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- ------------------------------------------------- -------------- <br />- ------------------------------------- <br />NCk~-OE-'E? i5:5c ID: CO h11 NED LRND F.EC'L TEL ND:~O_-E_2-E1 Fib ttase. P0= <br /> <br />' Mr. Gordon Morgan <br /> <br /> <br />I~ <br />1 <br /> <br /> <br /> <br /> <br />1 <br /> <br /> <br /> <br /> <br /> <br /> <br />-2- <br />Phase One Corrective Action Plan (continued) <br />November 7, 1989 <br />3. Please provide the evergreen tree density of ad,)acent undisturbed slopes. <br />This figure would De used as a measure of success for those areas where <br />evergreens wits be re-established. <br />4. Please commit to establishing replacement evergreens to the same density <br />as the undisturbed slopes. The Division will evaluate tree este~blishment <br />success no sooner than during the summer of the fifth growing sE~ason. <br />5. Page 19 of the Access Road Corrective Action Plan addressed the use of <br />fertilizer tablets during tree plenting. Please address xhether• you will <br />use fertilizer tablets with the trees replanted in the Phase One area. <br />6. Please provide your estimete of an appropriate financial warranty adequate <br />to ensure reclamation of the Phase One area. <br />Quarry Access Road Corrective Action Plan <br />drology and Water Quality <br />7. Please Commit to eddresstng site-specific culvert entrance and ~>x1t <br />conditions and to submitting specifications and supporting calculations <br />for any headwalls, end sections, end rip-rap splash blocks for each of the <br />six (6) proposed culverts. These analyses should ensure stable, non-erosive <br />channels below the proposed culverts. <br />8. The "typical culvert installation and roadway section" detail shows an <br />18" minimum thickness of fill over a culvert. This 18" depth would be <br />adequate only for Culvert No. HR-5 based on an actual HW/D value of 1.75. <br />All of the other culverts will require more than 18 inches of cover to <br />provide the required freeboard. Please commit to specifying these amounts <br />of cover required for each culvert to ensure the road is not overtopped <br />during the 25-year storm runoff. <br />9. Please commit to providing anti-seep Collars that provide an equivalent <br />flowpath length of 120 percent of culvert length. for s11 proposed culverts <br />over 100 feet in length. <br />10. Please demonstrate that the ditch (or road/ditch combination) :.ltuated below <br />Culvert No. HR-6 is designed to pass the excess runoff not conveyed through <br />the 24-inch culvert proposed in a stable. non-erosive manner and that the <br />54-inch downstream receiving culvert is designed to accommodate this <br />additional amount of runoff which bypasses HR-6. This demonstration should <br />consider the 24" culvert situated immediately above the 54" culvert, as <br />well as the hydraulics of the reduction of size of the 54" culvert down to <br />30 Inches. <br />11, If these demonstrations cannot be made, then a new 36" culvert should be <br />' installed at the HR-6 site. It is our interpretation that arty problems that <br />occur downstream of Culvert No. HR-6 that are due to tulverts :being installed <br />improperly by the Cedar Heights.Subdivision are the responsibility of the <br /> <br />