Surface Water Vulnerability Analysis

1
Surface Water Vulnerability Analysis
Assessment Report Guidance Module 4

• RFP Teleconference
• Martin Keller, Ministry of the Environment
• November 6, 2006

2
Overview

• Eligible Technical Studies
• Outline of Surface Water Vulnerability Analysis
  process
• Delineating Intake Protection Zones
• Determining Level of Uncertainty

3
Eligible Technical Studies

• Draft Guidance Module 3 Groundwater
  Vulnerability Analysis
• Draft Guidance Module 4 Surface Water
  Vulnerability Analysis
• Draft Guidance Module 5 Issues Evaluation and
  Threats Inventory
• Draft Guidance Module 6 Water Quality Risk
  Assessment

4
Surface Water Vulnerability Analysis

• All surface waters are intrinsically vulnerable
• Intake Protection Zones (IPZs) are delineated to
  protect surface waters from sources of
  contamination (spills as well as chronic
  loadings)
• Information about local site characteristics are
  important to delineate protection zones

5
Drinking Water Sources from Watershed
Characterization
Great Lakes
Inland Rivers Streams
Great Lakes Connecting Channels
Inland Lakes
Collect and Analyze Existing Data Characterize
Intake
Set Default Delineation Zones (IPZs)

• Account/Analyze for Site-Specific Conditions
• Review Existing Studies Reports
• Interview WTP Operators for History of Events
• Local Conditions - slope, soil, land cover, etc
  
• Consider Impact of Preferential Pathways
• Examine Total Water Contributing Area (TWCA)

Refine Delineated Zones
Assign Vulnerability Scores and Level of
Uncertainty to IPZs
Input to Semi Quantitative Risk Assessment
6
Delineating Intake Protection Zones

• Basic approach using existing information
• Limited additional field work and modeling
• IPZ-2 dye tracing, simple hydrologic modeling
• TWCA digital elevation models, air photo
  interpretation

7
Determining Level of Uncertainty

• Confidence in vulnerability assessment process
• Input into Water Quality Risk Assessment
• Determines need for additional data collection /
  analysis
• Uncertainty will be high or low depending on
• Completeness and quality of information
• Model application
• Site specific natural variation
• Other considerations
• Travel time
• Resolution of spatial layers

8
Summary

• All surface water are intrinsically vulnerable
• Protection zones are different for various types
  of intakes
• Site-specific approach has been recommended
• Delineation of these zones is independent from
  the type of the contaminant of concern
• Basic approach using existing information
• Vulnerability scores will be used for risk
  assessment
• Uncertainty determines need for additional data
  collection / modeling

9
Thank You
10
(No Transcript)
11
Surface Water Vulnerability Analysis

• Characterization of intakes is useful for
• delineation of vulnerable zones
• assigning vulnerability score
• Identify data gaps
• Delineate intake protection zones

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Delineating IPZs - Great Lakes

• Great Lakes IPZ-1 (GL IPZ-1)
• Most vulnerable area due to its close proximity
  to the intake
• A set radius of not less than 1 km around intake
• Administrative zone
• Great Lakes IPZ-2 (GL IPZ-2)
• To account for influence of shore, streams and
  rivers that could directly impact on the quality
  of water at the intake
• Based on minimum 2hr travel time and operators
  emergency response time

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Delineating IPZs - Great Lakes
One zone off-shore
Two-zones off-shore
Two zones near-shore
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Delineating IPZs - Great Lakes Connecting Channels
Preliminary one-zone scenario
Revised one-zone scenerio
GC IPZ-1 will extend to a minimum distance of 1
km upstream of the intake. GC IPZ-2 extend the
GC IPZ-2 up-current for a distance derived from
site specific data based on maximum current flows
and drinking water treatment operator response
time.
15
Delineating IPZs - Inland Rivers

• Inland river IPZ-1 (IR IPZ-1)
• Area directly adjacent to the drinking water
  intake
• Semi-circle with radius of at least 200 m around
  river intake
• Inland river IPZ-2 (IR IPZ-2)
• To account for land-use activities directly
  adjacent to the watercourse on which the intake
  is located
• Extends upstream of IR IPZ-1, incorporates a
  setback on land from the watercourse
• Total Water Contributing Area (TWCA) IPZ-3
• To account for chronic contaminant loadings
• Includes the remaining watershed area upstream of
  the drinking water intake

16
Delineating IPZs - Inland Rivers
Three zones scenario
Nested intake scenario
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Delineating IPZs - Inland Lakes

• Inland Lakes IPZ-1 (IL IPZ-1)
• Area immediately adjacent to the drinking water
  intake.
• Circle with radius of at least 1 km around the
  intake.
• Inland Lakes IPZ-2 (IL IPZ-2)
• Acts as a secondary protective zone for the IL
  IPZ-1.
• Includes all land area and stream mixing zones
  that could potentially influence the intake.
• Total Water Contributing Area (TWCA) IPZ-3
• To account for chronic contaminant loadings
• Includes the remaining watershed area upstream of
  the drinking water intake.

18
Surface Water Vulnerability Score (V Vfz x Vfs)
Ranking of vulnerability score Low (V 5)
Medium (5 lt V 6) High (V gt 6)
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Other Designated Systems
Intake Clusters
Lake Shoreline
Stream Reaches