * 17 95 * 47 * 87 * -10 95 * 81 * 96 * 46 * 66 * -7 -34 *
MERCURY MeHg
-5 -4
NAPHTHALENE NICKEL Org_Cmplx_Mercury PCT_CLAY PCT_H20 PCT_SAND PCT_SILT PHENANTHRENE PYRENE SELENIUM SILVER THALLIUM TOTAL_SOLIDS TOT_ORG_CARBON TVS ZINC
80 -8 -21 -12 -3 -53 77 96 95 54 -4 1 -6 -3 -9 68
*
* * * * *
*
Factor2 16 16 28 -41 * 29 8 4 -1 -6 -3 -4 -1 -1 -1 -1 -41 * -4 -21 14 -46 * -2 16 0 -64 * 23 34 * -66 *
Factor3 28 28 22 25 30 14 55 * 60 * -14 -15 -16 -14 -13 -68 * -4 17 -15 -2 -7 -32 * -16 27 -13 18 2 23 -10
Factor4 35 * 35 * 14 56 * 25 17 -27 -54 * -17 -20 -20 -19 -17 48 * -7 16 -19 -1 -18 -42 * -22 34 * -17 24 6 17 10
Factor5 -5 -5 -23 39 * -30 -2 13 9 6 5 4 4 4 -32 -3 -17 5 -17 -8 -12 3 -5 5 21 13 18 47 *
Factor6 11 11 -7 -8 2 9 -15 7 1 -5 -4 -9 -7 -3 -28 72 * -3 68 * -22 34 * -10 10 -11 0 20 -48 * -15
Factor7 4 4 22 -5 25 -1 12 0 -8 -4 -4 -1 -2 21 26 -8 -5 -19 14 8 0 5 -1 21 -31 1 -4
Factor8 25 25 -12 8 -19 18 32 * -13 11 6 4 4 8 18 -15 -13 6 -20 -14 30 1 24 7 -13 -21 0 24
39 * 33 *
-8 -8
3 -1
0 2
9 -1
-36 * -28
5 10
16 -72 -33 76 39 -16 -44 -2 -2 -17 0 -2 58 28 74 -45
28 -5 -33 * -16 -18 27 -6 -15 -16 29 47 * -72 * -21 21 -23 1
35 19 -13 2 -2 -7 6 -20 -21 16 -38 51 -2 44 -2 19
* * * * *
* * *
*
* * *
-5 49 25 9 60 -35 18 4 3 17 -4 -32 58 33 51 16
*
* *
* * * *
11 -25 31 -5 39 * 20 -7 -8 -8 11 14 -2 35 * -4 28 13
4 8 -35 -40 52 33 4 -1 -2 -16 14 18 38 -43 20 -1
* * * *
* *
25 7 33 * 8 -5 24 -15 4 1 -22 40 * 10 -3 6 0 -28
THg and MeHg are associated w/ low heavy metals, high total volatile solids, total solids , percent clay
Method of Analysis • Principal components of other measured compounds are viewed as possible, though unlikely, explanatory variables – Based on PCA
• Principal components of river bound biota are also viewed as possible explanatory variables, based on previous analyses – This will be explored
Method of Analysis: SW •
Regression model fit to South River SW THg with – Discharge/flow rate • Serves as surrogate for annual and seasonal variation and storms • 1-10-day “lookbacks” capture lingering storm effects
– Month • Capture seasonal variation
– Amount of other Hg, MeHg, and chemicals in sediment • 60-day, 1-3-RRM “lookbacks” capture relevant upstream sediment • Sediment chemicals of possible relevance from correlations and PCA
– Loads from banks • 1-5 RRM and all upstream “lookbacks” by left/right and total capture relevant upstream loading from riverbank
– Loads from tribs and floodplain • 1-3 RRM “lookbacks”
– Flow rate at sample time and 1-10 day “lookbacks” • a surrogate for storm and seasonal effects
– Land use at river edge
Method of Analysis: SW • Stepwise methods to select most important explanatory variables • Residual analysis, regression diagnostics to refine model and identify important observations • Bank loading values are annual means – Most of load from banks expected to enter river during high flow, i.e., storms – Interactions of load and flow in model
Flow Rates-2008
Storms and low and high flow rate periods easy to detect
Flow Rates-2006
Storms and low and high flow rate periods easy to detect. Note also the generally higher flow rates compared with 2008
River Bank THg Loading
The left bank contributes more THg than the right bank. Note hotspots near RRM 6, 9, and 23.
Model Results SW THg Variable Intercept MON5 MON6 MON7 MON8 MON9 MON12 MEHG_1 MEHG_2 CHROMIUM_3 MANGANESE_1 MANGANESE_2 PCT_SAND_1 PCT_SAND_3 HgLRateL1 HgLRateR2 HgLRateR3 HgLRateR4 HgLRate1 HgLRateallr
ParmEst 0.81116 0.23483 0.31795 0.84913 0.24790 0.39450 -0.37037 -0.01469 0.05526 -0.00000625 -3.7872E-7 3.090427E-7 0.01313 -0.01002 -1.20371 -2.72519 2.01481 -0.71473 1.80014 0.48278
t Value 13.66 2.47 3.38 7.38 2.38 5.04 -2.23 -1.80 5.64 -4.95 -1.83 2.51 3.88 -3.19 -4.62 -11.20 4.76 -2.16 6.79 18.56
Pr > |t|
Data Considered • Water Samples – 42,336 measurements on 5581 samples
• Sediment Samples – 10,800 measurements on 1788 samples
• Floodplain – 11,280 measurements on 627 samples
• Riverbank – 184 samples or predictions
• Loading – 40,032 measurements on 2224 samples
• Flow (Discharge) – Daily averages at three locations since 1926
Data Considered • Storm Data – 10,062 measurements on 559 samples • Included in Loading dataset
• Samples have – GPS coordinates • Translated to NAD83 coordinates and RRM
– Date collected – Many also have time of sample – Other identifying info
Data to be Included Later • Biota – Approximately 35,000 measurements on 5000 samples
• Storm – 70 samples have not yet been identified as to time collected relative to storm beginning • Will be done by comparing flow at collection time against daily flow values
Treatment of Data • Where replicates were collected, the values across reps of each measurement (chemical) were examined for consistency. • A few unbelievable extremes (hi or low) were discarded • Replicate means (or geometric means) were used for analysis • Distributions were fit to each response
Sampling Points
Sampling Points Reach 1
Sampling Points Reach 2
Sampling Points Reach 3
Sampling Points Reach 4
Sampling Points Reach 5
Sampling Points Reach 6
SW THg vs. Others
Total Suspended Solids • Previous plot indicates a positive correlation of THg and TSS • Expect a correlation of TSS and flow rate, especially storm related • Next plot explores this idea
TSS vs. Storm Flow Rate
THg vs. Storm Flow rate
MeHg vs. FLOWRATE
THg, MeHg vs. Flow rate • Baseline negative correlation consistent with dilution of MeHg with higher flow volume. • Storm plots suggests increased flow of MeHg into river during storms, but plots “noisy” • THg positively correlated with flow rate at baseline and during storm day
SW THg vs. Others
SW THg vs. Others
SW THg vs. Others
Annual THg Load From Bank
Mercury Entering South River Surface Water from Eroding Banks (ng/L) Year 2001 2002 2003 2004 2005 2006 2007 2008 2009
meanHg 142.224 210.388 36.723 64.615 73.860 65.558 106.381 139.395 105.790
mdHg 229.361 333.982 55.180 85.559 101.260 115.375 186.637 203.604 137.949
minHg 10.1260 28.7134 1.5230 4.6774 3.1106 4.7005 13.0390 24.5638 16.2709
maxHg 432.658 543.913 218.816 260.780 292.876 307.048 328.223 432.658 209.197
Annualized rate is approximately 17 kg/Yr. Table based on Mean, median, minimum and maximum measured flow volumes.
Table: Mercury Observed in South River (ng/L) YEAR 2001 2002 2003 2004 2005 2006 2007 2008
mdHg 1.50000 7.85000 3.04000 3.78460 5.43000 7.92000 6.43000 8.73737
minHg 1.500 1.500 1.500 0.690 0.150 0.280 0.100 0.265
maxHg 38 449 415 2887 739 4656 3430 642
Table based on median, minimum, and maximum flow volumes and sample THg values. This works out to between 0.18 and 2 kg/Yr. Values from riverbank thus exceed measured SW THg levels, possibly due to deposition of THg from banks into sediment and floodplain. This, in turn suggests possibility of relationships between sediment chemicals and SW THg and MeHg. Next plots compare sediment THg to other chemicals
SED THg vs. Others
SED MeHg vs. Others
MeHg as Percent of THg Year Stream %(MeHg/THg) 2004 2005 2006 2007 2008
SR SR SR SR SR
2.99 5.54 3.07 2.81 3.46
Q1
1.17 2.09 1.08 0.93 1.25
Q3
n
THg
MeHg
6.34 11.37 6.81 7.03 6.15
38 303 754 417 152
3.79 5.43 7.92 6.43 8.74
0.4975 0.2650 0.3925 0.3157 0.3477
Thus, MeHg is only a small fraction of THg in the South River. Similar calculations hold for sediment, floodplain, Tribs, reference streams. High correlation of THg and MeHg suggests similar models may apply
SW MeHg vs. Others
SW MeHg vs. Others
SW MeHg vs. Others
THg vs. RRM
In baseline plot one can discern the “hump” between RRMs 4.5 and 12 (Ln(RRM)=1.5 to 2.5). Storm plots may suggest greater flow of THg downriver during storms.
MeHg vs. RRM
No “hump” observed in the baseline plot between RRMs 4.5 and 12 (Ln(RRM)=1.5 to 2.5). Storm plots may suggest greater flow of MeHg downriver during storms.
Principal Component Analysis • PCA can identify relationships among a large number of chemicals that simple correlation analysis misses. • PCA was done separately on – All SW chemicals and water quality criteria – All sediment chemicals
• This potentially provides useful associations to explain THg or MeHg – In fact, little useful info found in this way
SW PCA, Excl Ref Samples Factor1 ALKALINITY AMMONIA BOD5DAY CALCIUM CARBON_ORG CHLORIDE COD DOC F_COLIFORM HARDNESS MAGNESIUM
75 14 -10 39 23 48 17 33 8 77 39
MEHG MERCURY
12 8
NITRATE NITRITE NITRITE_P_NITRATE NITROGEN_KJELD OPHOSPHATE ORTHOPHOSPHATE PHOSPHORUS POTASSIUM RESIDUE_VOLNONFIL SILICA SODIUM SPECIFIC_CONDUC SULFATE TOTFIX_SOLIDS_NONFIL TOT_SUSP_SOLIDS TURBIDITY
50 11 40 36 62 46 51 72 18 47 46 48 37 -6 23 20
*
* * * * *
* * * * * * * * * * *
Factor2 -30 * 23 9 -10 20 -29 * 16 -8 11 -12 -9
Factor3
*
-18 17 46 39 29 19 54 26 -6 -19 38
15 11
-29 * -1
-2 -9
-7 27 -20 54 4 24 61 -36 78 13 -32 -12 -9 30 74 3
12 7 30 17 16 -38 17 20 6 -39 41 -18 8 -15 10 28
-17 7 -10 3 -13 -3 -9 4 -7 -38 * 41 * -13 1 65 * -14 14
*
* * * *
* *
15 29 39 -65 13 42 6 -38 -12 -18 -65
Factor4
* * * * *
*
*
* *
* * * *
*
Factor5 -20 28 * 1 10 33 * -41 * 20 -11 8 5 10
-19 -10 44 45 25 29 47 -26 2 -8 -36 -4 -34 -4 -15 -10 -40 -27
Factor6 7 -42 -10 -38 36 -14 57 -13 19 7 -38
* * * *
*
8 1 * * * *
* *
*
9 -11 3 -32 * 8 12 -11 -4 -9 36 * -7 21 -2 46 * -9 12
Factor7 5 33 * 19 -18 -23 5 -13 7 19 1 -18
Factor8 -3 -15 -2 5 16 -7 4 12 -9 -4 4
46 * 26 -21 40 -35 20 8 15 -15 4 -32 22 -5 -1 13 9 -26 30
* *
*
*
52 * 76 * 18 -7 18 -11 5 -29 * -5 6 -1 -24 1 -11 -4 -9 17 -7
THg appears uncorrelated with other chemicals and water quality criteria in PCA. MeHg mildly associated with low magnesium and calcium and high sodium
SED PCA, Excl Ref Samples ACENAPHTHENE ACENAPHTHYLENE ACETOPHENONE ALUMINUM ANILINE ANTHRACENE ANTIMONY ARSENIC BENZO_A BENZO_APYRENE BENZO_B BENZO_GHI BENZO_K BERYLLIUM CADMIUM CHROMIUM CHRYSENE COPPER DIBENZ_AHA DRY_FRACTION FLUORANTHENE FLUORENE INDENO_PYRENE IRON LEAD LOI MANGANESE
Factor1 80 * 80 * 70 * -6 52 * 93 * -7 -7 93 * 95 * 95 * 96 * 96 * 1 37 * 17 95 * 47 * 87 * -10 95 * 81 * 96 * 46 * 66 * -7 -34 *
MERCURY MeHg
-5 -4
NAPHTHALENE NICKEL Org_Cmplx_Mercury PCT_CLAY PCT_H20 PCT_SAND PCT_SILT PHENANTHRENE PYRENE SELENIUM SILVER THALLIUM TOTAL_SOLIDS TOT_ORG_CARBON TVS ZINC
80 -8 -21 -12 -3 -53 77 96 95 54 -4 1 -6 -3 -9 68
*
* * * * *
*
Factor2 16 16 28 -41 * 29 8 4 -1 -6 -3 -4 -1 -1 -1 -1 -41 * -4 -21 14 -46 * -2 16 0 -64 * 23 34 * -66 *
Factor3 28 28 22 25 30 14 55 * 60 * -14 -15 -16 -14 -13 -68 * -4 17 -15 -2 -7 -32 * -16 27 -13 18 2 23 -10
Factor4 35 * 35 * 14 56 * 25 17 -27 -54 * -17 -20 -20 -19 -17 48 * -7 16 -19 -1 -18 -42 * -22 34 * -17 24 6 17 10
Factor5 -5 -5 -23 39 * -30 -2 13 9 6 5 4 4 4 -32 -3 -17 5 -17 -8 -12 3 -5 5 21 13 18 47 *
Factor6 11 11 -7 -8 2 9 -15 7 1 -5 -4 -9 -7 -3 -28 72 * -3 68 * -22 34 * -10 10 -11 0 20 -48 * -15
Factor7 4 4 22 -5 25 -1 12 0 -8 -4 -4 -1 -2 21 26 -8 -5 -19 14 8 0 5 -1 21 -31 1 -4
Factor8 25 25 -12 8 -19 18 32 * -13 11 6 4 4 8 18 -15 -13 6 -20 -14 30 1 24 7 -13 -21 0 24
39 * 33 *
-8 -8
3 -1
0 2
9 -1
-36 * -28
5 10
16 -72 -33 76 39 -16 -44 -2 -2 -17 0 -2 58 28 74 -45
28 -5 -33 * -16 -18 27 -6 -15 -16 29 47 * -72 * -21 21 -23 1
35 19 -13 2 -2 -7 6 -20 -21 16 -38 51 -2 44 -2 19
* * * * *
* * *
*
* * *
-5 49 25 9 60 -35 18 4 3 17 -4 -32 58 33 51 16
*
* *
* * * *
11 -25 31 -5 39 * 20 -7 -8 -8 11 14 -2 35 * -4 28 13
4 8 -35 -40 52 33 4 -1 -2 -16 14 18 38 -43 20 -1
* * * *
* *
25 7 33 * 8 -5 24 -15 4 1 -22 40 * 10 -3 6 0 -28
THg and MeHg are associated w/ low heavy metals, high total volatile solids, total solids , percent clay
Method of Analysis • Principal components of other measured compounds are viewed as possible, though unlikely, explanatory variables – Based on PCA
• Principal components of river bound biota are also viewed as possible explanatory variables, based on previous analyses – This will be explored
Method of Analysis: SW •
Regression model fit to South River SW THg with – Discharge/flow rate • Serves as surrogate for annual and seasonal variation and storms • 1-10-day “lookbacks” capture lingering storm effects
– Month • Capture seasonal variation
– Amount of other Hg, MeHg, and chemicals in sediment • 60-day, 1-3-RRM “lookbacks” capture relevant upstream sediment • Sediment chemicals of possible relevance from correlations and PCA
– Loads from banks • 1-5 RRM and all upstream “lookbacks” by left/right and total capture relevant upstream loading from riverbank
– Loads from tribs and floodplain • 1-3 RRM “lookbacks”
– Flow rate at sample time and 1-10 day “lookbacks” • a surrogate for storm and seasonal effects
– Land use at river edge
Method of Analysis: SW • Stepwise methods to select most important explanatory variables • Residual analysis, regression diagnostics to refine model and identify important observations • Bank loading values are annual means – Most of load from banks expected to enter river during high flow, i.e., storms – Interactions of load and flow in model
Flow Rates-2008
Storms and low and high flow rate periods easy to detect
Flow Rates-2006
Storms and low and high flow rate periods easy to detect. Note also the generally higher flow rates compared with 2008
River Bank THg Loading
The left bank contributes more THg than the right bank. Note hotspots near RRM 6, 9, and 23.
Model Results SW THg Variable Intercept MON5 MON6 MON7 MON8 MON9 MON12 MEHG_1 MEHG_2 CHROMIUM_3 MANGANESE_1 MANGANESE_2 PCT_SAND_1 PCT_SAND_3 HgLRateL1 HgLRateR2 HgLRateR3 HgLRateR4 HgLRate1 HgLRateallr
ParmEst 0.81116 0.23483 0.31795 0.84913 0.24790 0.39450 -0.37037 -0.01469 0.05526 -0.00000625 -3.7872E-7 3.090427E-7 0.01313 -0.01002 -1.20371 -2.72519 2.01481 -0.71473 1.80014 0.48278
t Value 13.66 2.47 3.38 7.38 2.38 5.04 -2.23 -1.80 5.64 -4.95 -1.83 2.51 3.88 -3.19 -4.62 -11.20 4.76 -2.16 6.79 18.56
Pr > |t|
