COMPASS09

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COMPASS09 Annual Conference of Compass
Informatics
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Use of Geographic Information Systems (GIS) to
Calculate the Assimilative Capacity of Rivers to
Receive Proposed Discharges

• Vivienne Kelly
• Informatics Reporting
• Office of Environmental Assessment
• t 053-9160612
• e v.kelly_at_epa.ie

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Presentation Outline

• Introduction to Assimilative Capacity
• Calculating Assimilative Capacity
  Concentrations
• Integrating Data Sources
• Demonstration of GIS Assimilative Capacity Tool

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Our Vision

• Aim
• To develop environmental management systems that
  assess and report on environmental quality using
  integrated data from multiple data sources to
  provide more intelligence to data users see and
  to increase the efficient use of EPA resources.
• Systems Developed
• Assimilative Capacity Tool
• Risk Assessment Tool (Landfills, Quarries Mines)

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Assimilative Capacity

• What is assimilative capacity?
• the ability of a body of water to cleanse
  itself its capacity to receive waste waters or
  toxic materials without deleterious effects and
  without damage to aquatic life or humans who
  consume the water.
• How is it calculated?
• Simple calculation (AC (cmax cbackground) x
  (F95 or DWF) x 86.4)
• Environmental Quality Standards (EQS) (cmax)
• Background Chemical Monitoring (cbackground)
• Hydrometric Flow (95iles DWF)
• EPA Role?
• When assessing proposed discharges from IPPC,
  Waste and Waste Water Discharge Applications, the
  EPA must determine the capacity of a waterbody to
  receive the discharge and the potential
  environmental impacts.

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Questions to Ask
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Calculations

• Assimilative Capacity
• Non Toxic Substances ? AC (cmax
  cbackground) x F95 x 86.4
• Dangerous Substances ? AC (cmax cbackground)
  x DWF x 86.4
• The capacity of a water body is calculated in
  kg/day

Variables AC Assimilative
Capacity Cmax      Maximum permissible
concentration (EQS) Cbackground      Background
concentration in river F95 95ile flow in
the river (m3/sec) DWF Dry Weather Flow in
the river (m3/sec)
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Other Calculations

• Resultant Concentration
• Capacity Absorbed

Cmax      Maximum permissible concentration
(EQS) Cfinal      Concentration in river after
discharge of effluent Cback      Background
concentration in river Ceffluent      Treated
effluent concentration Vflow      Volume of flow
in river (95ile or DWF m3/sec) Veffluent     
Volume of effluent (m3/sec)
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Waste Water Discharge Licence Substances
Total Calculations 93 Per Discharge Point
Total Substances 31
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Assimilative Capacity WebGIS Tool

• The Assimilative Capacity Tool is a web based GIS
  application designed to allow licence inspectors
  to calculate the capacity of rivers and the
  surrounding environment to receive pollutants
  from waste water treatment discharges.
• Function
• Determine the capacity of waterbodies to receive
  specific pollutants from proposed discharges.
• Determine the potential impacts to the
  surrounding environment.
• Improve the use of resources produce better
  response times.
• Support decision making.

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Model Concept
Run Engine
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Integration of Internal External Data
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Assimilative Capacity Tool Demonstration
Demonstration
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Caveat

• Decision Support Tool
• Indication of waterbody capacity, not absolute
  rule
• Inspectors must have full understanding of EQS
  for a site and ensure appropriate data used in
  any calculation
• All borderline cases should be examined in full

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Improved Resource Use

• EPA Aim To increase the efficient use of EPA
  resources
• Manual Effort 4-6 days
• No. of Discharges 177
• Approx. Time to Calculate Manually 3yrs
• Total Time using AC Tool 4 days

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Development Team

• EPA Team
• Breen Higgins
• Gavin Smith
• Fiona ORourke
• Deirdre Kirwan
• Tom Stafford
• Ozan Emem
• Jason Larkin
• Claire Byrne
• Aisling McElwain
• George McHugh

• Compass Team
• Ken Dowling
• Pavel Janda
• Seth Girvin
• Maurizio Taddei
• Mick Lennon

THANK YOU
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COMPASS09 Annual Conference of Compass
Informatics