David Dilks

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David Dilks

  1. 1. Including Science into Policy to  Address Pollution in the Great Lakes Address Poll tion in the Great Lakes David W. Dilks, Ph.D. LimnoTech, Inc. LimnoTech Inc Ann Arbor, Michigan, USA
  2. 2. Outline • Introduction to the Great Lakes • Science and Great Lakes Restoration Science and Great Lakes Restoration • Relevance to Lake Tai
  3. 3. Great Lakes Geography Great Lakes Geography • International waters p • One fourth the size of the Sea of Japan – 245,000 km2, 22,600 km3
  4. 4. Management of the Great Lakes Management of the Great Lakes • Lakes are managed under many agreements – Boundary Waters Treaty of 1909 • Boundary Waters Treaty created oversight agency  called International Joint Commission (IJC)  – Mission of IJC is to help prevent and resolve disputes  about the use and quality of boundary waters • Conducts biennial review of the quality of the lakes
  5. 5. Great Lakes Pollution Great Lakes Pollution • IJC report in 1970 concludes that pollution on both  sides of the border was causing injury of health and  property on the other side – Immediate concern was excess nutrients in smaller lakes  and bays – Subsequent reports identify problems caused by toxic  substances bt
  6. 6. Great Lakes Water Quality Agreement Great Lakes Water Quality Agreement • Formal agreement committing Canada and US to  control pollution in the Great Lakes • Sets shared goals and water quality objectives • Agreement respects the different ways each country Agreement respects the different ways each country  deals with water quality issues  – Each government implements programs and reports progress Each government implements programs and reports progress  – IJC reviews and evaluates these programs and progress • Agreement calls for periodic review and revision Agreement calls for periodic review and revision – 4000 people provided public comment on latest revision http://www.ijc.org/en/activities/consultations/glwqa/index.php
  7. 7. Science and the Saginaw Bay Example Science and the Saginaw Bay Example • Among first sites targeted by Among first sites targeted by  Great Lakes Water Quality  Agreement • Similar in size to Lake Tai  – 2960 km2 vs. 2250 km2 • Similar water quality  problems – Excessive phosphorus load – Blue‐green algal blooms – Water supply problems • Taste and odor problems 42% of  the time
  8. 8. Science and the Saginaw Bay Example Science and the Saginaw Bay Example • Mathematical model developed – Scientific equations representing the natural  q p g system – Defines relationship between phosphorus load and Defines relationship between phosphorus load and  resulting algal blooms/water supply problems Climate Model Water Quality Phosphorus  Load
  9. 9. Components of Water Quality Model Components of Water Quality Model • Water movement • Water quality interactions q y Vid[Ci]/dt =  Qi‐1 [Ci-1] - Qi [Ci] +Vimax ([Ni]/{Ni+k½})[Ci] - Vir [Ci] –vs/Hi [Ci] + ….
  10. 10. Results of Water Quality Model Results of Water Quality Model • Non‐linear response observed between phosphorus Non linear response observed between phosphorus  load and blue‐green algae 1.6 e (mg/l) 1.2 reen Algae 0.8 0.4 Blue Gr 0 0 500 1000 1500 Phosphorus Load (MT/yr) • Target phosphorus loading defined as 440 MT/yr Target phosphorus loading defined as 440 MT/yr
  11. 11. Saginaw Bay Outcome Saginaw Bay Outcome • Science supports new policy that large municipal  pp p y g p wastewater treatment plants treat phosphorus to 1 mg/l • Water quality improved dramatically – through 1991 q y p y g 1 .6 0 80 P eak B l G r n B i ass,m g/L N um berofD ays w ih O dor> 3 1 .2 0 60 ue- een om s t 0 .8 0 8 40 0 .4 0 20 0 .0 0 0 1974 1975 1976 1980 1991 B lu e -G re e n s OdorDays Bierman, et al., 1986. Environ. Sci. Technol., 18:23‐31. 
  12. 12. Invasive Species Change Ecosystem Invasive Species Change Ecosystem • Zebra mussels  introduced to  Great Lakes in late  1980s • Changed behavior  ty (ml) of ecosystem 50,000 e Green Algal Cell Densit • Blue green algae  40,000 30,000 returned to  20,000 Saginaw Bay 10,000 0 Blue 1991 1992 1993 1994 1995 1996
  13. 13. Science in Adaptive Management Science in Adaptive Management 1.6 16 gae (mg/l) 1.2 Blue Green Alg 0.8 ? 0.4 0 0 500 1000 1500 Phosphorus Load (MT/yr) • Updated questions p q – Where does new target loading need to be? • Research underway to address new questions Research underway to address new questions
  14. 14. Relevance to Lake Tai Relevance to Lake Tai • Science can play key role in informing policy • Define the significance of the problem – Spatial extent, severity, frequency, affected  population • Inform management decisions – Define the required magnitude of controls q g – Define the response time – Identify key sources y y – Guide adaptive management
  15. 15. Role of Science In Lake Tai Policy Role of Science In Lake Tai Policy • Define the required magnitude of controls 1.6 ue Green Algae (mg/l) 1.2 0.8 0.4 0 Blu 0 500 1000 1500 Phosphorus Load (MT/yr)
  16. 16. Role of Science In Lake Tai Policy Role of Science In Lake Tai Policy • Define the response time – Response times vary greatly between lakes Saginaw Bay (3 years) Saginaw Bay (3 years) Lake Okeechobee (60 years) Lake Okeechobee (60 years) 1 .6 0 80 P eak B lue-G re B iom ass m g/L N um ber of D ays w ith O do > 3 or s, 1 .2 0 60 0 .8 0 40 een a 0 .4 0 20 0 .0 0 0 0 1974 1975 1976 1980 1991 B lu e -G re e n s OdorDays
  17. 17. Role of Science In Lake Tai Policy Role of Science In Lake Tai Policy • Inform management decisions – Define most important sources to control Saginaw Bay Before controls Present Point Source NonPoint N P i t Sediment
  18. 18. Role of Science In Lake Tai Policy Role of Science In Lake Tai Policy • Guide adaptive management – How to adjust when the system changes 1.6 lgae (mg/l) ) 1.2 Blue Green Al 0.8 ? 0.4 0 0 500 1000 1500 Phosphorus Load (MT/yr) Ph h L d (MT/ )
  19. 19. Known Science/Policy Problems Known Science/Policy Problems • Incorporation of science into lake restoration policy  has encountered some problems, including: – Lack of proper communication • Lack of shared understanding of expectations, necessary  resources, scales, and degree of confidence resources scales and degree of confidence – Dealing with uncertainty • Ignore uncertainty ignore results due to uncertainty Ignore uncertainty, ignore results due to uncertainty – Timing • Uncertain answer now, better answer later Uncertain answer now, better answer later
  20. 20. Addressing Science/Policy Problems Addressing Science/Policy Problems • Detailed case studies and  discussion of incorporating  science into Great Lakes  policy http://www.esf.edu/es/documents/GreatLakesRpt.pdf htt // f d / /d t /G tL k R t df

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