Tides movement

[micson]

Hello, i am a student from germany and my project is a simulation of a estuare in south of spain. I will be create a 2D or ·3D model for flood risk estimation.
There is a town (Huelva) in the center of a estuare.
I have a lot of dates of historical floods and tides and rainfalls and river marces.

It is posible to create this information with HEC Ras? It look likes a Flow stream model and i think thank it is imposible to create tides in this.
What do you think or you can tell me your opinion if you know another program.
Thank you!!!!

Michael

University of Huelva (Spain)
www.uhu.es

[jarvus lunt]

If the question is: "can I model tides and an eustary?", the answer is yes.

You can model tides in HEC-RAS. Just enter a downstream stage boundary that matches the tide height. You need to extend the cross sections into the ocean.

From a previous post:


"The key to using a tidal boundary with unsteady flow is to have some additional large cross sections at the downstream end. Essentially, just extend the reach out into the ocean (or bay) so that you have some large cross sections that have a greater area than the river cross sections. The tidal boundary is then applied to the downstream, large cross section. The reason for this is at the end of the river, the water surface does not match the tide level. The mouth of the river is influenced by the river flow. So the cross sections need to be extended out to where the water surface does match the tide."


However, you say you want a 2D or 3D model? HEC-RAS is only 1D, so I am not sure if that is want you want.

[Robert Freeman]

This is my second reply. After looking at a map of Spain when I got home, I realized that HEC-RAS could model flooding up the two main tributaries. The marsh areas could be modeled as secondary tributaries. A 2_D model would do a better job though because it will better account for the difference in water level between the main channel and the outer edge of the floodplain during the rising and falling portion of the flood hydrograph. The difference may be insignificant depending upon the depth in the estuary and the extent of the marshes. The tide would be input as a stage hydrograph at the downstream boundary.