Laserfiche WebLink
-38- <br />MINNESOTA CREEK DRAINAGE EVALUATION <br />As part of its initial permit review MLRD evaluated preliminary <br />hydrologic characteristics of Minnesota Creek drainage. Subsequently, <br />WECC withdrew its request to mine or affect this drainage basin as part <br />of its mining permit. Therefore, WECC will not affect this area and <br />consequently hff Rn no longer needs to consider this drainage in its <br />impact assessment. The following discussion is for informational <br />purposes only, and may give a better understanding of issues that will <br />need to be addressed in later permit terms. <br />Minnesota Creek drains approximately 53.5 square miles. A small part <br />of this drainage system lies within the Mt. Gunnison coal lease <br />boundaries. Water is diverted from Little Gunnison Creek to the <br />headwaters of the D[y Fork of Minnesota Creek via Deep Creek Ditch. <br />4~'ECx has placed a water stage recorder and an 18-inch Par shall flume on <br />the ditch and has measured flows for this transbasin diversion from <br />June 1977 to December 1979. Unfortunately, the time period chosen for <br />the data recorded reflects drought conditions. In addition the <br />location of the site was not the most desirable since activity by <br />beavers caused backup and flooding of the fl~nne. It appears that for <br />the time of record reported by t9ECC, as well as for past ditch records, <br />approximately 1,000 acre-feet of water transferred into Minnesota Creek <br />annually. <br />A major outflow from Minnesota Creek is through irrigation ditches. By <br />consulting the straight-line diagram as comq~iled by WECC, it was <br />concluded that irrigation ditches annually remove approximately 20,000 <br />acre-feet. <br />Table 9 illustrates the approximate mass balance for the Minnesota <br />Creek watershed. Once again, it should be noted that on a mean annual <br />analysis, an excess amount of water exists within the watershed <br />boundaries. However, during the months of May through September, a <br />deficit occurs. This implies that any alteration of the hydrologic <br />characteristics of the watershed should be carefully monitored to <br />insure minimal impacts will occur during dry months. <br />Table 9 Minnesota Creek mass balance analyses (all units in AF). <br />Inflow Mean Annual Mean May-September <br />Precipitation 71,G00 22,000 <br />Transbasin Diversions 1,000 1,000 <br />Total 72,000 23,000 <br />Outflow <br />AET 31,000 22,000 <br />Total gation Ditches 1~5 O~OOD 1~5 O~DOD <br />