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Southside Realty Trust <br /> Engineering Review <br /> Page three <br /> 5. emergency shut-down for possible spill containment. There is no <br /> further mention of what the emergency shutdown procedure is or <br /> how the containment is handled. <br /> 6. Page 7, paragraph 4 indicates that riprap slope protection is to be <br /> used at certain points within the drainage system. It is not clear <br /> where these will be placed or how they are to be constructed. <br /> 7. Page 7, Stormwater Operation and Maintenance Post <br /> Construction: <br /> A maintenance plan as required by the DEP Stormwater <br /> Regulations is included. However, there is no mention of what <br /> entity will be responsible for the operation and maintenance of the <br /> drainage facility or if regular reports will be generated or to whom <br /> they might be submitted. If there is a spill or other routine <br /> maintenance is required who will do the work or notify the proper <br /> authority? <br /> 8. The drainage calculations include a determination of pre- <br /> construction runoff from the site as well as post-construction runoff <br /> from the finished project. Both sets of calculations were done <br /> using a generally accepted HydroCAD computer program. Plans <br /> of the watersheds are included in the report. <br /> Post development runoff calculations assume sources will be <br /> impervious surfaces, forest areas or grass. No mention is made <br /> of whether building roofs and drives are included in the numbers <br /> shown on the land coverage tables. The drainage area plan <br /> seems to indicate that they may be. Please verify. There is also <br /> no mention of those areas that would be covered in wood chips. <br /> These areas would need a separate curve number and infiltration <br /> rate and should be figured into the calculations. <br /> Calculations indicate, however, that there is a significant increase <br /> in stormwater runoff from the site due to the increase in <br /> impervious surfaces. Surfaces not covered by forest or grass may <br /> increase runoff even further. <br /> 9. Drainage calculations indicate that infiltration is the primary source <br /> of stormwater disposal with a secondary disposal method being <br /> through the use of broad crested weirs. The infiltration uses <br /> bioretention facilities that include planting areas, gravel curtain <br /> overflows and grass filter strips. <br /> The infiltration depends on open, porous soil conditions for proper <br /> functioning. It is not clear where the broad crested weirs <br /> discharge or what the receptors are. <br /> There is a substantial concern that during winter months there will <br /> not be sufficient drainage through the natural soils to adequately <br /> handle the storm water runoff. This year has been exceptional for <br /> frozen ground conditions however it is quite possible that even a <br /> mild winter could have frozen ground for a period of time when <br /> infiltration is nearly zero. What provisions have been made to <br /> address potential flooding or runoff leaving the site under these <br /> conditions? <br /> There is a significant concern that the dramatic topography of this <br /> site will generate runoff at a rapid rate that cannot be handled by <br /> bioretention methods only. <br />