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.. ~ . <br />Rule 4.03.2(7)(a)(ii) supports this recommendation. This rule states that, "immediately <br />after access roads are no longer needed for operations, reclamation or monitoring, the <br />natural-drainage patterns shall be restored". DMG's suggested two rock- riprapped <br />channels would more closely resemble the natural drainage prior to disturbance. <br />The proposed plan has been reevaluated as a small area exemption (SAE). The SAE <br />rules aze given in 4.05.2(3)(a)-(b). With respect to the size of the area, the rules simply <br />state that an exemption "may be authorized only if the disturbed surface drainage area <br />within the total disturbed surface area is small...". In BME's proposed plan an additional <br />10.7 acres of undisturbed area drainage will flow through the disturbed area and require <br />treatment. Thus, the total area requested for a small area exemption is increased by 10.7 <br />acres, from 1.5 acres to 12.2 acres. The Division's general policy is that SAE's should <br />not be larger than about two acres. This is an additional factor wnsidered by DMG in <br />recommending that BME route the undisturbed area drainage through the rock riprapped <br />channels. <br />We have one additional concern with the amended plan. <br />In Item 4 of the Apri120 letter, DMG had requested a demonstration that effluent <br />limitations would be met (.Sml/I settleable solids) for reclaimed road segments. BME's <br />response was that the road segments outside sub-watersheds defined on Map 89 would <br />comply with the applicable requirements of Rule 4.03.2(4)(6)-(e) per Rule <br />4.03.2(4)(a)(iv), and that effluent limitations are applicable only to access roads within <br />the disturbed area as described in Rule 4.05.2(4). <br />BME is correct that specific settleable solids limits are not applicable to roads "not within <br />the disturbed area as described in 4.05.2(4)." However, the reclaimed road segments will <br />be relatively steep, and the Scullion Gulch channel is immediately adjacent to the toe of <br />the reclamation. As such, sedimentation control measures (as described in 4.03.2(4)(6)) <br />such as silt fencing or berms to silt fence outlets would be appropriate to minimize <br />sedimentation until vegetation becomes established. Such measures should be installed <br />along the toe of the reclamation, with the exception of the outlets of any rock channels <br />that carry concentrated upland flow. These measures will be required by the DMG <br />pursuant to Rule 4.03.2(b)(iii). <br />Please contact me if you have questions, or if you would like to schedule a meeting with <br />DMG staff who reviewed this proposal. <br />Sinc ly'e' <br />Dan T. Mlathe/w(s//p4~ <br />Environmental Protection Specialist <br />c: Denver File <br />Mike Boulay <br />