Zebra and Quagga Mussels: Scoping to Incorporate Mussels in Flow and Water Quality Models
Current reservoir lumped parameter water quality models are structured around bioavailable phosphorus and the resulting algal biomass that affects dissolved oxygen concentrations. With quagga and zebra mussels infesting reservoirs, the water column may be stripped of nutrients and organics. Current reservoir models are not set up to investigate water quality of reservoirs infested with mussels. Scoping is required to proactively determine which parameters need to be collected and which model algorithms and calibration knobs will need changing. Monitoring water quality data are being or will be collected at about sixty reservoirs for identification and detection of zebra and quagga mussels.
As one example of concern, typically calcium is collected to determine suitability of environmental conditions for mussel formation. However, most water quality models do not include calcium as an input. Therefore incorporating colonization of mussels in existing models is not likely. An alternative method of simulating their growth and consequent impact on water quality needs to be investigated and included in future water quality models. The question of how the data will be used for multiple future purposes including modeling of water quality needs to be investigated before a second round of sampling occurs.
Need and Benefit
There is a multi-agency need to incorporate mussels into the CEQUAL-W2 model and other models. The benefit is that water quality of reservoirs can be modeled more adequately. Mussels will infest lakes and reservoirs, and there will be a need to model and coexist with the consequences of mussel infestation.
Tom Cole, the original developer of W2 has retired from the U.S. Army Corps of Engineers (Corps). Many other Corps modelers are also retiring. Model development is lacking. Fortunately, W2 model development still occurs at Portland State University (PSU). However, PSU needs funding and Federal champions to encourage enhancing the W2 model and other models.
Reclamation has many reservoirs that could be infested with mussels, thereby preventing optimization of water deliveries. With much at stake, there is a need to proactively investigate mussel inclusion in models. A conference with the theme of "Preserving the CE-QUAL-W2 legacy" was held in July 10-12, 2007. A technical wish list from that conference revealed a long list of model developments needed for the W2 model. Reclamation's need for mussel incorporation into W2 was not on that list, since mussels were not a major priority two years ago. Reclamation's priorities have changed over the last two years with a third of the research program focusing on mussel research. Not having the foresight to place mussel incorporation on that technical list of needed W2 modeling improvements was an undersight at the time that needs to be corrected.
The following documents were not reviewed. Statements made in these documents are those of the authors. The findings have not been verified.
Zebra WQ Model 07 (final, PDF,
By Merlynn Bender
Report completed on June 16, 2015