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<br />~inr:e the benohe,; will be eollatru.oted of the aanle ae.l~d <br />used In the growth media, no additional covering will be <br />made other than preparing the surface and adding <br />fertilizer. Stone berm filters depend upon the stone for <br />their velocity reduction effect, therefore no growth <br />media covering will be added to them. <br />The Division request that bench slopes be no steeper than <br />3H:1V is complete'l.]I detrimental to the performance of <br />benches (see e-t-~b~e~ww.t). As designed, three-fourths of <br />the rainwater that falls on the benches will fall on the <br />upper flat, and infiltrate immediately, or run toward the <br />back of the bench for infiltration at that point. For <br />most of the water, velocities will be kept very low, and <br />the water will be detained. The outer slope will be kept <br />to a minimum area, so that little water falls on !t to <br />run down the slope. A stone berm filter at the base then <br />can handle the small volume of rapid runoff and control <br />any erosion at the toe of the slope. By using a 3H:1V <br />angle on the outer slope, the slope must be extended a <br />great distance to meet the already steeply dipping <br />sandstone floor below. This causes two-thirds of th~s <br />water to fall on the outer slope, and results In a v~>lume <br />of water, approximately 5 times as large as that coming <br />off the short, steep, originally-designed slope, running <br />down the still-steep slope. A stone berm filter at the <br />bottom would probably not be enough to control the <br />resulting erosion. NOLNAM will not commit to <br />guaranteeing the successful functioning of such a <br />structure. <br />Given that HOLNAM has committed to a temporary <br />demonstration seeding plot to be installed In the spring <br />oP 1994 (which will be destroyed In final reclamation), <br />we feel that the requested "soil characterization <br />analysis" is redundant. <br />10. HOLNAM commits to seeding the Plat areas with the SC'.~- <br />recommended seed mix minus the mountain mahogany seed. <br />The outer slopes of the benches will be seeded with <br />mountain mahogany, and, !f approved by the SCS, with <br />Indian Ricegrass. <br />The Division-requested commitment to "---a 50% survival <br />rate for a period of 3 years---", Ls very confusing. <br />If planted trees have only a 4595 survival rate, then the <br />condition can never be met no matter how many trees are <br />replanted to give a desired density of survivors. <br />If this !s a commitment to guarantee that the tree pads <br />have half of the recommended diamond pattern surviving <br />after 3 years, this is also a problem. The tree pads <br />are, and always have been, an experimental concept. No <br />guarantees can be made. we think they will work. And, <br /> <br />3 <br />