Chlorophyll Criteria based on SAV Minimum Light Habitat

Requirements

• ca. 22% surface light for PH/MH

• ca. 13% for OH/TF

• => KdZ=1.5 PH/MH or 2.0 OH/TF

Four Factors Contribute to Water-column Light Attenuation

1. Water

2. Colored dissolved organic matter

3. Chlorophyll

4. Suspended particulate matter

Crudely, we can write ChlakTSSkKK csCDOMWd

Parameter Value Units

KW+CDOM 0.32 m-1

ks 0.094 m2 g-1

kc 0.016 m2 mg-1

Bay-wide Average Parameters

Rearrange to Calculate Water Quality Threshold for SAV Survival

Maximum allowable median Chl during SAV growing season

0 10 20 30 40 500

2

4

6

8

10

12

14

16

Chlorophyll (mg m-3)

TS

S (

g m

-3)

SAV Habitat Requirements Algal contribution to TSS

0 10 20 30 40 500

2

4

6

8

10

12

14

16

Chlorophyll (mg m-3)

TS

S (

g m

-3)

SAV Habitat Requirements Algal contribution to TSS "Unmanageable" TSS

Maximum allowable median Chl during SAV growing season

Chlak

k

k

KZKTSS

s

c

s

CDOMWd

Problems & Caveats• Application depth for water clarity criterion

varies with location

• Contribution of CDOM to light attenuation varies with location (scheduled for monitoring)

• Optical properties of suspended particulate matter highly variable

• Uncertain how to deal with bloom vs. chronic levels