I am having trouble calibrating my hydrologic model in HEC HMS. The outlet of my basin does not have a designated discharge monitoring station, so I cannot compare my simulated values with any observed values. What do you think I should do?

How does it help in terms of flood mitigation

Hello,

I apologize if my question is a bit dumb, but a local issue has tuned me into the world of hydrology, and I am struggling to find an answer to my question elsewhere on the internet.

Basically the issue is as such:

The local community has a large agricultural sector that has historically relied very much on pumping underground ground water from a large underground aquifer to irrigate their crops (largely alfalfa). The community has significantly depleted the aquifer to the point that some local scientists attribute an 8 mile fissure that formed in 2015 to its depeltion. To this day the community still draws more water from the aquifer then is recharged.

However, it is not all bad, as the local conservancy district and various other parties have taken up recharging projects (not to mention we had a otherworldly year last year in terms of precipitation). These recharging projects are at the heart of my question.

The community is situated in a valley that receives most of its precipitation in the form of snowpack/snowfall in the mountains that melts in mid-spring (around this time, actually) and runs into the valley. As part of the objective to recharge the ground water, much of the runoff is directed to recharge reservoirs where it is directed back to the aquifer. However, the associated streams can be rather violent, and often much of this water ends of draining into empty fields.

Obviously, the aquifer must be replenished for the good of the community, but assuming the aquifer has been replenished, wouldn't it make more sense to build a more "traditional" reservoir (and by that, I mean a surface reservoir like Lake Mead - though much much smaller in this case)?

To expand and get more specific with my question, there has been a surface reservoir site that has been identified (very preliminarily from what I understand). Doing some research I found that the following stats might be of interest to give a proper response to my question:

- The site is much higher in elevation than these recharge reservoirs (recharge reservoirs sit within the range of 5,000-6,000 feet of elevation wheres the surface of the surface reservoir would be at about 7,900 feet of elevation).

- The location of the surface reservoir is warmest around July and August where the temperature might max out of 80 degrees, but even in July and August it generally sits around 60-70 degrees during the mid day. The location hardly reaches above 32 degrees during November, December, January, and February.

- The humidity is generally higher at the surface reservoir location.

- The surface reservoir location is well shielded from the wind by surrounding mountains (though this is admittedly the most nebulous item of all to me).

- The reservoir has been preliminarily designed to be very deep (average depth of 160 feet) and have very little surface area (200 acres of surface area). Max storage capacity will be around 30,000 acre feet.

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Finally my question: given all the information above, ignoring for financial costs (which I know is a big ask), is there any reason to pursue a reservoir such as the proposed one, or do the pre-existing recharge reservoirs get the job done?

Been working as a council engineer for 3-years, but I'm tempted to switch to consultancy for better pay and career opportunity.

Hello everyone, I'm an urban planning student in some urgent need of guidance. One of my projects this semesters is focused on implementing flood mitigation strategies in areas prone to urban and coastal floods. From the site selected for the study I've already identified the areas prone to coastal flooding, and around 45 locations within the city prone to waterlogging. We are looking to delineate the exact area in these 45 locations that will be underwater in the event of a flood.

To move forward with the work I need to identify the bounds to these locations. I've never really worked with flood modelling before, but have heard of softwares such as HEC-RAS, and SWMM.

There are several data and time constraints that i am working with. What will be the easiest/least data consuming way to get the flood extent for these 45 locations?

Curious for those who have used HOBOs if you have opinions about tidbit loggers vs the pro loggers? Tidbits are obviously smaller and cheaper but any experience with durability or functionality?

Thanks in advance. These will be for a mid size stream temp project so either could work.

Hi all. I work as hydrologist on larger watersheds for small dams and hydropowers. I have no experience of urban hydrology but recently came across a problem of how to convert 24 hr rainfall to 5, 10, 30, 120 min etc rainfall. I have no hourly data for study area. Only daily data is available. There are no previously developed IDF curves for the area. How can I convert my one day rainfall to 5,10 , 20 mins. Kindly guide me and mention reference book/ manuals well.

Hi everyone! I need some help with calibrating my hydrologic model of a hypothetical storm with a 25-yr return period. How can I calibrate this? I am still lost at the process of calibrating this type of meteorologic model in HEC HMS.

How can I use observed discharge data from a historical storm to calibrate my hypothetical storm event?

Im interested in going back to get post-secondary education but am unsure what path is best

Im debating BSc Civil Engineering w/ Master's in Hydrology or BSc Geology w/ Master's in Hydrology/Hydrogeology.

For engineer's and scientists, what is your day to day like? Im interested in seeing what the difference is, and which may suit me better.

Cheers!

Hi everyone, help please!

I have an existing model completed, and I just opened up the project to take some additional screenshots and results.

The terrain associated for all my Plans is saying "error reading terrain file or dependancies", and it looks to be that HEC RAS isn't finding the tif file, only the vrt. Unsure why this is the case as the directory hasn't changed, no file name changes etc.

How do I update connection, without re-running plan?

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I'm stuck here. Need some help. Can anyone give me idea on this?
I'm using Deficit and constant loss method, clark unit hydrograph, linear reservoir, and muskingum method

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I need your help.

When I try to import terrain data (DEM) in HEC-HMS and associate the basin model with the same DEM, the terrain does not appear in the basin window. I've read somewhere that the file size could be too big, but my DEM is only 13 MB. Also, I am quite sure I have entered the right coordinates/projection for it. I just do not understand what could be the problem.

+++ I noticed that my DEM does not have .ovr and .xml files BUT i have its .tif, .tfw, and .prj files. Could this be the reason? If so, how can i generate the .ovr and .xml files of my DEM?

Just started my new career in H&H, and starting work on a CLOMR. As exciting as it is, I’m also feeling lost.

Is there checklist somewhere on FEMA’s site that spells out the requirements? So I can know the minimum requirements to correctly model.

I have asked my manager about this but he says to keep checking the site?

Please any help would be greatly appreciated.

Edit: if there are any resources with flowcharts that help guide through the process, I greatly appreciate it!

I was just wondering because I heard about this job and it seems right for me. Since a lot of entry positions are in the field, I was wondering if it meant working away a lot. So, does it? I’m referring to on average.

Hi guys, I will be graduating this year with a BSc Environmental Science, and would appreciate any guidance into entry-level positions in hydrology, particularly modelling. For reference, I live in SE England.

My degree is accredited by the CIWEM and I have completed module topics relating to hydrology i.e. rainfall-runoff modelling, simulating hydrology of a catchment, and I'm pretty comfortable using QGIS due to volunteer work. My dissertation is based on mire systems, but more related to the impacts of vegetation on different hydrological factors rather than modelling. I feel like I have a decent background to move into grad-level work, but I notice that a lot of graduate/entry positions seem to require a postgraduate qualification, and whilst I would love to complete a master's I would prefer to do so with the support of an employer and a bit of work experience, and then have a start entry next year. This is especially because I have such a broad range of interests in enviro-sci (mostly forestry) and I want to make sure this is the career for the long haul before embarking on further education.

I would be interested to know what skills I should develop further to stand out a bit and if any specific companies provide graduate/entry-level opportunities in the area/remotely, or is it really necessary to pursue post-grad first?

Thanks in advance, hopefully I didn't waffle too much !!

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Hi everyone- my senior capstone project is a stream restoration, and we are trying to model steady flow for a small stream (with a pond in the middle) in HEC-RAS. When I run steady flow, it seems the program is running analysis for the terrain layer, not my designed channel. I've tried everything to fix this but not sure what's going on... any tips? Thanks

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I have model the catchment by using the Hec Hms. I have added the time series data, but in the tabular format, it's shows 30 minutes delay. For your reference, i have attached the screen shot what i got? Please give me suggestion to get rid of this?

https://preview.redd.it/24nnq6lqjmsc1.png?width=1748&format=png&auto=webp&s=a38dc7cb318821ae79326756f001a839cc55bd8c

I just upgraded to HEC-HMS 4.11. When trying to print the Global Summary, it doesn't print the results for the hydrologic elements. It has the run information at the top and the column headings. It just doesn't have any of the results. We have tried to print from two different computers.

Individual element summary tables seem to print fine. It's just the most important summary table isn't printing correctly.

Let me know if anyone else is having the same issue and if you've found a solution.

Thank you.

Hi all! I have a question regarding the best methods for filling gaps in stage data.

I've been going through my agency's backlogged HOBO logger data files and importing them to a remote database. We have a bunch of data from in-stream loggers that I've been pressure compensating in order to retrieve water level estimates in anticipation of developing rating curves down the line. Unfortunately, data retrieval for my agency back in the day was highly inconsistent and we have a lot of gaps where out-of-stream baro loggers either were not downloaded properly or simply weren't deployed. I'm now faced with having to backfill these gaps which is a process I'm largely unfamiliar with.

Does anyone have any suggestions for how to estimate these data? Thanks in advance!

I would like to ask for suggestions whether what software can I use to simulate the groundwater flow of an area based on hydraulic head data from 2 observation wells. Also is it possible to identify its effect on the regional flow patterns? Any leads would be appreciated. Thank you.

My teacher asked the class to create a hyetogram using a database he gave us, in excel, and calculate the effective rain using the SCS Curve Number method. Ok, I can do that. But then he asked us to run it through HEC-HMS multiple times using different porcentages of impervious areas. Then we should compare and find out how HEC calculates the impervious areas in the hytograpgh and insert that method in the excel sheet. So, anyone knows how the HEC calculates the impervious areas, and how it affects the Excess column in it?

I'm running a rain on grid analysis of a watershed. I'm wondering what limitations there are in the HEC-RAS 2D Flow analysis method that I should be aware of? I've attached a screen shot of the watershed. Some of the questions I have are what are the slope limitations? The upper portions of the watershed are really steep (eg. 20%-52%). The other thing I noticed while setting up the precipitation, the significant figures round up to 3 decimal places. When I ran the model in HMS, i used the nested NRCS Rainfall Distribution using now per NEH part 630. Rounding the decimal points to 3 decimal places makes the curve no so smooth. I've also attached the image of the precipitation curve. I've ran the simulation 3 separate ways. One in HMS using SCS loss, transformation etc. The second in RAS with larger cells, the last with smaller cells in the steeper portions. The setup and max flows are shown below.

• HMS : Q = 639.20 cfs
• RAS : Q = 474.43 cfs
  • Perimeter = 30 x 30 Hexagons
• RAS : Q = 766.87 cfs
  • Perimeter = 15x15 Hexagons
  • Refinement Region = 8x8 Hexagons

As you can see, the results vary pretty widely. This leads me to think that there are certain limitations. I'm trying to figure out the best way to run this for the best results. Let me know what you think.

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Hi all, I'm trying to run a quasi-unsteady sediment model but when I try and run it I get a 157 error indicating an access violation and several errors at all of my cross sections, what is wrong with model to cause this?

How can i get a model for flood depth different for pre and post development by using the Hec ras?

What are the details that need to include for a detention tank placement and simulation for post development state in HEC HMS?

I'm currently working on a NZ project. How can i get the rainfall data for that particular development area?