Hydrodynamic modeling in the channel network of Venice

A combined framework of hydrodynamic models is presented that describes the water dynamics in the channel network of the city of Venice. The applicati on of these hydrodynamic models is part of a larger project carried out by UNESCO that has the aim of describing the mater quality of the channels in Venice. An existing 2-dimensional finite clement model simulates the hydrod ynamic features in the Venice Lagoon. The simulated data is then used as th e boundary condition for the 1-dimensional hydrodynamic model of the inner channels of Venice. Inside the channel system the water elevation and the c urrent velocities are computed. The simulated variables are calibrated and compared with data from field measurements that UNESCO has carried out duri ng the years 1990-92 and during 1998. It was possible to use a constant fri ction parameter for all the channels in the network. Simulated water elevat ion shows an excellent agreement with the measured data, and also current v elocities are generally reproduced quite faithfully, Some low-energy channe ls show major errors in the reproduction of the velocity speed. It is belie ved that changing bathymetry (silting-up of the channels) could be a cause of this phenomenon. The hydrodynamic data will eventually be used in the se cond part of the project where the water quality of the channel network wil l be investigated. For this purpose the hydrodynamic parameters simulated w ill be used by the water quality model as a boundary and initial condition in order to simulate the biological and chemical variables and to describe the ecological dynamics.