REP34915 - Laserfiche WebLink

Home Browse Search

' The Williams Fork study included discussion on a paleoflood analysis which had been provided ' for the Williams Fork drainage ba~ln. The conclusion of tiffs analysis was that there was no evidence observed within the Williams Fork drainage basin that suggested any significant flooding beyond what could be attributed to snowmelt runoff. As part of the analysis for the Henderson ' Mill drainage, paleoflood data were collected at about a dozen locations within the Henderson Mill tailing pond watershed. No evidence of significant flooding was observed at any of the sites. Figure 4 shows the sites visited in the Henderson Mill basin and the sub-basins associated with the sites. The data have not been analyzed at this time. When the analysis is completed, the results will be provided. The conclusions from the paleoflood analysis for the Williams Fork study as stated above do apply. This conclusion is consistent with other high altitude watersheds in the Rocky Mountain region. t Watershed Characteristics Relative io PMP Considerations The Williams Fork watershed is bounded by prominent mountain ridges. These essem:ially ' continuous ridges present significant obstacles to low level wind flow and moisture intrusion on all sides of the watershed except the northwest. Airflow entering the basin from all directions t except the northwest is strongly downslope, causing a pronounced warming and drying of the airmass. The Henderson Mill tailing pond drainage basin location is within the region of strong downslope for the Williams Fork Mountain range under southwest wind flow. This rain shadow location limits the potential for extreme rainfall over the basin. ' Each topic that was addressed in the PMP study for the Williams Fork study was reviewed by AWA to determine if the conclusions were applicable to the Henderson Mill drainage. A brief ' discussion is provided. 1 1 1 Page 6