Including Science into Policy to Address Poll tion in the Great LakesAddress Pollution in the Great Lakes

David W. Dilks, Ph.D.LimnoTech IncLimnoTech, Inc.

Ann Arbor, Michigan, USA

OutlineOutline

• Introduction to the Great Lakes

• Science and Great Lakes RestorationScience and Great Lakes Restoration

• Relevance to Lake Tai

Great Lakes GeographyGreat Lakes Geography

• International waters• One fourth the size of the Sea of Japanp

– 245,000 km2, 22,600 km3

Management of the Great LakesManagement 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

Great Lakes PollutionGreat 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 b tsubstances

Great Lakes Water Quality AgreementGreat 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 countryAgreement respects the different ways each country deals with water quality issues – Each government implements programs and reports progressEach 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

Science and the Saginaw Bay Example

• Among first sites targeted by

Science and the Saginaw Bay Example

• Among first sites targeted by Great Lakes Water Quality AgreementAgreement

• Similar in size to Lake Tai 2 2– 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

Science and the Saginaw Bay ExampleScience and the Saginaw Bay Example

• Mathematical model developed– Scientific equations representing the natural q p gsystem

– Defines relationship between phosphorus load andDefines relationship between phosphorus load and resulting algal blooms/water supply problems

Climate

Phosphorus Load

Model Water Quality

Load

Components of Water Quality ModelComponents of Water Quality Model

• Water movement • Water quality interactionsq yVid[Ci]/dt =  Qi‐1 [Ci-1] - Qi [Ci] +Vimax ([Ni]/{Ni+k½})[Ci] - Vir [Ci] –vs/Hi [Ci] + ….

Results of Water Quality ModelResults of Water Quality Model• Non‐linear response observed between phosphorusNon linear response observed between phosphorus load and blue‐green algae

1.2

1.6e (m

g/l)

0.4

0.8

reen

 Algae

0

0 500 1000 1500Blue

 Gr

• Target phosphorus loading defined as 440 MT/yr

Phosphorus Load (MT/yr)

• Target phosphorus loading defined as 440 MT/yr

Saginaw Bay OutcomeSaginaw Bay Outcome• Science supports new policy that large municipal pp p y g pwastewater treatment plants treat phosphorus to 1 mg/l

• Water quality improved dramatically – through 1991q y p y g1.60

, mg/L 8 0

r > 3

0 8 0

1.20

n B

iomass

4 0

60

s w

ith O

do

0 .40

0.80

lue-G

reen

2 0

40

er of Days

1 9 74 1975 1976 1980 19910.00P

eak B

0 Numb

B lue-Greens Odor Days

Bierman, et al., 1986. Environ. Sci. Technol., 18:23‐31. 

Invasive Species Change EcosystemInvasive Species Change Ecosystem

• Zebra mussels introduced to Great Lakes in late 1980s

• Changed behavior of ecosystem 50,000ty

 (ml)

• Blue green algae returned to  30,000

40,000l Cell D

ensit

Saginaw Bay

0

10,000

20,000

e Green

 Alga

01991 1992 1993 1994 1995 1996Bl

ue

Science in Adaptive ManagementScience in Adaptive Management1 6

1.2

1.6

gae (m

g/l)

0.4

0.8Green

 Alg

?

0

0 500 1000 1500

Blue

 

• Updated questions

Phosphorus Load (MT/yr)

p q– Where does new target loading need to be?

• Research underway to address new questionsResearch underway to address new questions

Relevance to Lake TaiRelevance 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 controlsq g

– Define the response time

– Identify key sourcesy y

– Guide adaptive management

Role of Science In Lake Tai PolicyRole of Science In Lake Tai Policy

• Define the required magnitude of controls

1.6

g/l)

0.8

1.2

Algae

 (m

0

0.4

ue Green

 

0 500 1000 1500Blu

Phosphorus Load (MT/yr)

Role of Science In Lake Tai PolicyRole of Science In Lake Tai Policy

• Define the response time– Response times vary greatly between lakes

Saginaw Bay (3 years) Lake Okeechobee (60 years)

1.60

s, mg/L 8 0

or > 3

Saginaw Bay (3 years) Lake Okeechobee (60 years)

0.80

1.20

een B

iomass

4 0

60

ays w

ith O

do

0 00

0.40

eak B

lue-G

re

0

2 0

Number of Da

1 9 74 1975 1976 1980 19910.00P 0 N

B lue-Greens Odor Days

Role of Science In Lake Tai PolicyRole of Science In Lake Tai Policy

• Inform management decisions– Define most important sources to control

Saginaw BayBefore controls Present

Point Source

N P i tNonPoint

Sediment

Role of Science In Lake Tai PolicyRole of Science In Lake Tai Policy

• Guide adaptive management– How to adjust when the system changes

1.6)

1.2

lgae

 (mg/l)

0.4

0.8

e Green

 Al

?

0

0 500 1000 1500

Blu

Ph h L d (MT/ )Phosphorus Load (MT/yr)

Known Science/Policy ProblemsKnown 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 confidenceresources, 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 laterUncertain answer now, better answer later

Addressing Science/Policy ProblemsAddressing Science/Policy Problems

• Detailed case studies and discussion of incorporating science into Great Lakes policy

htt // f d / /d t /G tL k R t dfhttp://www.esf.edu/es/documents/GreatLakesRpt.pdf