We have a class web page on the PRISM page.

It's going to be an interdisciplinary effort for those with various backgrounds from UW and agencies. We all are going to learn in this together. There are many faculty involved and some students, but most all are working at ground zero (i.e. without previous experience using such models) and all are working towards a common goal: to produce a good tool for Puget Sound, that being a biological-chemical model that describes water quality issues.

We all are asking different questions, ranging from the very broad PRISM-type question to the specific need-driven KC question.

The unifying theme is that in order to answer any of these questions, we really need the same tool. That is, a reasonably accurate model that describes biological and chemical processes; simple enough to use and run, yet complex enough to mimic reality well enough to be useful in planning decisions.

Check out the PRISM web site if not!

Their interest is in basic science of the PS system, to provide the knowledge gained from our scientific understanding of PS so that it can be used in planning and decisions, and to promote and facilitate education about PS.

PRISM wants to model the entire PS. Kawase has a hydrodynamic model (POM) now. They seek to have a bio-chem model interface with this model.

They have chosen to focus a study (SPASM) on South Puget Sound and its ability to assimilate nutrients loading from humans. There will be very high population growth in this region, and its circulation is more sluggish than other parts of PS.

Instead of permitting things piecemeal, the idea is to have a regional assessment of this area so wise planning can occur. They have a SPS hydrodynamic model EFDC (based on POM) and have the code for a bio-chem model (HEM-3D) which we will use in this class.

They have a very specific need to site a new WWTP (sewer) outfall in North King County (Central basin of PS). While they don’t have a catchy acronym (yet) they are undertaking a large study to assess this.

They will use Kawase’s POM model and seek a bio-chem model to interface. They used EFDC and a chem transport model in Elliott Bay.

coupled to a
biological-
chemical model
"HEM-3D"

Ecology’s approach for SPASM is to use EFDC and the HEM-3D models. This shows salinity output for the EFDC. When several of us met awhile back, we decided that we should use the HEM-3D model as a starting place, since no one knows a better one and since there are many good aspects about this one.

So, this class will strive to run, calibrate and assess the HEM-3D model. We will use the SPASM grid, since HEM-3D is compiled and running on it now.

As the class progresses, we will do some sensitivity analyses. Probably we will be adept enough to do this with the HEM-3D model, but another tool we have for this is a “user-friendly” ECOS-3 software package that does ecosystem modeling.

The goal of the class is to decide if HEM-3D is OK as is, or if we think modifications are definitely needed for accuracy, what modifications, and also, to recommend what sampling may need to be done to complement the model.

Academic models of the water column biology and chemistry have often focussed on the flow of carbon throughout the system. There is a focus on trophic linkages, such as in the Nutrient-Phytoplankton-Zooplankton models that are common.

Agencies, although dealing with carbon transfers often focus on oxygen (DO or O2), since this is an important water quality variable. Because the models are used to plan how to allocate human wastes, an engineering perspective is strong.

The intent here is to blow the boundaries and take the best of both to make a really good tool for PS to describe bio-chem processes and protect water quality.

Well, first, its scientific importance is obvious, being involved in photosynthesis, respiration, and also non-biological chemical reactions. It is tricky, since in is the end-result of both physical and biological forcing mechanisms (and I should have said chemical too!). Its critical importance to most heterotrophic organisms is also very obvious…fish and crab need to breathe…

This is why it is one of the few criteria we have for assessing marine water quality and why it is critical to regulation and permitting decisions. We know anoxia is bad for organisms and we want to prevent human-caused lowering of oxygen from happening.

So, we will dissect the HEM-3D model and see if it is one we can live with, see if there are things we know are inappropriate for PS, and see if we should develop new format for it.

First we all need to see if we can understand it!

There are manuals and documents on reserve at the Library that you can check out for 24 h or xerox. In week 3, Greg Pelletier, Ecology, who has the HEM-3D model up and running will bring us all up to speed. It will initially be on Jeff’s computer and will probably spread to others so we can “play” with it.