Hi,
Long time reader, first time poster.
I've been tasked to determine if a structure being built along the stream will have an affect to the BFE for the area. Luckily, a flood control channel was built within the stream to convey all of the flowing water. Unforunately, though, it doesn't look like the City or FEMA updated their flood maps as it still shows the flood zone boundaries AROUND the built channel. So that's weird.
My question, though, is that I created the channel using HEC-RAS and the information available to me (sections and flow rate). The sections included the channel and the flood zone boundaries outside the channel. The resulting water levels are below the top of of wall elevations of the channel and everything contained within the channel. So, Good. But then when I add my structure OUTSIDE of the channel, and run the same test, with the same values, the water level is now increased and my structure is now within it.
Am I missing something in my analysis? Or am I missing something with the final product (ie, the answer is correct and I am looking at it wrong).
Please let me know.
Thanks,
Long time reader, first time poster.
I've been tasked to determine if a structure being built along the stream will have an affect to the BFE for the area. Luckily, a flood control channel was built within the stream to convey all of the flowing water. Unforunately, though, it doesn't look like the City or FEMA updated their flood maps as it still shows the flood zone boundaries AROUND the built channel. So that's weird.
My question, though, is that I created the channel using HEC-RAS and the information available to me (sections and flow rate). The sections included the channel and the flood zone boundaries outside the channel. The resulting water levels are below the top of of wall elevations of the channel and everything contained within the channel. So, Good. But then when I add my structure OUTSIDE of the channel, and run the same test, with the same values, the water level is now increased and my structure is now within it.
Am I missing something in my analysis? Or am I missing something with the final product (ie, the answer is correct and I am looking at it wrong).
Please let me know.
Thanks,