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III. HYDROLOGIC BALANCE -RULE 4.05 <br />A. Water Quality Standards and Effluent Limitations <br />Receiving stream standards for the Yampa River and its tributaries have been set <br />by the Colorado Department of Health in their publication, "Classification and <br />Numeric Standards for Upper Colorado River Basin and North Platte River <br />(Planning Region)". Dry Creek is within segment 12 of the Upper Colorado <br />River sub-basin and basin. Colorado Department of Health NPDES (National <br />Pollution and Discharge and Elimination System) limitations on discharge and the <br />Division's standards for determining material damage to the hydrologic balance <br />("Division Procedures for the Assessment of Material Damage with Respect to <br />Alluvial Valley Floors, the Cumulative Hydrologic Impact Assessment and <br />Subsidence at Coal Mines") are based in part on these standards. <br />1. Most disturbed area drainage passes through one of two existing sediment <br />ponds (see SAE's described in # 2, below). Discharges from these ponds are <br />monitored to verify compliance with water quality standards and effluent <br />limitations (4.05.2(2)). <br />2. The Division has approved three small areas (SAE'S) to be exempted from <br />the use of sediment ponds due to the limited size of areas and due to the fact <br />that ponds and treatment facilities are not necessary for the drainage to meet <br />the effluent limitations of Rule 4.05.2 and applicable State and Federal water <br />quality standards for receiving streams. These areas have also been exempted <br />because no mixing of surface drainage with a discharge from underground <br />workings will occur. Exemptions from use of sediment ponds have been <br />approved for three topsoil stockpiles. Documentation of these exemptions is <br />found in Volume 12, Tab 12 of the permit application (4.05.2(3)(b)(i)). <br />B. Diversions and Conveyance of Overland Flow <br />1. All diversions within the permit area are designed and constructed in <br />accordance with Rule 4.05.3. Designs are discussed in the text and diversion <br />locations are displayed in Exhibit 12-1 and Exhibit 12-2 of Volume 2, Tab 12 <br />of the permit application (4.05.3). <br />Due to weather conditions (winter snowpack) and the inadequacies of the <br />previous permit application, HGTI was unable to verify the size and location <br />of all conveyance structures. In order to verify the design adequacy of <br />existing water conveyance structures, some of which may not have been <br />included in the HG Mine permit application, the following stipulation has <br />been added to the HG Loadout permit: <br />16 <br />