About Delta TRIM

Hydrodynamics and associated transports in the Sacramento-San Joaquin Delta are simulated using Delta TRIM3D, a multi-dimensional hydrodynamic and scalar transport model. Casulli and Cattani (1994) developed the hydrodynamic core of TRIM3D and Gross et al. (1999) incorporated the associated scalar transport routines. Monsen (2001) applied Delta specific bathymetry and hydraulic operations to the model and compared the results against measured stage, flow, and salinity. The model is driven with a tidal boundary condition using observed stage at Martinez and observed flow boundary conditions at the river boundaries on the Sacramento at Freeport and the San Joaquin at Vernalis.

All pump and gate operations as well as the placement of temporary barriers within the Delta are also represented in the model. All the results presented here use a 50 m grid resolution and a 40 second time step in a two-dimensional depth-averaged mode.

We have used the Delta TRIM3D model in a variety of applications including: salt transport, particle tracking, and source tracing.

The most traditional use is modeling of salt intrusion into the Delta system. For example, we can model salt intrusion into Suisun Bay.

We have done several particle tracking studies. Animations of particle tracks in Mildred Island and Franks Tract help use to understand how these shallow water habitats are connected to the surrounding channels. Please see: (http://www.esapubs.org/archive/appl/A012/015/default.htm) for additional information about these animations. The animations for Mildred Island also helped us better define transport timescales in tidal systems. (http://aslo.org/lo/toc/vol_47/issue_5/1545.pdf)

We have also used the model to predict freshwater sources around the Delta. For example, we can model Sacramento source water exchange through Three Mile Slough.

References

Casulli, V., and E. Cattani (1994), Stability, accuracy and efficiency of a semi-implicit method for three-dimensional shallow water flow. Comput. Math. Appl., 27, 99-112.

Gross, E.S., J.R. Koseff, and S.G. Monismith (1999), Three-dimensional salinity simulations of South San Francisco Bay, J. Hydraul. Eng., 25, 1199-1209.

Lucas, L.V., J.E. Cloern, J.K. Thompson, and N.E. Monsen (2002), Functional variability of habitats within the Sacramento-San Joaquin Delta: Restoration implications, Ecological Applications, 12, 1528-1547.

Monsen, N.E., J.E. Cloern, L.V. Lucas, and S.G. Monismith (2002), A comment on the use of flushing time, residence time, an dage as transport time scales, Limnology and Oceanography, 47(5), 1545-1553.

Monsen, N.E. (2001), A study of sub-tidal transport in Suisun Bay and the Sacramento-San Joaquin Delta, California, PhD thesis. Stanford Univ.