2007 Upper Thames River Watershed Report Cards

• 1.1 Introduction & 1.2 The Process

• 1.3 Water Quality (this page)

• 1.4 Forest Conditions

• 1.5 Watershed Features, Action Plan and Highlights of Progress

• 1.6 References

Back to the 2007 Report Card homepage.

1.3 Water Quality

1.3.1 Introduction

The water quality of the Thames River has undergone vast changes over the past century as a result of human activity in the watershed. Surface water quality has fluctuated in response to changes in urban sewage treatment, agricultural practices, industrial waste management, stormwater management, and other land management practices. Weather also influences water quality.

The UTRCA watershed report cards were developed to outline current water quality conditions and to document changes over relatively short periods of time (five year increments). Thus, the 2007 report cards show changes in surface water quality since the 2001 report cards. It is important to note that water quality varies from year to year and the indicators that measure water quality can fluctuate independently of each other in any given year. The watershed report cards give a general assessment of surface water quality in the watersheds based on key indicators. A more extensive assessment of the data would be required for site specific issues. The Thames Watershed & Region Interim Watershed Description Report, recently completed as part of the local Drinking Water Source Protection process, provides a more comprehensive assessment of water quality over the long term in this region (available through the UTRCA).

1.3.2 Surface Water Quality Indicators and Grades

The 2007 watershed report cards use the provincial grading system developed for conservation authorities: Watershed Reporting: Improving Public Access to Information, May 2003 (Conservation Ontario, 2003). The grading system incorporates provincial guidelines and the range of water quality conditions across Ontario. Three indicators are used to assess surface water quality for each watershed:

• Benthic invertebrates,

• Total phosphorus,

• Bacteria (E. coli).

Descriptions and definitions for these indicators are given in Table 1, as well as in each watershed report card.

Table 1. Description of Surface Water Quality Indicators

Indicator	What it measures	How it is calculated	Why it is important
Benthic	Benthic invertebrates - organisms without a backbone that live in the sediments of a waterbody	A system called the ‘Family Biotic Index’ is used to assess water quality based on the number and type of invertebrates found in a sample. Each invertebrate species is given a score that relates to its pollution-tolerance. The larger the number, the more pollution-tolerant that organism is. The average benthic value was calculated for samples taken from 2001–2005 for the outlet of each watershed.	Benthic organisms are an excellent indicator of the quality of the water and the habitat where they live. Since they are relatively immobile and spend all or most of their life in water, the presence or absence of certain species gives good information on water conditions over time. These organisms are at the bottom of the food chain; therefore, they reflect the health of the aquatic ecosystem.
Phosphorus	The amount of phosphorus in the water	The 75th percentile was calculated for the data for the period 2001-2005 for the site closest to the outlet of each watershed. The 75th percentile (means 75% of the data fall below this value) is used to reflect the tendency for this sampling data to be dry weather biased and, therefore, more accurately reflects pollution levels.	Phosphorus binds to soil particles and thus is an indicator of soil delivery to streams (as well as other contaminants that are carried to the stream on soil particles). Phosphorus is found in soaps, detergents, fertilizers, and pesticides, and contributes to algae blooms in streams and lakes.
Bacteria	The amount of fecal bacteria (E. coli) in the water	A 5 year geometric mean measured in number of E. coli bacteria per 100 ml of water.	E. coli bacteria are found in human and animal waste and their presence in water indicates fecal contamination. E. coli are also a strong indicator of the potential to have other disease-causing organisms in a stream.

Each indicator is given equal weight in determining the overall surface water quality score for each watershed. Point scores for each indicator were calculated, added together, and divided by three to determine the overall letter grade for water quality in each watershed (Table 2). The words used to describe status are “improving,” “declining,” and “steady.” For phosphorus, a change in status resulted when there was an increase or decrease of at least 0.03 mg/l. For bacteria, a change in status resulted when there was an increase or decrease of 100 E.coli/100 ml for levels over 200, or a change of 50 E.coli/100 ml for levels under 200. These two standards were used for bacteria because levels under 200 are rare in this watershed and smaller changes at these lower levels are more significant. For the benthic indicator, a change in status was determined by an increase or decrease of 0.5 from the 2001 result.

Table 2. Surface Water Quality Scoring Grid (Provincial Grading System)

Benthic Score	Phosphorus	Bacteria	Points	Grade		Final Points	Final Grade*
< 5.00	< 0.03	0 – 10	5	A		> 4.5	A
5.00 – 5.75	0.03 – 0.10	11 – 100	4	B		3.6 – 4.5	B
5.76 – 6.50	0.11 – 0.17	101 – 1000	3	C		2.6 – 3.5	C
6.51 – 7.25	0.18 – 0.24	1001 – 10000	2	D		1.5 – 2.5	D
> 7.25	> 0.24	> 10000	1	F		< 1.5	F

* Final grade is determined by adding the points for each indicator and dividing by three.

1.3.3 Surface Water Quality Data Sources

There are several water quality monitoring programs operating in the upper Thames River watershed. Data from the following programs was used to evaluate the watersheds for these report cards.

Benthic Monitoring Program

Benthic invertebrate data has been collected at various sites throughout the upper Thames River watershed since 1994. The Benthic Monitoring Program is a cooperative effort between the UTRCA and the University of Western Ontario (UWO) Zoology Department. Every year, UTRCA staff collect samples from approximately 100 sites across the watershed (fewer sites were sampled in the early years). Each site is sampled once in the spring and some are re-sampled in the fall. The samples are analyzed at the UWO zoology laboratory. The data used for these report cards is from the site closest to the outlet of each watershed.

Provincial Surface Water Quality Monitoring Network

Surface water chemistry is presently monitored at 24 sites within the upper Thames River watershed as part of the Provincial Water Quality Monitoring Network (PWQMN) (Map 4). The network is a cooperative program of the Ministry of the Environment (MOE) and Conservation Authorities. Some of these sites are part of the original PWQMN program that was initiated in the 1960s. Prior to 1996, data was collected from 23 sites in the upper Thames watershed. In 1996, the number of sites was reduced to 15 due to provincial funding cutbacks. In 2002, the UTRCA and MOE redesigned the monitoring program for the upper Thames, bringing the number of sites up to 24 to better reflect the UTRCA’s subwatershed approach of monitoring, reporting and implementing work on the 28 watershed units.

The UTRCA would like to see monitoring stations added in three of the 28 watersheds that currently do not have stations: Whirl Creek, Glengowan (North Thames River above St. Marys), and Mud Creek. Scores for these watersheds are based on benthic data and water chemistry and bacteria of the closest PWQMN station. Whirl Creek and Glengowan were combined with North Mitchell, using the North Thames River station located at the top of the Glengowan watershed. Mud Creek was combined with the Middle Thames, using the station located on the Middle Thames River near Thamesford.

Nine of the 24 PWQMN sites are monitored eight times a year. Water samples are collected at these stations on a monthly basis from May to December and analyzed for the presence of metals, nutrients, and bacteria. The other 15 stations are monitored four times a year, with samples collected on a bimonthly basis from May to December. Since 2006, samples from these 15 stations have not been analyzed for metals as MOE deemed this analysis unnecessary due to low levels.

Data from 2001 to 2005 was used in this report card, although some sites had data missing for 2001 and 2002. The 2001 grades were recalculated using the current provincial methodology. Some sites had data gaps from 1997-2000; at these locations, data from 1990-2000 was used.

Other Water Quality Data Sources

Bacteria (fecal coliform or E. coli) were monitored in river samples as part of the PWQMN until 1996, at which time the Province discontinued this part of the program. In 2001, the UTRCA formed a partnership with the local health units to continue monitoring bacteria at the PWQMN locations. Samples are analyzed at the Ministry of Health laboratory in London.

Data from the City of London was used in the four watersheds not included in the PWQMN. The city has 16 long term monitoring sites around the city and this data was used in the Pottersburg Creek, Medway Creek, Forks and Dorchester watershed report cards.

1.3.4 Water Quality Results

• 1.1 Introduction & 1.2 The Process

• 1.3 Water Quality (this page)

• 1.4 Forest Conditions

• 1.5 Watershed Features, Action Plan and Highlights of Progress

• 1.6 References

Back to the 2007 Report Card homepage.

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