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Stage - Storage volume of a DAM/Reservoir

durga637durga637 Global Mapper UserPosts: 44Trusted User
edited March 2012 in Elevation Data
I am having 30mX30m aster DEM. Generated all files/layers including contours with global mapper/arcgis/archydro also.
I struck while generating a DAM (with my top elevation and bottom elevations) for my chosen location. How I can generate this on my DEM ???
After that I need to calculate stage-storage volume at 1m intervals from my DAM botton elevation to top elevation. How to generate this stage -storage volume to my DAM ??
Requesting to help me by providing step-by-step guide/doc/tutorial to understand and implement it.
Either with global mapper/arc gis/arc hydro or any other software/tool like autocad/bently etc.... or a combination of softwares to accomplish this.

Comments

  • global_mapperglobal_mapper Administrator Posts: 17,238
    edited March 2012
    What you need to do is first create an area feature for the dam with the Digitizer Tool and add an elevation attribute equal to the height at the top of the dam. Then select that and right-click, then select the Advanced Feature Creation submenu option to create/flatten terrain. Make sure to uncheck that the elevations are relative to the ground so you get the dam surface at the specified height above sea level.

    This should give you a new terrain layer from the dam on top of your other DEM data. Then use the Digitizer Tool to draw an area that covers the possible fill area of your terrain up to the dam height (it can go outside that is fine, so long as it doesn't cover any lower areas downstream of the dam). Select that, then right-click and select the option to calculate cut-and-fill volumes. This will allow you to specify to calculate the cut/fill volume at a range of elevations with some step. Start at your minimum elevation and step up by 1 up to your dam height. You should get results that include the cut/fill volume for each step. What you are interested in is the fill volume at each step as that would be the water volume behind the dam.

    Let me know if I can be of further assistance.

    Thanks,

    Mike
    Global Mapper Guru
    gmsupport@bluemarblegeo.com
    http://www.globalmapper.com
  • durga637durga637 Global Mapper User Posts: 44Trusted User
    edited March 2012
    Hi Mike,
    I just followed you and got results.
    I need to compare with actual values how close the results are. Hope those values are in acceptable limits.
    In continuation to this,
    1. In some cases, I need to have two or more retaining walls/DAM's to make a reservoirs. Should I follow the same procedure ? (I mean by creating top surfaces with elevation at all locations and then create area.....cut-fil operation)
    2. I have many locations in my dem, Is there any way we can do all at a time ? ( I mean, if I take lower elevations attribute to all locations of dams by line type (not an area type) and top area,s of all locations . Is it possible to automate/program/model so that it will calculate cut-fill to all locations start from lower/botom elevations taking from line types and end at constant dam heights (say all dam heighs=36/50/100 m) or ends at top elevation area what ever height we are giving)

    Please let me know, if you need any info from me for better understanding.
    Thanks for your support and time.
    Thanks,
    Prasad.
  • global_mapperglobal_mapper Administrator Posts: 17,238
    edited March 2012
    You could create multiple terrain surfaces from the tops of multiple dam areas and those will all be used for the cut-and-fill. If you just have lines, you can first convert those into areas by selecting them with the Digitizer Tool and then selecting to create buffers around them of some small size, so you'll just get a small area around the line. You can then create terrain from that.

    You can do cut-and-fill operations on multiple selected areas at once using the Digitizer Tool, but you will currently have to use the same elevation range for each one. If you have different ranges of elevation to calculate at you will have to do those separately.

    Thanks,

    Mike
    Global Mapper Guru
    gmsupport@bluemarblegeo.com
    http://www.globalmapper.com
  • durga637durga637 Global Mapper User Posts: 44Trusted User
    edited March 2012
    Thanks much for your inputs and time. I will follow.

    Thanks,
    Prasad.
  • durga637durga637 Global Mapper User Posts: 44Trusted User
    edited March 2012
    Hi Mike,
    I am checking the results with the below formulas....
    V2= [(a1+a2)/2]*[(h2-h1)/2],
    V3=V2+[(a2+a3)/2]*[(h3-h2)/2]..... In my case I took step 1 as increment height so simply I can say v2=(a1+a2)/4, v3=v2+(a3+a2)/2......etc....
    But the results are matching with fill volume computed with fill area.
    Am I checking in wrong way ?
    Please guide me.
    Thanks,
    Prasad.
  • durga637durga637 Global Mapper User Posts: 44Trusted User
    edited March 2012
    Hi Mike,
    I am checking the results with the below formulas....
    V2= [(a1+a2)/2]*[(h2-h1)/2],
    V3=V2+[(a2+a3)/2]*[(h3-h2)/2]..... In my case I took step 1 as increment height so simply I can say v2=(a1+a2)/4, v3=v2+(a3+a2)/2......etc....
    But the results are matching with fill volume computed with fill area.
    Am I checking in wrong way ?
    Please guide me.
    Thanks,
    Prasad.
  • global_mapperglobal_mapper Administrator Posts: 17,238
    edited March 2012
    Prasad,

    To compute the fill area for say a height of 2, you would have to find every sample that is below a height of 2, then multiply the area of that sample times how far below 2 that sample is. That would be the fill volume for that particular sample. Repeat that for every sample cell within an area feature that is below 2 and sum up the results to get the fill volume. I think that is basically what you are doing, just at a step of 1 rather than a smooth transition between values.

    Also assuming I'm guessing at what your attributes mean correctly, I don't think your formulas are quite correct. For example, the volume of height "3", would be the volume of height 2 plus the total area covered by height 3 or below (a3 I think), times the height different from 2 to 3 (or 1, so just a3). So for a step of 1 meter, if there was 500 sq meters of coverage at height 2 and 1000 sq meters of coverage at height 3, moving from height 2 to height 3 would add 1000 cubic meters of water to whatever the volume at height 2 was.

    Thanks,

    Mike
    Global Mapper Guru
    gmsupport@bluemarblegeo.com
    http://www.globalmapper.com
  • durga637durga637 Global Mapper User Posts: 44Trusted User
    edited March 2012
    Yes Mike,
    The formula is incorrect. Now I got the calculations which are matching with fill volume. Thanks for your support and time.
    Thanks,
    Prasad.
  • ChisangaChisanga Posts: 1
    Dear Mike

    I followed this discussion and guidance. I also have a similar question: When generating the dam capacity, should i choose the option of using the same base height value or the multiple calculation option.


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