P1252109394GaCLU

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Fine-scale Analysis of Water Quality on the
Southeast Shores of Lake Huron Relevance and
Approach
Presented to RDX Conference Remote Sensing
Across the Great Lakes Observations, Monitoring
and Action April 5, 2006
Presented by Todd Howell Ontario Ministry of
the Environment Environmental Monitoring and
Reporting Branch
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Does spatial focus of the study design influence
the outcome of water quality monitoring in SE
Lake Huron ?

• Widely Recognized Water Quality Concerns
• Adverse microbial water quality resulting in
  posting of public beaches
• Fouling of shoreline by algae.
• Yet Conventional Vessel-based Monitoring Provides
  Limited Insight on the Basis of the Concerns
• Little indication of nearshore eutrophication as
  evidenced by water column levels of phosphorus or
  chlorophyll a
• Fecal indictor bacteria (E. coli) levels
  generally low in the nearshore.
• Study Initiated to Examine Water Quality at the
  Shoreline
• Focus on small tributaries and other small-scale
  sources on the shoreline
• Intent is to examine degree to which
  spatially-localized impacts on water quality
  account for concerns

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Levels of fecal indicator E.coli are low in the
nearshore as assessed in vessel-based surveys
2003 MOE study of nearshore water quality over
shoreline adjacent to three large rivers to SE
Lake Huron
Saugeen River median - 2 cfu/100mL max -320 n -
66 Maitland River median - 2 cfu/100mL max -150
n - 55 Bayfield River median - 3 cfu/100mL max
-380 n - 44
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Total P and Chlorophyll a at MOE
nearshore reference stations suggest oligotrophic
conditions
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Lake Huron Water area 59,600 km2 Mean depth 59
m Trophic status oligotrophic

• Character of Coastline
• clay-dominated till plain backs the shoreline
• numerous watercourses to shoreline
• widespread sandy beaches
• exposed, high energy coastline
• recreational properties at shoreline
• agricultural lands dominates behind coastal
  fringe

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Many small tributaries discharge to lakeshore
Size Distribution of Watersheds Draining to the
Lake Huron Shores from Ausable River to Point
Clark
Goderich
Bayfield
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Eighteen Mile River Study Area
data source NOAA Lake Huron bathymetry
Usually difficult to gain access to immediate
shoreline waters in vessel-based surveys
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Eighteen Mile River Nearshore Water Quality Study

• Diverse Information Collected to Support
  Fine-Scale Analysis of Water Quality at the
  Shoreline
• spatially-intensive field measurements and
  lab-based chemical analysis in the nearshore over
  five survey periods in 2005
• through-time monitoring of water quality in
  Eighteen Mile River
• deployed current meters and water quality sensors
  over the study period
• Three Spatial Elements Surveyed Concurrently in
  the Lake to Provide Integrated Coverage of
  Nearshore
• Depth gt3 m as typical in vessel-based surveys
• Shallow depths accessible with small boat (3 m to
  1.5 m)
• Depths accessible by wading from shoreline (0 to
  1.2 m).

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Study Area Eighteen Mile River Watershed and
Adjacent Lake Huron Shoreline - Rural
environment dominated by agriculture - drainage
area106 km2 - medium to fine sand beach at
shoreline - clay-dominated bluffs behind
beach - scattered recreational properties at
shoreline
18 Mile River Poultry Cattle Swine Humans
18 Mile River 63,000 4,200 6,200 1,400
Study Area
Data Sources Land use - OMNR analysis
Livestock Numbers - Statistics Canada 2001Cenus
Data Aerial Photo -MVCA
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Eighteen Mile River Study Area
3 m
Continuous measurement of six WQ parameters over
track using flow-through sensor set Sensor array
on profiler for periodic water column
measurements
Minimum Working depth limit is 3 meters
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3 m
Positioning using Trimble Pro-XR GPS using Arcpad
on hand-held computer to navigate track. GPS
is interfaced with YSI 600 QS. Conductivity and
temperature logged at waypoints.
Working depth limit is 1.5 meter
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Positioning using Trimble Pro-XR GPS using Arcpad
on hand-held computer to navigate track. GPS
is interfaced with YSI 600 QS. Conductivity and
temperature logged at waypoints.
Maximum working depth 1.2 meters
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- shoreline current flow to south - dry weather
precedes survey
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- slight elevation of TP in narrow band
adjacent to shoreline south of 18 Mile River
Mouth - elevated conductivity adjacent to
shoreline downstream of tributary mouths
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- shoreline current flow light and varied (NW to
SW) - dry weather precedes survey -
tributaries flowing
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- conductivity in whole of shallow water zone
affected by inputs from shoreline - narrow
bands of elevated conductivity adjacent to
shoreline south of tributary mouths - gradient
in nitrates from shoreline to offshore indicates
influence of shore-based inputs on conditions in
immediate nearshore
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- shoreline current flow moderate and to north -
dry weather precedes survey - no tributary flow
- conductivity uniform and suggests little
influence of shore-based discharges on water
quality - shoreline band of slightly elevated
levels of E. coli likely due to wave-induced
physical agitation of shoreline and lakebed
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- subtle gradient in nitrates from offshore to
offshore consistent with little influence from
shore-based discharge on conditions
3D representation of turbidity
- shoreline band of elevated turbidity
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Summary

• Fine-scale effects on water quality at the
  shoreline may not be detected in vessel-based
  surveys
• Fine-scale effects on water quality at the
  shoreline may contribute to formulation of water
  quality concerns
• Localized effects of the discharge from small
  tributaries may be of concern when the area of
  impact is coincident with locations used for
  recreation and or habitat suitable for benthic
  algae.
• Scale of effects is a key consideration in the
  design of water quality monitoring studies

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Acknowledgements

• the staff of EMRB-MOE Great Lakes field
  operations
• Susan Weir, LSB-MOE
• Tanya Kon, University of Guelph
• Emil Bandelj, EMRB-MOE
• Georgina Kaltenecker, EMRB-MOE