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worse case scenario, would be baze soil (postmining grading). Subwatershed #2 (interpreted as
<br />the undisturbed area between the pit and the pond) is probably too steep and bare for a curve
<br />number of 41. Inclusion of a third subwatershed, the undisturbed area adjacent to the Section 29
<br />Collector Ditch, may be appropriate. I do not see where the Section 29 Collector Ditch is in this
<br />SEDCAD run (flows discharge into Pond 29). I suggest the applicant be asked to provide (1) a
<br />supplement table of curve numbers and cover and land use conditions, with consideration
<br />of terrain, used in the analyses, and (2} a supplement to Map 41A outlining subwatersheds
<br />and cover and land use conditions, flow paths, ditch segments, and nodes. Such information
<br />would reduce the guesswork in our review.
<br />The cover letter indicated, on page 2, that Exhibit 7, Item 14, is to be submitted under sepazate
<br />cover. I did not find it in the box of materials in your office. This material is reported as
<br />containing introductory test of the Sediment Pond Hydrologic Design, SEDCAD information for
<br />temporary side collector ditches and the permanent ditches, and an update to a summary
<br />spreadsheet showing pond design information. A suggested comment to the applicant is: Please
<br />include engineer general and detailed design plans, profiles and
<br />specifications for the ponds and ditches. Rule 4.06.3.
<br />A summary of sedimentation pond characteristics is provided in Exhibit 7, Item 20, Table 4, so
<br />the general and detailed design plans for these ponds were probably prepared. A suggested
<br />comment to the applicant is: Please include the information required by Rules 2.05.3(4);
<br />4.05.2(1), (2), (5), (8), (7), and (8); 4.05.8; 4.05.7; and 4.05.9, including stability demonstrations, etc.
<br />in the revised pages to the PAP. Rule 4.06.3
<br />Rule 4.05.7 - Dischazge Structures. The SEDCAD runs, such as they are, provide flow rates for
<br />dischazge structures. a°...° °« .. °.w°_ :.,F ....,°,:,.., .. ,. c ....,1 «°1°.:.,,..° .1,° ..,~.,....«°,. Some
<br />of the design requirements aze listed in Exhibit 7, Item 20, Table 4. A suggested comment to the
<br />applicant is: Please include engineer designs plans, profiles and
<br />specifications for the discharge structures, including riprap or other protection of the
<br />emergency spillways, and primary and emergency spillway outfalls. Rule 4.05.7. These are
<br />commonly included in the engineer designs of Rule 4.05.6.
<br />Rule 4.09-4.13. Disposal of Excess Spoil. The locations of excess spoil (permanent and
<br />temporary) piles are shown on Map23A. T''^ ° «'°"°- ~~a:°°'°° ° °' ''~°' °°'~~'~~"'
<br />> >
<br />,'
<br />T,..,1,.« C.,.. °..~ C:I1,, i A:A ....t F.«.~ :~ :.. Q.° 1.,... ,.F ...,...t°«: ,. L.: .. FF...° D~,.....,...~L •1.,.
<br />f f f
<br />€eF-the-fiNs:
<br />The geotechnical report is now in Volume 13, and the disposal of excess spoil is reviewed
<br />herewith. The geotechnical report contains (incomplete detailed) construction plans for the fills
<br />(see page 80, 6/30/06). This review considers the terms "should" as meaning "will be done".
<br />Two soil samples were taken. However, the analyses are based on only one representative sample
<br />(ST-2 is located in a different geologic section). The grain size distribution of unsorted spoil is
<br />appropriate.
<br />
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