2008-02-11_PERMIT FILE - M2007069

• Permit No: M2007069
• IBM Index Class Name: PERMIT FILE
• Doc Date: 2/11/2008
• Doc Name: Methodology for the Calculations
• From: Young Technology Group
• To: LJ Development
• Media Type: D
• Archive: No

Civil Engineering
Punning &. Deveiopment
Construction Management
Product Development
February 8, 2008
L.J. Development, Inc.
256 N. Merrill Drive
Pueblo West, CO 81007
Attn.: Joseph P. Gagliano
Re: Pheasant Run Gravel Pit
Division at t~e.^,t~:er~at:on,
Mining and Safety
Dear Joe: /
The Methodology for the calculations regarding the determination of the extent of ditch and groundwater phreatic sur-
face, un er a ig me ana , is as o ows:
1. The permeability of the material is determined. in this case the value utilized is for clay material. This represents
the bottom portion of the canal, which acts like a clay lining. It is true that there is an existing gravel layer between
the bottom of the canal and the water table. However, clay is assumed throughout, in order to model a "worse case"
scenario. If the permeability for gravel is substituted in column 1 of the spread sheet, then the phreatic surface from
the canal drops vertically, from the water surface in the canal, to the groundwater. This is due to the high rate of per-
meability of the gravel
2. The depth to the water table is assumed.
3. The KD value is calculated in the spreadsheet.
4. Avoids ratio of i 5% is assumed.
5. The value of a is calculated in the spreadsheet.
6. The horizontal distance from the water surface in the ditch is assumed.
7. The total time during which the ditch is saturated, is assumed to be 8 months.
8. The value of X/{{46t)^.5) is calculated by the spreadsheet. From this result, the value of fe^-u^2du/u^2 can be de-
termined from table 9.
9. A seepage rate of 1 cfs per mile of ditch is assumed
10. The height of the phreatic surface, at distance x, is calculated.
Please reference the' notes in the spreadsheet, and the tables, for the tabular values.
My intent is to show the "worse case" scenario. In reality, the phreatic surface under the canal, will drop straight down to
the water table, once the seepage encounters the gravel layer. 1 do not believe that the activity indicated on the plans
will affect the water table, or canal seepage, at all.
If you have any questions please contact me.
Sincerely,
YOUNG TECHNOLOGY GROUP
~o~
Youxc TECtIIaowcY GRO{rn~ Ph: [phone]
702 PoLK Fa~u [phone]
Pueblo, Colorado 81004 Emaih [e-mail]
Ken Young P.E., Principal
`'~ - ~ 00'7- ©~~
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~FEB 1 12008
Ken Young, P.E., Principal