Water resources assessment of the Toklat Basin in the vicinity of the Stampede Trail Alignment : Final Report

2005·3.2 MB·English

by  Karle, K.

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WATER RESOURCES ASSESSMENT OF
THE TOKLAT BASIN IN THE VICINITY
OF THE STAMPEDE TRAIL ALIGNMENT
FINAL REPORT
Prepared for
National Park Service
Denali Nati< rial Park ar-i Preserve
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WATER RESOURCES ASSESSMENT OF
THE TOKLAT BASIN IN THE VICINITY
OF THE STAMPEDE TRAIL ALIGNMENT
FINAL REPORT
Prepared for
National Park Service
Denali National Park and Preserve
Kenneth F. Karle, P.E.
Hydraulic Mapping and Modeling
Denali Park, Alaska
May 2005
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Table of Contents
List ofFigures iii
Abstract v
Introduction 1
Hydrologic Inventory 4
Water Quality 4
Toklat River Studies 6
Fish Studies 8
Flood Flow Statistics 8
Water Quality 12
Channel Geometry Analysis 15
Morphological Description 17
Hydraulic Modeling Analysis 19
Flood-Prone Area Delineation 20
Toklat Springs 22
Recommendations 25
Companion Products 26
References 27
Appendix A. Flood magnitudes, estimates oferror, and confidence limits 30
Appendix B. Annual exceedance probability graphs 33
Appendix C. High flow and low flow duration statistics for Toklat basin study watersheds
38
Appendix D. Surveyed cross-sections for the East Fork and Toklat Rivers 43
Appendix E. HEC-RAS Modeling results for the Toklat and East Fork Rivers 46
I
List of Figures
Figure 1. Study location map, and project field work sites 3
Figure 2. Watershed map developed from GIS data 5
Figure 3. Annual exceedance probability and flood magnitudes for Sushana River
watershed 10
Figure 4. High flow and low flow duration statistics for the Clearwater Fork 12
Figure 5. Discharge measurement at the East Fork River 14
Figure 6. High suspended sediment load and turbidity in the Toklat River 16
Figure 7. Lower cross-section, East Fork River 16
Figure 8. Particle size distributions for the East Fork and Toklat Rivers 18
Figure 9. HEC-RAS estimate for the 200-year flood for the Toklat River 20
Figure 10. Approximate flood-prone area for the East Fork River 21
Figure 1 1. Approximate flood-prone area for the Toklat River 22
Figure 12. Location ofthe Toklat Springs, and extent ofopen water during a March 2005
site visit 23
Figure 13. Upper end ofopen water channel at Toklat springs 24
Figure 14. Open water channel extending downstream from Toklat Springs 24
Figure 15. Salmon head at Toklat Springs 25
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List of Tables
Table 1. Water quality data from Tranel and Edwards (1998) for East Fork and
Clearwater Fork 7
Table 2. Basin characteristics for Toklat basin study watersheds 9
Table 3. Flood frequency estimations for Toklat basin study watersheds 9
Table 4. Estimates ofbankfull discharge for the 5 Toklat basin study sites 1
Table 5. Water quality for Sushana River, Toklat River, and Wigand Creek 13
Table 6. Results from cross-section surveys ofEast Fork and Toklat Rivers 17
IV