And our future

Presentation by

Thomas Neudorfer

Puget Sound Watershed

•Puget Sound has 2100+ miles of shorelines

• The canal is shallow at the entrance… very deep along the long arm…. and becomes considerably shallow again within the short arm

• The region was ‘carved’ out by the most recent glacial retreat nearly 13,000 years ago.

•The glacial activity created a long, L-shaped, like body of water

• Hood Canal is about 60 mile long with nearly 200 miles of shoreline

U.S. Coastal ‘Dead Zones’ Associated with Human Activity

National attention in 2003

Pew Ocean Commission report June, 2003

The Hood Canal Dissolved Oxygen Program (HCDOP) is a collaborative effort between many parties to study and model the canal in order to recommend corrective actions and, in parallel, to direct effort towards education and early potential corrective actions.

Southern Hood Canal (Dabob Bay to Great Bend)

Average Dissolved Oxygen Measurements (below 20m) – 1950s - 2004

Low oxygen conditions appear to be getting worse. The 2004 inventory of the oxygen is the lowest on record.

RESULT: Hood Canal is naturally predisposed to low dissolved oxygen, much more so than Puget Sound which is better flushed and less stratified.

Hood Canal Attributes

Strong stratification, distinct layers maintained with different characteristics.› Deep waters with low oxygen don’t get mixed.

Slow circulation, long residence time.› Bulk of waters are “old” – with no recent air

contact.

High productivity, high organic load.› Oxygen is respired away during decomposition

of this matter.

Where is Dissolved Oxygen a Problem?

Oxygen concentration and marine life…

bad

real bad

good

OK

anoxic…no oxygen

real bad…

…throughout year

The lower portion of the canal suffers from low DO levels for most of the year.

HCDOP Integrated Assessment and Modeling

Science Plan

Marine Water Monitoring Utilize profiling moorings and nearshore transects to measure circulation and water quality

Fresh Water Flow & Nutrient Loading Monitor flow and water quality in rivers, streams, groundwater and map associated land use

Marine Life Studies

Assess DO effect on biota and biota effect on DO

Modeling and Analysis Develop and verify computer models of marine and terrestrial system, run scenarios and corrective action analysis

Rapid Response & Diver Program Respond to fish kills and algal blooms, maintain diver observation records

A multi-disciplined science plan (IAM) has been formed by multiple stakeholders to better understand Hood Canal oxygen variation.

http://www.hoodcanal.washington.edu

Increased Nutrients: Nitrogen

• Essential for life• But can be harmful at high levels• Increased human development

Increased levels of nitrogen enter Hood Canal

watershed

WARM

COLD

temperature salinity determine density

FRESH

SALTY

+

less dense

more dense

Stratification: persistent

Stratification gets even stronger in the summer and fall

Low nutrient High oxygen

High nutrient Low oxygen

Organic (primary) production:

Phytoplankton Sinks And Decays (decay uses up oxygen and leaves nutrients)

{ CO2 + H2O C(H2O) + O2 }

sunlight nutrients

Respiration

Photosynthesis

High production and respiration

Phytoplankton Grows(growth uses up nutrients and creates oxygen)

More Humans = More Nutrients

Phytoplankton Grows More Rapidly

(uses additional nutrients and creates oxygen)

Additional nutrients (plant food)

Low oxygen…

…can get lower Nutrient additions from human activity can

make the low dissolved oxygen problem worse.

More organic material to sink and decompose

Dense (colder, salty) ocean water

Dense (colder, salty) ocean water

Light (warmer, fresher) canal/river water

Intermediate (warming, freshening) water

Hood Canal bridge area Big Bend areaN

Slow Circulation = Poor Flushing

Ocean Input

River Inputs

**

*

* *Change ocean input:

O2, density

Change river input:

flushing, stratification

Change light availability:

more sun

Change organic biomass/prod’n:

better growing conditions, carcass loads

Change nutrient availability:

septics, forest, runoff loads

To what degree each of these processes is driving the oxygen variation in Hood Canal is not known

Sources: DOE , HCDOP, EPA, PSP, HCOW.GOV, PEW, ECY.GOV