My WebLink
|
Help
|
About
|
Sign Out
Home
Browse
Search
FLOOD05980
CWCB
>
Floodplain Documents
>
Backfile
>
5001-6000
>
FLOOD05980
Metadata
Thumbnails
Annotations
Entry Properties
Last modified
1/25/2010 7:07:30 PM
Creation date
10/5/2006 1:55:27 AM
Metadata
Fields
Template:
Floodplain Documents
County
Gilpin
Community
Black Hawk
Stream Name
North Clear Creek, Gregory Gulch, Chase Gulch
Basin
South Platte
Title
Reconstitution of 1979 Flood Peaks, North Clear Creek, Gregory Gulch& Chase Gulch
Date
4/26/2001
Prepared For
CWCB
Prepared By
Love & Associates, Inc.
Floodplain - Doc Type
Flood Documentation Report
There are no annotations on this page.
Document management portal powered by Laserfiche WebLink 9 © 1998-2015
Laserfiche.
All rights reserved.
/
56
PDF
Print
Pages to print
Enter page numbers and/or page ranges separated by commas. For example, 1,3,5-12.
After downloading, print the document using a PDF reader (e.g. Adobe Reader).
Show annotations
View images
View plain text
<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 />CALIBRATION <br /> <br />Flood peak discharges were calibrated by making slight adjustments to Curve Numbers. <br />As noted on Figure 2, a small portion of the watershed includes soils of Hydrologic Soils <br />Group A, B, or C. Calibration was affected by substituting "A" soils for "D" soils in the <br />high density forest category. The results of the curve number adjustment are shown in <br />Table 3. Curve numbers were decreased by about 4 points in most catchments. The <br />resulting average curve numbers are within the range used by previous hydrologic <br />analysis in the study area. <br /> <br />Table 3. Curve Number Adjustmeuts for Calibratiou, Catchments 1-10, 1979 Land Use. <br /> <br />Land Use CN 1 2 3 4 5 6 8 9 10 <br />Area (ac) 5962 3875 5208 490 1884 810 691 1552 1870 <br />Area Isa.mi.) 932 6_05 8.14 0.77 2.94 127 1.08 2.43 2.92 <br />High Density <br />Forest - D soil 79 56% 40% 56% 41% 55% 2% 45% 32% 60% <br />High Density <br />Forest -A soil <br />(calibration) 36 9% 9% 8% 9% 10% 10% 3% 5% 9% <br />Low Density <br />Forest - D soil 83 19% 31% 21% 25% 15% 45% 21% 4% 0% <br />Meadow 75 16% 20% 10% 24% 20% 40% 31% 50% 23% <br />Low Density <br />Residential 84 0% 0% 5% 0% 0% 0% 0% 0% 7% <br />Med. Density <br />Residential 90 0% 0% 0% 0% 0% 2% 0% 3% 0% <br />Commercial 95 0% 0% 0% 1% 0% 1% 0% 6% 1% <br />Avera"e eN 75 75 76 75 74 75 77 76 74 <br /> <br />Note: See Figure 4 for Catchment location. <br /> <br />RESULTS <br /> <br />Flood peaks for the I OO-year flood obtained from the TR20 hydrologic analysis are <br />compared to the flood peaks in the 1979 study in Table 4. The flood peak from the 1979 <br />study did not include Silver Gulch, and the peak was adjusted using weighted area <br />calculations for mountainous areas recommended by CWCB (McCain et aI., 1976). The <br />results on Table 4 indicate this study has successfully reconstituted the 1979 flood peak <br />estimates using 1979 data with the TR20 using only minor adjustments to curve numbers. <br />Program output is found in the Appendix to this report. <br /> <br />-9- <br />
The URL can be used to link to this page
Your browser does not support the video tag.