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low the gravel and making up the hillsides on both sides of the River is Mancos Shale, which is more than 1000 feet thick in all areas surrounding the site. 3. Surface Water Hydroloey The permit area is located on the top of the first shallow terrace above the North Fork of the Gunnison River. Approximately 640 square miles drain to the River at this location. The River makes a gradual bend just north of the property and further bends to the west to the northwest of the permit area, No main streams enter the River within the vicinity of the permit azea. The river itself consists of igneous and metamorphic gravels and cobbles from the Raggeds and the West Elk moun- tains upstream from the site. During high flow conditions in eazly June, the river flows approxi- mately 2500 cfs maximum during an average yeaz and can flow 6,000 to 11,500 cfs fora 100 year event. During non-peak flow conditions, most of the water flow in the river is from groundwater and the flow rate is only 8 to 100 cfs. To ensure that the river never captures the lake made from mining, an embankment protection plan is outlined in the Mining Plan section. The entire permit azea is within the 100 year floodplain of the River. Details of river flow and qual- ity aze presented in Appendix B, from 2 USGS Gages neaz Paonia. Suspended solids range from ap- proximately 20 mg/liter to 4000 + mg/liter, demonstrating the same wide variability of the sediment load in the stream as shown for the River, depending upon the time of yeaz, spring thaw and summer thundershowers. During peak flow in spring thaw, the river is extremely muddy. The Paonia Reser- voir, upstream from the permit area, has severe sediment deposition problems from the upper parts of the watershed. The pH of the River is fairly steady from 8.1 to 8.5. Selenium is a dissolved ion of concern in the area, especially to Fish populations. The CDPHE determined that the level of sele- nium chronic to aquatic life is 4.6 µg/liter. The acute level is 18.4 µg/liter. The USGS gage down- stream of the junction of the North Fork with Leroux Creek showed a level of is 4.0 µg/liter in Sep- tember of 2002. Considerable agricultural water moving through irrigated fields dissolves some sele- nium from contact with the Mancos Shale and increases its dissolved concentration. Since this oper- ation is so small and so close to the river (within 100 feet), it is not expected to have any impact on the selenium concentrations in the River. Due to its proximity to the river, this azea has been flushed with water since the last ice age and does not contribute additional selenium. Selenium loading in North Fork PiY Mazch 04