The LOWER DELAWARE MONITORING PROGRAM’S

WATER QUALITY DATA ANALYSIS PROTOCOL

Robert Limbeck

Watershed Scientist, DRBC

NJ Volunteer Monitoring Summit

October 1, 2004

Lower Delaware

River Study Area

Control Point Monitoring Concepts

Study Design Objectives

Establish baseline Existing Water Quality for future comparison;Set targets to maintain water quality where standards are met;Set targets to improve water quality where standards are not met;Set geographic and water quality priorities to meet the targets; andMonitor long-term to assess trends, prioritize management activities, and assess effectiveness of implementation.

How does water quality change from the Delaware Water Gap to Trenton?Which tributaries produce such changes?Where should resources be devoted for most water quality benefit?

QA/QC Considerations

Know Your Data:

Precision - The degree of agreement of repeated measurements Accuracy - How close your results are to a true or expected value Representativeness - Data represent the true environmental condition Completeness - Compare amount of valid or useable data planned to be

collected versus the amount actually collected Comparability - The extent to which data can be compared to other sample

locations or periods of time

Data Management

Go to www.drbc.net, click on Lower Delaware

See reports, QAPP, and data files for data management details

The LDMP Excel FileAvailable at www.drbc.net

Sampling Site# rp rt st Mon Year yr-mo RivMile Shortnm Concatnm Flow (cfs)DO

mg/lDO%Sat

SpC umhos/cm

pH Air Temp C Air Temp F WT C WT F TDS

DRBCNJPAC10 P R DR 2000 2000-5 207.40 DelPortland 207.4 DelPortland 6,398.00 9.1 101.7% 92 7.9 36.0 96.8 20.8 69.4DRBCNJPAC10 P R DR 2000 2000-5 207.40 DelPortland 207.4 DelPortland 16,685.00 10.6 98.6% 70 7.7 14.4 57.9 12.1 53.8DRBCNJPAC10 P R DR 2000 2000-6 207.40 DelPortland 207.4 DelPortland 28,181.00 10.2 100.9% 73 7.2 22.8 73.0 14.9 58.8DRBCNJPAC10 P R DR 2000 2000-6 207.40 DelPortland 207.4 DelPortland 11,566.00 9.2 100.0% 69 7.4 25.6 78.1 19.4 66.9 164DRBCNJPAC10 P R DR 2000 2000-7 207.40 DelPortland 207.4 DelPortland 3,173.00 7.8 90.9% 105 8.7 28.5 83.3 23.0 73.4 74DRBCNJPAC10 P R DR 2000 2000-7 207.40 DelPortland 207.4 DelPortland 3,718.00 8.1 91.6% 97 7.8 20.4 68.7 21.4 70.5 70DRBCNJPAC10 P R DR 2000 2000-8 207.40 DelPortland 207.4 DelPortland 5,920.00 8.8 103.9% 88 7.5 30.3 86.5 23.7 74.7 70DRBCNJPAC10 P R DR 2000 2000-8 207.40 DelPortland 207.4 DelPortland 3,524.00 9.4 104.0% 99 8.2 23.5 74.3 20.3 68.5 110DRBCNJPAC10 P R DR 2000 2000-9 207.40 DelPortland 207.4 DelPortland 3,718.00 8.8 100.5% 109 8.5 27.0 80.6 21.9 71.4 82DRBCNJPAC10 P R DR 2000 2000-9 207.40 DelPortland 207.4 DelPortland 3,524.00 9.7 94.7% 94 7.9 16.9 62.4 14.3 57.7 196DRBCNJPAC10 P R DR 2001 2001-5 207.40 DelPortland 207.4 DelPortland 3,285.00 10.9 113.7% 108 8.0 27.7 81.9 17.4 63.3 91DRBCNJPAC10 P R DR 2001 2001-5 207.40 DelPortland 207.4 DelPortland 4,563.00 9.4 96.2% 110 7.4 25.5 77.9 16.5 61.7 280DRBCNJPAC10 P R DR 2001 2001-6 207.40 DelPortland 207.4 DelPortland 6,534.00 10.5 112.3% 87 7.7 27.2 81.0 18.6 65.5 70DRBCNJPAC10 P R DR 2001 2001-6 207.40 DelPortland 207.4 DelPortland 5,084.00 7.8 91.6% 102 7.4 25.6 78.1 23.4 74.1 70DRBCNJPAC10 P R DR 2001 2001-7 207.40 DelPortland 207.4 DelPortland 3,129.00 8.2 96.0% 113 7.5 25.3 77.5 23.2 73.8 90DRBCNJPAC10 P R DR 2001 2001-7 207.40 DelPortland 207.4 DelPortland 2,745.00 7.2 88.7% 122 7.6 26.4 79.5 26.0 78.8 83DRBCNJPAC10 P R DR 2001 2001-8 207.40 DelPortland 207.4 DelPortland 2,558.00 6.7 86.0% 110 7.6 29.6 85.3 28.3 82.9 86DRBCNJPAC10 P R DR 2001 2001-8 207.40 DelPortland 207.4 DelPortland 1,896.00 8.3 99.7% 115 7.4 31.4 88.5 24.6 76.3 86DRBCNJPAC10 P R DR 2001 2001-9 207.40 DelPortland 207.4 DelPortland 2,175.00 8.6 98.7% 110 7.4 30.4 86.7 22.2 72.0 100DRBCNJPAC10 P R DR 2001 2001-9 207.40 DelPortland 207.4 DelPortland 3,491.00 8.8 92.2% 120 7.9 20.6 69.1 17.6 63.7 150DRBCNJPAC10 P R DR 2002 2002-5 207.40 DelPortland 207.4 DelPortland 7,200.82 9.4 94.8% 76 7.5 14.3 57.7 15.8 60.4 86DRBCNJPAC10 P R DR 2002 2002-5 207.40 DelPortland 207.4 DelPortland 10,860.78 12.3 110.8% 65 7.4 24.3 75.7 10.7 51.3 79DRBCNJPAC10 P R DR 2002 2002-6 207.40 DelPortland 207.4 DelPortland 7,934.48 9.4 100.7% 76 6.8 25.3 77.5 18.7 65.7 88DRBCNJPAC10 P R DR 2002 2002-6 207.40 DelPortland 207.4 DelPortland 8,444.20 9.5 103.9% 88 6.9 29.6 85.3 19.7 67.5 65DRBCNJPAC10 P R DR 2002 2002-7 207.40 DelPortland 207.4 DelPortland 2,613.66 8.0 95.2% 117 25.9 78.6 24.1 75.4 110DRBCNJPAC10 P R DR 2002 2002-7 207.40 DelPortland 207.4 DelPortland 2,694.40 7.9 97.3% 109 7.6 20.7 69.2 26.0 78.8 94DRBCNJPAC10 P R DR 2002 2002-8 207.40 DelPortland 207.4 DelPortland 2,013.44 8.4 99.8% 113 7.8 27.3 81.1 24.0 75.2 120DRBCNJPAC10 P R DR 2002 2002-8 207.40 DelPortland 207.4 DelPortland 1,978.62 8.2 100.7% 112 7.6 27.9 82.2 25.8 78.4 99DRBCNJPAC10 P R DR 2002 2002-9 207.40 DelPortland 207.4 DelPortland 1,944.10 8.8 99.5% 103 8.3 23.6 74.5 21.4 70.5 110DRBCNJPAC10 P R DR 2002 2002-9 207.40 DelPortland 207.4 DelPortland 2,155.90 8.6 94.8% 104 8.0 19.7 67.5 20.1 68.2 100DRBCNJPAC10 P R DR 2003 2003-5 207.40 DelPortland 207.4 DelPortland 7,794.00 10.3 98.0% 84 7.1 15.5 59.9 13.1 55.6 150

Always Prepare MetadataMETADATA for 00-03 DATABASE

FIELD (Column) DESCRIPTION

Sampling Site# site number for STORET

rp R-riffle or fast water; P-Pool or just downstream of large pool

rt R-river site; T-tributary site

st State - PA, NJ, or DR=Delaware River Interstate Control Point

Mon Year Calendar year of sample

yr-mo Year-Month combination for seasonal stratification of data

RivMile River mile location upstream from mouth of Delaware Bay

Shortnm Short site name for graphic plots by site

Concatnm Concatenation of river mile and short site name for river mile plots

Site Name Long version of site name, or full site name

DA sq mi drainage area in square miles

MO month of sample

day day of sample

Date date of sample

Time time of day, military

Flow Percentile 0=<10th; 1=10-25%ile; 2=25th-50th%ile; 3=50th-75th%ile; 4=75th-90th%ile; 5=>90th%ile

Flow (cfs) discharge corresponding to time of sample and gage height of sample

log(cfs) log transformation of flow

cfs/sqmi discharge per unit drainage area

log cfs/mi2 log transformation of discharge per unit drainage area

DO mg/l dissolved oxygen concentration

DOSat Value dissolved oxygen concentration at 100% saturation at sample water temperature

DO%Sat calculated dissolved oxygen saturation = DO/DOSatValue

Gage Ht gage height of water level - use gage height vs discharge regression to estimate discharge

Etc.

Data Checking and CleaningCheck accuracy of data entry (multiple checks are best)

Check validity of data (can fish live in 1000 degrees F?)

Check precision and accuracy of data (QA/QC process)

Once in table form, sort all columns, check formats and ranges

Make sure blank cells are really blank…

Plot data, explain outliers (we rarely exclude outlier data)

Quantify non-detect values: we use ½ MDL if <20% non-detects

If more than 20% of data are non-detects, they may bias data set

The % of non-detects may be a good water quality indicator

Stats Packages Used at DRBC

Analyse-It Excel Add-In from www.analyse-it.com

SAS Powerful! www.sas.com

Excel Statistical functions available, but…

There are many other good statistical software applications available. Prices range from $100 to $$$$$.

Representative Data

0.00%

10.00%

20.00%

30.00%

40.00%

50.00%

60.00%

70.00%

80.00%

90.00%

Lehi

gh, P

A

Lack

awax

en, P

A

Nev

ersi

nk, N

Y

Bro

dhea

d, P

A

Mon

gaup

, NY

Pau

linsK

ill, N

J

Bus

hkill

(Mon

roe)

, PA

Peq

uest

, NJ

Mus

cone

tcon

g, N

J

Tohi

ckon

, PA

Cal

licoo

n, N

Y

Sho

hola

, PA

Bus

hkill

(Nor

tham

pton

), P

A

Flat

Bro

ok, N

J

Equ

inun

k, P

A

Poh

atco

ng, N

J

Tenm

ile, N

Y

Mar

tins,

PA

Cal

kins

, PA

Mas

thop

e, P

A

Coo

ks, P

A

Tributary

Pe

rce

nt

of

To

tal

Wa

ters

he

d A

rea

Is your data representative of watershed conditions?

Natural Variability

What range of stream flow does your data cover?

OvercomeNatural

Variability

n 894  

Mean 11:12.895% CI  11:07.3 to 11:17.2

Variance 0:03.46SD 1:15.79SE 0:02.53CV 11%

Median 11:15.095.2% CI  11:05.0 to 11:20.0

Range 7:15IQR 1:50

Percentile

10th 9:30.025th 10:15.050th 11:15.075th 12:05.090th 12:50.0

Coefficient p

Shapiro-Wilk  0.9897 <0.0001Skewness 0.1101 0.1773

Kurtosis -0.5621 <0.0001

-4

-3

-2

-1

0

1

2

3

4

0.33

0.35

0.38

0.4 0.43

0.45

0.48

0.5 0.53

0.55

0.58

0.6 0.63

0.65

Time

No

rmal

Qu

anti

le

0

20

40

60

80

100

120

140

160

180F

req

uen

cy

0

1

What time of day does your data represent?

Summary Stats – Frequency Plot

n 40  

Mean 97.48%95% CI  95.46% to 99.49%

Variance 0.398%SD 6.309%SE 0.998%CV 6%

0

2

4

6

8

10

12

14

Fre

qu

ency

DO % Saturation at Portland, PA 2000-2003

Summary Stats (Box and Normal Plots)Median 97.18%

96.2% CI  94.77% to 99.78%  

Range 27.7%IQR 8.6%

Percentile

10th 89.71%25th 92.15%50th 97.18%75th 100.71%90th 103.99%

Coefficient p

Shapiro-Wilk  0.9578 0.1406Skewness 0.6536 0.0802

Kurtosis 0.5128 0.3805

-3

-2

-1

0

1

2

3

0.85 0.9 0.95 1 1.05 1.1 1.15

DO%Sat

No

rmal

Qu

an

tile

0

2

4

6

8

10

12

14

Fre

qu

en

cy

0

1

DO % Saturation at Portland, PA 2000-2003 (Data are normally distributed)

Non-Normal

Data

n 35  (cases excluded: 5 due to missing values)

Mean 148.195% CI  48.2 to 248.0  

Variance 84,563.20SD 290.80SE 49.15CV 196%

Median 32.095.9% CI  12.0 to 76.0  

Range 1,298IQR 89

Percentile

10th 7.225th 11.050th 32.075th 100.090th 534.0

Coefficient p

Shapiro-Wilk  0.5443 <0.0001Skewness 2.9033 <0.0001

Kurtosis 8.5876 <0.0001

-3

-2

-1

0

1

2

3

4

0 200 400 600 800 1000 1200 1400

Entero col/100ml

No

rmal

Qu

anti

le

0

5

10

15

20

25

30

Fre

qu

ency

0

1

Enterococcus counts at Portland, PA 2000-2003

Transformed Data

n 35  (cases excluded: 5 due to missing values)

Mean 1.5876195% CI  1.34714 to 1.82808

Variance 0.490041SD 0.700029SE 0.118327CV 44%

Median 1.5051595.9% CI  1.07918 to 1.88081

Range 2.8129IQR 0.9604

Percentile

10th 0.8531125th 1.0395950th 1.5051575th 2.0000090th 2.72752

Coefficient p

Shapiro-Wilk  0.9466 0.0891Skewness 0.5866 0.1341

Kurtosis -0.3869 0.6987

-3

-2

-1

0

1

2

3

0 0.5 1 1.5 2 2.5 3 3.5

Ent Log

No

rmal

Qu

anti

le

0

2

4

6

8

10

12

14

Fre

qu

ency

0

1

Enterococcus counts, Portland, PA 2000-2003, log transformed – produces normality (antilog of results is the geometric mean)

Comparative Stats

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

134.34DelCalhoun

141.8DelWXing

148.7DelLambertvll

155.4DelBullsIsl

167.7DelMilford

174.8DelRiegelsBr

183.82DelEaston

197.84DelBelvidere

207.4DelPortland

River mile plot of log Fecal Coliform counts in the Delaware River 2000-2003

Means or Medians?

Use means and parametric stats if normality assumptions are met (sample population must be a random sample following the normal distribution).

Medians and non-parametric tests make no assumption about the data distribution. Valid for any data set.

Note: Parametric tests like the t-test require at least 30 data points for the assumption of normality to be met. Do you collect that much information? In order for parametric comparisons between sites to be made, their data distributions must be the same shape. Do not assume this is the case! Non-parametric stats are safe…

Parametric vs Non-Parametric Tests

Parametric Non-Parametric

Testing for a Difference:T-Test Mann-Whitney U Test

1-Way ANOVA Kruskal-Wallis 1-Way ANOVA

Testing for a Change:Paired Samples T-Test Wilcoxon Signed Ranks Test

1-Way Repeat Measures ANOVA Friedman 1-Way ANOVA

Testing for an Association (Correlation):Pearson Correlation Spearman Rank Correlation

Kendall Rank Concordance

Prediction:Linear, Deming, or Polynomial Regression Passing & Bablok Regression

Presentation of Data – GraphsAll Data Plot

Presentation of Data – GraphsMedians and Percentiles

Presentation of Data - Tables

Flow Percentile N Median Fecal Coliform 10th%ile to 90th%ile <10th 32 18 5 to 111

10th to 25th 55 50 5 to 130 25th to 50th 80 50 5 to 820 50th to 75th 66 52 16 to 461 75th to 90th 52 80 20 to 3,070

>90th 24 190 57 to 1,450

ResourcesUSGS Statistical Guidance Manual for Water Resource Studies (USGS manual is excellent…)

USEPA guidance (numerous sources, try a web search)

Zar, J.H. Biostatistical Analysis.

Many others, give me a call…

Bob Limbeck, DRBC

609-883-9500 ext 230

Robert.Limbeck@drbc.state.nj.us

www.drbc.net