AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |
Back to Blog
Hec ras ineffective flow areas11/20/2022 ![]() You can edit the area by simply repeating the steps for adding. Once your mouse button has been released, the ineffective area is set. The X, Y coordinates are always shown on the Status Bar at the bottom of your screen. The ineffective area will draw itself as a shade of green using your mouse pointer as the station offset and trigger elevation as shown below. Then move your mouse cursor to the canvas and drag. Choose “Ineffective Flow Area” from the sub-menu. To add an ineffective area, click the left or right ineffective area button. Use the left button to draw ineffective areas on the left side of the section and the right button for adding areas on the right. Ineffective flow areas can only be added to channel-type sections, not bridge or culvert sections. Ineffective flow areas are added and removed on the left and right sides of a section separately using the following three buttons. It is done only at the X-Sections tab and is performed graphically. How to Add Ineffective Flow AreasĪdding ineffective flow areas is quite easy. The top elevation of the ineffective area would be the Low Bridge Chord for Section 2 and the Top Bridge Chord for Section 4. The total width of the ineffective flow areas would span from the edge of the channel to the bridge abutments. In this bridge plan you would need to add ineffective flow areas at Sections 2 and 4. This is done by modifying the channel section geometry for both sections, upstream and downstream, from bridge or culvert structures or any other channel section. These inactive flow areas need to be eliminated from the calculations in order to get the most accurate results. Once this elevation is reached, the area becomes effective again. The velocity of the water within these ineffective areas is basically zero and does not contribute to the conveyance of that section until a certain water surface or “Trigger Elevation” is reached. So in these circumstances we need to remove the abruptness. Water prefers to flow in gradual patterns, not abrupt. ![]() ![]() This is a common occurrence at channel sections in close proximity to bridge and culvert sections with large embankment constrictions as well as channel sections with wide overbank areas. In most cases abrupt changes can be fixed by adding extra horizontal n-value break points.Ĭlick hereto download a PDF to follow along with screenshots. For more information, contact Hector Olmos.Ineffective flow areas are portions of a channel cross section that contain water but are not actively being conveyed. Keep in mind that you need to have smooth conveyance curves.
0 Comments
Read More
Leave a Reply. |