1. COMPASS09 Annual Conference of Compass Informatics

2. 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@epa.ie

3. Presentation Outline nIntroduction to Assimilative Capacity nCalculating Assimilative Capacity & Concentrations nIntegrating Data Sources nDemonstration of GIS Assimilative Capacity Tool

4. 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: nAssimilative Capacity Tool nRisk Assessment Tool (Landfills, Quarries & Mines)

5. Assimilative Capacity nWhat 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. nHow is it calculated? àSimple calculation: (AC = (c max – c background ) x (F 95 or DWF) x 86.4) àEnvironmental Quality Standards (EQS) ( c max ) àBackground Chemical Monitoring ( c background ) àHydrometric Flow (95%iles & DWF) nEPA 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.

6. Questions to Ask River Q1: What is the capacity upstream of the discharge? Q2: What is the concentration following the discharge? Q3: What proportion of the capacity has been absorbed as a result of the discharge? UWWTP

7. Calculations nAssimilative Capacity: nNon Toxic Substances AC = (c max – c background ) x F 95 x 86.4 nDangerous Substances AC = (c max – c background ) x DWF x 86.4 n The capacity of a water body is calculated in kg/day Variables: AC= Assimilative Capacity C max = Maximum permissible concentration (EQS) C background = Background concentration in river F 95 = 95%ile flow in the river (m 3 /sec) DWF= Dry Weather Flow in the river (m 3 /sec)

8. Other Calculations nResultant Concentration: nCapacity Absorbed: C max = Maximum permissible concentration (EQS) C final = Concentration in river after discharge of effluent C back = Background concentration in river C effluent = Treated effluent concentration V flow = Volume of flow in river (95%ile or DWF – m 3 /sec) V effluent = Volume of effluent (m 3 /sec) % AC Absorbed = (C max - C back ) - (C max - C final ) (C max - C back ) x 100 C final = (C back x V flow ) + (C effluent x V effluent ) (V flow + V effluent )

9. Waste Water Discharge Licence Substances Total Substances = 31 Total Calculations = 93 Per Discharge Point

10. Assimilative Capacity WebGIS Tool nThe 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. nFunction: à Determine the capacity of waterbodies to receive specific pollutants from proposed discharges. à Determine the potential impacts to the surrounding environment. à Improve the use of resources & produce better response times. à Support decision making.

11. Discharge Point Hydrometric Station Monitoring Station River Flow Direction ENGINE Hydrometric Data AQUARIUS Assimilative Capacity at Proposed Point of Discharge Hydro Flow Data Water Quality Data Proposed Limit Calculation Proposed Discharge Run Engine Model Concept

12. Integration of Internal & External Data

13. Demonstration Assimilative Capacity Tool Demonstration Table of Contents Toolbar Zoom to Area of Interest Zoom to Area of Interest Discharge Point Upstream Monitoring Point Downstream Monitoring Point Select Assimilative Capacity Tool Select Discharge Point Summary of local EPA Monitoring Stations Click to Highlight Station on Map Click Next Hydro Data Report Window Appears User Selects Required Report Summarry Information on Discharge Map of Discharge EQS Exceeded Prior to Discharge Option to Change EQS User Selects New EQS, Saves and Re-runs Report With New EQS Capacity is not Exceeded. Select Environmental Report River Data Water Quality Up & Down Stream Conservation Data Other UWWTPs

14. Caveat nDecision Support Tool nIndication of waterbody capacity, not absolute rule nInspectors must have full understanding of EQS for a site and ensure appropriate data used in any calculation nAll borderline cases should be examined in full

15. Improved Resource Use nEPA Aim: To increase the efficient use of EPA resources nManual Effort: 4-6 days nNo. of Discharges: 177 nApprox. Time to Calculate Manually: 3yrs nTotal Time using AC Tool: 4 days

16. Development Team EPA Team: nBreen Higgins nGavin Smith nFiona ORourke nDeirdre Kirwan nTom Stafford nOzan Emem nJason Larkin nClaire Byrne nAisling McElwain nGeorge McHugh Compass Team: nKen Dowling nPavel Janda nSeth Girvin nMaurizio Taddei nMick Lennon THANK YOU

17. COMPASS09 Annual Conference of Compass Informatics