Laserfiche WebLink
<br />001013 <br /> <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br /> <br />According to the USGS topographic map (10-foot contour interval), the riverbed <br />elevation at Arapahoe Road was 5632 feet in 1964. This value is 3.5 feet <br />higher than indicated by the streamgage records, which could be accounted for <br />by the accuracy of interpolation. <br /> <br />Using the map records, the conclusion is that the streambed has degraded <br />I-foot between 1964 and 1983. Using the streamgage records, the conclusion is <br />that the streambed has aggraded 2.5 feet in the same period. The streamgage <br />records were considered to be more accurate and were used to develop general <br />trends for Cherry Creek. <br /> <br />D. Expected Changes <br /> <br />1. Effects on Urbanization on Hydrology <br /> <br />As reported above, the Melvin gage was reactiviated in 1982. These <br />meaurements will enable one to assess the long term impacts of the upstream <br />development, but data must be coli ected for at 1 east a peri od of 10 years or <br />more. Howerver, some estimates of the impact can be made, based on previous <br />hydrological analysis. <br /> <br />As development occurs in the basin and additional farm land is removed <br />from the land use, the base flows are expected to increase, possibly increasing <br />the annual streamflow. Certain sub-basins tributary to Cherry Creek wi 11 <br />develop more than others which could result in higher annual peak discharge <br />values from the localized storms that do not cover the entire basin. <br /> <br />The development projections for the basin by ORCOG (Reference-l7) are <br />presented below. <br /> <br />Year <br /> <br />% Imperviousness <br /> <br />1985 <br />1990 <br />2000 <br />2010 <br /> <br />13 <br />16 <br />19 <br />23 <br /> <br />-21- <br />