TDS/Nitrogen Management Plan for the Santa Ana River Basin Groundwater Monitoring Requirements Ambient Water Quality: Update April 19, 2017
Point Statics for 20-Year Moving Average 1. Annualized Averages 2. At least 3 years of water quality (TDS or NO3-N) in 20 year period 3. Shapiro Wilk test for normality 4. Point Statistics – mean plus t*standard error of the mean 2
Method Shapiro-Wilk Test for Normality Annualized Averages Assumes “normal” data Shapiro-Wilk test for Bias towards low values normality to remove “Most No apparent limit on the Discordant Value” (MDV) number of iterations iteratively until data is Rejects data that may normalized correspond to event changes 3
4
5
Potential Bias on Bimodal data 1003134 1003134 2.0 2.0 1.5 1.5 1.0 1.0 0.5 0.5 Normal Quantile Normal Quantile 0.0 0.0 -0.5 -0.5 -1.0 -1.0 -1.5 -1.5 Mean = 8.5 Mean = 6.8 -2.0 -2.0 0 5 10 15 20 Remove 1 MDV 25 0 5 10 15 20 25 NO3-N NO3-N 6
Potential Bias on Bimodal data 1003134 1003134 2.0 2.5 2.0 1.5 1.5 1.0 1.0 0.5 Normal Quantile Normal Quantile 0.5 0.0 0.0 -0.5 -0.5 -1.0 -1.0 -1.5 -1.5 Mean = 8.5 Mean = 5.6 -2.0 -2.0 0 5 10 15 20 Remove 2 MDV 25 0 5 10 15 20 25 NO3-N NO3-N 7
Potential Bias on Bimodal data 1003134 1003134 2.0 2.0 1.5 1.5 1.0 1.0 0.5 0.5 Normal Quantile Normal Quantile 0.0 0.0 -0.5 -0.5 -1.0 -1.0 -1.5 -1.5 Mean = 8.5 Mean = 4.2 -2.0 -2.0 0 5 10 15 20 Remove 3 MDV 25 0 2 4 6 8 10 12 14 16 NO3-N NO3-N 8
Potential Bias on Bimodal data 1003134 1003134 2.0 2.5 2.0 1.5 1.5 1.0 1.0 0.5 Normal Quantile Normal Quantile 0.5 0.0 0.0 -0.5 -0.5 -1.0 -1.0 -1.5 -1.5 Mean = 8.5 Mean = 3.1 -2.0 -2.0 0 5 10 15 20 Remove 4 MDV 25 0 2 4 6 8 10 12 NO3-N NO3-N 9
Potential Bias on Bimodal data 1003134 1003134 2.0 2.0 1.5 1.5 1.0 1.0 0.5 0.5 Normal Quantile Normal Quantile 0.0 0.0 -0.5 -0.5 -1.0 -1.0 -1.5 -1.5 Mean = 8.5 Mean = 2.1 -2.0 -2.0 0 5 10 15 20 Remove 5 MDV 25 0 0.5 1 1.5 2 2.5 3 3.5 NO3-N NO3-N 10
Updated Shapiro Wilk 1003134 1003134 2.0 2.0 1.5 1.5 1.0 1.0 0.5 0.5 Normal Quantile Normal Quantile 0.0 0.0 -0.5 -0.5 -1.0 -1.0 -1.5 -1.5 Mean = 4.8 Calculated Statistic = 6.8 -2.0 -2.0 0 5 10 15 20 No MDV Removed 25 0 5 10 15 20 25 NO3-N NO3-N 11
12
Questions?
Criteria for Determining Point Statistics: Identifying Outliers: Outcome: 1. Limit S-W iterations to no 1. Fewer data points more than 2 times removed 2. Median absolute difference: Nitrate-N > 5x; TDS > 10x 2. Accounts for bimodal and non-linear trends Checking for Normality: 1. Linear Normality: Pass = Point 3. Does not significantly Statistic change contouring 2. Log Transform Normality: Pass = Point Statistic 3. Fail Both = ‘Average’ 14
1996 – 2015 AWQ Data Flow Diagram Yes n < 3 or Mean Detects = 0 No Shapiro- Pass Mean +SE Remove MDV Wilks UCL84 Test Yes Fail MDV Remove Yes 5x (NO3-N) MTV <2 & Max C > 1 /10x (TDS) No No Pass GM + GSE S-W Log Transform UCL84 Fail Median
Annualized Nitrate Samples and Outliers Annualized TDS Samples and Outliers Removed Removed [CELLRANGE] 40000 40000 [CELLRANGE] [CELLRANGE] 35000 [CELLRANGE] 35000 [CELLRANGE] [CELLRANGE] 30000 30000 25000 25000 20000 20000 [CELLRANGE] [CELLRANGE] [CELLRANGE] [CELLRANGE] 15000 15000 [CELLRANGE] 10000 10000 [CELLRANGE] 5000 5000 0 0 Period 1 2000 2003 2006 2009 2012 Period 1 2000 2003 2006 2009 2012 Nitrate Nitrate Outliers TDS TDS Outliers 16
Recommend
More recommend
