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<br />vegetative cover of 47 percent was obtained. Therefore, the <br />revegetation success criteria for areas without replaced topsoil, <br />pursuant to Rule 4.15.10(1), is 47 percent vegetational cover. <br />The cover standard for riparian areas is 55 percent cover. <br />Riparian areas along Oak Creek were disturbed prior to <br />August 3, 1977. No topsoil was salvaged in these areas, and so <br />diversity will be evaluated accordingly. <br />The Division finds that the cover standards for non-topsoiled and <br />riparian areas are in compliance with the requirements of <br />Rule 4.15.10. <br />E. The Division approved of the reference areas which the applicant <br />selected based on the requirements of Rule 4.15.7(3). <br />F. The reference areas will be utilized to determine revegetation <br />success in a manner which the Division finds acceptable 4.15.7(4)). <br />VII. Protection of Underground Mining <br />A. The Division approved surface coal mining activities being <br />conducted within 500 feet of an active or abandoned underground <br />mine. This approval was based on the fact that approval for such <br />was granted by MSHA and the Colorado Division of Mines. The <br />variance was granted by MSHA based on the thickness of material <br />vertically separating the current strip operation from previous <br />underground workings (4.19(1) and 4.22.4(1)). <br />VIII. Operations ort Alluvial Va11ev Floors <br />Alluvial Valley Floor Identification <br />Information on alluvial valley floors can be found in Volume 2, Section 2.4, <br />Volumes 3 and 4, Section 2.5, Volume 5, Section 2.9 and Volumes 11 and 12, <br />Section 4.6 of the permit application. <br />From an investigation of potential areas using geomorphic and <br />water-availability criteria, two alluvial valley floors (AVFS) have been <br />identified along Trout Creek and Oak Creek. Both areas have unconsolidated <br />alluvial deposits and sufficient water available to be classified as alluvial <br />valley floors. <br />The alluvial deposits along Trout Creek consist of four terraces (Qtl, <br />Qt2, Qt3, Qt4>, of which only two (Qtl and Qt2) are water bearing. <br />The terraces are shown on Map 2.5-21 of the permit application, which <br />delineates the boundaries of the AVF. The Qtl terrace, equivalent to the <br />active floodplain, is hydrologically connected with Trout Creek. Since Trout <br />Creek is a perennial stream, baseflow throughout the year is maintained by <br />discharge from the Qtl alluvial ground water. The Qt2 terrace is also <br />water bearing since it contains a perched aquifer situated atop bedrock; the <br />Qt2 terrace, however, is not in direct communication with the Qt1 <br />terrace. Discharge from the Qt2 terrace will eventually reach Trout Creek <br />via seeps along the bedrock face which separates the Qt2 terrace from the <br />_29_ <br />