Laserfiche WebLink
this confluence, Rapid Creek flows westward approximately 1.2 miles and empties into the Colorado <br />River. Flows in these creeks occur primarily in response to annual snowmelt and seasonal <br />precipitation events. Both streams are intermittent during most years, but they do flow continuously <br />during wet years. This is evident by a recent photo taken of the stream in March, 2014 showing base <br />flow in the stream prior to snowmelt (see Photograph No. 36). Late 2013 was wetter than normal <br />with an extended period of above average precipitation in the late summer months July through <br />October. <br />To determine whether subsidence from coal mining is impacting the quantity of water in Rapid and <br />Cottonwood Creeks, the Division obtained and reviewed the following information: Annual <br />Hydrology Reports (AHRs), historic surface water and groundwater information, U.S. Geologic <br />Survey (USGS) data, and mine inflow studies conducted at the Roadside North and South portals <br />mine. A summary of the Division's findings is provided below. <br />Snowcap Coal Company has monitored the flow of Rapid and Cottonwood Creeks from 1986 through <br />2013 and flow values have been reported to the Division in SCC's Annual Hydrology Reports. Since <br />this is the best source of information, much of the discussion to follow was taken directly from <br />previous AHRs submitted to the Division. In the 2013 AHR, SCC prepared an analysis of historic <br />flows at a point located below the confluence of Rapid and Cottonwood Creeks to determine if there <br />is a downward trend in flow and if so, whether it is due to subsidence or climatic conditions. <br />Monitoring point SWGS O1 is located on Rapid Creek downstream from the confluence of Rapid <br />and Cottonwood Creek's. Please refer to Attachment 8 - Rapid & Cottonwood Creek Hydrologic <br />Monitoring Map for location of the surface water and groundwater monitoring points located along <br />these creeks. <br />Based on the data presented, there is an overall downward trend in flow at SWGS O1 over the last <br />several years. SCC provided the following explanation for the downward flow trend for Rapid Creek <br />in the 2013 AHR. <br />Flow data for this site was collected from the AHRs for the peak irrigation months of July through <br />October, 1987 through 2012. The Martin -Crawford irrigation ditch, Structure #7200764, is located <br />above SWGS-01 on Rapid Creek. The flow (diversion) reported for this ditch from 1991 through <br />2012 was added back into the total flow monitored at SWGS O1. This data was collected from the <br />Colorado Division of Water Resources, Structure (Diversion) Records. The flow through SWGS O1 <br />varied from 0.4 cfs to 2.7 cfs with a slight downward trend in flow from 1987 to 2012 as shown on <br />the enclosed SWGS O1 diagram provided in Attachment 9 - Precipitation and Flow Data for Rapid <br />and Cottonwood Creeks Study Area. <br />Data was collected for both the Colorado River and Plateau Creek in order to determine if the <br />downward trend in SWGS 01 was climatic. The USGS monitoring sites for these two bodies of water <br />are in close proximity to Rapid Creek. The mean daily flows at the Colorado River site, USGS Station <br />09095500, varied from 1,655 cfs to 6,544 cfs with a slight downward trend in flow from 1985 to <br />2012. The mean daily flows at Plateau Creek, USGS Station 09105000, varied from 51.3 cfs to 424.5 <br />cfs with a downward trend in flow from 1986 to 2012. Flow diagrams for the Colorado River and <br />Plateau Creek are also provided in Attachment 8. <br />Page 27 <br />