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The hatched area is the regulatory floodway. This is the channel and areas immediately adjacent to the channel. Here is FEMA's definition of that: A "Regulatory Floodway" means the channel of a river or other watercourse and the adjacent land areas that must be reserved in order to discharge the base flood without cumulatively increasing the water surface elevation more than a designated height. The map that I show in the video is from King County, Washington, and I believe they require no rise.

The blue area is defined by FEMA as follows: Flood hazard areas identified on the Flood Insurance Rate Map are identified as a Special Flood Hazard Area (SFHA). SFHA are defined as the area that will be inundated by the flood event having a 1-percent chance of being equaled or exceeded in any given year. The 1-percent annual chance flood is also referred to as the base flood or 100-year flood. SFHAs are labeled as Zone A, Zone AO, Zone AH, Zones A1-A30, Zone AE, Zone A99, Zone AR, Zone AR/AE, Zone AR/AO, Zone AR/A1-A30, Zone AR/A, Zone V, Zone VE, and Zones V1-V30. So, the blue area shows where the 1% (or 100-year) floodplain is.

The shaded area that is not blue (looks yellowish) is defined as follows: Moderate flood hazard areas, labeled Zone B or Zone X (shaded) are also shown on the FIRM, and are the areas between the limits of the base flood and the 0.2-percent-annual-chance (or 500-year) flood.

Areas outside of the shaded regions are defined as follows: The areas of minimal flood hazard, which are the areas outside the SFHA and higher than the elevation of the 0.2-percent-annual-chance flood, are labeled Zone C or Zone X (unshaded).

So, the blue shaded area is more likely to get flooded than the yellowish shaded area, which is more likely to get flooded than the unshaded areas. If you have specific questions about your property, each county should have a floodplain coordinator that can give you specific guidance. Hope that helped.

Thanks for watching the video. This video deals with a situation when the gates have to be opened or the rising water in the reservoir will overtop them. That is one situation that determines when we have to open spillway gates. We can also have a situation where the reservoir will not overtop the gates, but it is higher than the target elevation. We compute a desired release (typically based on what is happening downstream). Depending on the outlets available, the spillway may be used. For example, if there are hydropower units, those will normally be used first. But if more release is needed above the hydropower capacity, then the spiilway may be used. Once release amount is determined, we use graphs that give us the spiilway outflow based on reservoir elevation and the amount that the gate is opened.

Is it possible to release too much water to where the spillway can't handle it?

Based on that error, I suspect that you have an issue with not having flow coming into the upstream end of the model. ResSim needs a flow at the upstream end (most upstream junction) of all streams. You will want to specify a name for the flow on the local flow tab in the junction editor. In the alternative editor, you then link that inflow name with a DSS file. You also need to make sure that the data in your DSS file covers the lookback period and the simulation period. It sounds like you already have your simulation created. After making sure that you have a DSS file (with no missing data) linked, go to Simulation > Edit and "Run New Extract". This lets ResSim know that you need it to extract a new time series. This is automatically done when you first create a simulation, but any changes to dss mapping will require "Run New Extract" after that for it to take effect. Hope that works for you. Let me know in the comments, and I can try to do some additional trouble shooting if you are still getting an error.

Hi, thanks for the reply,! Do you do private lessons or troubleshoot sessions? @@hecressim

Here is some historical information regarding the saltwater wedge that comes from a comment about this topic from LinkedIn. This commenter made this in response to whether or not this could be solely attributed to climate change and sea level rise. It can be difficult to find historic information about this topic, but this provides some additional perspective: "It is not that simple. In 1936, 1939, and 1940, low flow caused the saltwater wedge to migrate up the Mississippi River to RM 115 above New Orleans (or higher). The authorized navigation channel in the river at the time was 35 ft draft in Southwest Pass (1902 authorization) and likely 35 ft between New Orleans and Head of Passes (1937 authorization) for part of the 1930s. Saltwater wedge has been observed in the river up to RM 115 in the 1950s. The navigation channel has been deepened over time, most recently beginning in 2020 to 50 ft draft below Port of Louisiana. Deepening the river removes the shallower crossings, in effect removing speed bumps so the saltwater wedge can more easily propagate upriver. There are many contributors to the saltwater wedge propagation and many questions to be answered. Is this drought due to climate change or is this drought part of a hydrologic cycle that spans centuries? How does the effect of 15 ft of channel deepening compare to the effect of 3 ft of sea level rise (Grand Isle NOAA gage trend)?"

Thank you for watching the video and for the kind words.

Thanks for the feedback and good job on developing a model with that many different features.

Thanks for watching.

Thanks for the comment about the transcription. I have just started to add subtitles so I am figuring that part out. It should be better now. I like the other topics you mention. Not sure that I would be able to find enough information on that to give a comprehensive overview, but I will keep it in mind.

You should be able to create any number of zones that you want. I believe you can also rename zones. So, if you rename the conservation zone, it will still be the guide curve, only with a different name. I will have to do a video to show this and make sure it works.

You're welcome!

You can make several hydropower rules and put them under various IF statements where the IF statements look at the elevation of the downstream reservoir.

​@@hecressim trying that.... let you know how it goes! Thank you!

For the model that I made, I did not have local inflow coming in at the junction that the diverted outlet goes to. I did, however, have flow routed from upstream. Is the junction that you have the diverted outlet going into at the upstream end of one of your streams? If that is the case, then you will need to specify a local flow at the junction since ResSim requires an inflow at the upstream end of all of the streams. Let me know if that is the issue. If not, I will ask my contacts at HEC if they have run into that issue.

@@hecressim The junction that I want to have the diverted outlet going into it is at the upstream end of the stream, so as you said that's why it is needed to specify a local flow at that junction. Thanks for clarifying this.

In a Monte Carlo simulation in ResSim, you will specify the minimum and maximum number of iterations along with specifying the variable or variables to use for convergence. If the simulation converges after the minimum number of iterations, the simulation is completed. If it never converges, it will continue to run until it reaches the maximum number of iterations. So, you can have thousands of iterations run with different sampled values for your inputs in a single alternative. However, if you want to run multiple seeds, you can duplicate an alternative and change the seed. You can run multiple alternatives in a single simulation. Once I have time, I can make a video to better illustrate this.

I believe you can connect a diverted outlet from one reservoir to the inflow junction of the receiving reservoir. This should allow you to write rules pertaining to the diverted outlet to move water to the receiving reservoir.

I may have to make a video to test and show this.

@@hecressim that’s a good point, since I’ve just tried my model with the “flow-thru” operation set you recommend, so I don’t have any rule in my model so far. I’ll try adding some rules and will let you know. Again, thanks a lot for sharing knowledge.

Hi! I tried adding a rule to send water to the parallel junction thru a diverted outlet and it didn't work. Still the only way it's working is with the "dummy" local flow. Did you have any breakthrough?

I need to do a video to show this, but I have a diverted outlet (found in the reservoir network module) connected from a reservoir to a junction above the reservoir, and it appears to work. I am not sure if I can connect to a reservoir junction or to the reservoir itself (it seemed to be giving me a problem with that). However, you can put in a dummy junction just above the upstream reservoir junction and connect to that if there is a problem with connecting to the upstream reservoir junction or the reservoir itself.

Check out this video and let me know if you have any questions. ruclips.net/video/mXUolwkB3SQ/видео.html

Thanks for the kind words. More videos are on the way.

The basic equation that governs what happens at the reservoir is "change in storage = inflow - outflow". You have to describe the physical features of the reservoir (elevation-storage table) so that the storage can be converted into an elevation. The rules of operation that you apply will govern the outflow and the inflow is put into the model by using the DSS paths. Your question is a good one, and I believe a video can be helpful for understanding this. I have a few that I am working on right now, and I will add that one to the list.

Also, can you tell me what error message you are getting?

Thanks.

I believe a diversion would work better for the situation you are describing since a diversion can remove water from the system. A controlled outlet is going to move it through the dam, but it will keep it in the system. In other words, it releases it to the channel downstream of the dam.

@@hecressim Hello, asking for help again. If I want to optimize the reservoir operation, how could I realize it? I found hec-resprm which could do this. But I could not find any material or the update software. Do you have any suggestions? Thank you very much.

Are you asking if it is reasonable to have a zero in the elevation-storage table? If so, it would be reasonable if you are at a very low elevation where there is minimal or no storage. However, you could also start at zero storage at whatever your lowest elevation is. For example, you may start the bottom of the conservation pool at zero with appropriate storages from that point. ResSim would be ok with that. It just needs to know the true difference in storage between each elevation in the elevation-storage table.

@@hecressim got it. Thank you very much.

I am glad that you found the video to be helpful. A forum is a great idea. As I have time, I will look into that. For now, I have just been using the comments to answer questions.

Thanks for the comment. I did not film it with a potato, but I do appreciate the feedback. I use screen sharing software. I went back and viewed the video, and I have it zoomed out too far. Lesson learned as I continue to develop these.

Thanks for the feedback. Glad you liked it.

That is a good idea for another video. I will try to get something done in the next few days.

@@hecressim yeah as I'm also learning on this model sequence of steps in model working along with data requirements and availablity will help us lot

@@hecressim thank you so much for accepting the request

I accept u have done many videos on this model but for any beginners it's difficult to got all those without basic model structure sequence so ......if you are ready to provide any personal training on this model please let me know I want it soon

I put a new video on the channel that deals with the setup of ResSim.

I have a video that shows the development of a model from start to finish located here: ruclips.net/video/IwRWX6Bv9Gw/видео.html

It is a flow through model meaning that I have not added any rules to it. Basically the dam passes the inflow. Please let me know if you have any questions about that model or any other ResSim questions.

@@hecressim sure sir

Where can I get ur mail id?

I prefer communication to remain in the comments section only so that the ResSim community can view questions and responses.

Thank you for the comment.

Can you take a look at the elevation-storage data that you entered on the physical tab for that reservoir? ResSim will typically solve for the storage at each time step and then convert that to an elevation based on the elevation-storage relationship that you input. I am wondering if there is an issue there in your model. Also, can you provide more detail about how you are using the elevation time series?

@@hecressim to enter the elevation time series, I enter daily elevation data into hec-dss. Excuse me sir, for the storage-elevation data entered in the physical tab for the reservoir is it also daily data ? because for other data I use daily data. can you provide a detailed explanation of the data entered on the physical tab for that reservoir or do you have any suggestion ? thank you

Storage-elevation data on the physical tab is paired data meaning that each elevation will have an associated storage value with it. At the elevation increases, the storage need to increase. There should be no time series associated with the storage-elevation data.

Thanks for the question. I had to go into DSS to test it, and I also found that I was having issues with weekly data. I don't think that I have ever run into that since I have not used weekly data very much. I need to do some testing on this, but a possible solution would be to enter the data in as daily data and then change it to weekly. That would be under Tools > Math Functions > Time Functions > Average Over Period > 1 Week.

You can export a path from HEC-DSSVue by selecting the path and then going to Data Entry > Export. You can select Excel format, which you can then convert to .csv from Excel. When I get some time, I will develop a video showing this.

Here are a few things to check. Your DSS needs to cover both your simulation and lookback period. You also need to have flow data at the upstream end of your main stem and at the upstream end of any tributaries. You can have additional flow entering at intermediate junctions, but ResSim won't run without flow at the upstream ends of all of the streams.

One additional item to look at is to make sure that your stream alignment is in the correct direction. If you try to put in a reservoir from upstream to downstream and ResSim complains, then your alignment is in the incorrect direction. This sometimes happens when you import a GIS shapefile. Here is a blog post of mine that goes into detail about that. hec-ressim.blogspot.com/2016/08/developing-stream-alignment-in-hec.html

Also, I have seen gaps in the stream alignment that can be difficult to see. You may need to zoom in on your junctions to make sure that there are no gaps. That can cause issues due to ResSim thinking there is a false upstream end of a stream. Since the gap is making ResSim think there is another upstream end, it is then looking for the flow information at that point.