This routine draws a pond stage storage curve with pond elevation on the
vertical axis and acre-feet of storage on the horizontal axis. It will plot
and label the emergency spillway, principal spillway and cleanout levels
and will produce a table of storage data. The program will read and write
a .CAP file of pond storage, based on areas at each stage or elevation.
CAP files (short for "capacity")
are made by Bench Pond Design, Valley Pond Design, Rectangular Pond Design,
Calculate Stage Storage and by the Stage Storage Curve program itself. These
programs output two types of CAP files, one which is read by SEDCAD, a
popular hydrology and sedimentology program, and another which is a simple
comma-delimited file for easy viewing in spreadsheets or text editors.
In addition to file-based inputs, the user can enter pond dimensions directly by length-width, area at each stage, or volume at each stage. The above drawing was created by the entry of widths and lengths at increasing elevation, entered within the routine itself. Also shown at the bottom is the default certification, obtained by clicking on the certification option. All text is editable. If stage-storage curves are loaded from file, which contains only volumes at different stages, then the width and length columns are filled in as "N/A" (not applicable). Since volume-based entry does not include area information, no CAP files are stored with this option. However, the curves plot in all cases. Plots are sized to fit on 8.5 x 11 sheets at the selected scale for plotting. They are particularly suited for permit applications, so the program will prompt for permit number and page.
The program is dialog-driven. The first dialog controls file loading and some pre-calculation options, and is shown below:
In this case we have loaded a stage-storage curve from a stored capacity file. The program will automatically display the top of structure. If your goal is to set the emergency spillway at an elevation with storage 5.5 acre-feet, you can enter the storage in the lower left and calculate the appropriate elevation. You can also compute permanent pool elevations by entering runoff quantities. A total runoff of 3.5 acre feet, subtracted from the acre-feet at the principal spillway, will set the recommended elevation of the "clean out level". If the pond silts up above that level, then the silt needs to be removed. In Kentucky, for example, the minimum vertical separation between principal spillway and clean out level is 1.5 feet.
If you choose to manually enter the pond area, dimensions or volume at
increasing stages (elevations), then all the options in the lower portion
of the dialog "ghost" and are not available, since the pond characteristics
are not yet known. Then prompting appears as shown below:
Elev Width Length Area Interval Avg. Area Inc. Vol Acc. Vol Stage
(Ft) (Ft) (Ft) (Acre) (Ft) (Acre) (Acre Ft) (Acre Ft)
-----------------------------------------------------------------------------
940 20.0 60.0 0.028 0.00 0.028 0.000 0.000 0.00
945 30.0 70.0 0.048 5.00 0.038 0.189 0.189 5.00
950 40.0 80.0 0.073 5.00 0.061 0.304 0.494 10.00
Areas are in acres. If the area method of entry were chosen instead, the
user would have been prompted for area at each elevation (stage), and the
summary table would be blank under the width and length columns. Similarly,
if entry was by volume (in cubic feet), all width, length and area columns
would be blank.
Calculate Storage or Elevation Points (y/<n>): y
Regardless of whether the stage-storage information was hand-entered or
loaded from a capacity file, you are in all cases led to the next dialog,
which governs the drawing and labeling of the stage-storage curve graph and
text:
Note that it is often beneficial to "skip every 2nd table entry", since
the table of text for each stage may exceed the space alloted to it. You
can also plot a "Stage-Area Curve" as well as a Stage-Storage Curve, with
the Stage-Area horizontal access scale information plotted on the top of the
graph.
A business address or typed-in certification can be entered here as well.
Pick Starting Position: pick lower left corner of stage storage
curve on screen
Company Name: Maysville Survey & Engineering
Address Line 1: 105 W. 2nd Street
Address Line 2: Maysville, KY 41056
Address Line 3:
Store Pond Capacity File (y/<n>): y This prompt
appears if you hand-enter stage-storage information without the routine and
is followed by the normal store file dialog.
Note that if Drawing Setup is set to metric, the stage-storage curve is calculated
in cubic meters and all entries are in meters. The final result of
a typical combined Stage-Storage and Stage-Area plot is shown below: