issue determination town of orangeville wells€¦ · september 11, 2013 • wells 2a, 5/5a, 6,...

Issue Determination

Town of Orangeville Wells

Prepared by:

Donald Ford, P.Geo. Kerry Mulchansingh, P.Geo.

CTC Source Protection Region

September 11, 2013

Issue Determination Town of Orangeville Wells September 11, 2013

Table of Contents

Page

1.0 INTRODUCTION ....................................................................................................... 3 1.1 Study Objective .................................................................................................. 3 1.2 Background ........................................................................................................ 3

1.2.1 The Technical Rules and “Issue” Definition .............................................. 3 1.2.2 Water Quality Issues in Orangeville Municipal Wells ................................ 3 1.2.3 Issue Contributing Areas .......................................................................... 4 1.2.4 CVSPA Assessment Report ..................................................................... 4

1.3 Summary of Previous Assessments ................................................................ 4 1.3.1 Sodium (ODWS - 200 mg/l) ...................................................................... 5 1.3.2 Chloride (ODWS - 250 mg/l) ..................................................................... 6 1.3.3 Nitrate (ODWS - 10 mg/l) ......................................................................... 6

1.4 Probable Sources of Sodium and Chloride ...................................................... 7 1.5 Issue Contributing Areas .................................................................................. 8 1.6 Study Criteria ..................................................................................................... 8

2.0 METHODOLOGY ...................................................................................................... 9 2.1 Statistical Review ............................................................................................... 9 2.2 Datasets .............................................................................................................. 9 2.3 Analysis .............................................................................................................. 9 2.4 Land Use Review ............................................................................................. 10

3.0 RESULTS .............................................................................................................. 12 3.1 Overview ........................................................................................................... 12 3.2 Sodium (ODWS = 200 mg/L) ............................................................................ 12

3.2.1 Confirmed: Wells with No Issue(s) .......................................................... 12 3.2.2 Issues Not Retained ............................................................................... 12 3.2.3 Issue(s) Retained ................................................................................... 13

3.3 Chloride (ODWS = 250 mg/L) .......................................................................... 13 3.3.1 Confirmed: Wells with No Chloride Issue(s) ............................................ 13 3.3.2 Chloride Issues Not Retained ................................................................. 13 3.3.3 Chloride Issue(s) Retained ..................................................................... 13

3.4 Nitrate (ODWS = 10 mg/L) ................................................................................ 14 3.4.1 Confirmed: No Issues ............................................................................. 14

3.5 Land Usage Review ......................................................................................... 14

4.0 CONCLUSIONS AND RECOMMENDATIONS ................................................................ 15 4.1 Wells with No Water Quality Issues ................................................................ 15 4.2 Wells with Water Quality Issues ..................................................................... 15 4.3 Issue Contributing Areas ................................................................................ 16 4.4 Future Monitoring and Re-analysis ................................................................ 16

5.0 REFERENCES........................................................................................................ 17

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Page Tables Table 1-1: ............................................................................................................................ 4 Table 3-1: .......................................................................................................................... 12 Appendices Appendix 1: 2010 Issues Analysis, Water Quality Graphs Appendix 2: Statistical Analysis with XLSTAT® Appendix 3: Land Use Assessment

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1.0 INTRODUCTION 1.1 Study Objective An “Issue” is defined under the Clean Water Act, 2006 (CWA, 2006) as an existing water quality problem associated with a drinking water source, or evidence of a trend that suggests a deterioration of municipal drinking water quality in respect of one or more parameters on the MOE-prescribed list.

The Issues analyses for various municipalities within the CVSPA were undertaken by different consultants, each utilizing a methodology which in part, involved professional interpretation of the content of the CWA, 2006, and of the MOE’s Technical Rules (2009). In the interest of standardizing the methodology, the SPC has asked staff to do a re-evaluation of the Issues that were previously identified for Orangeville’s municipal wells, using the most recently available water quality data and applying the same assumptions / criteria utilized for the a recent study of the Halton Region’s wells (CTC, 2013).

This report summarizes the updated analyses and as required, sets out recommendations for amendments to the approved AR for CVSPA to reflect this new work. This report is intended as a foundation document for review and acceptance by the CTC SPC. The CTC SPC will endorse any revisions to the CVSPA AR before they are submitted to the MOE for approval.

1.2 Background 1.2.1 The Technical Rules and “Issue” Definition Issues must result from the deterioration of the quality of water for use as drinking water, and must be amply documented. Where adequate documentation exists, drinking water Issues are defined and described in compliance with Technical Rules, Part XI.1, Rules 114–117. The basic requirements for identifying an Issue include the following:

• An Issue can only be identified in one of the four vulnerable areas (wellhead protection area, intake protection zone, significant groundwater recharge area, or highly vulnerable aquifer).

• There must be data to support the identification of the Issue.

• The parameter of concern must:

o Be from an anthropogenic source;

o Be present at a concentration at the surface intake, well or monitoring well that may result in the deterioration of the quality of the water for use as a source of drinking water, or

o Exhibit a trend of increasing concentration, which, if continued would result in the deterioration of the quality of the water for use as a source of drinking water.

1.2.2 Water Quality Issues in Orangeville Municipal Wells The identification of Issues in the CVSPA AR was based on an assessment of sodium, chloride and nitrate concentrations in the raw water of Orangeville’s municipal wells over a period of 24 years (1984-2008). This analysis was completed by R.J. Burnside (2010) using data collected through the town’s municipal raw water sampling program. The data were assessed against prescribed concentration limits set for each parameter, known as the Ontario Drinking Water Standards (ODWS).

Burnside’s study identified sodium and chloride Issues at the following municipal wells:

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• Wells 2A, 5/5A, 6, 9A/9B, 10, and 11

These parameters are not removed through typical municipal drinking water treatment processes. No nitrate issues were identified at any of the town’s wells. A summary of the analysis is provided in Table 1-1, below.

Orangeville 2AIncrease from 9 mg/L to 25 mg/L, 1983 to 2008

Increase from 25 mg/L to 55 mg/L, 1985 to 2008 No concern Sodium and Chloride Issues

Orangeville 5Increase from 20 mg/L to40 mg/L, 1983 to 2008

Increase from 20 mg/L to 40 mg/L, 1983 to 2008 3.5 to 5 mg/L 1983-2008 Sodium and Chloride Issues

Orangeville 5A

Increase from 15 mg/L to 25 mg/L, 1983 to 2008

Increase from 20 mg/L to 50 mg/L, 1984 to 2008

3.5 to 5 mg/L 1983-2008; concentration close to or above the half MAC since 2007. Sodium and Chloride Issues

Orangeville 6Increase from 3.5 mg/L to 25 mg/L, 1983 to 2008

Increase from 3.5 mg/L to 40 mg/L, 1983 to 2008 2.7 to 3.1 mg/L 2001-2008 Sodium and Chloride Issues

Orangeville 7Slight upward trend; below 10 mg/L

Slight upward trend; below 20 mg/L No concern No Issues

Orangeville 8B No upward trend; below 10 mg/LSlight upward trend; below 20 mg/L No concern No Issues

Orangeville 8CSlight upward trend; below 10 mg/L

Slight upward trend; below 50 mg/L No concern No Issues

Orangeville 9A

Increase from 33 mg/L to over 85 mg/L, 2001 to 2008; close to or over half MAC since 2009

Increase from 67 mg/L to over 170 mg/L, 1999 to 2008; close to half MAC since 2004 No concern Sodium and Chloride Issues

Orangeville 9B

Increase from 45 mg/L to over 90 mg/L, 2001 to 2008; close to or over half MAC since 2009

Increase from 90 mg/L to over 180 mg/L, 2001 to 2008; close to or over half MAC since 2005 No concern Sodium and Chloride Issues

Orangeville 10Increase from 50 mg/L to over 95 mg/L, 2002 to 2008

Increase from 153 mg/L to over 170 mg/L, 2001 to 2008; close to or over half MAC since 2009 No concern Sodium and Chloride Issues

Orangeville 11Increase from 5 mg/L to over 17 mg/L, 1999 to 2008

Increase from 6 mg/L to over 50 mg/L, 1999 to 2008 No concern Sodium and Chloride Issues

Orangeville 12 Insufficient data Insufficient data Insufficient data No Issues

Well Issue(s) IdentifiedSodium (ODWS:200mg/L)Chloride

(ODWS: 250 mg/L)Nitrate

(ODWS: 10 mg/L)

1.2.3 Issue Contributing Areas As part of the Burnside study, the land area thought to contribute to the identified Issues was delineated and identified as the Issue Contributing Area (ICA). The report formed the foundation data for the technical content of the CVSPA Assessment Report (AR), which received MOE approval in July 2011 (CVSPA, 2011). Further details regarding the assessment and documentation process are provided below.

1.2.4 CVSPA Assessment Report Microsoft Office Excel® software was used to perform the analyses and to carry out linear regression analyses on the data (Burnside, 2010). The data were plotted, and trend lines for averaged parameter concentrations computed. Statistical projection of the trend lines past the current time series (linear regression analyses) suggested that the concentrations may exceed the ODWS within a period of 50 years. The CVPSA technical staff concluded that the test for an Issue as per the Technical Rules was met. This decision was peer reviewed, with participation of both the consultant and the Town of Orangeville. The CVSPA AR, including the information on Issue Identification was released for public consultation, accepted by the CTC Source Protection Committee (SPC) and ultimately approved by the Ministry of the Environment (MOE).

1.3 Summary of Previous Assessments Graphs of the chemical concentration trends in the various municipal wells are included in Appendix 1, and a summary of the previous assessments is provided below.

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1.3.1 Sodium (ODWS - 200 mg/l) The following is a summary of the sodium assessments for the Orangeville municipal wells:

• Well 2A - averaged 9 mg/l from the mid-1980’s to the late 90’s; between 2002 and 2008, average concentration doubled to approximately 20 mg/l. During the period 2009 to 2012, the average increased further to around 30 mg/l.

• Well 5 – averaged19 mg/l from the mid-1980 to the late 90’s; between 2002 and 2008, average concentration doubled to approximately 37 mg/l. During the period 2009 to 2012, the average rose further to around 45 mg/l.

• Well 5A – averaged18 mg/l from the mid-1980 to the late 90’s; between 2002 and 2008, the average increased to approximately 27 mg/l. During the period 2009 to 2012, the average concentration rose slightly to around 30mg/l.

• Well 6 - averaged 4 mg/l from the mid-1980 to the mid 90’s; between 2002 and 2008, the average increased six-fold to approximately 26 mg/l. During the period 2009 to 2012, the average concentration doubled to around 60mg/l.

• Well 9 B- averaged 68 mg/l from 2001 to 2008. During the period 2009 to 2012, the average rose to around 105 mg/l. This well has shown concentrations close to or over half of the Maximum Acceptable Concentration (MAC) since 2009. The “half of MAC” criterion is commonly used as a warning threshold.

• Well 9A- averaged around 50 mg/l from 2000 to2008. During the period 2009 to 2012, the average doubled to about 103 mg/l. This well has shown concentrations close to or over half of the Maximum Acceptable Concentration (MAC) since 2009.

• Well 10 - averaged 67 mg/l from 2000 to 2008. During the period 2009 to 2012, the average maintained, with the concentration topping off at about 75 mg/l.

• Well 11 - averaged 11 mg/l from 2000 to 2008. During the period 2009 to 2012, the average concentration doubled to approximately 23 mg/l.

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1.3.2 Chloride (ODWS - 250 mg/l) The following is a summary of the chloride assessments for the Orangeville municipal wells:

• Well 2A - averaged about 25 mg/l from the mid-1980’s to the late 90’s; between 2002 and 2008, the average concentration increased to approximately 44 mg/l. During the period 2009 to 2012, the average rose further to about 52 mg/l.

• Well 5 – averaged 49 mg/l from the mid-1980 to the late 90’s; between 2002 and 2008, the average concentration rose to about 76 mg/l. During the period 2009 to 2012, the average rose further to around 86 mg/l.

• Well 5A – averaged around 42 mg/l from the mid-1980 to the late 90’s; between 2002 and 2008, the average increased to approximately 55 mg/l. During the period 2009 to 2012, the average maintained at about 58 mg/l.

• Well 6 - averaged 8 mg/l from the mid-1980 to the mid 90’s; between 2002 and 2008, the average increased eight-fold to approximately 62 mg/l. During the period 2009 to 2012, the average doubled to around 133 mg/l.

• Well 9 B- averaged 131 mg/l from 2002 and 2008. During the period 2009 to 2012, the average concentration rose to about 185 mg/l. This well has shown concentrations close to or over half of the Maximum Acceptable Concentration (MAC) since 2009. The “half of MAC” criterion is commonly used as a warning threshold.

• Well 9A- averaged 115 mg/l from 1999 and 2008. During the period 2009 to 2012, the average concentration increased to 190 mg/l. This well has shown concentrations close to or over half of the Maximum Acceptable Concentration (MAC) since 2009.

• Well 10 – averaged 144 mg/l from 2000 and 2008. During the period 2009 to 2012, the average increased to approximately 160 mg/l.

• Well 11 - averaged 29 mg/l from 2000 and 2008. During the period 2009 to 2012, the average concentration rose to around 75 mg/l.

1.3.3 Nitrate (ODWS - 10 mg/l) No nitrate issues were identified at any of the town’s wells. However, increasing trends were observed at the following wells:

• Well 5 – generally fluctuated between 3.5 and 5 mg/l from1983 and 2008. During the period 2009 to 2012, the average concentration remained around 4-4.5 mg/l.

• Well 5A – generally fluctuated between 3.5 and 5 mg/l from1983 and 2008. In 2007, a concentration of 5.8 m/g was recorded. During the period 2009 to 2012, the average concentration fluctuated around the 5 mg/l mark.

• Well 9 B- showed general increase in concentration from 2.7 mg/l in 2001 to 3.1 mg/l in 2008. During the period 2009 to 2012, average concentration remained between 3.2 and 3.5 mg/l.

• Well 9A - showed general increase in concentration from 2 mg/l in 2000 to 3.2 mg/l in 2008. During the period 2009 to 2012, average concentration remained rise between 3.2 and 3.5 mg/l.

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1.4 Probable Sources of Sodium and Chloride The sources of sodium and chloride were suspected to be linked to road salt application as a part of winter road maintenance. It was anticipated that this impact would be more significant in areas with higher percentages of impervious surfaces such as roads and parking lots that require road salt application (Burnside, 2010). The trend graphs (Appendix 1) show a significant change in gradient between the pre- and post -2000 periods. The gradient of the trend graph becomes steeper after 2000 indicating that there may have been a significant increase in the amount of sodium and chloride (road salt) reaching the aquifer in this period.

The area on the west end of the town features several subdivisions and developments that have been built since 2000. This area also features the Wellhead Protection Areas (WHPA) for Wells 2A, 5/5A, 6, 9A/9B, 10 and 11 identified as having sodium and chloride issues (Burnside, 2010). The WHPA defined for Well 2A, Well 5/5A and Well 9A/9B overlap with one another and have been mapped as a single WHPA. The WHPA for Wells 6 and 11 have been mapped as single WHPA for the same reason. Based on the pattern of development in this area and the winter road maintenance practices it has been determined that road salts are the main cause of the water quality issue being observed at these wells. The WHPA for Well 2A, 5/5A and 9A/9B features the main east west arterial road through the town as well as the new bypass. Discussions with Orangeville Public Works staff indicate that besides the standard road salt applications that would occur in this area, the town also maintains sidewalks within the subdivisions (Burnside, 2010); there is therefore an additional component of salt application that takes place in this area. There are also a number of large parking lots that have been developed in this area as part of shopping facilities that have been developed on the west side of the town. It is assumed that salt application will also occur on these facilities in an effort to maintain a customer friendly environment for shoppers. The observed increase and trend in sodium and chloride at Wells 2A, 5/5A and 9A/9B are linked to this occurrence. The fact that these wells are characterized GUDI also indicates that they would be very susceptible to this form of water quality impact. The WHPA for Well 6 and Well 11 encompasses an area on the western edge of the town within which new subdivisions and shopping facilities have also been developed since 2000. Alongside these developments are a number of major roadways including the recently constructed Country Road 109 which connects Highway 10 east of the former Highway 9, now County Road 109 and Townline. It is thought that the winter maintenance of these roadways is a major contributor to the observed sodium and chloride concentrations (Burnside, 2010). The WHPA for Well 10 encompasses a large area to the south of the town and includes a number of major roadways, including Highway 10 which runs north to south within the WHPA-A. This is a major provincial highway and has been expanded in the past decade in the vicinity of Well 10. There are also a number of other roadways that traverse the WHPA and the WHPA also includes the edges of one sub-division in Orangeville. The winter maintenance programs on these roadways and especially on Highway 10, is interpreted as being a major contributor of the sodium and chloride impact at this well. Well 10 is identified as a GUDI well which makes it more susceptible to this form of impact. Runoff from parking lots, streets and stormwater ponds within the WHPA-E may also be contributing to the occurrence of the issue (Burnside, 2010).

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1.5 Issue Contributing Areas The Technical Rules require that the land area where activities are thought to contribute to a parameter’s increase be delineated as the Issue Contributing Area (ICA) for that parameter. The ICA would then be the area subject to Source Protection Policy (SPP) application.

In absence of detailed land-based data for the town’s wellfield areas, the ICA was delineated as the combined extent of the Well Head Protection Area (WHPA) A to E for the municipal well. It was thought that by applying the specific SPP to these ICAs, the activities contributing to the increase could either be identified or regulated– eventually leading to a stabilization or reduction of the parameter concentration in question.

1.6 Study Criteria The methodology utilized for this assessment is fully described in the sections below. As mentioned earlier, the previous Issues analyses completed for Orangeville (Burnside, 2010) utilized a 50-year cut-off time frame for parameter exceedance of ODWS values, as a criterion for determining an ICA. This study adopted a 30 -year time-frame in keeping with that used for the Halton Region Study (CTC, 2013). In addition, the analysis also considered confirmed exceedances of the ½ MAC (Maximum Allowable Concentration) values.

The Town of Orangeville also supplied additional raw water data, collected during the January 2009 to December 2012 period.

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2.0 METHODOLOGY CTC staff undertook a review of the parameter trends by subjecting the datasets to advanced methods of statistical analyses. In addition, a review of land use around municipal wells was undertaken to try and supplement the understanding of how changes on the landscape may have influenced or impacted concentration trends in the past, and how proposed changes in the future could potentially impact these trends.

2.1 Statistical Review A review of the full datasets (those used for the assessment report, plus recent data to the end of 2012) using the XLSTAT® software. This software includes the Mann-Kendall trend test, which is a tool which is able to determine if a trend exists in a series and can also assess seasonal trends in the data set. This test is a nonparametric test to assess time series data for possible trends and if there is a seasonal component in the series. This test was first suggested by Mann (1945), further studied by Kendall (1975) and improved by Hirsch (1982, 1984) to account for seasonality.

XLSTAT® provides additional insight into a series of data, when compared to Excel®, which provides basic trend analysis tools - linear, exponential, and logarithmic curve fitting and projection. This functionality allows for the visual assessment of trends and prediction of future water levels, but does not provide an objective assessment as to the validity of the trend.

2.2 Datasets The Town of Orangeville provided Excel spreadsheets of water quality test results from 1984 to 2012 as inputs for the statistical analysis. These files included the average annual concentrations of sodium, chloride, and nitrate for following municipal well systems:

• Orangeville Well 2A, 5/5A, 6, 7, 8B/8C, 9A/9B, 10, 11, and 12.

2.3 Analysis Trend analysis involves two distinct steps. The first is a determination of whether the probability distribution of a dataset has changed over time, while the second is the description of rate of that change (USGS, 1991). To complete this analysis, CTC Staff undertook a review of the entire dataset spanning from 1984 to end 2012 for each well, because measuring changes in the data distribution over time requires large datasets.

XLSTAT® was used to complete the analysis. This software package includes the Mann-Kendall trend test, which is a tool which is able to determine if a trend exists in a series and can also take into consideration seasonal variations in the data set.

The null hypothesis (known as “H0”) for these tests is that there is no trend in the series. The three alternative hypotheses are that there is a negative, non-null, or positive trend to the data. The Mann-Kendall tests are based on the calculation of Kendall's “tau” measure of association between two samples, which is itself based on the ranks with the samples. The variance of the statistic can be calculated assuming that the series are independent (e.g., values of January and February are independent) or dependent, which requires the calculation of a covariance

XLSTAT® provides additional insight into a series of data, when compared to Excel®, which provides basic trend analysis tools - linear, exponential, and logarithmic curve fitting and projection. This functionality allows for the visual assessment of trends and prediction of future water levels, but does not provide an objective assessment as to the validity of the trend.

The confidence limits of the datasets are the lower and upper boundaries / values of a confidence interval, and are the values which define the range of a confidence for the data. Confidence limits of 95 % have been chosen for this assessment. This means that if the same

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data population is sampled on numerous occasions and interval estimates are made on each occasion, the resulting intervals would bracket the true population values in approximately 95% of the cases. i.e., there is a 5% chance that the representative data would fall outside this range. This is a useful measure of the reliability of a dataset, especially where a wide scatter in the data is evident.

Projection of the mean and of the confidence limits into the future allows for an assessment of the timeline within which a parameter concentration could potentially meet or exceed a set quality criterion – in this case, the ODWS. The projection of the mean gives an average time within which the ODWS could potentially be met, while the projection of the confidence limits give an indication of the earliest and latest expected time within which the ODWS could potentially be exceeded, given the statistical properties of a dataset.

Detected exceedances of the ½ MAC were also considered in the analysis, particularly for wells with uncertain trends or predicted exceedances of the ODWS close to 2043. The ½ MAC is a commonly used trigger for enhanced vigilance.

The findings of this analysis are presented in Section 3, while the detailed graphical interpretations are provided in Appendix 2.

2.4 Land Use Review Mapping dating back to the 1990s was accessed in order to study the changes in land use over the last two decades, and to find out if water quality could have been impacted by these changes. Planned land usage was also reviewed to determine whether there was a potential for land use changes to impact water quality in the future. The review was undertaken as follows:

1. Past and Current scenario - land use mapping / data for the past was compared with current data. For past scenarios, Ecological Land Classification (ELC) mapping for the year1999 was accessed. Per the current scenario, mapping for the year 2012 was utilized.

In addition, the Official Plans for the Town of Amaranth (Town of Amaranth, 2004), and Township of East Garafraxa (Township of East Garafraxa, 2006) were consulted to update land use outside the Credit River Watershed. Residential and Commercial developments located in these areas were reviewed to represent current land use as interpreted from aerial photographs.

2. Future scenario – Referenced using the land use analyses undertaken for the Tier 3 Water Budget and Local Area Risk Assessment Study (AquaResources Inc., 2011).

Future land use was created by merging the Official Plans from the Towns of Caledon, Mono, and Townships of East Garafraxa and Amaranth, as well as the Official Plan Land Use mapping compiled by the CVC in their Subwatershed 19 Study (CVC, 2009). In consultation with the Town of Orangeville’s planners, CVC modified the Town of Orangeville’s Official Plan mapping to take into consideration lands which could not be developed due to environmental or infrastructure constraints.

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The mapping related to the land usage review is shown in Appendix 3. The various mapping products were compared to assess land use changes, specifically with respect to increases in urban land uses compared to employment areas (industrial/commercial land uses) and urban areas (industrial /commercial/mixed use and residential land uses).

If the proposed development in these areas is realized per the mapping shown for the future scenario, it is thought that winter salting activities on roads and parking lots may increase. If this occurs, then the timelines associated with the future projection for sodium and chloride concentrations will likely change.

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3.0 RESULTS 3.1 Overview The detailed results from the statistical analyses are presented by wellfield in Appendix 2. The statistical equation and associated statistical properties generated by each dataset are indicated with each figure. The results of the hypotheses testing are also shown, as are the confidence intervals for the mean and limits of each dataset. The results are summarized in Table 3-1, below.

3.2 Sodium (ODWS = 200 mg/L) 3.2.1 Confirmed: Wells with No Issue(s) The enhanced statistical analysis and land use assessment has confirmed the previous interpretation by Burnside (2010) that there are no issues associated with sodium in the following wells:

• Orangeville Well 7, 8 B/8C, and 12.

3.2.2 Issues Not Retained The enhanced statistical analysis and land use assessment has NOT confirmed the previous interpretation (Burnside, 2010) that there are issues associated with sodium in the following wells:

• Orangeville Wells 2A, 5/5A, 10 and 11.

Therefore, the issues with respect to sodium in these wells should NOT be retained.

Table 3-1: Summary of Water Quality Statistical Review

Early Median Late Early Median Late Early Median LateOrangeville 2A >2200 >2200 >2200 Sep-2145 Mar-2156 Apr-2162 Nov-2079 Aug-2098 May-2117 No Issues retainedOrangeville 5 Jul-2183 May-2091 Aug-2102 Aug-2098 Mar-2107 Mar-2111 >2200 >2200 >2200 No Issues retainedOrangeville 5A >2200 >2200 >2200 >2200 >2200 >2200 Jun-2043 Jun-2056 May-2069 No Issues retained

Orangeville 6 Mar-2033 Nov-2034 May-2036 Jun-2031 Jun-2043 Mar-2055 >2200 >2200 >2200Sodium and Chloride Issues retained based on trend since 2002.

Orangeville 7 Nov-2034 Nov-2034 Nov-2034 >2200 >2200 >2200 >2200 >2200 >2200 No Issues Orangeville 8B May-2036 May-2036 May-2036 >2200 >2200 >2200 >2200 >2200 >2200 No Issues Orangeville 8C >2200 >2200 >2200 >2200 >2200 >2200 >2200 >2200 >2200 No Issues

Orangeville 9A Dec-2023 Nov-2025 Oct-2027 Aug-2013 Jan-2018 Mar-2022 Nov-2049 Aug-2056 Jun-2063Sodium and Chloride Issues retained

Orangeville 9B May-2023 May-2026 Jun-2029 Nov-2013 Oct-2018 Sep-2023 Nov-2056 Apr-2062 Sep-2067Sodium and Chloride Issues retained

Orangeville 10 Oct-2071 May-2088 Dec-2104 Mar-2020 Jul-2033 Dec-2046 >2200 >2200 >2200Chloride Issue retained; sodium issued NOT retained

Orangeville 11 Sep-2115 Apr-2118 Nov-2120 Jan-2039 Mar-2041 May-2043 >2200 >2200 >2200Chloride Issue retained; sodium issued NOT retained

Orangeville 12 >2200 >2200 >2200 Sep-2161 Aug-2163 Jul-2165 >2200 >2200 >2200 No Issues NotesND - Not detected

Aug-2013 Parameter may exceed criterion by this date, which is within the 30-year planning horizon

Recommended ActionWellSodium Chloride Nitrate

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3.2.3 Issue(s) Retained The enhanced statistical analysis and land use assessment has confirmed the previous interpretation (Burnside, 2010) that there are issues associated with sodium in the following wells:

• Orangeville Wells 6 and 9A/9B.

The median concentration is expected to exceed the ODWS prior to 2043 for each of these three wells. For Well 6, a break in the trend line was observed in 2002, which correlates with a major commercial and retail development in the capture zone of the well. Therefore, the data from 2002 to 2012 were used to predict future sodium concentrations for this well. Wells 9A and 9B have had recorded exceedances of the ½ MAC, in addition to the predicted ODWS exceedance by 2025 (Well 9A) and 2026 (Well 9B).

Therefore, the issues with respect to sodium in these three wells should be retained.

3.3 Chloride (ODWS = 250 mg/L) 3.3.1 Confirmed: Wells with No Chloride Issue(s) The enhanced statistical analysis and land use assessment has confirmed the previous interpretation by Burnside (2010) that there are no issues associated with chloride in the following wells:

• Orangeville Wells 7, 8B/8C, and 12.

3.3.2 Chloride Issues Not Retained The enhanced statistical analysis and land use assessment has NOT confirmed the previous interpretation (Burnside, 2010) that there are issues associated with chloride in the following wells:

• Orangeville Wells 2A, and 5/5A.

Therefore, the issues with respect to chloride in these wells should NOT be retained. 3.3.3 Chloride Issue(s) Retained The enhanced statistical analysis and land use assessment has confirmed the previous interpretation (Burnside, 2010) that there are issues associated with chloride in the following wells:

• Orangeville Wells 6, 9A/9B, 10, and 11.

The median concentration is expected to exceed the ODWS prior to 2043 for each of these five wells. For Well 6, a break in the trend line was observed in 2002, which correlates with a major commercial and retail development in the capture zone of the well. Wells 6, 9A/9B, and 10 have had recorded exceedances of the ½ MAC, in addition to the predicted ODWS exceedance by 2018 (Wells 9A/9B), 2033 (Well 10), 2041 (Well 11), and 2043 (Well 6). Given the predicted chloride exceedance by 2043 for Well 6, combined with the detected exceedances of the ½ MAC, consideration of the 2002-2012 period for the statistics was not required. If the 2002 to 2012 data were considered for this well, the exceedance of the ODWS would be about 2022.

Therefore, the issues with respect to chloride in these five wells should be retained.

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3.4 Nitrate (ODWS = 10 mg/L) 3.4.1 Confirmed: No Issues Although nitrate was detected in some of the municipal wells in the Orangeville area, Burnside (2010) did not identify any Issues for any of these wells. This interpretation was confirmed by the enhanced statistical analysis. Although some wells have upward trends (Wells 2A, 5/5A, and 9A/9B), of these, only Wells 5/5A have had concentrations over the ½ MAC. None of the median values are predicted to exceed the ODWS by 2043. Therefore, no Issues related to nitrate are considered to exist. Monitoring of nitrate in the raw water should continue annually, however, since detectable nitrate has been found in the wells, and nitrate levels may increase in the future because of increasing urbanization and resultant increases in nutrient applications for lawn maintenance. Given the higher nitrate concentrations observed in Wells 5 and 5A, monthly monitoring is recommended for these two wells.

3.5 Land Usage Review Figure 3, Appendix 3 illustrates land areas where land use may change according to the Official Plans as compared to current land use. This figure was created by digitally overlaying Figure1 and Figure 2 using a Geographic Information System. The most significant land use changes that may potentially occur in the Study Area are located on the western reaches of the Town of Orangeville and in the nearby Townships of Amaranth and East Garafraxa. This area is a sensitive area as the source areas for many of the Town of Orangeville and Township of Amaranth (Pullen Well) wells are derived from this recharge area.

If the proposed development in these areas is realized, it is thought that winter salting activities on roads and parking lots may increase. If this occurs, then the timelines associated with the future projection for sodium and chloride concentrations may be impacted.

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4.0 CONCLUSIONS AND RECOMMENDATIONS The Technical Rules (Part XI.1, Rules 114–117) define an existing water quality problem associated with a drinking water source, or evidence of a trend that suggests a deterioration of water quality. They further state that Issues must result from the deterioration of the quality of water for use as drinking water, and must be amply documented.

The rules are not explicit on the mechanisms or guidelines used to define an Issue, and leave a fair amount to professional interpretation. This has led to some degree of disagreement on the basis for which Issues have been identified in the Town of Orangeville municipal wells.

The identification of an Issue in the UAR was predicated on an assessment of sodium, chloride and nitrate concentration at each of the Region’s municipal wells, over a time span of 25 years (1984-2010). Microsoft Office Excel® software was originally used to perform the analyses and to carry out linear regression analyses on the data. The data was assessed against prescribed concentration limits set for each parameter, known as the Ontario Drinking Water Standards (ODWS). Water quality deterioration was premised on the fact that an upward trend in the average concentration of each parameter was observed over the 25-yr time span.

It is widely understood that statistical analysis of the properties of historic water quality data is a powerful tool in the assessment of trends and the prediction of how such trends might extend into the future, given the current land usage. It is also understood that future projection of trends based on past data can be impacted by many factors and as such, has limitations (USGS, 1991).

This updated analysis was completed to develop a better understanding of the statistical properties of the data, by applying a more advanced statistical package (XLSTAT®). This study also undertook a review of the historic land usage around municipal wells, to see whether correlations could be made between activities on the landscape and trends in the data. Future land use plans for the Town of Orangeville were also reviewed in an attempt to understand whether potential changes on the landscape may impact water quality in the future.

The previous Issues analyses for Orangeville (Burnside, 2010) utilized a 50-year cut-off time frame for parameter exceedence of ODWS values, as a criterion for determining an ICA. This study adopted a 30 year timeframe in keeping with that approved for the Halton Region Study (CTC, 2013).

4.1 Wells with No Water Quality Issues The updated statistical analyses conclude that sodium, chloride, and nitrate will all remain below the respective criteria until after 2043 for all of the following:

• Orangeville wells 2A, 5/5A, 7, 8A/B, and 12;

Therefore, no water quality issues should be considered to have been identified for any of the above wells.

4.2 Wells with Water Quality Issues The updated statistical analyses conclude that the average sodium concentration may exceed the criterion before 2043 in the following:

• Orangeville wells 6, 9A and 9B;

In addition, the updated statistical analyses conclude that the average chloride concentration may exceed the criterion before 2043 in the following:

• Orangeville wells 6, 9A and 9B, 10, and 11.

15 |


However, the nitrate concentration is not expected to exceed the criterion in any of the wells studied before 2045.

4.3 Issue Contributing Areas Based on the analyses described above, it is recommended that the previous Issue Contributing Areas (ICA) delineations (Burnside, 2010) be retained for the wells concerned.

Although sodium and chloride issues identified for Wells 2A and 5/5A no longer pertain, the WHPA for Wells 9A and B does extend across the full extent of the combined ICA. As such, the current ICA should be retained to ensure full protective coverage. In support, the land use analyses do suggest that most significant future land use changes in the Town of Orangeville will likely occur in the western extent of this ICA.

4.4 Future Monitoring and Re-analysis A number of the municipal wells in the Study Area have increasing trends for one or more of the parameters considered (i.e., sodium, chloride, nitrate). Therefore, continued monitoring would be prudent and would also confirm if implementation of risk management measures is effective.

It is further recommended that the MOE, as part of its review of the Proposed Source Protection Plan policies, consider this re-analysis. As deemed necessary by the Ministry, they may request the Source Protection Authority review policies which require prohibition of activities which are significant in the ICAs beyond the areas where these activities are deemed significant under the standard provincial criteria. This review could assess if a management approach in parts of the ICAs may be sufficient to meet the goal of ensuring that the threat ceases to be or does not become significant.

16 |


5.0 REFERENCES CVSPA, 2011. Updated Assessment Report, Credit Valley Source Protection Area. Approved by

the Minister of the Environment, July, 2011.

Genivar, May 2011. Drinking Water Threats in Issue Contributing Areas, Credit Valley Source Protection Area. Report prepared for Credit Valley Conservation Authority, May 2011.

Hirsch, R.M., 1982. “A comparison of four record extension techniques”. In: Water Resources Research 15, 1781-1790.

Hirsch, R. M., 1988. “Statistical Methods and Sampling Design for Estimating Step Trends in Surface-water Quality”. In: Water Resources Bulletin, 24, 493-503.

Kendall, M.G., 1975. Rank Correlation Methods, 4th edition. Charles Griffin, London.

Mann, H. B., 1945. “Nonparametric Test against Trend”. In Econometrica 13, 245-259.

R.J Burnside & Associates Limited, May 2011. Memo, Town of Orangeville Issue Contributing Areas. Memo prepared for Credit Valley Conservation Authority, May 2011..

R.J Burnside & Associates Limited, July 2010. Issues Evaluation and Threats Assessment, Town of Orangeville. Report prepared for Town of Orangeville, July 2010.

USGS, 1991. Statistical Methods in Water Resources. U.S. Geological Survey, Techniques of Water-Resources Investigations Book 4, Chapter A3 by D.R. Helsel and R.M. Hirsch.

XLSTAT Users Guide, 2013. Published by AddinSoft Inc. XLSTAT Version 2013.2.03.

17 |

Issue Determination Town of Orangeville Wells – Draft for Discussion September 3, 2013

Appendix 1

Issues Analysis Water Quality Graphs

1984-2008

The average parameter (nitrate, sodium and chloride) concentration is indicated on each figure.

18 |


Figure 1: Historical Sodium Concentration, Orangeville Wells 2A, 5,5A,7, 9A, 9B : 1984-2012

0

20

40

60

80

100

120

140

160

180

200

1975 1980 1985 1990 1995 2000 2005 2010 2015 2020 2025 2030 2035 2040 2045 2050 2055 2060

Year

Sodi

um C

once

ntra

tion

(mg/

L)

Orangeville Well 2A Orangeville Well 5A Orangeville Well 5 Orangeville Well 7 Orangeville Well 9A Orangeville Well 9B

ODWQS - 200 mg/L

1 |


Figure 2: Historical Sodium Concentration, Orangeville Wells 6, 10, 11 : 1984-2012

0

20

40

60

80

100

120

140

160

180

200

1975 1980 1985 1990 1995 2000 2005 2010 2015 2020 2025 2030 2035 2040 2045 2050 2055 2060

Year

Sodi

um C

once

ntra

tion

(mg/

L)

Orangeville Well 6 Orangeville Well 10 Orangeville Well 11

ODWQS - 200 mg/L

2 |


Figure 3: Historical Sodium Concentration, Orangeville Wells 8A, 8B, 8C,12 : 1984-2012

0

20

40

60

80

100

120

140

160

180

200

1975 1980 1985 1990 1995 2000 2005 2010 2015 2020 2025 2030 2035 2040 2045 2050 2055 2060

Year

Sodi

um C

once

ntra

tion

(mg/

L)

Orangeville Well 8A Orangeville Well 8B Orangeville Well 8C Orangeville Well 12

ODWQS - 200 mg/L

3 |


Figure 4: Historical Chloride Concentration, Orangeville Wells 2A, 5,5A,7, 9A, 9B : 1984-2012

0

25

50

75

100

125

150

175

200

225

250

1975 1980 1985 1990 1995 2000 2005 2010 2015 2020 2025 2030 2035 2040 2045 2050 2055 2060

Year

Chl

orid

e C

once

ntra

tion

(mg/

L)


ODWQS - 250 mg/L

4 |


Figure 5: Historical Chloride Concentration, Orangeville Wells 6, 10, 11 : 1984-2012

0

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75

100

125

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175

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225

250

1975 1980 1985 1990 1995 2000 2005 2010 2015 2020 2025 2030 2035 2040 2045 2050 2055 2060

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Chl

orid

e C

once

ntra

tion

(mg/

L)


ODWQS - 250 mg/L

5 |


Figure 6: Historical Nitrate Concentration, Orangeville Wells 2A, 5,5A,7, 9A, 9B : 1984-2012

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

10.0

1975 1980 1985 1990 1995 2000 2005 2010 2015 2020 2025 2030 2035 2040 2045 2050 2055 2060

Year

Nitr

ate

Con

cent

ratio

n (m

g/L)


ODWQS - 10 mg/L

6 |


Figure 7: Historical Nitrate Concentration, Orangeville Wells 6, 10, 11: 1984-2012

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

10.0

1975 1980 1985 1990 1995 2000 2005 2010 2015 2020 2025 2030 2035 2040 2045 2050 2055 2060

Year

Nitr

ate

Con

cent

ratio

n (m

g/L)


ODWQS - 10 mg/L

7 |


Figure 8: Historical Nitrate Concentration, Orangeville Wells 8A 10, 11: 1984-2012

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

10.0

1975 1980 1985 1990 1995 2000 2005 2010 2015 2020 2025 2030 2035 2040 2045 2050 2055 2060

Year

Nitra

te C

once

ntra

tion

(mg/

L)

Orangeville Well 8A Orangeville Well 8B Orangeville Well 8C Orangeville Well 12

ODWQS - 10 mg/L

8 |

Appendix 2

Statistical Analysis

With XLSTAT

9 |

Summary statistics:

Variable ObservationsObs. with missing

data

Obs. without missing

data

Minimum Maximum Mean Std. deviation

Na 28 0 28 8.700 30.000 15.533 5.558

Mann-Kendall trend test / Two-tailed test:

Kendall's tau 1 Sodium = 0.0018*date - 48.51S 305 Criterion = 200 mg/LVar(S) 2496 Earliest date to exceed criterion: Sep‐2267p‐value (Two‐tailed)

Summary statistics:


data


data


Na 30 0 30 19.000 47.000 30.689 8.401


Kendall's tau 1 Sodium = 0.0024*date - 56.09S 378 Criterion = 200 mg/LVar(S) 3141 Earliest date to exceed criterion: Jul‐2183p‐value (Two‐tailed)

Summary statistics:


data


data


Na 30 0 30 3.000 76.000 18.873 19.858

Mann-Kendall trend test / Two-tailed test: Y1 =

Kendall's tau 1 Sodium = 0.0163E-02*date - 603S 55 Criterion = 200 mg/LVar(S) 0 Earliest date to exceed criterion: Mar‐2033p‐value (Two‐tailed)

Summary statistics:


data


data


Na 22 0 22 2.800 16.500 7.897 3.515


Kendall's tau 0 Sodium = 0.0006*date - 15.854S 47 Criterion = 200 mg/LVar(S) 0 Earliest date to exceed criterion: Jan‐2836p‐value (Two‐tailed) 0 Date for median to exceed criterion: Dec‐2884alpha 0 Latest date to exceed criterion: Nov‐2933Sen's slope: 0

Test interpretation:H0: There is no trend in the seriesHa: There is a trend in the series

The risk to reject the null hypothesis H0 while it is true is 19.82%

Summary statistics:


data


data


Na 21 0 21 3.200 6.400 4.945 0.934


Kendall's tau 0 Sodium = 0.0003*date - 6.99S 82 Criterion = 200 mg/LVar(S) 1092 Earliest date to exceed criterion: May‐3770p‐value (Two‐tailed) 0 Date for median to exceed criterion: Jan‐3789alpha 0 Latest date to exceed criterion: Sep‐3807Sen's slope: 0


The risk to reject the null hypothesis H0 while it is true is lower than 1.42%

As the computed p‐value is lower than the significance level alpha=0.05, one should reject the null hypothesis H0, and accept the alternative hypothesis Ha.

As the computed p‐value is greater than the significance level alpha=0.05, one cannot reject the null hypothesis H0.Na = 0.0006*Date ‐ 15.8 (R²=0.156)

Na = 0.0006x ‐ 26.6

Na = 0.0006x ‐ 5.13

0

20

40

60

80

100

120

140

160

180

200

1‐Jan‐82 1‐Jan‐92 1‐Jan‐02 1‐Jan‐12 1‐Jan‐22 1‐Jan‐32 1‐Jan‐42

Na (m

g/L)

Date

Sodium in Orangeville Well 8B

Active Model Conf. interval (Mean 95%) Conf. interval (Obs. 95%)

Na = 0.0003*Date ‐ 6.99 (R²=0.536)Na = 0.0003x ‐ 9.03

Na = 0.0003x ‐ 4.94

0

20

40

60

80

100

120

140

160

180

200


Na (m

g/L)

Date

Sodium in Orangeville Well 8C


Summary statistics:


data


data


Na 14 0 14 28.000 115.000 70.552 27.490


Kendall's tau 1 Sodium = 0.0177*date - 613.63S 83 Criterion = 200 mg/LVar(S) 0 Earliest date to exceed criterion: Dec‐2023p‐value (Two‐tailed)

Summary statistics:


data


data


Na 13 0 13 50.425 96.000 67.225 12.487


Kendall's tau 0 Sodium = 0.0044*date - 102.71S 37 Criterion = 200 mg/LVar(S) 268 Earliest date to exceed criterion: Oct‐2071p‐value (Two‐tailed) 0 Date for median to exceed criterion: May‐2088alpha 0 Latest date to exceed criterion: Dec‐2104Sen's slope: 2


The risk to reject the null hypothesis H0 while it is true is lower than 2.78%

Summary statistics:


data


data


Na 14 0 14 4.000 28.800 14.111 7.042


Kendall's tau 1 Sodium = 0.0045*date - 158.8S 85 Criterion = 200 mg/LVar(S) 0 Earliest date to exceed criterion: Sep‐2115p‐value (Two‐tailed)

Summary statistics:


data


data


Na 6 0 6 7.800 10.100 9.033 0.809


Kendall's tau 1 Sodium = 0.0009*date - 28.05S 9 Criterion = 200 mg/LVar(S) 0 Earliest date to exceed criterion: May‐2588p‐value (Two‐tailed) 0 Date for median to exceed criterion: Oct‐2593alpha 0 Latest date to exceed criterion: Mar‐2599Sen's slope: 0


The risk to reject the null hypothesis H0 while it is true is 13.61%

As the computed p‐value is greater than the significance level alpha=0.05, one cannot reject the null hypothesis H0.Na = 0.0009*Date ‐ 28.053 (R²=0.608)

Na = 0.0009x ‐ 29.8

Na = 0.0009x ‐ 26.3

0

20

40

60

80

100

120

140

160

180

200


Na (m

g/L)

Date

Sodium in Orangeville Well 12


Summary statistics:


data


data


Cl 18 0 18 18.250 56.000 38.181 13.056


Kendall's tau 0.61 Chloride = 1.37*date - 2694S 229 Criterion = 250 mg/lVar(S) 2561 Earliest date to exceed criterion: Sep‐2145p‐value (Two‐tailed)

Summary statistics:


data


data


Cl 30 0 30 27.000 90.000 62.409 15.694


Kendall's tau 0.819 Chloride = 0.0047*date - 105.7S 356.000 Criterion = 250 mg/lVar(S) 3140.667 Earliest date to exceed criterion: Aug‐2098p‐value (Two‐tailed)

Summary statistics:


data


data


Cl 26 0 26 3.590 22.000 10.245 5.841



Summary statistics:


data


data


Cl 21 0 21 3.000 13.100 9.909 3.521


Kendall's tau 0.510 Chloride = 0.0014*date - 44.35S 106.000 Criterion = 250 mg/lVar(S) 1092.000 Earliest date to exceed criterion: Dec‐2465p‐value (Two‐tailed) 0.001 Date for median to exceed criterion: Aug‐2475alpha 0.05 Latest date to exceed criterion: May‐2485Sen's slope: 0.370833333


The risk to reject the null hypothesis H0 while it is true is lower than 0.15%.

Summary statistics:


data


data


Cl 25 0 25 13.000 205.000 102.086 56.230



Summary statistics:


data


data


Cl 25 0 25 13.000 192.000 112.693 48.169


Kendall's tau 0.893 Chloride = 0.0228*date - 739.23S 268.000 Criterion = 250 mg/lVar(S) 0.000 Earliest date to exceed criterion: Nov‐2013p‐value (Two‐tailed)

Summary statistics:


data


data


Cl 14 0 14 6.200 91.500 42.473 25.126


Kendall's tau 0.978 Chloride = 0.0161*date - 580.37S 89.000 Criterion = 250 mg/lVar(S) 0.000 Earliest date to exceed criterion: Jan‐2039p‐value (Two‐tailed)

Summary statistics:

Variable Observations

Obs. with missing

data


data


N 28 0 28 0.875 3.500 2.020 0.753


Kendall's tau 0.590 Nitrate = 0.0002*date - 4.5108S 222.000 Criterion = 10 mg/LVar(S) 2558.000 Earliest date to exceed criterion: Nov‐2079p‐value (Two‐tailed)

Summary statistics:


Obs. with missing

data


data


N 30 0 30 3.800 5.200 4.384 0.356


Kendall's tau 0.167 Nitrate = 4E-05*date + 2.94S 72.000 Criterion = 10 mg/LVar(S) 3134.000 Earliest date to exceed criterion: Jul‐2320p‐value (Two‐tailed) 0.205 Date for median to exceed criterion: May‐2383alpha 0.05 Latest date to exceed criterion: Feb‐2446Sen's slope: 0.014286


The risk to reject the null hypothesis H0 while it is true is 20.47%.

Summary statistics:


Obs. with missing

data


data


N 30 0 30 0.000 4.100 0.165 0.744


Kendall's tau ‐0.750 Nitrate = -1E-04*date + 3.8229S ‐303.000 Criterion = 10 mg/LVar(S) 2971.000 Earliest date to exceed criterion: ‐p‐value (Two‐tailed)

Summary statistics:


Obs. with missing

data


data


N 26 0 26 0.000 0.095 0.016 0.024


Kendall's tau ‐0.618 Nitrate = -5E-06*date + 0.1828S ‐175.000 Criterion = 10 mg/LVar(S) 1789.667 Earliest date to exceed criterion: ‐p‐value (Two‐tailed)

Summary statistics:


Obs. with missing

data


data


N 21 0 21 0.050 2.000 0.272 0.401


Kendall's tau 0.595 Nitrate = 8E-05*date - 2.5473S 122.000 Criterion = 10 mg/LVar(S) 1083.333 Earliest date to exceed criterion: Jun‐2287p‐value (Two‐tailed) 0.000 Date for median to exceed criterion: May‐2329alpha 0.05 Latest date to exceed criterion: May‐2371Sen's slope: 0.01



Summary statistics:


Obs. with missing

data


data


N 14 0 14 1.960 3.600 2.795 0.500


Kendall's tau 0.559 Nitrate = 0.0003*date - 7.1656S 50.000 Criterion = 10 mg/LVar(S) 330.000 Earliest date to exceed criterion: Nov‐2049p‐value (Two‐tailed) 0.007 Date for median to exceed criterion: Aug‐2056alpha 0.05 Latest date to exceed criterion: Jun‐2063Sen's slope: 0.01



As the computed p-value is lower than the significance level alpha=0.05, one should reject the null hypothesis H0, and accept the alternative hypothesis Ha.


N = 8E‐05*Date ‐ 2.55 (R²=0.159)N = 8E‐05x ‐ 3.77

N = 7E‐05x ‐ 1.32

0

1

2

3

4

5

6

7

8

9

10


N (m

g/L)

Date

Nitrate in Orangeville Well 8C


N = 0.0003*Date ‐ 7.17 (R²=0.619)

N = 0.0003x ‐ 7.91

N = 0.0003x ‐ 6.42

0

1

2

3

4

5

6

7

8

9

10


N (m

g/L)

Date

Nitrate in Orangeville Well 9A


Summary statistics:


Obs. with missing

data


data


N 12 0 12 2.350 3.700 2.958 0.432


Kendall's tau 0.657 Nitrate = 0.0003*date - 7.7839S 43.000 Criterion = 10 mg/LVar(S) 211.667 Earliest date to exceed criterion: Nov‐2056p‐value (Two‐tailed) 0.004 Date for median to exceed criterion: Apr‐2062alpha 0.05 Latest date to exceed criterion: Sep‐2067Sen's slope: 0.01



Summary statistics:


Obs. with missing

data


data


N 14 0 14 0.000 0.300 0.024 0.080


Kendall's tau ‐0.356 Nitrate = -2E-05*date + 0.61S ‐17.000 Criterion = 10 mg/LVar(S) 121.000 Earliest date to exceed criterion: ‐p‐value (Two‐tailed) 0.146 Date for median to exceed criterion: ‐alpha 0.05 Latest date to exceed criterion: ‐Sen's slope: 0





N = 0.0003*Date ‐ 7.78 (R²=0.703)N = 0.0003x ‐ 8.37

N = 0.0003x ‐ 7.19

0

1

2

3

4

5

6

7

8

9

10


N (m

g/L)

Date

Nitrate in Orangeville Well 9B


N = ‐2E‐05*Date + 0.608 (R²=0.083)N = ‐2E‐05x + 0.423

N = ‐2E‐05x + 0.793

0

1

2

3

4

5

6

7

8

9

10


N (m

g/L)

Date

Nitrate in Orangeville Well 10


Summary statistics:


Obs. with missing

data


data


N 6 0 6 0.200 0.600 0.450 0.152


Kendall's tau 0.358 Nitrate = 0.0001*date - 4.26S 5.000 Criterion = 10 mg/LVar(S) 26.333 Earliest date to exceed criterion: Feb‐2278p‐value (Two‐tailed) 0.436 Date for median to exceed criterion: Jul‐2290alpha 0.05 Latest date to exceed criterion: Dec‐2302Sen's slope: 0.05



As the computed p-value is lower than the significance level alpha=0.05, one should reject the null hypothesis H0, and accept the alternative hypothesis Ha.N = 0.0001*Date ‐ 4.26 (R²=0.280)

N = 0.0001x ‐ 4.72

N = 0.0001x ‐ 3.81

0

1

2

3

4

5

6

7

8

9

10


N (m

g/L)

Date

Nitrate in Orangeville Well 12


Appendix 3

Land Use Assessment

Issue Determination Orangeville Wells September 3, 2013

Figure 1: Orangeville Land Use: Past Conditions – CVC Ecological Land Classification of 1999 Airphotos

1 |


Figure 2: Orangeville Land Use: Current Conditions – CVC Ecological Land Classification of 2012 Airphotos

2 |


Figure 2: Official Plan land Use - 2031

3 |


Figure 3: land Use Change: Current to Official Plan

4 |

1.0 Introduction1.1 Study Objective1.2 Background1.2.1 The Technical Rules and “Issue” Definition1.2.2 Water Quality Issues in Orangeville Municipal Wells1.2.3 Issue Contributing Areas1.2.4 CVSPA Assessment Report

1.3 Summary of Previous Assessments1.3.1 Sodium (ODWS - 200 mg/l)1.3.2 Chloride (ODWS - 250 mg/l)1.3.3 Nitrate (ODWS - 10 mg/l)

1.4 Probable Sources of Sodium and Chloride1.5 Issue Contributing Areas1.6 Study Criteria

2.0 Methodology2.1 Statistical Review2.2 Datasets2.3 Analysis2.4 Land Use Review

3.0 Results3.1 Overview3.2 Sodium (ODWS = 200 mg/L)3.2.1 Confirmed: Wells with No Issue(s)3.2.2 Issues Not Retained3.2.3 Issue(s) Retained

3.3 Chloride (ODWS = 250 mg/L)3.3.1 Confirmed: Wells with No Chloride Issue(s)3.3.2 Chloride Issues Not Retained3.3.3 Chloride Issue(s) Retained

3.4 Nitrate (ODWS = 10 mg/L)3.4.1 Confirmed: No Issues

3.5 Land Usage Review

4.0 Conclusions and Recommendations4.1 Wells with No Water Quality Issues4.2 Wells with Water Quality Issues4.3 Issue Contributing Areas4.4 Future Monitoring and Re-analysis

5.0 References

issue determination town of orangeville wells€¦ · september 11, 2013 • wells 2a, 5/5a, 6,...

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