Laserfiche WebLink
• adjacent ephemeral areas occurs as bedload. The remaining 90 percent presumably occurs as suspended <br />sediment load. <br />There is no significant effect on groundwater systems caused by the abandoned mine. Storm runoff from <br />old mine tailings would have some minor effect on surface water systems. A site visit has shown that the <br />condition has essentially stabilized and that little or no excess runoff or sedimentation is caused by the old <br />tailings. <br />The suspended sediment load of the White River above Rangely, Colorado was estimated using the <br />station's long-term flow duration curve and a suspended sediment discharge rating curve, developed using <br />guidelines given by Strand (1975). The resulting suspended sediment load duration curve is given in <br />Figure II.C-23. Through arithmetic integration (see Table II.C-8), the average suspended sediment load at <br />the station was determined to be 1230.5 tons per day (449,440 tons per year). Assuming a sediment unit <br />weight of 80 pounds per cubic foot (see Flaxman, 1975), this load converts to a yield of 0.09 acre-foot per <br />square mile per year. Again, based on guidelines presented by Strand (1975) for rivers with sand and <br />cobble bottoms and intermediate suspended sediment concentrations it is anticipated that bedload flowing <br />past the station above Rangely equals 44,940 tons per year, resulting in a total sediment yield at the station <br />of 494,380 tons per year or 0.10 acre-foot per square mile per year. This low basin wide yield relative to the <br />lease area yield implies that a large portion of the sediment in the White River comes from the lower basin <br />areas, which agrees with the conclusions of the Colorado Land Use Commission (1974). <br />• II.C.2.e Surface Water Monitoring Program The surface water monitoring program consisted of <br />monitoring surface water at the following seven (7) stations: <br />SW1-1 SW6-1 <br />SW11-1 SW23-1 y~i„ ~ L _/ ~ //- ~- <br />SW24-1 SW31-1 <br />SW33-1 <br />The location of each of these stations is shown on Map 137. Stations SW1-1, SW11-1, SW31-1, SW23-1, <br />and SW24-1 were crest stage gages with single stage samplers and were designed to measure the crest of <br />flow events and collect samples as the result of those events. Stations SW6-1 and SW33-1 were the <br />locations of stock watering ponds where grab samples were to be collected. SW12-1 and SW11-2 were <br />stations where grab samples from the White River were collected. <br />At stations SW6-1, SW33-1, SW12-1 and SW11-2 only water samples were collected for analysis. Crest <br />gage and water sample station SW23-1 was to be monitored only if there was discharge from the sediment <br />pond (RP-1) located below the refuse disposal area. To date, January, 1999, only one event was recorded <br />in March, 1995. Crest gage and sample station SW24-1 along Red Wash above the mine was washed out <br />. by a flash flood in the Spring of 1983. Grab samples were collected at SW24-1 until July 1986 when a new <br />Permit Renewal #3 (Rev. 8/99) II.C~6 <br />