Radloff March 21 st , 2016 ~:\ mber of th Assocl tNI Engin ring - - PowerPoint PPT Presentation

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Radloff March 21 st , 2016 ~:\ mber of th Assocl tNI Engin ring - - PowerPoint PPT Presentation

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~ E ~ N ~ S ~ O ~ ~ R ~ City of Prince George Wells Protection Plan: For CN Related Risks Presented by: CITY OF ENGINEERING PLANNING CONSULTING www.radloffeng.com PRINCE GEORGE Radloff March 21 st , 2016 ~:\ mber of th Assocl tNI Engin

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SLIDE 1

City of Prince George Wells Protection Plan:

For CN Related Risks

ENGINEERING PLANNING CONSULTING www.radloffeng.com Presented by:

March 21st, 2016

Radloff

CITY OF

PRINCE GEORGE

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mber of th Assocl tNI Engin ring Group of Compan, s

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SLIDE 2

Purpose

Assessment of risk to the City’s wells from CN related activities and the means to mitigate this risk.

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SLIDE 3

The Nechako Aquifer

The aquifer:

  • Provides 95% of City’s well water (PW660, PW605,

PW602/601)

  • Is a highly valuable natural feature producing

excellent well water

  • Is classified by MOE as “1A” (heavily developed

and highly productive and highly vulnerable)

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SLIDE 4

Nechako Aquifer

Area in Pink

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SLIDE 5

Scope

Focus of study between Mile 0 (CN Rail Yard) to Mile 6.31 (Miworth Subdivision)

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SLIDE 6

Wells

Three (3) active wells along the Nechako River: PW601/602, PW605, PW660

  • Located between the CN rail lines & the river
  • Installed value of aprox. $6 million per well
  • Radial Collector Wells
  • Located primarily in glacio-fluvial sand & gravel with

no confining unit to protect from surface spills

  • Vertical migration could be very swift (18 min. worst

case)

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SLIDE 7

Radial Collector Well

VERTICAL TURBINE PUMPS & MOTORS REINFORCED CONCRETE CAISSON

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  • BOTTOM SEAL

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SLIDE 8

Capture Zones

RAILWAY R/W GROUND WATER FLOW ARROWS

LEGEND

CJTYWEU. WATER MAIN WA.TEAT~

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  • PUMPING
FLOW
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CIIPTURE ZONE 600AVS

  • I YEAR

5YEARS

  • 20YEARS
  • 250m

500r1 750m

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WATERTABLE CONTOURS

  • ELEV. (m)

PWWELL605 PW WELL 601

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SLIDE 9

Predictive Contaminant Model

RAILWAY R/W RAILWAY R/W

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CllY WELL @) WATER NAIN WATERTABLE NO PUMP FLOW

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CAPTURE ZONE

60 DAYS

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5 YEARS

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20 YEARS

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SPILL IMPACT AREA

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SLIDE 10

Likelihood Consequence 1 Insignificant 2 Minor 3 Moderate 4 Major 5 Catastrophic A (almost certain) Moderate High Very High Very High Very High B (likely) Moderate High High Very High Very High C (possible) Low Moderate High Very High Very High D (unlikely) Low Low Moderate High Very High E (rare) Low Low Moderate High High

Risk Matrix

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SLIDE 11

Potential Source Likelihood of Occurrence Magnitude of Consequence Risk to Drinking Water Derailments in CN yard D (Unlikely) 2 (Minor) Future wells would need to avoid the CN yard. Low Derailments on railway track and train collisions C (Possible) 4 (Major) The City has 3 active wells; therefore, loss of all wells with one derailment is unlikely. Very High (within 60 days**)

Risk Summary

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SLIDE 12

Potential Source Likelihood of Occurrence Magnitude of Consequence Risk to Drinking Water Grade crossing accidents C (Possible) 4 (Major) The City has 3 active wells; therefore, loss of all wells with one derailment is unlikely. Very High (within 60 days**) Well houses (train collision) E (Rare) 4 (Major) The City has 3 active wells; therefore, loss

  • f all wells with one

derailment is unlikely. High (within 1 day**)

Risk Summary

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SLIDE 13

Potential Source Likelihood of Occurrence Magnitude of Consequence Risk to Drinking Water Track maintenance chemicals D (Unlikely) 2 (Minor) Low Track switch C (Possible) 4 (Major) Very High

Risk Summary

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SLIDE 14

High Priority Actions Initiating Party Preventative (P)

  • r

Responsive (R) Remote pump shut‐down capabilities and procedures (for the wells) City R Emergency water quality monitoring plan (spill incident) City R Remote operation capabilities and procedures (for the wells) City R Additional studies (i.e. groundwater flow direction study; updating numerical flow model of capture zones near CN tracks) focusing on risk and mitigation options. City P Additions to City’s Groundwater Protection Areas (wellheads and Nechako River) City P

Recommendations

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SLIDE 15

High Priority Actions Initiating Party Preventative (P)

  • r

Responsive (R) Reduction of train speeds CN P Creation of a joint emergency response committee (to provide emergency plans and a contact list)* Joint P Enhancement of track maintenance CN P

Recommendations

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SLIDE 16

Moderate Priority Actions Initiating Party Preventative (P)

  • r

Responsive (R) Creation of alternate supply capability (redundancy for PW605) City P/R Greater transparency and improved communication Joint P Minimization/elimination of at grade crossings Joint P

Recommendations

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SLIDE 17

Additional Actions Initiating Party Preventative (P)

  • r

Responsive (R) Advance notification if dangerous goods are being transported CN P/R Installation of at grade crossing arms Joint P Installation of a ground seal (significantly reduces speed of infiltration) – option to be determined based

  • n additional studies

City P Installation of interceptor wells and trenches – option to be determined based on additional studies City P

Recommendations