Clear Creek Project Phase I - Feasibility Study Final Report - Appendixes
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November 1987 I I I I FINAL REPORT APPENDIXES CLEAR CREEK PROJECT I PHASE I - FEASIBILITY STUDY I I VOLUME II I I· I Prepared For: Colorado Water Resources & Power Development Authority 1580 Logan Street, Suite 620 I' Denver, Colorado 80023 I I Prepared By:
Tudor Engineering Company I In Association With: Cheryl Signs Engineering Woodward-Clyde Consultants I Western Environmental Analysts, Inc. I I I November 1987 I I,
I T ABLE OF CONTENTS I APPENDIX A
I 1 • 1 INTRODUCTION ••••••••..•••.•.••.•.•.•..••..••••••.•...... ••. A-1 2. 1 PHYSICAL FACILITIES •...••....••....••••••••.•.•...... '. A-1
" 2.2 WEST UNIT SUPPLY SySTEMS ...... •.•..••..••••....•.••....•.• A-l 2.2. 1 The Welch Di tch ..••...... •....•...•.•••.•...... A-2 I 2 . 2 • 2 Chur ch Ditch...... A-3 2.2.3 Farmers High Line Canal ...... •...... ••.....•••..•.. A-3 2.2.4 Croke Canal ...... ••...... ••...... ••...... A-4 I 2.2.5 Standley Lake ...... •. A-4 2.2.6 Great Western Reservoir ....•...••...... •...... •• A-5 I 2.2.7 Arvada Reservoir ...... A-6 2.2.8 Agricultural Ditch ...... A-6 I 2.2 .9 Wannamaker Ditch ...•...... •••...... ••...... A-7 2.2.10 Lee Stewart & Eskins Ditch ...... •...... • A-7 I 2.2.11 Rocky Mountain Ditch ...... A-7 2.2.12 Maple Grove Reservoir .•.•••...... A-8 I 2.2. 13 Jefferson Storage System ...•.•...... •...•...... A-8 2.3 EAST UNIT SUPPLY SySTEMS ..•..•..•.•....•...•...... A-9 ,I 2.3.1 The Miles and Eskins Ditch ...•.....•...... A-9 2 .3.2 The Reno-Juchem Ditch .....••••••.•...•...... •.....•. A-9 ,I 2.3.3 The Slough Association ...... A-9 2.3.4 Ouelette Ditch .••••••••...... •...•...... A-l0 2.3.5 South Side ••••...... •...... •.•...... A-10 I 2.3.6 The Cort Graves and Hughes Ditch .•••.•.•...... •..•... A-l1 2.3. 7 The Boyles Ditch .••...•.••.•...•...... A-l1 I 2.3.8 The Kershaw Ditch ...... A-ll 2.3.9 The Fisher Ditch ...... •..••...... A-ll 2.3.10 Clear Creek and Platte River Ditch and Colorado I Agr icul tural Ditch ...... •.•...... •. A-12 I 3.1 LOWER BASIN WATER SUPPLIERS AND USERS ...... A-12 I I II
/' TABLE OF CONTENTS (CONTINUED) I APPENDIX A I Page 3.2 AGRICULTURAL WATER USERS •••••••••••••••••••••••••••••••.•••• A-15 I 3.2. 1 General •••••••••••.•••••••••••••••••••••••••••••••••• A-15· 3.2.2 Clear Creek Water Rights ••••••••••••••••••••••••••••• A-15 il 3.2.3 Existing Water System •••••••••••••••••••••.••.••••••• A-16 3.2.4 Planning and Future Projects ••••••••••••••••••••••••• A-16 I 3.2.5 Clear Creek Project ••••••••••••••••••••..••••.••••••• A-16 3.3 THE CITY OF ARVADA •••••••••••••••••••••••••••••••••••••••••• A-16 3.3. 1 General •••.•••••••••.•••••••••••••••••••••••••••••.•• A-16 I 3.3.2 Clear Creek Water Rights ...... A-17 3.3.3 Existing Water System •••••••••.•••••••••.••••.••••••• A-17 I 3.3.4 Planning and Future Projects ••••••••••••••••••••••.•• A-18 3.3.5 Clear Creek Project •.•••••••••••••••••••••••••••.•.•• A-18 I 3.4 CITY OF BROOMFIELD •••••••..•..••••.•••••••••••••.••.••.••••• A-18 3.4. 1 General •••.••••••••••••••••••••••••.•••••.••..••••••• A-18 I 3.4.2 Clear Creek Water Rights ...... A-19 3.4.3 EXisting Water System ••.•..•.••••••••••..•••••.•••.•• A-19 3.4.4 Planning and Future Projects ...... A-20 I 3.4.5 Clear Creek Project •.•••.•..•.•••.••.....•••.•.•••••• A-20 3.5 CONSOLIDATED MUTUAL WATER COMPANy ••••.•••.••••••.••••••••••• A-20 I 3.5. 1 General .•••.•.••...•.••••.•....••••••••••••••.••••••• A-20 3.5.2 Clear Creek Water Rights ...... A-21 3.5.3 Existing Water System •••••••••••.•••••••.•••••.•••••• A-21 - 3.5.4 Planning and Future Projects .••••••••••••.••••••.•••• A-21 I 3.5.5 Clear Creek Project •••••••••••••••••••••.••••••••••.• A-22 3.6 ADOLPH COORS COMPANy ••••••••••••••••••••••••..•••••••••••••. A-22 3.6. 1 General ••••••••••••••••••••••••••••••••••••••.••••.•• A-22 I 3.6.2 Clear Creek Water Rights ••••••••••••••••.•••••••••.•• A-22 3.6.3 Exist~ng Water System •••••••••.•••••••••••••••••••••. A-23 I 3.6.4 Planning and Future Projects ••••••.••••••••••.••••••• A-24 3.6.5 Clear Creek Project ..••••••••••••••••••••••••.••.•.•. A-25 I I I I
I TABLE OF CONTENTS (CONTINUED) I APPENDIX A
I 3.7 CRESTVIEW WATER AND SANITATION DISTRICT .•.•...... •... A-25 3.7. 1 General ••••••••••.•••.•.•...••.....•...... ••... A-25 I 3.7.2 Clear Creek Water Rights ...•..••.••...... A-25 3.7.3 Existing Water System ...... •..•...... A-25 I 3.7.4 Planning and Future Projects ...... •...... A-26 3.7.5 Clear Creek Project .•....•...•...... •...... A-26 I 3.8 EASTLAKE WATER AND SANITATION DISTRICT ....•...... A-26 3.8. 1 General ....•...... A-26 3.8.2 Clear Creek Water Rights ••.••••.•...•...... •.....•... A-27 I 3.8.3 Existing Water System ...... A-27 3.8.4 Planning and Future Projects ...... A-27 I 3.8.5 Clear Creek Project ...... A-27 3.9 CITY OF GOLDEN ...... •...... A-27 I 3.9. 1 General ...... A-27 3.9.2 Clear Creek Water Rights ...... •...... •...... A-27 I 3.9.3 Existing Water System ...... •...... •... A-28 3.9.4 Planning and Future Projects ...... A-28 3.9.5 Clear Creek Project ...... A-29 I 3. 10 CITY OF LAKEWOOD ..•....•...••...... A-29 3. 10. 1 General ••....••....•...... •...... A-29 I 3. 10.2 Clear Creek Water Rights ...... •...... A-30 3.10.3 Existing Water System ...... A-30 I 3.10.4 Planning and Future Projects .....••...... A-30 3.10.5 Clear Creek Project ...... ~ ...... A-30 I 3. 11 CITY OF NORTHGLENN ...... A-31 3. 11 . 1 General ...... •...... A-31 3.11.2 Clear Creek Water Rights ...... A-31 I 3.11.3 Existing Water System ...... A-31 3. 11 .4 Planning and Future Projects ...... A-32 I 3.11.5 Clear Creek Project ...... A-32 I I I T ABLE OF CONTENTS (CONTINUED) I APPENDIX A I Page 3.12 NORTH TABLE MOUNTAIN WATER AND SANITATION DISTRICT ...... •••• A-33 I' 3. 12. 1 General ••••••••••. ~ ....••...••.•••••..•.••..•••..•.•. A-33 3. 12.2 Clear Creek Water Rights ..•••...••••...••••••••...••• A-33 I 3.12.3 Existing Water System .....•...•....•.••.••..•.•...••• A-33 3.12.4 Planning and Future Projects ..••....•.•••••••.••••••. A-33 :1 3.12.5 Clear Creek Project •••••••••••.••••••..•••....•.••••• A-34 3.13 PLEASANT VIEW WATER AND SANITATION DISTRICT •.•.•.••.•....••• A-34 3. 13. 1 General •...•....•.••.•...•••••••••••••.••••.•••....•• A-34 I
3. 13.2 Clear Creek Water Rights ..•••••.••.•.•...•.•.•• 0 ••••• A-34 3.13.3 Existing Water System •.•.••••.••••.•...... •. A-35 I 3.13.4 Planning and Future Projects •..••...... •...... A-35 3. 13.5 Clear Creek Pro j ect ..•.•.•..•..••.•.....•...... A-35 I 3.14 PUBLIC SERVICE COMPANY - LOWER BASIN ...... •...... A-35 3. 14. 1 General ....••...... •...•..•..•...... •...... •.. A-35 3.14.2 Clear Creek Water Rights ..••..•.•...... •...... •.. A-36 I 3.14.3 Existing Water System ...... ••...... •.....•• A-36 3.14.4 Planning and Future Projects •..•...... •.. A-36 I 3.14.5 Clear Creek Project •...... •....•...•.••.. A-36 3.15 ROCK MINING COMPANIES .••.•...•....•...••.•.•...... •...•. A-36 I 3. 15. 1 General ...... ••...... A-36 3.15.2 Clear Creek Water Rights •••.•..••..•...... A-37 I 3.15.3 Existing Water System •.•.•••••••••.••...... •...•. A-37 3.15.4 Planning and Future Projects •••.••..•...... A-37 3.15.5 Clear Creek Project .•.•.•••••.•••..•....•...... A-3B I 3. 16 THE CITY OF THORNTON ..••..•••••.•••••.•••.•••..•...... •..... A-3B 3. 16. 1 General ..••.••••...... •..•••.•..•.•...... •....••• A-3B I 3. 16.2 Clear Creek Water Rights .•••...... •.•.••.....•...... • A-3B 3.16.3 Existing Water System ...• ',' .•.•.•..•...... A-39 I 3.16.4 Planning and Future Projects ..•....•.....•...... •• A-39 3. 16.5 Clear Creek Project ...... •.•.•....•.•...•...••...•.. A-40 I I I I
I TABLE OF CONTENTS (CONTINUED) I APPENDIX A
I 3. 17 THE CITY OF WESTMINSTER ..••..•.•••••...•.•...... A-40 3.17.1 General .•...... ••...••.•.•.•••••••.•...... A-40 I 3.17.2 Clear Creek Water Rights .•..••..••...... A-40 3.17.3 Existing Water System ...... •.... A-41 I 3.17.4 Planning and Future Projects ...... •...• A-42 3.17.5 Clear Creek Project ...... ••...... •...... A-42 I 4.1 SUMMARY OF SAFE YIELD ESTIMATES ...••...... •...... A-43 4.2 SUMMARY OF PRESENT SUPPLIES AND PROPOSED ALTERATIONS TO EXISTING SySTEMS .....•..•...... •...... ••...... A-44· I 4.2.1 Safe Yields and Projected Demands .....••...... •.... A-44 I 4.2.2 Currently Proposed Developments .•...... A-47 I I I I I I I I I I I LIST OF TABLES I APPENDIX A I Table Page A. 1 Lower Basin Water Suppliers Membership ...... A-14 I A.2 Summary of Clear Creek Safe Yield Estimates .....•...... A-44 A.3 Comparison of Current Safe Yield and Projected Future I Demands ...... •.. -...... A-46 A.4 Proposed Project Alterations Clear Creek Water Users ...... A-47 I I I I I I I I I I I I I I I
I TABLE OF CONTENTS I APPENDIX B·
I 1 • 1 SUMMARY AND CONCLUSIONS ••••••.•.••..•••••••••.•••.....•.•••• B-1 1 • 1 • 1 Introduction ...... B-1 I· 1 • 1 • 2 Pu.rpose •••••••••••••••••••••.••...••••••..•••.•••••.. B-1 1.1.3 Data Base ...... B-2 I 1.1.4 Projected Water Quality For Impoundments and Potential Benefits of Impoundment ..•...••..••.•.••.•• B-2 'I 1 • 1 .5 Canclua ions ...... B-4 1.1.6 Additional Studies Required ..•...... ••..•••...... B-5 2.1 HISTORICAL OVERVIEW AND DESCRIPTION OF MAJOR MINE I DRAINAGE SITES ...... •...... •..•....••..•••...••...••••.•••• B-5 2. 1 • 1 Introduction •.•••.•••.....••...... ••....•...•....•.•• B-5 I . 2. 1 . 1 • 1 General ••.••....••••..•..••••...... B-5 2.1.1.2 Mine Drainage Sites ..•••...... •...•... B-6 I 2.2 DESCRIPTION OF THE DATA BASE •.••••.••••••.••.•...... •... B-9 2.3 SEGMENTATION, CLASSIFICATION, AND NUMERIC I ST ANDARDS ••••••••••••••••••••••••••••••••••••.••••.•••• eo •••• B-16 2.4 GENERAL WATER CHEMISTRY CHARACTERISTICS OF CLEAR CREEK ...... B-19 2.5 OVERVIEW OF METALS CHEMISTRY IN CLEAR CREEK •...•...... •.... B-25 I 2.6 DISCHARGE-WEIGHTED CONCENTRATIONS FOR CRITICAL VARIABLES .••. B-36 2.7 PROJECTED WATER QUALITY FOR IMPOUNDMENTS ...... •.....•...... B-37 I 2.7.1 Quality of Water Entering the Impoundment ...•.•..•.•• B-37 2.7.2 Correction for Sedimentation ...... ••.•...•...... •.... B-39 I 2.7.3 Correction for Ligation and Flocculation in the Lake ...... •..•... ~ ...... B-41 I 2.7.4 Correction for Water Diversions ...•.•.....•..•...... B-44 2.7.5 Correction for Remedial Action •....••...••...... B-47 2.8 ESTIMATED SUITABILITY OF AN IMPOUNDMENT FOR I AQUATIC LIFE .•••.•••••...... ••.•.....••...... •..... B-47 'I I 1 I TABLE OF CONTENTS (CONTINUED) I APPENDIX B I Page 2.9 POTENTIAL FOR AQUATIC LIFE AND FISHERIES ...... B-49 I 2.9.1 The Present Fishery and its Management ...... B-50 2.9.2 Potential for a Reservoir Fishery •...... ••.•... B-53 2.9.3 Stream Fishery Potential. ...•. -..•...... ••..... B-53 'I 2.9.4 Other Considerations .•.••.•...... ••....•.•... B-54 I I I I I I I I I I I I I I I' I LIST OF TABLES APPENDIX B I Table I B. 1 List of Water Quality Sampling Sites ....•...... B-11 B.2' Summary of Numeric Stream Standards and Aquatic Life Classifications for the Upper Clear Creek Basin ...... B-17 I B.3 General Water Chemistry Data for Clear Creek ...... B-21 B.4 Summary of Water Chemistry Data West Fork of Clear Creek I and North Clear Creek ...... B-22
~. B .:;1 Summary of Water Chemistry Data Clear Creek at Hidden I Valley and Clear Creek above Golden ...... B-23 B.6 Clear Creek Metals Chemistry Summary ...... B-26 I B. " Clear Creek Metals Chemistry at Mouths of West Fork and North Clear Creek ...... B-28 B.B Clear Creek Metals Chemistry at Hidden Valley and I above Golden ...... •..•...... B-29 B.9 Metal Criterion Values and Frequency Distributions ...... B-31 I B.10 Elements and Their Probable Relation to Aquatic Life in Clear Creek ...... •...... B-32 I B.11 Projected Quality of Reservoir Inflows Before and After Corrections for Sedimentation ...... B-39 I B.12 Projected Reservoir Water Quality ...... B-43 B.13 Metal Concentrations for Williams Fork at Sugarloaf I Campground ...... ' B-45 B.14 Potential Diversions from Williams Fork ...... B-46 I B.15 Stocking and Creel Census ...... •....•...... B-52 I LIST OF FIGURES
I B. 1 Clear Creek Watershed Water Quality Sampling Locations ...... B-55 B.2 State of Colorado Segmentation of Watershed ...... B-56 I B.3 Spatial Distribution Copper and Zinc Concentration ...... B-57 B.4 River Discharge vs Concentration Cadmium and Lead ...... B-58 I B.5 River Discharge vs Concentration Copper and Zinc ...... B-59 B.,6 River Discharge vs Hardness ...... B-60 I I
I TABLE OF CONTENTS I APPENDIX C
I 1.1 GROUND WATER HYDROLOGY OF THE UPPER CLEAR CREEK BASIN ...••.. C-1 1 • 1 • 1 Introduction .••.••••••..••••••••••••.•••••.••••.•.•.. C-1 I 1. 1.2 Geology ...... C-1 1.1.3 Occurrence of Ground Water ..•..••••..••..•...•....••• C-1 I 2.1 GROUND WATER HYDROLOGY OF THE DENVER BASIN .•••••..••...•... C-2 2. 1 • 1 Introduction •...•.••••.•••••.•...••.•••••..•••.•..•.• C-2 I 2.1.2 Geology ...... C-2 2.1.2.1 Recharge, Discharge, and Occurrence of Ground Water in the Denver Basin ..•••..•.... C-2 I 2.1.2.1.1 Recharge and Discharge ...•....•.. C-2 2.1.2.1.2 Occurrence of Ground Water •..•... C-3 I 2.1.2.2 Extent of Development ....••...••..•••..•.... C-4 2.1.2.3 Description of the Aquifers ..••••.••••..•... c-6 I 2.1.2.3.1 Laramie-Fox Hills Aquifer ••.•..•. C-6 2.1.2.3.2 Arapahoe Aquifer ••••••.••..•.•••. C-8 I 2.1.2.3.3 Denver Aquifer ••..•••••••.....••. C-8 2.1.2.3.4 Dawson Aquifer ••...•••.•••..••... C-9 I I I I I I I I ·1
LIST OF TABLES I APPENDIX C I Table C. 1 Annual Yield of Unappropriated Water Beneath Municipal I Boundar ies .•...... •...•...... C-5 C.2 Water in Storage in Denver Basin Aquifers ...... C-6 I LIST OF FIGURES I Figure Page I C. 1 Location of Denver Basin and Clear Creek Basin ...... C-l1 C.2 Generalized Geologic Sections Through Denver Basin ...... C-12 I I I I I I I I I I I I I TABLE OF CONTENTS
I APPENDIX D I 1 • 1 INTRODUCTION .•••••••.•...•.••••••..•••••••••••••.••.•••....• D-l I 1.2 NORTH CLEAR CREEK PROJECT ..••••••••••••••••...... •..•.•.••.• D-l
1 .2. 1 General ...... e' •••••••••••. D-l I 1.2.2 Geotechnical Overview ••.••••••••••••••..••.•.•..•.•.• D-l 1.2.3 Project Description ••••••••••.••••••••••••.••••.••••. D-2 1.2.4 Relocations Required .••••••••••••••••••.•.•.•.•••...• D-5 I 1.2.5 Preliminary Cost Estimate .••••••••••••..•.••••.••.... D-5 1 .3 GUY GULCH PROJECT ••••••••••••.••••••••••.••••••••••.••••..•• D-1 I 1 .3. 1 General •••••••...... •••••••••••••.••.••••.••.••.••... D-1 1.3.2 Geotechnical Overview ••••••••••.•.•...... •••••••.••• D-1 I 1.3.3 Project Description •••••••••• ~ •..•••.••••••..••.••••• D-1 1.3.4 Relocations Required ••.••••.•.•...•.•••.••...••..•.•• D-10 I 1.3.5 Preliminary Cost Estimate ..••.•...•...... ••..•....••. D-lO 1 .4 SODA CREEK PROJECT .••..•••...... •...... •.....•...... • D-12
1 .4. 1 General ••..••.. ~ •....•.•••••....•..•••.••..••.•.....• D-12 I 1.4.2 Geotechnical Overview ...... D-12
1.4.3 Project Description .••..•...... ••...... ~ •...... •.. D-13 I 1.4.4 Relocations Required •••••••....•••...•..••....•..•... D-15
••••••••••••••••••••••• D-16 1.4.5 Preliminary Cost Estimate ••••.o I 1 .5 F ALL RIVER PROJECT ••..••..•.•.•••.•••.•.....•..•••..•.••.••• D-18 1 .5. 1 General ••••••..•••••.••..••.••.•.•••••..•...... •... D-18 I 1 .5.2 Geotechnical Overv iew •.••••••.•.•••••...•...... •..... D-18 1 .5.3 Project Descr iption •••••••••••••••••••..•••...•...... D-19 I 1.5.4 Relocations Required •...•.....•••.••.•••••••..••.•.•. D-21 1.5.5 Preliminary Cost Estimate .•••.•.•..•.•..•.....•...... D-22 1.6 PINE RIDGE PROJECT ••....••••.•....•••••••••••.•••.•.•...... D-24 I 1 .6. 1 General .....•...... ••...... •...... •..•..•.•..•.. D-24
1.6.2 Geotechnical Overview ••••••••.••.•..•.•.••.•.• 0 ••••••• D-24 I 1.6.3 Project Description •.•..•..•...... •..•..•...••...•.. D-25 1.6.4 Relocations Required •.....•••.....••....•...•..•.•... D-28 I 1.6.5 Preliminary Cost Estimate .•••.•.•...... ••.•...•...••. D-28 I I I LIST OF TABLES I APPENDIX D I Table D. 1 North Clear Creek Project ..•••..•••.•••.•.•...... •....•.• D-4 I D.2 Preliminary Cost Estimate North Clear Creek Project ...... D-6 D.3 Guy Gulch Project ...•...... •...... •...... •.....•...... D-9 I D.4 Preliminary Cost Estimate Guy Gulch Project ...... D-11 D.5 Soda Creek Project ...... •...... ••...... D-15 D.6 Preliminary Cost Estimate Soda Creek Project ...... •..•.... D-17 I D.7 Fall River Project •....•...... •...... •.. D-21 D.8 Preliminary Cost Estimate Fall River Project ...... D-23 I D.9 Pine Ridge Project ...... •...... •...... •..... D-27 D.10 Cost Estimate for Pine Ridge Project ...... •.•...... D-29 I LIST OF FIGURES I Figure I D. 1 North Clear Creek Project ...... •...... D-30 D.2 North Clear Creek Plan and Profile ...... D-31 I D.3 Guy Gulch Project ..•...... •...... D-32 D.4 Guy Gulch Plan and Profile .••...•...•...... •...... D-33 D.5 Soda Creek Project D-34 I D.6 Soda Creek Plan and Profile .•...... D-35 D.7 Fall River Project ...... D-36 I D.8 Fall River Plan and Profile ...... •...... D-37 D.9 Pine Ridge Project ...... D-38 I D.10 Pine Ridge Plan and Profiles ...... D-39 I I I I I I
I TABLE OF CONTENTS I APPENDIX E
I 1.1 PREVIOUS REPORTS...... E-1 2. 1 OTHER DATA COLLECTION...... E-3 I 2.2 TOPOGRAPHI C MAPS...... E-3 2.3 AERI AL PHOTOS...... E-4 I 2.4 GEOLOGIC MAPS...... E-4 2.5 OTHER MAPS...... E-4 I 3. 1 DATA RELATED TO ENVIRONMENTAL ISSUES...... E-5 4. 1 BIBLIOGRAPHY. • . . . . . • ...... • . • • . • . . . • . . • • • ...... E-5 I I I I I I I I I I I I I I I I I Appendix A I LOWER BASIN WATER FACILITIES. I AND SUPPLIERS I I I I I I I I I I I I I
I APPENDIX A I LOWER BASIN WATER FACILITIES AND SUPPLIERS 1.1 INTRODUCTION I A general description of the Lower Clear Creek basin water suppliers and user's is given in Section 2 of the Final Report. The following is a detailed list of the lower basin water users, their water rights, existing water I systems, and their plans for future water projects. It is prefaced by a I description of each of the active ditches and reservoirs in the lower basin. 2.1 PHYSICAL FACILITIES I The physical facilities in the lower basin include diversion structures, ditches, canals, augmentation stations, storage reservoirs, and pump I stations. A general description of the facilities was given in Section 2 of the main report.
I The description of the existing facilities is divided into two raw water supply systems: the west unit and the east unit. The dividing line between I the east and west units is the Croke Canal and Rocky Mountain diversion dam. This division has been made for two reasons. First, because development I originally occurred in the downstream portion of the lower bas in, the more senior decrees are generally located there. Secondly, the diversions in the I west (upstream) portion depend almost entirely on water flowing through the Clear Creek Canyon. The east (downstream) portion diversions are supplied by return flows from the ditches as well as flow through the canyon. This I distinction is becoming less defined with time, because change of use decrees usually require return flows from the various ditches. These return flows are I typically introduced to Clear Creek directly below the ditch headgate.
I 2.2 WEST UNIT SUPPLY SYSTEMS The west unit supply systems include the following: Welch Di tch, Church I Ditch, Farmers High Line Canal, Croke Canal, Standley Lake, Great Western Reservoir, Arvada Reservoir, Wannamaker Ditch, Rocky Mountain Ditch, Lee Stewart and Eskins Ditch, Agricultural Ditch, Maple Grove Reservoir, and I Jefferson Storage System. These systems were generally described in Section 2 I of the main report. I A-1 I
The Church Ditch, the Farmers High Line Canal, and the Croke Canal divert I from the north side of Clear Creek. All three serve lands in the Clear Creek and Big Dry Creek basins. The Farmers High Line and Croke serve lands in the I South Platte River basin proper. The Croke also serves lands in the St. Vrain basin. The Church Ditch and Farmers High Line Canal serve direct flow users as well as contributing to Standley Lake, Great Western Reservoir, and Arvada I Reservoir. The Croke Canal serves oniy Standley Lake although the City of Arvada has a contract for capacity in the Croke Canal. This capacity is used I to carry the water exchanged to the Croke to a pumping station, which lifts water to Arvada Reservoir. I The remaining water supply systems in the west unit primarily supply water I to the Adolph Coors Company and to the Consolidated Mutual Water Company.
2.2.1 The Welch Ditch I The Welch Ditch is the most upstream diversion in the lower basin. It diverts from the south side of Clear Creek in the Canyon, approximately two I miles west of the City of Golden. The wooden flumes can be seen along the Canyon walls from its diversion point just upstream of Tunnel No. 1 on U.S. I Highway 58 to the mouth of the canyon. The ditch traverses the side of the canyon in an easterly direction and then runs southerly a total distance of 17 I miles.
It has three decrees which total 28 cfs and were appropriated from 1860 to I 1871. The first two decrees were transferred to the ditch from downstream sources. The system has been water short for its agricultural users. I Shareholders in this ditch also usually owned Agricultural Ditch water, and the two systems have been intermingled. Welch decrees can be diverted at the I Agricultural Ditch headgate under a temporary court order. Some shares are owned by Adolph Coors Company and by Consolidated Mutual Water Company. I However, the Welch Ditch's Board of Directors have adopted by-laws which tie the water to land historically irrigated. Therefore, the water is currently used only by remaining agricultural owners. I I I A-2 I I
I 2.2.2 Church Ditch The Church Ditch diverts from Clear Creek approximately one mile west of I the intersection of U.S. Highway 6 and State Highway 58. The diversion dam is about 0.6 miles upstream of the USGS gaging station on Clear Creek at I Golden. The City of Golden also uses the Church's diversion dam for its water withdrawals from Clear Creek. The Church Ditch runs almost straight north for about 26 miles to the Ketner flume (now replaced by the Wilson flume) in the I Big Dry Creek basin. The water continues north in the Dry Creek Valley and I Equity Laterals. Seven decrees totaling 213 cfs are attached to the Church Ditch with I appropriation dates ranging from 1862 to 1886. The earliest decree was a transfer for 0.90 cfs from the Swadley Ditch, a Slough Association ditch. The I primary operating decree was appropriated in 1865 for 41 cfs. This is a . relatively junior decree, and the Church system was water short for irrigation I demands. Church Ditch is a carrier ditch company owned by the Cities of Northglenn I and Broomfield. Northglenn acquired the Church Ditch facil i ty from the Farmers Reservoir and Irrigation Company (FRICD) in the late 1970's. It sold I one-third of the ditch to the City of Broomfield in the early 1980's. Ownership of water in the Church Ditch is represented by inches, which are an I annual right to receive water. Major inch holders in the ditch are FRICD and the Cities of Broomfield, Westminster, Northglenn, and Thornton. There is some agricultural use remaining in the northern portion of the service area, I however, the other inch holders are urban dwellers with large lots used for I horse pasture and gardens. 2.2.3 Farmers High Line Canal I The Farmers High Line Canal diverts from the north side of Clear Creek within the City of Golden. It traverses the foothills in a primarily I nort.herly direction until it enters the Big Dry Creek basin near Standley Lake. It then runs northeasterly and serves lands on the south side of the Big Dry Creek. The canal tails to the Signal Ditch Lateral, and the total I length of the system is 46 miles. The Farmers High Line Canal and Reservoir I Company has 12 decrees with appropriation dates ranging from 1860 to 1895. I A-3 I
The total amount appropriated is 734 cfs. The first three decrees were I transfers from downstream ditches for relatively small amounts.
The original appropriation made to the Farmers High Line (then known as I the Arapahoe Ditch or Golden Canal) was in 1860 for 40 cfs. The primary operating decree in the ditch is for 154 cfs appropriated in 1872. This is a I junior decree on Clear Creek, and the High Line system was a water short supply for the irrigation demands under it. I
Farmers High Line Canal and Reservoir Company is a mutual ditch company, I and ownership is indicated by shares issued by the company. Major shareholders are the Cities of Arvada, Westminster, and Thornton. Water is delivered to shareholders along the total length of the canal. Those in the I southern portion of the service area are primarily urban residents with large lots and requirements similar to those found on the Church Ditch. The I agr~cultural users are now located in the north portion of the ditch's service area in rural Adams County. I
2.2.4 Croke Canal I The Croke Canal is a feeder for Standley Lake and is owned by FRICO. It diverts from the north side of Clear Creek near McIntyre Street and .runs I northerly to Standley Lake, a distance of about 15 miles. It has one decree from Clear Creek for 944 cfs, which was appropriated in 1902. Summer diversions are made only during high runoff periods. During the winter, it is I essentially the only operative decree on Clear Creek. No direct flow deliveries directly from the Croke Canal are made to shareholders. I
2.2.5 Standley Lake I Standley Lake is the largest existing storage reservoir for Clear Creek water. It is located on Big Dry Creek, near 80th Avenue and Wadsworth I Boulevard. The dam is approximately 100 feet high and one mile long. Active storage in the reservoir is about 42,000 af. Standley Lake holds an absolute decree from Clear Creek for 32,361 af and a conditional decree for 16,669 af, I both appropriated in 1902. It is also filled by water from Coal Creek, Church Ditch, Farmers High Line Canal, Croke Canal, and tributary runoff. In the I early 1960's, the City of Westminster enlarged the reservoir from about 18,000 I A-4 I I
I af to its current capacity. This was done under contract with FRICO, which owns the structure and the water rights. The city received 12,000 af, and the I farmers got the remaining 12,000 af of the 24,000 af enlargement. I In the mid 1970's, FRICO and the City of Northglenn entered an agreement whereby Northglenn was allowed to use the farmers' water first and return the full amount plus a ten percent bonus as wastewater effluent of an acceptable I quality. In the late 1970' s, an agreement between FRICO and the Cities of Thornton, Westminster, and Northglenn, known as the Four-Way agreement, was I executed. This agreement essentially conveyed the use of 10,000 af of FRICO's Standley Lake capacity to Thornton and made arrangements for the modified I operation of Standley Lake between the four parties. FRICO is a mutual ditch company comprised of four divisions, which are Marshall Lake, Hilton Lake, I Barr Lake, and Standley Lake. Only the Standley Lake division directly utilizes Clear Creek" flows.
I The major shareholders in the Standley Division are the Cities of Westminster, Thornton, and Northglenn. Ownership of shares in the Standley I division include the water rights and the associated storage capacity. Thus, the Cities of Thornton and Westminster <;>wn independent capacity in Standley I Lake as well as capacity by virtue of their share ownership. Standley Lake is also filled by the three cities' ownership of Church and Farmers High Line I water. Water for the cities is delivered through pipelines from the outlet works at the base of the dam.
I The majority of the farmers' water is delivered down Big Dry Creek to the Bull Canal headworks located near Interstate 25. This water is carried I northeasterly to users in Adams and Weld Counties. The extreme northern portion of the Standley Lake service area is in the St. Vrain basin. The Bull I Canal system runs for about 41 miles from the Big Dry diversion point. The agricultural demand for water has always been larger than the Standley Lake I supply.
2.2.6 Great Western Reservoir I Great Western Reservoir is located on Walnut Creek about two miles I southwest of the Jefferson County Airport. The dam is about 70 feet high, and I A-5 .1 the reservoir has a storage capacity of about 3250 af. The dam and reservoir I are owned by the City of Broomfield. Water supplied to the reservoir comes from Clear Creek by virtue of the city's ownership of Church inches and I transferred agricultural storage rights. Water also comes from Coal Creek by virtue of the Great Western decree for 26,000 af. I 2.2.7 Arvada Reservoir Arvada Reservoir, formerly known as Blunn Reservoir, is located on Ralston I Creek below the Foothills Road and Ralston Reservoir. Its dam is about 70 feet high, and the reservoir capacity is about 5500 af. It is owned by the I City of Arvada. Sources of water for the reservoir are Ralston Creek and Clear Creek. Clear Creek water derives from Arvada's ownership in the Church I Ditch, Farmers High Line Canal, Reno-Juchem Ditch, and Slough Association ditches as well as the Blunn Lake decree from Clear Creek. I
Clear Creek water ~s transported to Ralston Creek through the Church Ditch, the Farmers High Line Canal, and the Croke Canal. A pump station is I located on the Croke Canal at Ralston Creek which lifts the Clear Creek water to the reservoir. Ralston Creek water is stored in the reservoir by virtue of I its own decree, by agricultural rights on Ralston Creek, which have been transferred to the reserVOir, and by exchange with Clear Creek, Ralston Creek, I and South Platte River sources owned by the City of Arvada.
2.2.8 Agricultural Ditch I The Agricultural (Ag) Ditch diverts from the south side of Clear Creek from a point in the City of Golden. It runs in a southeasterly direction into I the Bear Creek basin and is approximately 38 miles long. Storage in the Clear Creek basin associated with the system are the Ag Mountain Reservoirs located I in the upper basin and the Midway Reservoirs in the lower basin located near Union and Mississippi Avenues. I
The Ag Mountain Reservoirs were discussed in Section 4.2. The Midway Reservoirs are East, Main, and Smith Reservoirs, with a total decreed capacity I of 1346 af. Those reservoirs are under the Ag Ditch about halfway down the ditch. Releases from the Ag Mountain Reservoirs are used to supplement the I upper users' supply while the Midway Reservoirs supplement the lower users' supply. I A-6 I I
I Twelve decrees are associated with the Ag Ditch which have appropriation dates ranging from 1860 to 1888. The first nine decrees are transfers from I downstream ditches for relatively small amounts. The originai decree for the ditch was appropriated in 1874 for 102 cfs. This is a junior decree on Clear I Creek, and the system has been water short for irrigation demands.
The Agricultural Ditch and Reservoir Company is a mutual ditch company. I Major shareholders in the Ag Ditch are the Adolph Coors Company and the Consolidated Mutual Water Company. Many of the Ag Ditch shareholders also own I water in the Welch Ditch, and Welch Ditch water is diverted through the Ag I Ditch on occasion by virtue of a temporary court order. 2.2.9 Wannamaker Ditch I The Wannamaker Ditch diverts from the north side of Clear Creek near the Adolph Coors Company's main plant. It runs northeasterly about 4.5 miles but does not leave the Clear Creek basin. Two decrees, which total 21 cfs, are I associated with the ditch. Their appropriation dates are 1860 and 1868. The Wannamaker has had sufficient water for the agricultural lands located under I it. Wannamaker is a carrier ditch company owned by the Adolph Coors I Company. Coors is also the major holder of water in the company. 2.2.10 Lee Stewart & Eskins Ditch I The Lee Stewart & Eskins Ditch diverts from the south side of Clear Creek, just upstream of the Croke diversion dam. It runs easterly about three I miles. A lateral located near Youngfield Street conveys water to Maple Grove Reservoir located on Lena Gulch. Five decrees are associated with the ditch ranging in appropriation dates from 1861 to 1871. The total decreed to the I ditch is 36 cfs, and these decrees include no decrees transferred from other di tchs. It is a mutual ditch company, and the major share holders are the I Adolph Coors Company and the Consolidated Mutual Company.
I 2.2.11 Rocky Mountain Ditch The Rocky Mountain Ditch .diverts from the south side of Clear Creek using I the same diversion dam as the Croke Canal. It runs in a generally easterly direction to a bifurcation point located west of Wadsworth Boulevard. The I North Branch continues easterly to Dewey Lake located near Interstate 25 and I A-7 I 58th Avenue. The South Branch runs south into the Bear Creek basin. The I total length of the main canal and its longest branch is about 24 miles.
Five decrees are associated with the ditch, which total 190 cfs. The I appropriation dates range from 1862 to 1878. The ditch has been water short and has not met the historical agricultural demands for lands located below I it. The company is a carrier ditch company owned by Adolph Coors Company. Coors owns the majority of the water in the ditch. Consolidated Mutual Water I Company also owns water in the ditch. The City and County of Denver uses Rocky Mountain Ditch water to fill Sloan Lake and other reservoirs in its park I system.
2.2.12 Maple Grove Reservoir I Maple Grove Reservoir is owned by the Consolidated Mutual Water Company. It is located near Interstate 70 and 25th Avenue on Lena Gulch. Its dam is I approximately 30 feet high, and the reservoir capacity is about 1100 af. It is filled by its own decree from Clear Creek and by Consolidated Mutual Water I Company's ownership in the Lee Stewart & Eskins Ditch, Agricultural Ditch, and Rocky Mountain Ditch. The reservoir was constructed in 1957 at 600 af of I capacity. In 1973, the State Engineer's requirements caused Consolidated to modify its spillway and to enlarge the reservoir to its current capacity. The I new spillway capacity is 50~ of the Probable Maximum Flood (PMF).
2.2.13 Jefferson Storage System I Jefferson Storage-System is owned by the Adolph Coors Company. The system is a series of reservoirs located primarily on the south side of Clear Creek I near McIntyre Street. These structures are being formed as gravel is mined forming depressions which are converted to reservoirs. Their current total I storage capacity is about 7400 af. They are decreed for a total of 17,700 af with appropriation dates ranging from 1942 to 1975. These reservoirs are filled by their own decrees from Clear Creek, by the Coors Industrial decree, I the Wannamaker Ditch, the Rocky Mountain Ditch, and by exchange with several other decrees owned by Coors on Clear Creek. I I I A-8 I I
I 2.3 EAST UNIT SUPPLY SYSTEMS The water supply systems of the east unit of the lower Clear Creek basin I are: Hiles and Eskins Ditch; Reno-Juchem Ditch; the Slough Association, a collection of 20 ditches diverting from a common point on Clear Creek; the I Ouelette Ditch; the South Side; the Cort Graves and Hughes Ditch; the Boyles Ditch; the Kershaw Ditch; the Fisher Ditch; the Clear Creek and Platte River Ditch; and the Colorado Agricultural Ditch. The latter two ditches share a I common headgate on Clear Creek.
I 2.3.1 The Hiles and Eskins Ditch The Hiles and Eskins Ditch diverts from the south side of Clear Creek near I Indiana Street. I t has one decee for four cfs, which was appropr ia ted in 1861. The ditch is owned by Adolph Coors Company and is primarily used to I irrigate the Applewood golf course.
2.3.2 The Reno-Juchem Ditch I The Reno-Juchem Ditch diverts from the north side of Clear Creek east of Indiana Street. It runs northeasterly for about 11 miles into the Ralston I Creek and Little Dry Creek basins. The ditch has six decrees which total 35 cfs and range from 1861 to 1878 in appropriation dates. The Reno-Juchem Ditch I Company is a mutual ditch company and has three catagories of ownership, which are contract, inch, and share waters. The system was historically water short I for its agricultural users.. The major owner now is the City of Arvada . Adolph Coors Company also owns some water in· the company. Both of these I owners use the water as an exchange source in their plans for augmentation. 2.3.3 The Slough Association I Formally known as the Bayou Association, the Slough Association is a collection of 20 ditches diverting from a common point from the north side of I Clear Creek near Ward Road. The Slough was a historical stream bed of Clear Creek. It runs northeasterly from Clear Creek and the highest ditch in the I system, the Swadley Ditch, conveys water into the Ralston Creek basin. The total length of the Slough is about five miles. Return and unused flows from I the system returns to Clear Creek below Wadsworth Boulevard. I I A-9 I
The most senior decrees on Clear Creek are decreed to ditches in the I Slough Association. Many of the upstream transfers to the Church Ditch, Farmers High Line Canal, City of Golden, Agricultural Ditch, and Welch Ditch I were originally decreed to Slough ditches. The appropriation dates for ditches in the Slough range from 1860 to 1874. The decrees remaining in the Slough total 104 cfs. I
The water supply for the Slough's historical agricultural demand has been I in excess of available supply for most of the ditches. The ditch companies in the Slough vary in their organizational structure, but most are mutual ditch I companies. The area served by these ditches was one of the first in the basin to urbanize resulting in a change in water use in the area and in the I ownership of the ditch companies.
Major owners of Slough water at present are the City of Arvada and the I
Adolph Coors Company. These two entities use their Slough water ~n plans for augmentation, which allow using the historical depletion portion of the water I to repay depletions caused by the operation of their water systems. The decrees also allow exchange of these depletion credits to upstream diversion I points. Remaining users on the ditches are primarily urban people, who use the water to irrigate lawns and gardens. Some actual agricultural use still I exists on the land located in the Clear Creek flood plain.
2.3.4 Ouelette Ditch I The Ouelette Ditch diverts from the north side of Clear Creek near Simms Avenue extended. It holds a senior decree appropriated in 1860. Although the I ditch was originally decreed for 15 cfs, all but 1 cfs has been transferred out of the ditch. The remaining structure is less than one mile long and I serves land located in the same area as that served by the Slough Association. It has had adequate water for its agricultural demand. I
2.3.5 South Side The South Side Ditch is decreed for one cfs with an 1860 appropriation I date. A portion of this decree is owned by the Adolph Coors Company. This portion is left in the stream for use in the Coors' plan for augmentation. I I A-10 I I
I 2.3.6 The Cort Graves and Hughes Ditch The Cort Graves and Hughes Ditch di verts from the north side of Clear I Creek at Wadsworth Boulevard. It runs northeasterly for a distance of about one mile. It was decreed for three cfs with an appropriation date of 1861. I It has historically had adequate water to serve its irrigation demands. The City of Arvada is a major owner in the ditch. The city has recently filed an application with the water court for a plan for augmentation involving this I source.
I 2.3.7 The Boyles Ditch Boyles Ditch diverts from the south side of Clear Creek just east of I Sheridan Avenue. It runs southeasterly for less than a mile. It was decreed for two cfs with an appropriation date of 1863. Boyles Ditch has had adequate I water for its irrigation demand.
2.3.8 The Kershaw Ditch I The Kershaw Ditch diverts from the north side of Clear Creek at Tennyson Street. It runs in a northeasterly direction for about two miles. The ditch I can divert up to 11 cfs under a 1861 appropriation date. It has had adequate water for the historical irrigation demands. The major shareholders are I Crestview Water and Sanitation District and the City of Westminster. There are agricultural shareholders still using water from the ditch. They I primarily irrigate land in the Clear Creek flood plain.
2.3.9 The Fisher Ditch I The Fisher Ditch diverts from the south side of Clear Creek and runs in an easterly direction for about three miles. It terminates in Copeland Lake. I The decreed quantity for diversion is 35 cfs with an 1861 appropriation date. The ditch has had adequate water for its historical irrigation I demands. The major stockholders in the ditch are Public Service Company (PSC) and the United Ditch Company. PSC owns most of the stock in the United Ditch I Company. The City of Thornton also owns some Fisher Ditch shares as does Pleasant View Water and Sanitation District. There are also agric.ultural I users utilizing the ditch. I I A-11 I
2.3.10 Clear Creek and Platte River Ditch and Colorado Agricultural Ditch I These two ditches divert through a common headgate from the north side of Clear Creek near Pecos Street and 54th Avenue. This is the last diversion I from Clear Creek before its confluence with the South Platte. The ditches bifurcate about one-half mile below the Clear Creek headgate. Colorado Agricultural Ditch is the higher ditch, and they both run in a northerly I direction for about 10 miles. I There are three decrees associated with the ditches which total 132 cfs. The appropriation dates range from 1861 to 1874. The Clear Creek and Platte I River Ditch (known as Lower Clear Creek Ditch) is a senior source and has histor ically had enough supply to meet demand. The Colorado Agr icul tural I system has historically been water short in relation to its demands. Both ditches are organized as mutual ditch companies. The 'major shareholder in both ditches is the City of Thornton. Several agricultural users still I irrigate lands which are primarily located in the Clear Creek and South Platte River flood plains. I·
3.1 LOWER BASIN WATER SUPPLIERS AND USERS I There are more than 15 water suppliers in the lower Clear Creek basin that utilize Clear Creek as a raw water source. These water suppliers include I agricultural water users, municipal water suppliers, and two major industrial users. Most of the suppliers were interviewed to obtain the information presented below. The discussion during those interviews centered on water I rights, existing water supply systems, criteria used in safe yield analyses, planned development, viewpoints on the Clear Creek Project, and perspectives I on the institutional factors related to water development within the basin. I Some general terms are used in the following descriptions of the water suppliers and require definition. Metro Denver refers to the Metropolitan I Denver Sewage Disposal District No.1. This is a regional organization created by state statute in 1965. It treats wastewater from several municipalities and special districts in the metro Denver area. Its facilities I are located at 64th Avenue and York Street. Its effluent is discharged to the South Platte River about one mile south (upstream) of the Clear Creek and I South Platte River confluence. I A-12 I I
I The Metropolitan Water Providers (providers) and the Metropolitan Water Participants (participants) agreements with the Denver Water Department (Dwn) I refer to two documents which provide for cooperative water resource development. The providers' agreement involves financial participation in the I preparation of the environmental impact statement for projects being considered by the Dwn and provides for the opportunity to participate in
future projects. The participants' agreement provides. ~or participation in I specific Dwn projects. Each municipal provider had the opportunity to subscribe to these agreements. Those that subscribed, taken together, have I agreed to fund 80 percent of the ongoing Systemwide ErS. This study will evaluate the future projects which are contemplated by the DWD and the I providers.
I The water suppliers participating as providers and as participants in the various agreements with the Dwn are identified. The suppliers who are members of the Clear Creek Water Users Alliance and .the Alliance members who are also I participants in the Clear Creek project, which is the subject of this investigation, are also identified. For convenience, the membership status of I the various suppliers is summarized in Table A.1. I I I I I I' I I I A-13 I TABLE A.1 I Lower Basin Water Suppliers Membership I Clear Creek Wat1~ Denver Water Department Users Alliance - Member of the Sponsor of I Supplier Providers Participants Alliance Clear Creek Project Arvada X X X X I Broomfield X X X X Consolidated Mutual X X X X Adolph Coor~ Company X X Crestview X I Eastlake Golden X X Lakewood X X I Northglenn North Table Mountain X X Pleasant View X X I Public Service Co. X X Rock Mining Companies 2/ X X Thornton X X Westminster X X I
The sources of the information for Table A.1 and the discussions in the I Appendix have been the interviews with water suppliers in the Clear Creek basin and published appendices for the Systemwide EIS (SEIS) on the I Metropolitan Denver Water Supply. Current demands, future projected demands, safe yield figures, and size of service areas have been taken from the SEIS I and from the water suppliers where possible. Population estimates are from the SEIS. No evaluation has been made of the estimates nor has any attempt been made to standardize the various definitions of safe yield. The year 2035 I demand figures presented were abstracted from the SEIS. These figures are compared with the projections provided by the individual water suppliers. I I 1/ Agricultural Ditch and Reservoir Company, and Consolidated Juchem Ditch and Reservoir Company are also members of the Alliance but are not sponsors of the Authority's Study nor "providers" or "participants" in the Denver Water Department agreements. I
2/ The rock mining companies include Mobil Premix Concrete, Suburban Sand/Gravel, and Walt Flanigan & Company. I I A-14 I I I I 3.2 AGRICULTURAL WATER USERS 3.2. 1 General I 'The agricultural use in the basin has steadily declined as urbanization has encroached on its land as well as its water supply. Irrigated area was reported by State Engineers' Office to be 120,000 acres in 1950. In 1980, the I area in agricultural use utilizing Clear Creek for its water supply is estimated to be 28,000 acres. The current average annual supply for I agriculture is estimated to be 42,000 af per year, and the safe yield is I estimated at 25,000 af per year. 'The estimates of irrigated area in 1950 and in 1980 indicate that the I decrease in acreage has been on the order of 3000 acres per year. If that rate continues, there would be no agriculture lands irrigated by Clear Creek in about nine years. However, a linear relationship probably does not apply I to this situation. The factors which have contributed to agricultural's decline in the area are difficult to predict. Undoubtedly, the urban I development pressures for both land and water will continue. The satisfaction of this demand by agriculture depends on willing sellers. The market has I declined markedly in recent years. The agricultural system most removed from the land development pressures is the Farmers Reservoir and Irrigation I Company - Standley Division (FRICO). This system irrigates lands north of Big Dry Creek into Weld County. Land in the flood plains has also remained in agricultural production. It is probable that some of the younger farmers in I these and other systems will continue their livelihood. This study has also included park, cemetery, and golf course irrigation needs in the agricultural I portion of the demand. For these reasons, the prOjected agricultural demand I in the year 2035 is estimated to be 4500 af per year. 3.2.2 Clear Creek Water Rights I All of the water rights in the lower basin, with the exception of the Jefferson Storage, Golden Milling and Coors Industr ial decrees, were originally decreed for irrigation. There are now municipal and/or industrial I ownership in each of the Clear Creek ditch systems. Several small reservoirs I fed mainly by the Church Ditch, the Farmers High Line Canal, the Agricultural I A-15 I
Ditch, and the Welch Ditch were also decreed in the basin. Some of these are I still in agricultural use, and some have been changed to municipal use. I 3.2.3 Existing Water System The water facilities which were developed by the agricultural community are still used by the various water suppliers in the basin. These are I primarily ditches and canals for the conveyance of water and reservoirs for its storage. Water is still delivered to farmers through these systems. The I remaining active agricultural lands are primarily located in the northern portion of the Clear Creek servi~e area. I 3.2.4 Planning and Future Projects I The only known project plan that would result in an increase in the amount of water available to agricultural users in the basin is the enlargement of Standley Lake. That plan is currently under consideration by FRICO and the I cities sharing Standley Lake. I 3.2.5 Clear Creek Project A large reservoir in the Clear Creek basin could provide no direct benfits I to the agricultural community. Indirect benefits may include improved water quality and a more efficient flow regulation. I 3.3 THE CITY OF ARVADA I 3.3.1 General The City of Arvada's existing water supply system serves a population of I approximately 91,000. Its service area encompasses about 30.6 square miles in Jefferson and Adams Counties. The city's raw water is supplied by Clear Creek I water rights, nontributary wells, a contract with the Denver Water Department (DWD), and Ralston Creek water rights. It also contracts with the City of I Aurora for transbasin effluent to provide replacement credits to the South Platte. The current demand is about 15,500 af per year, and all of it could be supplied by the existing contract with Denver. Its future demand in 2035 I is projected in the SEIS to be about 33,600 af per year. The safe yield of the city's water supply from Clear and Ralston Creeks is about 4, 100 af per I year. I A-16 I I I 3.3.2 Clear Creek Water Rights I The City of Arvada owns water in the Church Ditch, Farmers High Line Canal, Reno-Juchem Ditch, Cort Graves & Hughes Ditch, and the Slough I Association. It has a decree of 7300 af for Arvada Reservoir (formerly Blunn Reservo ir ) from Clear Creek and Ralston Creek. I t has exchange decrees on Clear Creek, which involve not only Clear Creek, but also Ralston Creek and I the South Platte River.
I 3.3.3 Existing Water System The physical facilities for the city's Clear Creek raw water supply are I the Church Ditch; Farmers High Line Canal, augmentation stations~ a pumping plant on the Croke Canal, and Arvada Reservoir. It has a contract for 25 cfs I of capacity in the Croke Canal. Its Church Ditch and Farmers High Line Canal water is diverted from Clear Creek through those ditches, delivered to the Croke Canal through Ralston Creek, and pumped to Arvada Reservoir. The I reservoir is located on Ralston Creek below Ralston Reservoir and Foothills Road. It has a capacity of about 5500 af. Arvada owns a number of water I rights on Ralston Creek, which are also stored in Arvada Reservoir.
I The city has several decreed exchanges. These exchanges allow diversion of Clear Creek rights from Ralston Creek, Ralston Creek rights from Clear I' Creek, and South Platte rights from either Ralston or Clear Creeks. The city tries to store as much Ralston Creek water as possible in Arvada Reservoir I because its Clear Creek supply requires pumping to be stored in Arvada Reservoir. Clear Creek exchanges with the city's Reno-Juchem Ditch and Slough Association water are also diverted through the Croke Canal and pumped to I Arvada Reservoir.
I The city owns two water treatment plants. One treats DWD water from Ralston Reservoir. The other treats water from Arvada Reservoir. Both are I located below Arvada Reservoir. The city serves water to several areas outside its boundaries including Ralston Valley Water and Sanitation District, I, Ridge Home, Leyden Water District, and a portion of the City of Wheat Ridge. I I A-17 I
The city has its own wastewater treatment plant on Ralston Creek which has I been taken out of service. All of its wastewater is now treated at the Denver Metro wastewater facility. I
3.3.4 Planning and Future Projects Arvada's contract with the DWD is for 19,000 af per year. To meet its I growing demand, the city continues to acquire water on Clear Creek as it becomes available. If the Clear Creek exchange to the Croke Canal does not I provide water sufficient to utilize its downstream Clear Creek sources, the city may build a pump station near the Slough headgate. This facility would I lift the city's Reno-Juchem Ditch and Slough Association water to Arvada Reservoir. I
The city is a participant in the providers I and participants' agreements with the Denver Water Department. It is also a member of the Clear Creek I Water Users Alliance and a participant in the Clear Creek project. I 3.3.5 Clear Creek Project A large reservoir in the Clear Creek basin would provide benefits to the City of Arvada. It would provide a larger safe yield from the city's current and future sources. The reservoir could reduce Arvada's pumping requirements~ It should add flexibility to the city's operation and the quality of Arvada's raw water supply would probably be improved.
3.4 CITY OF BROOMFIELD
3.4. 1 General The City of Broomfield's existing water supply system serves a population I of approximately 25,000 and includes an area of about 12.7 square miles. The area served includes parts of Jefferson, Boulder, and Adams Counties. The I city's raw water supply system makes use of water rights, augmentation stations, non-tributary wells, a contract with the DWD for treated water, and physical facilities. Broomfield's current demand is 4200 acre feet per I year. Approximately one-half of its current demand is supplied by water from Clear Creek. The safe yield of the City's raw water supply from Clear Creek ,I is estimated to be 2500 af per year. The projected demand for the city in 2035 is 15,437 af per year. I A-18 I I:. I 3.4.2 Clear Creek Water Rights » The city's water rights includes ownership of Clear Creek, Big Dry Creek, Coal Creek, and Boulder Creek rights. Clear Creek water is obtained from I owriership of Church Ditch inches and through the change of agricultural reservoirs to municipal use and storage in Great Western Reservoir. The agricultural reservoirs were originally filled by the Church Ditch. The city I has an exchange decreed on Big Dry Creek which provides for use of its I wastewater effluent in excess of its return flow obligations. 3.4.3 Existing Water System I The physical facilities for the city's Clear Creek raw water supply system include the Church Ditch, augmentation stations, a pumping plant, and Great I Western Reservoir. The Church Ditch is owned by the City of Northglenn and the City of Broomfield. Maintenance costs are shared by Church Ditch inch I holdlers.
Great Western Reservoir, which is located on Walnut Creek about two miles I southwest of the Jefferson County Airport, has a storage capac i ty of 3,250 ar. The dam and reservoir are owned by the city. A pumping plant lifts the I· Church Ditch water to the reservoir. The plant is located at the base of the dam on the Dry Creek Valley Ditch, a Church lateral. The city's water I treatment plant for this water source is located about one-half mile downstream from the Great Western dam. I Diversions by the city from Clear Creek are made only during the summer months. Diverted flows are pumped from the Church Ditch into Great Western II Reservoir when the Church Ditch is diverting and there is capacity in the reservoir. The Church Ditch can divert for municipal use only during the I months of April through October. The safe yield of the City of Broomfield's I raw water supply from Clear Creek is estimated to be 2500 af per year. The city also diverts from Coal Creek into Great Western Reservoir. It I, currently leases its Boulder Creek water to other users. Broomfield owns three non-tributary wells. Because of the very low yield of these wells, they I! are not currently used in the water system. The city's contract with the DWD I A-19 :·1 provides for use of a maximum of 5500 af per year and a minimum of 2000 af per I year.
The city's wastewater is treated in its plant located on Big Dry Creek. I Effluent from DWD' s water supply is reserved by Denver. Effluent from Broomfield's water is used to pay r.eturn flow obligations from its changes of I agricultural water. Water in excess of these requirements can be reused by the city. I'
3.4.4 Planning and Future Projects I The City of Broomfield continues to acquire water as it becomes available on the market and has plans to enlarge Great Western Reservoir to about 12,000 af. Its Boulder Creek supply will be expanded, and a pipeline will be I constructed to convey this water to Great Western Reservoir. The city intends to use its excess wastewater effluent for park irrigation within the next few I years and eventually use it for direct reuse. I
The city is a participant with the DWD in both its participant f s and providers' agreements. It is a member of the Clear Creek Water Users Alliance I and a participant in the Clear Creek project. I' 3.4.5 Clear Creek Project A large reservoir in the Clear Creek basin would benefit the City of Broomfield by allowing better regulation of its existing and future I supplies. It would also probably improve the quality of its raw water supply. I
3.5 CONSOLIDATED MUTUAL WATER COMPANY I 3.5.1 General I Consolidated Mutual is a privately owned water supplier which serves portions of Wheat Ridge, Lakewood, and unincorporated Jefferson County. Its service area of about 25 square miles extends south from Highway 58 to Alameda I and from west of Indiana Street east to Kipling Street. Population served is about 61,000 people. Consolidated Mutual's current demand is estimated to be ,I 14,000 af per year and is projected to grow to about 18,500 af per year in I A-20 I I
I 2035'. Currently about 75 percent of its water is supplied by the Dwn. Consolidated Mutual has an independent supply for the balance of its demand. I, The estimated safe yield of the city's current raw water supply from Clear I Creek is about 3000 af per year. 3.5.2 Clear Creek Water Rights I Consolidated Mutual Water Company owns shares in the Lee Stewart & Eskins, Rocky Mountain, Welch, and Agricultural Ditches. I t also owns Maple Grove Reservoir, located on Lena Gulch near 1-70 and 26th Avenue. The reservoir is I decreed for 1073 af of Clear Creek water and is filled under its own junior I decree as well as by Consolidated Mutual's ditch ownership. Consolidated Mutual will be seeking a change decree to allow it to store I its Rocky Mountain Ditch water in Maple Grove Reservoir. The Welch Ditch's board has tied the Welch Ditch water to the land historically irrigated so I this source is currently unavailable for Consolidated Mutual's use.
3.5.3 Existing Water System I Consolidated Mutual's raw water facilities are a reservoir and the Lee Stewart and Eskins, Rocky Mountain, and Agricultural Ditches. Its water is ;1 diverted from Clear Creek through the three ditches and released to Maple I Grove Reservoir. The water is treated in Consolidated Mutual's plant, located below the I reservoir. After treatment, the water is pumped to the service area. In addlition to portions of Lakewood and Wheat Ridge, Consolidated serves the College Park Water and Sanitation District and a portion of Pleasant View II Water and Sanitation District. The portion of Pleasant View served by the I City of Golden will be served by Consolidated Mutual in the future. 3.5.4 Planning and Future Projects If Consolidated Mutual plans to acquire additional water to meet expected growth. Its contract with the Dwn does not limit the quantity of water which I can be delivered to the company. It does, however, limit the geograhical area which can be served with Dwn's water. I I A-21 I Consolidated Mutual is a participant in the providers' and participants' I agreements with the DWD. It is also a member of the Clear Creek Water Users Alliance and a participant in the Clear Creek project. I 3.5.5 Clear Creek Project A large reservoir located in the Clear Creek ,basin could benefit I Consolidated Mutual Water Company by providing additional capacity to regulate its existing and future water ownership. This would increase the Company's I safe yield and add flexibility to Consolidated's raw water system. The quality of its raw water supply would also probably be improved. I 3.6 ADOLPH COORS COMPANY I 3.6.1 General The Adolph Coors Company presently obtains all of its water supply from " the Clear Creek basin. It owns an array of senior agricultural water, most of which was changed in 1911 to industrial use. Its industrial complex, located I east of Golden in the Clear Creek valley, is primarily served by its independent water supply. Coors purchases a minor amount of water from the I City of Golden. It currently produces about 15 million barrels of beer and plans to expand to an ultimate production of 22 to 25 million barrels. Its I water supply also serves support facilities for this production. Its existing safe yield is estimated to be 6000 af per year from Clear Creek. Coors' current diversion demand is about 56,000 af per year. The bulk of this demand I is for cooling water, which requires about 41,500 af per year. The consumptive use for the cooling water use is about two percent. The remainder I of this water is returned to Clear Creek. Coors uses only the consumptive use portion of its cooling water needs when quantifying its demands. Thus, its I current demand is 9450 af per year. Coors' future demand is estimated to be 14,115 af per year when ultimate production is achieved. I
3.6.2 Clear Creek Water Rights The Coors plan for augmentation provides a system to replace depletions on I diversions under a junior direct flow right, junior groundwater rights, and several junior storage rights. The depletions, accrued when its junior rights ,I are out-of-priority, are calculated by taking the difference between its total j A-22 I I
I diversion and its effluent and cooling water returns to the stream. This amount is then replaced to the stream by using water that was historically I depleted by irrigation or is foreign to Clear Creek. I' Its senior, formerly agricultural water includes shares of the Welch, Church, Agricultural, Farmers High Line, Wannamaker, Rocky Mountain, Lee I Stewart and Eskins, Miles and Eskins, Reno-Juchem, the Slough Association, Ouelette, Cort Graves and Hughes, Lower Clear Creek, and South Side Ditches. Coors also uses Henderson Mine water, Vidler Tunnel water, Berthoud Pass I Ditch, and George R. Stewart (St. Mary's Lake) Reservoir and has rights to the London Fault Mine water and the Boreas Pass Ditch on the South Platte River. I The Golden Milling decree is used for a portion of its cooling water demand~
I Decreed storage, both absolute and conditional, is 17,682 af. The decreed junior direct flow rights are 157 cfs for a surface right and 32 cfs for various groundwater rights. Coors also has an exchange decreed with the Croke I Canal and has applied to the water court for an exchange with the Farmers High Line Canal. It has an agreement with the City of Golden, which essentially II provides for Coors' use of Golden's foreign water in excess of 750 af per II' year. 3.6.3 Existing Water System II Coors has three classifications for water: groundwater supply is a A water, sur£ace supply is B water, and cooling water supply is C water. The groundwater supply is diverted through numerous structures primarily on the I south side of Clear Creek from the City of Golden to McIntyre Street.
II The surface water supply is primarily diverted to lakes along Clear Creek, which are being formed by gravel mining. Some of these lakes (B lakes) are III clay lined to prevent seepage to and from Clear Creek. Others (A lakes) are unlined and are essentially used to recharge the Clear Creek alluvium. Coors II has currently developed 7~00 af of B storage. Both the groundwater and surface water supplies are treated at Coors' water treatment plant. Several ,11 cooling water intakes and return points are located on the south side of Clear CJ~eek near the main plant. II II, A-23 ,I
Wastewater is treated at Coors' two wastewater plants located on Clear I Creek. The domestic wastewater plant treats those wastes from Coors and also the City of Golden's wastewater. The process wastewater plant treats wastes from the brewing process. I
Coors diverts water from Clear Creek all year. Its complex operation is I' accounted for daily, and the appropriate senior sources are used to pay the junior rights' depletions on a reach by reach basis. It diverts its junior I decrees in several places but primarily takes the water for storage rights at the Wannamaker and the Rocky Mountain Ditches. Coors' junior groundwater I rights are diverted from numerous springs along Clear Creek located from the Agricultural Ditch's headgate to McIntyre Street. I The Golden Milling decree and the Coors Industrial decree are diverted at ,I cooling water intakes. Cooling water returns are made at various points on Clear Creek and can be pumped to above the Farmers High Line's headgate if necessary to replace depletions during low flow periods. I
The difference between Coors' total diversions and returns (depletion) is I made up by using the historical depletion portion of its senior decrees. These senior decrees are diverted, for the most part, and placed back in the I creek. This flow is made up of two components: 1) the return obligation and 2) the depletion credit. These components have been decreed in a change case and are based on the historical irrigation use of the water. I
Coors' winter supply is obtained primarily by exchange with the Croke I Canal, which essentially commands the stream in the west unit in the winter. I 3.6.4 Planning and Future Projects Coors uses a stringent criteria for its safe yield analysis. It derives I the dry year's diversions by its various rights and then sequences the values for three years. Coors continues to increase its. storage capacity in the Jefferson storage system as the gravel near the plant is mined. I t also I acquires water as it becomes available on the market. It has plans to increase its production capacity but may eventually become constrained by I land, and perhaps water, availability. I A-24 I I
I Coors is a member of the Clear Creek Water Users Alliance and a participant in the Clear Creek project. It is not eligible to become a member I of the providers' and participants' agreements with the DWD because those I agreements limit membership to municipal water suppliers. 3.6.5 Clear Creek Project I A large reservoir in the Clear Creek basin would benefit Adolph Coors Company by allowing fuller regulation of its senior water to increase its safe yield and by providing an independent winter water supply. It could also I allow increased utilization of its junior decrees, when they are in priority. Its operation could be considerably simplified, both in physical I faci.lities and in administration of its water. The reliability of its water supply could be improved. The quality of its raw water supply probably would I be j~proved, particularly if protection from old mining tailings' failures and truck spills was provided. I 3.1' CRESTVIEW WATER AND SANITATION DISTRICT
I 3.7.1 General Crestview Water and Sanitation District supplies water to the southwestern I corner of unincorporated Adams County. It serves an estimated 15,300 people, and its current demand is 2500 af per year. It owns nontributary wells, I shares of a Clear Creek and a Ralston Creek ditch, and holds a contract with the DWD for water supply. -DWD currently supplies about 12 percent of I' Crestview's demand. The demand in the year 2035 is projected to be 6619 af per year. The safe' yield of the city's water supply from Clear and Ralston I Creeks is about 2000 af per year. 3.'1.2 Clear Creek Water Rights I Crestview Water and Sanitation District owns shares of the Kershaw Ditch, a senior Clear Creek source. It also owns a portion of the Manhart Ditch, a I Ralston Creek source. I 3.1'.3 Existing Water System Crestview's raw water supply facilities include the Kershaw and Manhart I Ditches, four nontributary wells in the Arapahoe aquifer, and the Cooley I, A-25 I
Lakes. Crestview normally operates its wells year round, its Clear Creek I supply in the sUIIDDer, and its Ralston Creek supply in the winter. These surface sources are diverted to Cooley Lakes, which have a capacity of about 500 af. The lakes are used for water quality improvement. After being I retained, the water is treated at Crestview's plant and delivered into the system. I
Its DWD supply is treated water. No quantity limitation is imposed by I Crestview's contract with the DWD water. However, the contract does limit the geographical area which can be served. I Crestview's wastewater is treated at the Denver Metro plant. It has its I own wastewater treatment plant, but it was discontinued in 1977.
3.7.4 Planning and Future Projects I Crestview Water and Sanitation District is prohibited from expanding its independent supply by its contract with the DWD. Therefore, it does not I acquire additional water. Crestview is a member of the Clear Creek Water Users Alliance but is not participating in the Clear Creek project. I 3.7.5 Clear Creek Project I The only apparent benefit for Crestview from a large reservoir located in the Clear Creek basin would be a possible raw water quality improvement. I 3.8 EASTLAKE WATER AND SANITATION DISTRICT ,'I 3.8.1 General Eastlake Water and Sanitation District serves the community of Eastlake. I The town is a small, fully developed area in Adams County and an enclave of the City of Thornton. It serves 130 people and further growth is not I expected. Current demand is about 15 af per year. This water is produced from one non-tributary well. The District also owns water in the Eastlake Water Company but does not use this supply. Future demand is projected to be I 36 af per year. Safe yield for the District is estimated to be 13 af per year from its Clear Creek supply. I
A-26 - I I
I 3.8.2 Clear Creek Water Rights Eastlake owns one non-tributary well and shares in the Eastlake Water I Company. Eastlake Water Company owns shares of Farmers High Line and decrees for three reservoirs. Eastlake Water and Sanitation District does not I currently use its share ownership. I 3.8.3 Existing Water System The District has one non-tributary well which is pumped to serve its I demand. Current production is not enough to supp~y the summertime demand. 3.8.4 Planning and Future Projects I Eastlake Water and Sanitation District plans to drill another well to meet its peak demand in the summertime. Eastlake is not a member of the providers' I or the participants' agreements with the DWD. It does not belong to the Clear Creek Water Users Alliance. I 3.8.5 Clear Creek Project A large reservoir located in the Clear Creek basin does not appear to I offer any benefits to the Eastlake Water and Sanitation District. However, if
the Districts' d~mands increase as projected in the Denver SEIS, the delivery I system is in place to transport Clear Creek water to the District.
I 3.9 CITY OF GOLDEN I, 3.9.1 General The City of Golden serves about 16,800 people within an area of approximately 6.5 square miles. The city is located in Jefferson County and I is the county seat. The city's raw water supply is from Clear Creek and foreign sources. The current demand is about 3010 af per year, and the I proJected demand for the present service area in year 2035 is estimated to be 6494 af per year. The estimated' safe yield of the City's current raw water I supply from Clear Creek is 2500 af per year. I 3.9.2 Clear Creek Water Rights The City of Golden's decrees are two fairly senior municipal rights, two I transfers of agr icul tural water done in the mid-1950's and 1960' s, and a I' A-21 I portion of the Berthoud Pass Ditch, a transbasin import. It also uses non I tributary water from the Henderson Mine and transbasin water from the Vidler Tunnel. It holds decrees on Beaver Brook, a tributary to Clear Creek. It has applied to water court for decrees on three gravel pit lakes located near I Empire and transfers of additional agricultural rights and an exchange with the Croke Canal. The trial on these applications was held in April, 1985, but I a decree has not yet been issued. I 3.9.3 Existing Water System Golden receives its Clear Creek supply at the Church Ditch's headgate. I The city diverts year around from Clear Creek on an essentially direct flow basis. The flow is transported, via pipelines from the Church Ditch headgate, to small settling ponds which feed Golden's two treatment plants. The city I serves a part of Lookout Mountain and a portion of Pleasant View Water and Sanitation District, which are both located outside the city's corporate I boundaries. Service to Pleasant View will be assumed by the Consolidated Mutual Water Company. The Beaver Brook system, which is used to serve Lookout I Mountain, is on the market. I The bulk of Golden's effluent is treated in Adolph Coors Company's domestic wastewater plant. Golden has an agreement with Coors, which essentially gives Coors the use of Golden's foreign water exceeding 150 af per I year as a consideration for this wastewater treatment. The portion of Golden located in Lena Gulch receives wastewater treatment at the Metro Denver plant I through the Pleasant View Water and Sanitation District's connection. I 3.9.4 Planning and Future Projects The City of Golden plans to develop three reservoirs located near Empire J as the gravel is mined. The· decreed capacity is 2600 af, although the ultimate capacity will depend on the gravel availability. These reservoirs will be used to store water under their own junior priorities and sources I exchanged to the site. Golden is seeking to eliminate service outside its city limits in order to free the resource to serve undeveloped lands inside I the city. It will be acquiring new water as it becomes available on the market. Golden is a participant in the providers' and the participants' I agreements with the DWD. The city does not belong to the Clear Creek Water Users Alliance. I A-28 I I I· 3.9.5 Clear Creek Project I The City of Golden's new storage will increase the reliability of its supply, but the capacity will not be sufficient to provide long-term carryover I supply. A new reservoir on Clear Creek would provide longer term regulatory capacity for Golden and would allow it to increase the safe yield of its I existing and future supplies. The quality of its raw water supply would probably improve.
I 3.10 CITY OF LAKEWOOD
I 3.10.1 General The City of Lakewood, located in Jefferson County, is served by a large I number of special districts, which provide both water and wastewater service. In the mid 1910's, a study on the system was done and part of the I recommendation was that a board be created to assume utility responsibilities frOID. willing districts. Lakewood implemented this recommendation. There is, however, a strong independence in the city, which finally became a home rule I city in 1985. Eighteen of the special districts have not been consolidated wi th the city's uti! i ty . Some of these distr icts serve areas ins ide and I outside the Lakewood city boundaries.
,I Lakewood receives 93 percent of its supply from the DWD. The remaining seven percent is supplied by Consolidated Mutual Water Company's independent I supply. Lakewood is currently evaluating its options for future water supply. One of the options is development of an independent supply.
I The city's population is about 126,900 people within an area of about 41 square miles. Its current water demand is about 31,300 af per year. Future I projection of water demand in the SEIS is 681 af per year. It appears this projection is for areas not currently included in DWD's service contracts with I the various districts. The safe yield of its existing supply or the city's owner projection of future water demand have not been made public. Ii I I A-29 .1
3.10.2 Clear Creek Water Rights I The City of Lakewood has purchased water in the Agricultural Ditch and has leased water in the Rocky Mountain Ditch. This water is currently used by the city to irrigate parks. I
3.10.3 Existing Wat.er System I Lakewood's citizens receive treated water from the DW and Consolidated Mutual Water Company. The city does not currently utilize an independent I supply of water. However, it has begun acquiring water in the Clear Creek basin and evaluating its alternatives for meeting the city's projected I demands. I The city's wastewater is treated at Metro Denver plant, the Northwest Lakewood Sanitation District's wastewater plant, and the Clear Creek Valley Sanitation District's wastewater plant. I
3.10.4 Planning and Future Projects I The City of Lakewood is in the midst of evaluating its options for future water supply. One of the options it is considering is the development of an I independent supply. It has begun to acquire water in the Clear Creek basin. This acquisition will probably continue as water becomes available. Plans for I the future will become more clear as the city decides on its course for future supply. I The City of Lakewood is a member of the DW's providers' and participants' agreements. According to city officials, it will probably become a member of I the Clear Creek Water Users Alliance. I 3.10.5 Clear Creek Project Lakewood presently obtains about seven percent of its total raw water I supply from the Consolidated Mutual Water Company and has purchased and/or leased other Clear Creek sources. A la~ge reservoir on Clear Creek would be beneficial to the City of Lakewood indirectly since its supply from the I Consolidated Mutual Water Company would be more reliable. In addition, such a reservoir may be a source of additional raw water supply for Lakewood to meet I increased future demands. I A-30 I I I I 3. 1'1 CITY OF NORTHGLENN 3.1'1.1 General I 'The City of Northglenn's existing water supply' serves a population of approximately 29,900 people within an area of about 6.5 square miles in Adams I County. The city's raw water supply is derived primarily from Clear Creek through an exchange agreement with FRICO. The current demand is about 4900 af per year, and the projected demand in 2035 is about 4761 af per year in the I SEIS. No reason is given for this decrease in demand. The city projects its future demand at 6100 af per year. The safe yield of the city's independent I supply is about 3000 af per year. Its estimated yield from the FRICO exchange I is 4700 af per year. 3.11.2 Clear Creek Water Rights I The City of Northglenn receives the bulk of its supply by virtue of a St~1dley Lake exchange agreement with FRICO. This agreement allows Northglenn to use FRICO's water first and return it to them as wastewater effluent plus a I ten percent bonus. The city owns Church Ditch inches, Standley Lake shares, Farmer High Line Canal shares, and a portion of the Berthoud Pass right. Its I Farmers High Line water is used only to irrigate Webster Park. It has about 2400 af of storage in Standley Lake by virtue of its ownership of FRICO I shares. I Non-tributary wells within the city and water rights on Grange Creek and the South Platte supplement its supply. This water is used primarily to make I up the depletions caused by city use and to pay the bonus to FRICO. 3.11.3 Existing Water System I The physical facilities owned by Northglenn for its raw water supply . include the Berthoud Pass Ditch, the Church Ditch, and storage capacity in I Standley Lake. A transmission pipeline (shared with the City of Thornton) deHvers water from Standley Lake to the city's water treatment plant. I Water diversions from Clear Creek are made in the summer through the I Church Ditch and Croke Canal. These flows are conveyed to Standley Lake for I A-31 I storage. Winter diversions are made through the Croke Canal into Standley I Lake. I The Berthoud Pass right is a transbasin import. Northglenn's portion is carried in the Church Ditch to Standley Lake. The City of Golden also owns a portion of this right, although Northglenn owns and operates the facilities. I This ditch imports water from Fraser River tributaries into Clear Creek. I Northglenn purchased the physical facilities of the Church Ditch from FRICO. It has entered an agreement with the City of Broomfield which grants I Broomfield one-third ownership of the ditch's facilities. I The city's safe yield is estimated to be 3000 af per year from its independent supplies. The FRICO exchange increases this delivery to about 7700 af per year. The availability of the FRICO farmers' water is decreasing I due to the sale of FRICO farmers' water to municipalities. I The city's wastewater is treated in its lagoon system located near Big Dry Creek and the southern Weld County line. Bull Reservoir, which has about 4000 I af of capacity, is used to store the effluent for subsequent delivery to the FRICO farmers through the Bull Canal. I
3.11.4 Planning and Future Projects Northglenn continues to acquire water as it becomes available on Clear I Creek. Its exchange with FRICO may have a limited life, because the farmers' Standley Lake shares are being acquired by different entities. Northglenn has I a first right of refusal agreement with several of the farmers. The city is investigating enlargement of Standley Lake. I Northglenn is not a party to the DWD's agreements or a member of the Clear I Creek Water Users Alliance.
3.11.5 Clear Creek Project I A large reservoir located in the Clear Creek basin could benefit Northglenn by providing additional capacity to regulate its existing and ,I future water ownership. This would increase the city's safe yield. The quality of its raw water supply would probably improve. I A-32 I I I I NORTH TABLE MOUNTAIN WATER AND SANITATION DISTRICT 3.12.1 General I North Table Mountain Water and Sanitation District serves a portion of unincorporated Jefferson County, northeast of Golden and west of Arvada. Its I current service population is about 7500 people. However, its equivalent population served is about 15,000 because it serves the Ball Metal Container
Company. Its current demand is abou~ 1500 af per year. It currently receives I all of its raw water supply from the DWO. However, it has begun to develop an independent supply by purchase of Church Ditch, Farmers High Line Canal, and I Slough Association sources. Its projected demand in 2035 is 3023 af per I year. Its safe yield from the independent supply is about 125 af per year. 3.12.2 Clear Creek Water Rights I North Table Mountain owns water in the Church Ditch, Farmers High Line Canal, and Slough Association.
I 3.12.3 Existing Water System The physical facilities for the district's independent raw water supply is I the Church Ditch, Farmers High Line Canal, and Slough Association. These facilities are not currently used by the district. Raw water is obtained from I the DWO's Ralston Reservoir system. This water is treated in the District's plru1t, which is located below the reservoir. I North Table Mountain's wastewater is treated at the Denver Metro plant.
I 3.1.2.4 Planning and Future Projects North Table Mountain Water and Sanitation District plans to continue I acquisition of water in the Clear Creek basin as it becomes available. Its Denver Water Department supply is currently limited to 6000 af per year. If I Denver's Williams Fork system is completed, the District will be entitled to 75100 af per year. If additional water is made available to Denver's northern I system (Moffat), North Table Mountain will receive 7.5 percent of the increase. The District's contract also limits the geographical area which can I be served with Denver water. I A-33 I
To utilize its independent supply, the District will probably have to I acquire storage capacity. It will also need to arrange for physical facilities to transport its Clear Creek sources to its water treatment plant. I
North Table Mountain is not a member of the DWD's providers' or I participants' agreements. It is a member of the Clear Creek Water Users Alliance and a participant in the Clear Creek project. I
3.12.5 Clear Creek Project I North Table Mountain Water and Sanitation District could benefit from a large reservoir in the Clear Creek basin. The reservoir would increase the safe yield of its current and future supplies. A project would also help the I District build its independent supply. However, a deli very system to the District's water treatment plant would have to be arranged to utilize Clear I Creek sources. I 3.13 PLEASANT VIEW WATER AND SANITATION DISTRICT I 3.13.1 General Pleasant View Water and Sanitation District serves about two square miles I of unincorporated Jefferson County, east of Golden. It currently serves about 3800 people. The current demand of 800 af per year is supplied by the City of Golden and Consolidated Mutual Water Company. However, Golden intends to I discontinue its service to Pleasant View, and the District has entered a contract with Consolidated Mutual Water Company for a replacement supply. The I district's projected demand in 2035 is 1600 af per year. A separate future water demand for the district was not estimated in the SEIS, because it is I served by other entities. Its current safe yield from water rights owned directly by the District is 25 af per year. I
3.13.2 Clear Creek Water Rights Pleasant View Water and Sanitation District owns five shares in the Fisher I Ditch Company. It does not currently use this supply. ,I I A.-34 I I
I 3.13.3 Existing Water System Pleasant View receives treated water from the City of Golden and I Consolidated Mutual Water Company. The demand is split about equally between the t.wo suppliers. There are also shallow wells owned and used by individual I households in the District. I Pleasant View's wastewater is treated at the Denver Metro plant.
Planning and Future Projects I Pleasant View Water and Sanitation District has replaced the water supply that it receives from the City of Golden. The District is not a member of the I Providers' agreement with the DWD. It is a member of the Clear Creek Water User.s Alliance and is a participant in the Clear Creek project. I 3.13.5 Clear Creek Project I Pleasant View Water and Sanitation District would benefit at least indirectly from a large reservoir located in the Clear Creek basin. It should increase the yield to Pleasant View's suppliers. If Pleasant View must build I its own supply, a Clear Creek project should help this effort by increasing I the safe yield and reliability of its raw water supply. I 3.14 PUBLIC SERVICE COMPANY - LOWER BASIN 3.14.1 General I The Public Service Company of Colorado (PSC) diverts Clear Creek water in the lower basin to meet the needs of its Cherokee power plant, located near York Street and 64th Avenue. About 800 megawatts of electricity is produced I at the plant. Its demand of 7500 af per year is primarily for cooling water and is not expected to increase. This demand is met with' the Fisher Ditch I from Clear Creek and the Farmers and Gardners Ditch from the South Platte River. The South Platte River water is supplied under contract with the I DWD. Approximately one-third of the demand is met by the Clear Creek source. Public Service Company's Clear Creek supply has an estimated safe I yield of 2500 af per year. It rece i ves its domest ic water supply from the DWD. I I A-35 I
3.14.2 Clear Creek Water Rights I The Public Service Company owns shares of the Fisher Ditch and the United Ditch Company. The United Ditch Company also owns shares of the Fisher Ditch and all of Copeland Lake. This lake is decreed from Clear Creek. I
3.14.3 Existing Water System I The physical facilities for Public Services' Cherokee plant's raw water system are the Fisher Ditch, Copeland Lake, and cooling ponds on the site. I Cooling water is the primary water demand. Water is diverted year around from Clear Creek through the Fisher Ditch and delivered to the plant. The I remainder of the Cherokee plant's demand is supplied through the Farmers and Gardners Ditch, a South Platte River source. The Dwn provides this supply under contract with Public Service Company. Domestic water is also supplied I by the Dwn. I 3.14.4 Planning and Future Projects Public Service Company is a member of the Clear Creek Water Users Alliance I and a participant in the Clear Creek project. It is not eligible to become a member of the providers' or the participants' agreement with the Dwn because I those agreements limit membership to municipal water suppliers. PSC, however, prefers Clear Creek as a source for water quality reasons and would like to I increase the Clear Creek portion of its supply.
3.14.5 Clear Creek Project I The benefits for Public Service Company from a large reservoir located in the Clear Creek basin would be winter supply, increased safe yield from its I existing supply, and added flexibility in its raw water system. Minor modification may be required in its water supply facilities to use additional I Clear Creek water. I 3.15 ROCK MINING COMPANIES
3.15.1 General I There are three companies in the Alliance who are participating as one member in the Clear Creek project that either produce or consume rock I products. They are Mobil Premix Concrete (Mobil), Suburban Sand & Gravel I A-36 I I
I (Suburban), and Walt Flanagan & Company (Flanagan). Their need for water occurs during the mining process and, perhaps, to cover evaporation from the I open pits left after the mining is completed. The need for this post-mining I water is currently under discussion with the State Engineer. The lands for planned future mining belong to Suburban, Mobil, and I Flanagan . lie downstream of Clear Creek in the South Platte alluviUm. It is estimated that the maximum water demand which may occur from these future mining areas is 1800 af per year. The companies also report that this. I quantity would probably more than supply their needs during the mining I operation. The safe yield of the Clear Creek sources belonging to the companies is I about 50 af per year. Some of the companies also own sources of water other than Clear Creek. These sources were not quantified. I 3.15.2 Clear Creek Water Rights The rock mining companies own water in the FRICO Standley Lake system and I in the Slough Association.
I 3.1~5.3 Existing Water System I The rock mining companies have no existing water system. 3.15.4 Planning and Future Projects I The rock mining companies' future demand for water is uncertain at this point. They are aware that a requirement may exist and seem to be participating in those projects which may provide a source of water. They are I involved in negotiations with the State Engineer, which may quantify their future water needs. If these needs are too large, the companies may find I different alternatives for treatment of the exposed water areas.
I The rock mining companies are not eligible to become participants in the providers' and participants' agreements with the DWD. They are members of the I Clear Creek Water Users Alliance and a participant in the Clear Creek project. I I A-31 I
3.15.5 Clear Creek Project I A large reservoir in the Clear Creek basin could provide benefits to the rock mining companies. It could provide a larger safe yield from the I companies' current supplies as well as provide new safe yield from the junior decree. Whether the companies will participate in a project, should it proceed, will be largely a matter of cost and eventual resolution of their I water needs. Beca~se these needs are still being quantified and because the total safe yield of their supplies are unknown, their future demand was not I included in the demand projections. I 3.16 THE CITY OF THORNTON I 3.16.1 General The City of Thornton's current population is about 53,000 people. Its existing service area encompasses about 21.4 square miles, and it is located I entirely within Adams County. The city's raw water system is composed of Clear Creek and South Platte water rights; an agreement with the City of I Aurora, which permits temporary use of storage in Spinney Mt. Reservoir; Standley Lake storage; and exchange agreements with the Burlington Canal on I the South Platte River. Thornton has also recently acquired irrigation water in northern Colorado. I
Thornton's current demand is about 15,000 af per year, and its estimated safe yield is approximately 40,000 af per year. About 25 percent of this I yield is supplied by its Clear Creek sources, estimated to be 10,800 af per year. Its demand in the SEIS for 2035 is projected to be 26,455 af per I year. The city projects its future demand at 55,000 af per year. This projection includes its contractual obligations. It also reflects current I plans to serve areas outside city limits. I 3.16.2 Clear Creek Water Rights City of Thornton owns water in several Clear Creek supplies including the Church Ditch, Farmers High Line Canal, Standley Lake, Colorado Agricultural I Ditch, Lower Clear Creek, and the Fisher Ditch. The water from the first three ditches is stored in Standley Lake, where Thornton has about 11,500 af I of storage. The other three sources are available on a direct basis from the I A-38 I I
I lower end of the bas in; however, of these three, only the Lower Clear Creek I source is currently used in the city. 3.16.3 Existing Water System I The physical facilities for the city's raw water supply include the Church Diteh, Farmers High Line Canal, Croke Canal, Colorado Agricultural Ditch, I Lower Clear Creek Ditch,·· Standley Lake, and a pipeline (shared with Northglenn) which delivers water from Standley Lake to its Thornton '!Water I Treatment Plant. Water can also be diverted directly from the Farmers High Lim~ into small regulation reservoirs located near Interstate 25 and 92nd Avenue and thence into either of its two treatment plants. All sources except I the Croke Canal are diverted from Clear Creek only during the summer season.
I The city acquired 10,000 af of storage in Standley Lake from FRICO in the late seventies. The City of Westminster received 1500 af of this storage. I Thornton also owns storage in Standley Lake by virtue of its FRICO shares, and this capacity is estimated to be an additional 3000 af. These two components provide about 11,500 af of storage in Standley Lake for Thornton. In I addition, Thornton is developing gravel lakes in the lower east unit. These I ponds will have about 2600 af of capacity. I Thornton's wastewater is treated at the Denver Metro plant. 3.16.4 Planning and Future Projects I The City of Thornton has been acquiring water as it becomes available in the Clear Creek market, as well as in other systems in the state. It had planned a reservoir in South Park, but these plans have been on hold since the I providers' agreement was signed with the DWD. Thornton is investigating I enlargement of Standley Lake. It recently acquired agricultural water in northern Colorado. Thornton I plans to pump this water to the city, use it, and then return a portion of it to the farmer who used it originally. It is a participant in the providers' I and participants' agreements with the DWD; however, it has begun selling its sha.re in these agreements. It is not a member of the Clear Creek Water Users I AIUance. I A-39 I The city has water in excess of its current demands, primarily because the I City of Northglenn, which Thornton served, developed an independent system. Thornton currently leases a portion of this water to other municipalities. The city plans to serve large portions of unincorporated Adams County north I and east of its current city limits. I 3.16.5 Clear Creek Project A large reservoir located in the Clear Creek basin would add. to Thornton's I safe yield from its existing ownership. It would also provide more reliability to its water supply and probably improve the quality of its raw I water supply.
3.17 THE CITY OF WESTMINSTER I
3.17.1 General I The City of Westminster is located within Jefferson and Adams Counties. Its existing water supply serves a population of approximately 63,900 people I within an area of about 31.5 square miles. Water to serve this population is obtained from Clear Creek, Coal Creek, the DWD, the City of Thornton, and non I tributary wells. The city's current demand is about 14,000 af per year. About 80 percent of this demand is supplied by the city's Clear Creek I ownership. The safe yield for the city's raw water is estimated at 13,000 af per year. The projected demand in the SEIS for 2035 is 26,118 af per year. I 3.17.2 Clear Creek Water Rights The City of Westminster receives its Clear Creek water through ownership I in the Church Ditch, the Farmers High Line Canal, and FRICO. It also owns Calkins Reservoir, which has been changed to municipal use. This water is I stored in Standley Lake for subsequent use. Westminster's capacity in Standley Lake is about 20,600 af. The city also owns shares in the Kershaw I Ditch diverted from lower Clear Creek in the east unit. It does not currently use this source because of its quality. I Westminster has an exchange agreement with Farmers High Line Canal, whch allows first use of the High Line's raw water for subsequent return of I wastewater effluent in an equal amount. The city contracts for treated water I A-4o I I
I service from the City of Thornton. It also contracts with the DWD for water whieh can be either treated or raw water. Westminster has non-tributary wells I whieh are used as backup supply.
I 3~ n.3 Existing Water System The physical facilities for Westminster's raw water supply are the Church I Ditei1, the Farmers High Line Canal, the Croke Canal, augmentation stations, Standley Lake, and a pumping plant. Westminster diverts its Clear Creek \lIater through the Church Ditch, Farmers High Line Canal, and the Croke Canal. This I water is usually stored in Standley Lake although the Farmers High Line Ditch water can be taken directly to the two water treatment plants which serve the I city. Water stored in Standley can be pumped to either of the two plants for I use in the city. 'Iolater is diverted in the summer through all three sources when they are I in-priority. Water is also delivered through the Croke Canal during the winter.
I Westminster provides treated water to the City of Federal Heights and the Shalll Height Water District by contract. About 1500 af per year of the city's I estimated 10,100 af per year demand goes to these outside areas. Federal Heights owns non-tributary wells which can produce about 350 af per year. The I city also serves th.e Standley Lake Water and Sanitation District, a portion of which is inside the city boundaries. I Wastewater from the southern portion of the city is treated at Denver Metro. The remainder is treated at the city's wastewater plant located on Big I Dry Creek.
I The city usually pays the return flow obligations for its changed shares with wastewater effluent from the Denver Metro plant. It can also .use I effluent from its Big Dry Wastewater Treatment plant to pay these obliga tions. However, when the Clear Creek diversions are high, it must pay its I return flow obligations with raw water delivered from the ditches to Clear Creek through augmentation stations. This delivery is because its effluent is I not enough to meet the required return's quantity. I A-41 I 3.17.4 Planning and Future Projects I The City of Westminster uses the 1950 through 1980 period to define its safe yield. Operation studies, utilizing Standley's storage capacity, are used to define the carryover effect on its safe yield. I
The city acquires water as it becomes available on the market. The city, I in combination with the other Standley Lake entities (Thornton, Northglenn, and FRICO), has been investigating enlargement of Standley Lake to 62,000 I af. Westminster is not a member of the Clear Creek Water Users Alliance. It is a participant in the OWD's providers' and participants' agreements. I
3.17.5 Clear Creek Project The City of Westminster needs more storage capacity. Whether or not this I will be provided by enlarging Standley Lake has yet to be decided. Either the enlargement of Standley Lake or construction of a large storage reservoir on I Clear Creek could increase the safe yield from·the city's raw water sources, as well as increasing the yield from future acquisitions. This assumes that I Westminster would become a member of the Clear Creek Water Users Alliance. It appears, however, that the current carrying capacities of the existing I conveyance system to Standley Lake may not be adequate to convey all the water available to Westminster. A large storage reservoir on the upper Clear Creek I basin might provide the most efficient method for Westminster to increase its Clear Creek water supply since it could store its allocation in the reservoir and release it in a manner to accommodate the existing Standley capacity and I conveyance sytem. I One of the ongoing conflicts on Clear Creek is Adolph Coors Company's and the City of Golden's exchanges with the Croke Canal in the winter. The I entities divert the Croke's raw water and replace it with wastewater effluent to Standley Lake. It is possible that a new reservoir on Clear Creek could I provide this winter demand and remove the need to exchange with the Croke
Canal~ Regardless of this possibility, the quality of Westminster's raw water supply would probably improve with the project because low flows will I generally increase with releases from the project, because heavy metals should exhibit decreased concentration, and because the current winter eXChange of I effluent for Standley Lake water may no longer be necessary. I A-42 I I I 4.1 SUMMARY OF SAFE YIELD ESTIMATES I The safe yield estimates for the various suppliers presented in this Appendix are primarily based on the information provided by the water I suppliers, and these yields were not independently evaluated. I Another source for recent safe yield estimates for the water suppliers is the Appendix 3, Existing Water Supply, produced as a part of the ongoing SEIS for the Metropolitan Denver Water Supply. Except for the City of Thornton, I the safe yield estimates in this document were based on a questionnaire distributed by the Denver Regional Council of Governments (DRCOG) to the water I suppliers in December of 1982. A follow-up was conducted by DRCOG to clarify and complete the information received in the questionnaires. Although no I independent verifications of the safe yield estimates were made, the estimates were adjusted as necessary to be comparable with those made for the DWD. The I effective date of the safe yield estimates is not given in Appendix 3.
The City of Thornton's safe yield estimates in Appendix 3 of the SEIS were I obtained through personal interviews by the SEIS' personnel. Its estimates for safe yield were reviewed and evaluated for reasonableness. No extensive I operational calculations or complex model studies were included in this I work. Table A.2 presents a summary of the safe yield estimates from Clear Creek I for each of the suppliers from the two sources (suppliers and SEIS). Some differences can be seen in the estimates. The majority of these differences are probably due to acquisition of additional supplies after the SEIS I information was supplied. However, some of the more significant differences I are too large to be attributed to additional supplies. I I I I A-43 I TABLE A.2 I Summary of Clear Creek Safe Yield Estimates I Water 1/ SEIS ?/ Supplier .2/ Supplier Data (af/yr) Data, (af/yr) I Arvada 4,950 4,100 Broomfield 2,215 2,500 Consolidated Mutual 3,030 4/ 3,000 I Adolph Coors Company NA - 6,000 Crestview 2,825 2,000 Eastlake 13 13 I Golden 2,310 4/ 2,500 4/ Lakewood NA - NA Northglenn 1,100 3,000 North Table Mountain 50 125 I Pleasant View NA !!/ 25 Public Service Company NA !!/ 2,500 Thornton 5,300 2/ 10,800 I Westminster 9,015 13,000 Total 31,528 49,563 I
4.2 SUMMARY OF PRESENT SUPPLIES AND PROPOSED ALTERATIONS TO EXISTING I SYSTEMS
4.2. 1 Safe Yields and Projected Demands I The estimated present safe yield of raw water available to water suppliers and users that utilize Clear Creek for all or part of their supply is I presented in Table A.3. The safe yield is presented in two components; safe yields from Clear Creek, and safe yield from other sources. These safe yields I have not been independently evaluated. I
1/ Agriculture not included. I 2/ Information from Appendix 3, Systemwide EIS . I .2/ Information from water suppliers. 4/ Not available. I 2/ Does not include 5300 af from the lower Clear Creek/So Platte. I A-44 I I
I Table A.3 also presents the estimated demand for those water suppliers from the SEIS for the year 2035, and if available, the future demands I projected by the water suppliers. The differences in future demand proJ,ections from these two sources is about 49,800 af pel' year. One reason I for the disparity may be different planning horizons. Other reasons probably include differences in metQodology, approach, and viewpoint. Because the I future demand projections from the SEIS are lower in the aggregate, they were selected for the demand projections in this study. This is not a judgment on the validity of the different projections but simply represents a more I conservative estimate of need in the basin. Table A.3 also demonstrates that a significant difference exists between the current total safe yield and the I projected future demand. The projected shortage could possibly be met by sources outside of the Clear Creek basin; and it is also possible that a large I Clear Creek reservoir could provide all or a portion of the supply required. The limited supplier within the basin will probably dictate that sources both I within and outside of the basin be developed to meet the projected shoJrtages.
I At present, all of the suppliers and users listed in Table A.3 except for the Crestview Water and Sanitation District and the Eastlake Water District I intlend to acquire additional water from the Clear Creek basin as it becomes available. Several of the suppliers are members of the DWD's providers' and I participants' agreements. They will probably receive additional water in the future from DWD's proposed projects which are all located outside of the Clear I Creek basin. I I I I I I A-45 I TABLE A.3 I
Comparison of Current Safe Yield and Projected Future Demands I I Clear Creek Safe Yield Total Future Demand Safe Yield ~I From Other ~I Safe SEIS JI Water Supplier 41 SUDQlier .!I (af/yr) Sources (af) Yield (af/yr) (af/yr) I Agriculture 25,000 0 25,000 4,500 4,500 Arvada 4,100 19,450 23,550 33,579 34,000 Broomfield 2,500 5,500 8,000 15,437 16,400 I Consolidated Mutual 3,000 12,000 15,000 18,448 1 18,448 Adolph Coors Company 6,000 0 6,000 14,175 .2 14,175 Crestview 2;000 4,619 6,619 6,619 4,300 I Eastlake 13 15 28 36 15 Golden 2,500 ·2,500 6,494 7,000 Lakewood NA NA° NA 687 687 Northglenn 3,000 4,700 §.I 7,700 4,761 6,100 I North Table Mountain 125 6,000 71 6,125 3,023 7,750 Pleasant View 25 o - 25 1,600 1,600 Public Service 2,500 5,000 7,500 7,500 7,500 Thornton 10,800 8,700 19,500 26,455 55,400 I Westminster 13,000 8,000 21 1000 26 1118 37 1500 Total 74,563 73,984 148,547 169,432 215,375 I I I 11 Agriculture demand is estimated not projected. I 21 Estimated by water suppliers or taken from Denver SEIS.
~I Data abstracted from Denver SEIS Series 1 for year 2035 or supplied by user. I 41 From water supplier if available, or from the SEIS (Series 1). I 51 Based on 2 percent of cooling water diversion of 71,300 af per year plus surface water of 3, 150 af per year' and ground wa ter demand of 9,000 af per year. I 61 Based on Northglenn's exchange with FRICD. The source is Clear Creek.
71 Included in Golden's and Consolidated Mutual's figures. I I 1\-46 I I
I 4.2.2 Currently Proposed Developments Several projects are presently planned to develop additional supplies of I Clear Creek water. Those projects are presented in Table A.4. The total planned development will not fully develop the available Clear Creek flows. I If a larger reservoir were constructed in the upper Clear Creek basin, it could serve the same purpose as the projects listed in Table A.4 and could I almost fully develop the available surface water flow in the basin. I TABLE A.4 P·roposed Project Alterations I Clear Creek Water Users
I Project Golden Empire Reservoirs
I Broomfield Great Western Enlargement
Westminster, Thornton, Northglenn, & I Falrmers Reservoir and Irrigation Co. Standley Lake Enlargement I Adolph Coors Company Jefferson Storage Enlargement I I I I I I I I A-47 I I I I
I Appendix 8 I WATER QUALITY I I I I I I I I I I I I I - I
I APPENDIX B WATER QUALITY I 1. 'I SUMMARY AND CONCLUSIONS I 1. 'I. 1 Introduction While the primary purpose for the construction of an impoundment in the I Upper Clear Creek Basin would be to store native runoff, the possibility also exists for significant improvement of water quality within and downstream of I an impoundment. Concentrations of heavy metals presently exceed levels that are consistent with a full abundance and diversity of aquatic life in Clear I Creek. Improvement to water quality would occur as a result of dilution, sedimentation, and flocculation of heavy metals in an impoundment. I The Clear Creek drainage contains many small and dispersed sources of heavy metals. In addition, the drainage contains four important local ized I sources in the vicinity of Central City: the Argo Tunnel, the Gregory Incline and tailings depOSits, the National Tunnel, and the Quartz Hill Tunnel. The I Argo Tunnel, which may be the single largest source of metals, releases a steady stream of water containing metals at concentrations as much as 1,000 I times above the chronic exposure limits for aquatic life as shown by the data record. The Argo Tunnel and the other localized sources of metals near I Central City have been selected for EPA Superfund work. There is a good possibility of EPA-funded remedial action at the Argo Tunnel and possibly at other locations that will reduce the amounts of metals entering the streams I from these sources.
I 1.1,.2 Purpose The purpose of this portion of the study is to summarize what is now known I about the water quality of the Upper Clear Creek Basin, and to show on this basis what water quality problems now exist, how these water quality problems I might relate to impoundment of Clear Creek at various points, and what information would be needed for a final assessment of the water qual i ty of Clear Creek in relation to future impoundment. In addition, the fishery I potential of an impoundment and the water quality conditions required to support a fishery are considered, as are the downstream water quality benefits I of an impoundment. I B-1 I I 1. 1.3 Data Base There are six major data sets for general water chemistry and heavy metals chemistry for the Upper Clear Creek Basin. These were computerized in I standard form and merged to form a composite data set. The composite data set covers 32 sampling sites, 22 of which have been sampled 10 times or more, and I 10 of which have been sampled more than 25 times. I With respect to general water chemistry t the composite water chemistry data base shows that Clear Creek has very low concentrations of suspended I solids and a moderately low specific conductance as indicated by major ionic solid characteristics that are within or near the expected range for mountain waters in Colorado. Sulfate is somewhat enriched because of mine drainage, I but not extraordinarily so. There is no evidence of phosphorus enrichment associated with mining. Studies of frequency distributions involving all I stations show that a few stations have very unusual water chemistry, but these general water chemistry effects are localized and do not apply to the main I stem or major tributaries. I With respect to heavy metals, the composite data base shows that the concentrations within the main stem, major tributaries, and many individual minor tributaries substantially exceed the chronic exposure limits for aquatic I life with respect to cadmium, lead, copper, and zinc. The concentrations are most extreme for copper and zinc. During the least favorable seasons of the I year, concentrations of zinc in the main stem of Clear Creek exceed the aquatic life criterion by a factor of 15. In general, the concentrations of I heavy metals in North Clear Creek are two to four times higher than the concentrations in the main stem of Clear Creek at the sampling site above I Golden.
1 • 1 .4 Projected Water Quality For Impoundments and Potential Benefits of I Impoundment Projections were made of water chemistry for possible impoundments on I North Clear Creek and on the main stem of Clear Creek between North Clear Creek and Golden. These projections involve the following considerations: I (1) calculation of discharge-weighted mean concentrations, (2) allowances for ·1 B-2 I I
I sedimentation, (3) allowances for flocculation and ligation of metals in the upper water column of an impoundment, (4) allowances for diversion of water I from the Williams Fork drainage, and (5) allowances for future possible remedial action on the Argo Tunnel through the EPA Superfund program. II Insufficient data exist to assess the potential impact of other Superfund act.ivities on water quality. These projections, although handicapped by lack of eertain types of appropriate data', such as heavy metals sedimentation data I for Colorado Lakes, demonstrate that an impoundment on the main stem of Clear Creek, or on a tributary receiving substantial amounts of diversion water from I the main stem of Clear Creek, would probably meet the aquatic life numeric criteria for all metals except zinc, for which the concentrations would exceed I the criterion by a factor of approximately two without remedial action to remove metals in the watershed. I Because many forms of aquatic life acclimate to heavy metals and because of the somewhat conservative nature of the numeric criteria, it is concluded I that an impoundment on the main stem of Clear Creek would almost certainly be compatible with a full diversity and abundance of aquatic life, including I salmonid fishes. However, assuming the implementation of an EPA Superfund program to reduce the metals released from the Argo Tunnel, an impoundment on I the main stem of Clear Creek would probably meet the chronic exposure criteria fof' aquatic life for all metals. This would be the most advantageous I condition for development of a quality fishery.
A feasible management scheme for an impoundment on Clear Creek would I inelude the stocking of rainbow trout, mackinaw, and kokanee salmon. This group of stocked sport fish would be supplemented by brown trout and brook I trout, which would enter the reservoir from presently existing populations in the watershed. With insurance of sufficient minimum stream flow, a I significant downstream fishery could be developed in addition to the reservoir fishery, especially after investments in stream habitat improvement. On the I basis of usage at Chatfield and Cherry Creek ReserVOirs, it is estimated that a large impoundment and the associated downstream area could receive usage as I high as several hundred thousand visitor days per year. I I B-3 I The potential benefits to aquatic life and to recreation from an I impoundment may be especially high because the impoundment could offset some of the historical impairment of the stream. Impoundments can be expected to reduce the concentrations of metals, both in the impounded water and in the I water downstream of the impoundment. There are two major reasons for this. First, the impoundment mixes the water across all upstream portions of the I watershed and across all seasons. This results in an averaging of water quality that allows the dilution of waters that are chemically unsuitable for I aquatic life with waters that are of much better quality. If the mixture is favorable, the net result will be the creation of a waterbody suitable for I aquatic life, and this will be reflected in the downstream water quality as well. Equally important, or perhaps even more important, is the strong tendency of metals concentrations to decrease in waters that are impounded. I Metals that are associated with particulate material settle to the bottom because of the minimal current within an impoundment. Metals in solution I become flocculated as a result of prolonged contact with organic matter in reservoirs. The result is an improvement of the quality of the water within I the reservoir and downstream of the reservoir. I Major aquatic recreation facilities within easy reach of Denver are very limited; those that are now available are heavily used. An impoundment on Clear Creek, if suitable for a self-sustained fishery, along with major I improvements in water quality between the dam and the City of Golden, could constitute a major benefit in addition to water supply benefits that might I result from an impoundment. I 1.1.5 Conclusions The information now available indicates that an impoundment on the main I stem of Clear Creek, or an impoundment that receives substantial amounts of water from the main stem of Clear Creek, would support an excellent cold water fishery and a full diversity of aquatic life. This conclusion seems I particularly safe given the possibility of remedial action on the Argo Tunnel discharge, which would remove a substantial amount of the total metals load I from the main stem of Clear Creek. However, even without such remedial action, it seems very likely that an impoundment of the main stem or fed by I the main stem would support a healthy fishery and diverse aquatic life. I B-4 I I
I The data base that is now available on Clear Creek is not ideally suited for projections of the type that are required in full support of an evaluation I of aquatic life and recreation potential in an impoundment of Clear Creek. In ordE~r to make the tentative conclusions more secure, additional data I collection that is specifically focussed on the issue of water quality in an impoundment will be needed.
I 1. 'I. 6 Additional Studies Required Additional study of selected topics is recommended if an impoundment on I the main stem of Clear Creek is approved for further feasibility study. A refined water quality model should be developed on the basis of site-specific I characteristics, and should be supported by field data collection to improve confidence in specific model parameters. Aquatic life habitats, especially I downstream of a proposed impoundment, should be evaluated and potential improvements identified. The recreational requirements and benefits associated with a particular site also merit further consideration. However, I on the basis of the information that is presently available, it seems very likely that the concentrations of metals within and downstream of an I imlPoundment on Clear Creek would be compatible with a fishery and recreational I resource of high value. 2.1 HISTORICAL OVERVIEW AND DESCRIPTION OF MAJOR MINE DRAINAGE SITES I 2. 1 • 1 Introduction
I 2.1.1.1 General Clear Creek has been severely damaged by mining. This damage, which I prl.ncipally occurred before the turn of the century, is both physical and chemical. Mining was accompanied in" some areas by removal of stream beds and I by deposition of tailings, leading to physical degradation of the stream. Even more important is the continuing release of water from tailings deposits I ami from mine shafts containing large amounts of heavy metals. The geochemical basis for release of heavy metals from ores in this area is given by Wentz (1914) and Moran and Wentz (1914). Moran and Wentz (1914) also give I some valuable survey data on specific mines and streams in the Clear Creek I drainage. I 8-5 I
Damage to Clear Creek as a result of mining has impaired the ability of I the stream and many of its tributaries to support aquatic life, and has thus also impaired the fishery potential and the general recreational value of the I drainage. Wentz (1974) estimates that there are some 67 miles of impaired stream above Golden on the Clear Creek drainage. I The U.S. EPA .!I has·identified the entire Central City mining area as a Superfund site. Schedule of the Superfund work is somewhat uncertain because I of variations in the level of Superfund expenditures. However, a remedial investigation is scheduled for completion in early 1987, and will include the I results of data collection on Clear Creek. A risk assessment study will also be available in spring of 1987, and the final draft feasibility study should I be available for public comment in spring or early summer of 1987. The EPA hopes to reach its decisions concerning action on this particular Superfund site in the last half of the summer of 1987. If remedial action is called for I by the decision, this action will be planned or designed over approximately a one-year interval. This would be followed by a construction phase. Superfund I action involves state review and approval by the state along with state commitment to cost sharing on a formula basis. I Reduction of metals loading of Clear Creek through the EPA Superfund I program would obviously be beneficial to the prospects for aquatic life throughout the Clear Creek system, either with or without an impoundment of' Clear Creek. Estimates of the degree of improvement in water quality as a I result of' remedial action are given in this report along with the prOjections of' water quality in impoundments. I
2.1.1.2 Mine Drainage Sites I Part of' the water quality degradation of the Clear Creek drainage is caused by diffuse sources that are too numerous to list or to treat I individually. These include mine shafts and. tailings piles scattered I
11 All descriptions of' the Superfund Program in this report are based on inf'ormal discussions with the U.S. EPA and do not represent formal commitments I to any specif'ic actions by the U.S. EPA. All Superfund activities are subject to change based on funding and program constraints. I 8-6 I I
I throughout the drainage. In addition, however, the drainage contains a number of specifically identifiable sites that appear to be, on the basis of I presently available chemistry data, major sources of heavy metals for Clear Creek. These include four historic sites that are now inactive or minimally I act.ive: the Argo Tunnel, the Gregory Incline and tailings deposits, the National Tunnel, and the Quartz Hill Tunnel. These sites are clustered around the Central City area near the poirit where North Clear Creek meets the main I stem of Clear Creek. This is a historic mining district, and a number of the sit.es are on the National Historic Register. These sites have been studied I several times since 1970 by the U.S. Geological Survey and by other parties for various purposes (Wentz 1974, Moran and Wentz 1974, Weildeman 1914, Boyles I et al. 1974, Wentz 1977, McLaughlin Engineers 1981). Even so, a comprehensive overview of both the chemistry and the flows from all of these sites has not I been performed. Partly for this reason, the U.S. EPA, in connection with Superfund activities described below, contracted with Camp, Dresser, and McKee, Incorporated to obtain a data set encompassing both flows and chemistry I for all of these sites. This information is not available yet in final form, but should offer broad coverage and a good basis for interpretation. For I individual sites, some of the data collected earlier are extremely valuable and have been used to estimate the yields of heavy metals from some of the I sites. I The Argo Tunnel was constructed between 1893 and 1904 for the purpose of providing access to the ore veins in the vicinity of Idaho Springs. In addition, the tunnel allowed ores to be brought cheaply to the mill at the I Argo site. The tunnel was 23,000 feet long at the time it was completed, and contained numerous laterals. The tunnel is now only open for the first 1500 I feet.
I Although flow from the Argo Tunnel is typically considered to be essentially constant, reports on the volume of flow vary because of I differences in estimation procedures. Most of the estimates fall between 0.5 and 1.0 cfs, and the recent estimates commissioned by the EPA are in the vi
The Gregory Incline and tailings deposits may be the second largest single I source of heavy metals for Clear Creek on the basis of preliminary flow and chemistry data. The Gregory Incline is a tunnel that is thought to have a I length of approximately 1700 feet. However, the entrance to the incline has been blocked by mine tailings. The tunnel portal and the tail ings pile are "I located on North Clear Creek just above its confluence with Clear Creek. Water entering the stream at this point contains high concentrations of heavy metals. It is considered likely that both the tunnel and the tailings pile I contribute to these high metals concentrations. I The Gregory tailings deposit is located very close to the stream and is prevented from entering the stream only by means of a wooden retaining wall. I Collapse of the retaining wall would allow the tailings pile to surge into the stream channel, thus blocking the channel and causing flooding as well as possibly releasing substantial additional amounts of heavy metals into the '.1 stream. I Because of the imminent possibility of flooding and additional pollution of Clear Creek as a result of the failure of the retaining wall for the I Gregory tailings, the EPA, as an adjunct to its Superfund activities, has I B-8 I I
I identified the structural problems at the Gregory Tailings for expedited response action. This action is to be taken in addition to the more broadly I based program of Superfund work in the vicinity of Central City. The expedited response action is already planned and should be completed by April of 1987. The work will include either removal of the tailings or installation I of a culvert that will allow North Clear Creek water to pass the tailings area without being impounded or impeded by collapse of the" tailings retaining I wall. This expedited response action should not be confused with the main thrust of the Superfund program in the Clear Creek drainage. The main purpose I of the Superfund program, which is now in planning stages, is remedial action i to reduce the entry of heavy metals into Clear Creek. The National Tunnel enters the North Clear Creek approximately half a mile do\\mstream from the Gregory tailings. This tunnel was constructed between I 1905 and 1937, and was approximately 3100 feet long at the time of its completion. Only a few measurements of the discharge are available, but the I flow of water from the tunnel appears to be in the vicinity of 0.1 to 0.2 cfs (McLaughlin Engineers, 1981). The water from this tunnel has not been I extensively analyzed. I The Quartz Hill Tunnel empties into Nevada Gulch, which in turn flows into Gregory Gulch at Central City approximately one mile above the confluence of Gregory Gulch with North Clear Creek. The tunnel was originally over a mile I long. Construction on the tunnel began about 1860. The flow from the Quartz Hill Tunnel appears to be only about 0.02 cfs, which is considerably less than I the flow from the other tunnels. Reliable chemical data are not yet available I fOlr this tunnel. 2.2 DESCRIPTIoN OF THE DATA BASE I The data base on water chemistry for the Upper Clear Creek Basin comes from six sources. The most important of these is from the Colorado Department I, of Health's Water Quality Control Division, which has sampled the main stem of Clear Creek just above Golden on a routine basis since 1965, and has also sampled several other sites in the watershed extensively. The U.S. Geological I Survey has also sampled extensively. The Survey's work has been oriented I to\olJard short-term sampling programs of broad spatial coverage wi thin the I 8-9 I drainage rather than extended monitoring. A third source is the U.S. Forest I Service, which has also sampled over relatively short periods of time for specific purposes rather than over extended intervals. The fourth source is I' NUS Corporation, which assembled a one-year data set at several important stations during 1983-1984 for the Adolph Coors Corporation, which has provided this information for the present report. The fifth source is the U. S . I Environmental Protection Agency. As part of the Superfund environmental assessment on Clear Creek, the EPA contracted with Camp, Dresser, and McKee I for the collection of four sets of samples in 1985 at a number of sites throughout the watershed. The first quarter of data will be included in the I data base for this report. The other three quarters of data have not been released yet by the EPA and thus cannot be included in this report. The sixth source is the AHAX Corporation, which has been monitoring the chemistry i of Clear Creek since 1967. This data set, which has been released for this report by courtesy of AHAX, is especially valuable because of its continuity I over a long period of time. I If the sampling sites visited by each of the six sampling programs are listed separately, the total is 108. However, there is substantial overlap in I the station coverage, so the number of separate stations sampled across the six programs is only about two-thirds of this number (Table B. 1). Only 32 sites were sampled more than twice, and these are shown in Figure B.1. I Twenty-two sites were sampled 10 or more times, and 10 sites were sampled more than 25 times. I I I 'I I I I 8-10 I TABLE B.l
List of Water Quality Sampling Sites
Station Years Number of I Number .!I Location Agency ?J Collected Collections Clear Creek below Eisenhower Tunnel CDH 16 1 I 2 CCat Bakerville USGS 11 1 3 CC above Silver Plume CDH 16-77 11 4 CC above South CC in Georgetown USGS 71 1 I 5 South CC near Guanella Pass CDH 76 1 6 Leavenworth Creek at mouth USGS 71 1 1 South CC at mouth USGS 71 1 I 8 South CC at mouth CDH 76 1 9 CC below Georgetown WWTP CDH 76-71 10 10 CC above West Fork CC USGS 11-72 2 11 CC above West Fork CC AMAX 79-86 90 I 12 West Fork CC above Henderson Mine CDH 76-77 5 13 West Fork CC above Henderson Mine USGS 73 2 14 West Fork CC above Henderson Mine AMAX 67-86 226 I 15 West Fork CC above Woods Creek CDH 76-77 5 16 West Fork CC above Woods Creek USGS 71, 73 3 11 West Fork CC above Woods Creek AMAX 67-86 225 I 18 Woods Creek at mouth USGS 71, 73 3 19 West Fork CC below Berthoud Falls CDH 76, 11 5 20 West Fork CC below Berthoud Falls AMAX 79-86 216 21 Hoop Creek below Berthoud Falls USFS 79 8 I 22 Hoop Creek at mouth USFS 79 9 23 West Fork CC west of Empire USGS 71 1 24 West Fork CC west of Empire CDH 76-77 3 I 25 Lion Creek near headwaters USGS 13 2 26 Lion Creek at mouth USGS 72 1 21 Lion Creek at mouth USGS 71, 73 3 I 28 Lion Creek at mouth CDH 76 2 29 Bard Creek near mouth CDH 76 2 30 West Fork CC at mouth CDH 79-86 43 31 West Fork CC at mouth CDH 16-77 6 I 32 West Fork CC at mouth AMAX 67-86 90 I, 1/ Eight of the station numbers between 1 and 116 were not used (total number I Of stations used = 108). ~/ Abbreviations: CDM - Camp, Dresser, and McKee (for EPA); USGS - U.S. Geological Survey; CDH - Colorado Department of Health; NUS - NUS Corporation (for Adolph Coors, Corp.); AMAX - AMAX Corporation; USFS - U.S. Forest I Service. I I B-11 TABLE B.l (Continued)
List of Water Quality Sampling Sites
Station1/ Years Number of Number Location Agency ?J Collected Collections I 33 Clear Creek at 'Lawson CDH 76-77 6 34 Clear Creek at Lawson USGS 72 1 35 Fall River near mouth USGS 71 1 I 38 Big 5 at Clear Creek CDM 85 1 39 Clear Creek above Chicago Creek in Idaho Springs USGS 71 1 'I 40 Chicago Creek near headwaters USFS 79 15 41 Chicago Creek near headwaters USGS 79 5 42 Chicago Creek above Idaho Springs reservoir USFS 79 15 I 43 Chicago Creek above Idaho Springs reservoir USGS 79 5 44 Chicago Creek above Idaho Springs I reservoir CDH 76 45 Chicago Creek above Idaho Springs reservoir USFS 79 15 I 46 Chicago Creek above Idaho Springs reservoir USGS 79 5 47 Chicago Creek above Idaho Springs ,I reservoir CDH 76 2 48 Chicago Creek above South Chicago Creek USGS 72 1 49 South Chicago Creek at headwaters USFS 79 15 I 50 South Chicago Creek at headwaters USFS 79 4 51 South Chicago Creek near mouth CDH 76 52 Chicago Creek above West Chicago I Creek CDH 76 53 West Chicago Creek at mouth CDH 76 54 Chicago Creek below West Chicago ,I Creek CDH 76 1 55 Ute Creek at mouth USGS 71 1 56 Chicago Creek below Devil's Canyon USFS 79 13 57 Chicago Creek below Devil's Canyon USGS 79 5 I 58 Chicago Creek above Spring Gulch USGS 71 1 59 Chicago Creek at mouth CDH 76 2 61 Clear Creek above Virginia Canyon USGS 73 2 I 62 Virginia Canyon at headwaters CDM 85 1 65 Virginia Canyon at mouth USGS 71, 13 2 66 Soda Creek at mouth USGS 65, 71 2 68 Clear Creek above Argo,Tunnel NUS 83-84 12 I 69 Clear Creek above Argo Tunnel CDM 85 1 I I 8-12 I I,
I TABLE B.1 (Continued)
I List of Water Quality Sampling Sites
Station Years Number of I Number 1/ Location Agency 2/ Collected Collections
10 Argo Tunnel at Portal CDM 85 1 I 11 Argo Tunnel NUS 83-84 12 12 Clear Creek below Argo Tunnel CDM 85 1 '74 Clear Creek below Idaho Springs USGS 11, 13 3 15 Clear Creek at Hidden Valley CDH 19-86 86 I 16 Clear Creek at junction of 1-10 and us6 USGS 11 '71 Clear Creek above confluence C with NCC USGS 11 '78 Clear Creek above North Clear Creek CDH 85 1 I 19 Pine Creek at Apex CDH 16 2 80 Missouri Creek above Missouri Lakes USGS 11 1 81 North CC above Blackhawk CDH 16 2 82 North CC below Golden Gilpin Mill USGS 11 1 I 83 Chase Gulch at mouth USGS 11 1 84 North Clear Creek above Gregory Gulch USGS 11 I 85 North Clear Creek above Gregory Gulch CDM 85 86 Gregory tailings at North Clear I Creek CDM 85 81 North Clear Creek below Gregory Tailings CDM 85 1 88 Gregory Gulch above Central City CDM 85 1 I 89 Gregory Gulch above Nevada Gulch USGS 11 1 90 Nevada Gulch above Nevadaville CDM 85 1 91 Quartz Hill Portal CDM 85 1 I 92 Gregory Gulch at mouth CDH 85 1 93 Gregory GUlch at mouth USGS 11 1 94 North Clear Creek below Gregory Gulch CDM 85 I 95 North Clear Creek above National Mine CDH 16 2 96 Pool at National Portal CDM 85 1 I 91 National Tunnel below Marsh CDM 85 1 98 North Clear Creek below National CDM 85 1 99 North Clear. Creek above Russell I Gulch USGS 11 100 North Clear Creek above Russell I Gulch CDH 16 I I B-13 I TABLE B.l (Continued) I List of Water Quality Sampling Sites :1
Station Years Number of Number 11 Location Agency ?/ Collected Collections I 102 Russell Gulch at mouth USGS 71 1 103 Russell Gulch at mouth CDH 76 1 104 Russell Gulch at mouth CDM 85 1 I 105 North Clear Creek at mouth USGS 71, 73 3 106 North Clear Creek at mouth CDH 76-77 5 107 North Clear Creek at mouth CDH 79-86 43 I 108 North Clear Creek at mouth CDM 85 1 109 Clear Creek below North Clear Creek USGS 71-73 6 , 110 Clear Creek below North Clear Creek CDH 76-77 10 111 Clear Creek below North Clear Creek NUS 83, 84 12 I 112 Clear Creek below North Clear Creek CDM 85 113 Clear Creek at east tunnel above Golden AMAX 67-86 217 I 114 Clear Creek above Golden USGS 58, 71-73 9 115 Clear Creek above Golden NUS 83, 84 12 116 Clear Creek above Golden CDH 65-86 288 I
I I I I I 8-14 I I
I The data sets differ substantially in coverage and analytical methods. All of the data sets deal with heavy metals. In addition, some data sets I incOl'porate information on major ion chemistry, suspended solids, and other water quality characteristics. For all of the data sources together, some 66 individual water quality variables were measured. However, approximately half I .of these were measured so seldom that they are :only nominally represented.
I The most important source of variation in methods has to do with the analysis of heavy metals. Three fractions for individual metals are reported I in the data base: total, total recoverable, and dissolved. These are not dil"ec!tly comparable measurements. ( 1) The total concentration of a metal is I detE~r.mined by complete chemical digestion or heat decomposition of a sample, and therefore includes the dissolved component, the weakly bound particulate I component that consists of metals ·coating surfaces of particulate material or bound to organic matter, and the tightly bound component that is chemically
intE~grated into suspended solids. (2) The total recoverable, fraction is I measured after acid digestion of a sample, but without an attempt to break down all of the recalcitrant particulate material that the sample may I contain. Consequently, the total recoverable fraction includes the dissolved metals and the metals bound weakly to particulate material in the sample. I (3) The dissolved fraction is obtained by filtration of the sample under struldard conditions (typically through a filter of 0.45 micrometers per liter I porc:! size), and the filtrate is then analyzed. This is a functional definition of the dissolved fraction because it is based on filtration, and it may include metals that are bound to small organic molecules or very fine I particles capable of passing through the filter.
I Most of the measurements in the data base are designated as total recoverable metals, which is the convention of analysis used by the Colorado I Department of Health. Analysis of the total, rather than total recoverable, is typically found in the U.S.G.S. data. The U.S.G.S. has also sometimes I analyzed dissolved metals. The AMAX analyses were for total metals until 1983, when AMAX began analyzing total recoverable metals. The NUS analyses were for total recoverable metals. Few samples in the entire data set were I analyzed for more than one analyticai fraction. I I B-15 I Concentrations of heavy metals consistent with the presence of aquatic I life will vary according to the method of analysis. Allowable concentrations of total heavy metals will be consistently greater than allowable concentrations of total recoverable metals, which will in turn be greater than I allowable concentrations of dissolved metals. Colorado has in the past used total recoverable metals as an index of water quality for most heavy metals, I and the stream standards for heavy metals are set accordingly. Because of this and because analyses of this type are more common in the data base than I the analyses of any other fraction, the interpretation of the data base will focus mainly on total recoverable metals. ,I
2.3 SEGMENTATION, CLASSIFICATION, AND NUMERIC STANDARDS For purpOses of water quality regulation, the State of Colorado, through I its Water Quality Control Commission, has divided Clear Creek above Golden into 14 separate segments (13 consecutively-numbered segments plus an I additional segment that is derived from the division of segment 3 into segments 3a and 3bj Figure B.2). Such extensive segmentation is not typical I for Colorado streams, but is used in this case because of the wide variation in water quality within the Clear Creek drainage. This wide variation in I water quality has to do principally with the uneven distribution of heavy metals derived from mining (CDH 1980). Table B.2 summarizes the aquatic life I classification for each one of the 14 segments of Clear Creek upstream of Golden. In addition, Table B.2 gives the numeric standards for metals and for a few of the general water chemistry variables for each of the segments. I
In Colorado, aquatic life classification is based principally on physical I habitat characteristics and thus reflects the potential rather than the actual presence or absence of aquatic life suited to the physical habitat. Class 1 I designation for aquatic life may thus be assigned to a segment even when chemical conditions in the segment are not suitable for the maintenance of I aquatic life in maximum variety and abundance. Class 2 indicates physical degradation, or intrinsic physical limits, but does not rule out a reasonable diversity and abundance of aquatic life. I I I B-16 I ------...- - .. ------TABLE B.2
Summary of Numeric Stream Standards and Aquatic Life Classifications for the Uppep Clear Creek Basin
Segment
2 3a 31.1 4 5 6 7 !l 9 IU II 12 J] Variable Name l/ !!J Arsenic 50. 50. 50. 50. 50. 50. 50. 50. 50. 50. 50. 50. 5U. Cadmium .4 2. .4 .4 3. 3. .4 14. .4 .4 3. 10. .4
Chromium~III 50. 100. 50. 50. 50. 100. 50. 100. 50. 50. 50. 50. 50. Chromium, VI Z5. 25. 25. 40. 25. 25. 25. 25. 25. 25. 25. 5U. 25.
Copper II. 10. 5. 50. 17. 23. 5. 23. 5. 6. 60. 1000. 64~ Iron, IlIss 300. 300. 300. 300. 300. 300. 300. 30U. 300. Iron, Tot 1000. 1000. 1000. 1000. 1000. 1000. 1000. 1000. 1000. 1000. 1550. 5400. I.e ad B.S. 4. 4. 25. 25. 4. 25. 4. 4. 10. 50. 45. tfanganese, O'iss 50. 50. 50. 50. so. SO. 50. SO. 50. IJj I Hanganese, Tot 1000. 1000. 1000. 1000. 1225. 1100. 1000. 9400. 1000. 1000. 1100. IOUO. f-' -...J tlercury J:../ 50. 50. 50. 50. SO. 50. 50. 50. 50. 50. SO. 200. 50. Nickel 50. 50. 50. 50. )00. JOO. SO. 100. 50. SU. 50. 50. Selenfllll\ 10. 20. 10. 10. 10. 20. 10. 50. 10. 10. 10. 10. 20 • Silver • 1 .1 .1 .1 .1 .1 .1 .1 • I • 1 • 1 5U. • 1 Zinc BO. 2BO. 90. 450. 60. 100. SO. 740. SO. 110. 570. 500. 5U.
Boron 750. 750. 750. 750. 750. 750. 750. 750. 750. 750. 750. 750. 750. Chloride, Tot 3/ 250. 250. 250. 250. 250. 250. 250. 250. Sulfate, Totl/ 250. 250. 250. 250. 250. 250. 250. 250.
Class (Aquatic Life) 2 2 2 2 2
II Units are in micrograms per liter (pg/l) unless shown otherwise. gl Units in nanograms per liter (ng/1). 31 Units in milligrams per liter (mg/l). 41 Standards are based on total recoverable amounts unless otherwise noted. Abbreviations: Diss - Dissolved Fraction; Tot - Total Concentration I Numeric standards for certain metals vary widely among segments on Clear I Creek. These numeric standards were established by a two-stage process (CDH 1984). The State Water Quality Control Division reviewed the existing water ,I chemistry data that were available at that time the numeric standards were set and computed the mean and standard deviation for concentrations of metals at numerous points throughout the drainage. For a given stream segment and a I given metal, if the mean plus one standard deviation did not exceed the value set forth in the basic standards, the basic standard ("table value") was , I applied to the segment. Whenever the mean plus one standard deviation exceeded the basic standard, the numeric standard for a stream segment was set I to the higher value indicated by the mean plus one standard deviation, provided that this higher value was taken to represent ambient conditions. The ambient conditions are considered to be those that arise from all I circumstances that are not subject to a discharge permit, and would thus include historic metals contamination. For this reason, the numeric standards I for certain metals in certain segments were set above the levels that are known to be fully compatible with a wide diversity and variety of aquatic I life, and these higher numeric standards are justified solely on the grounds that they represent ambient conditions and are thus not subject to regulatory I control.
In the Colorado standards, typically only one analytical form of each I substance (usually total recoverable for metals) is regulated. Some water quality variables are not regulated at all, but this is - typically because I experience has shown that these variables are not likely to be significant in relation to aquatic life except under unusual circumstances. I
In its most recent water quality status report (CDH 1986a), the Colorado I Department of Health has classified segments 11 and 13 of Clear Creek as severely degraded due to acids and metals derived from mine drainage. These segments comprise the main stem of Clear Creek between the Argo Tunnel and I Golden and the main stem and tributaries of North Clear Creek. The numeric standards for these stream segments are higher than for many other segments on I Clear Creek because the numeric standards for these segments are determined by ambient concentrations rather than basic standards. I I 8-18 I I
I Segment 7, on Woods Creek, carries a temporary modification for zinc, manganese, and cadmium. This segment drains the Henderson mine. The use of a I temporary modification by the Water Quality Control Commission generally indicates the belief of the Commission, based on evidence presented at a I classification hearing, that there may be some potential for the improvement of water quality in such a way as to restore the feasibility of using basic I standards consistent with requirements of aquatic life. Segment 8, which is Lion Creek, is also designated as degraded with I respect to. acids and metals. However, Lion Creek, unlike the other segments thaI; are designated as degraded, lacks numeric standards. This reflects the 'I conclusion of the Water Quality Control Commission, based on testimony given principally by the Colorado Department of Health and Colorado Division of I Wildlife, that physical habitat characteristics of Lion Creek are degraded to such an extent that numeric standards are not meaningful in the absence of I dischargers.
Also in a special category is Segment 12, which consists of small I tributaries to the main stem of Clear Creek between Idaho Springs and Golden. Relatively high values are allowed for a number of metals on this I segment. This reflects the conclusion of the Colorado Department of Health and the Colorado Division of Wildlife that these are not perennial waters I (i. e., they do not flow through the entire year). Furthermore, the data record on these waters is essentially non-existent. Consequently, the numeric I standards on these segments reflect lack of information and lack of potential for continuous support of aquatic life rather than a degraded status.
I 2.4 GENERAL WATER CHEMISTRY CHARACTERISTICS OF CLEAR CREEK The general water chemistry of the Clear Creek drainage above Golden can I be eharacterized on the basis of total suspended solids, conductance (ionic solids), hardness, and alkalinity. In addition, it is important to consider I phosphorus concentrations, which are likely to control the trophic status of any impoundment on Clear Creek. Data were used in two different ways for I quantifying these general variables. First, frequency distributions were obta.ined for each of the variables at each one of the stations for which three I or more samples had been analyzed. On the basis of these frequency I B-19 I distributions, medians were obtained across stations for each variable. I Frequency distributions were then obtained across stations for the medians of each variable. Frequency distributions were defined to differing degrees depending on the number of stations represented for a given variable. When 5 'I or fewer stations were represented for a given variable, only the median of medians was calculated. For 6 to 10 stations, percentiles were calculated at I intervals of 20%, in addition to the median. For variables, represented by 10 or more stations, percentiles were calculated by 10% increments from 10% to I 90%. The results of the frequency analysis on the 32 stations where 3 or more samples were taken are summarized in Table B.3. I
The second approach to characterization of the general water chemistry was based on more detailed analysis of the water chemistry at the four stations I' where sampling was most intensive. These stations include Clear Creek above Golden, North Clear Creek at its mouth, Clear Creek at Hidden Valley (below I the Argo Tunnel and above North Clear Creek), and the mouth of the West Fork of Clear Creek. Information from these four stations gives a good impression I of the chemistry of major subdivisions of the drainage. Frequency distributions were constructed for general water chemistry variables analyzed I at each of the four stations. These percentiles are reported in Tables B.4 and B .5. The scope of analys is is somewhat smaller than it was for the complete data set as reported in Table B.3, but is still sufficiently complete I to allow good characterization of general water chemistry. I Concentrations of total suspended solids at most locations in the watershed are quite low by comparison with Colorado streams in general. The I major tributaries in the main stem have medians between 5 and 17 milligrams per liter, and do not exceed 60 mHligrams per liter even at the 90th I percentile. The West Fork has generally about half the suspended solids load of North Clear Creek at the mouth. The suspended solids concentrations in the main stem below Idaho Springs fall between the concentrations typical of the I West Fork and North Clear Creek. Table B.3, which deals with the medians for all stations, shows that extremes in suspended solids concentrations are rare, I and comparison with Table B.5 shows that the solids concentrations in the smaller tributaries are generally lower than in the main stem of Clear Creek. I I B-20 I ------.. - .. - - - TABLEB.3
General Water Chemistry Data for Clear Creek 1/ ~/J/
N of Percentiles for Station Medians
Variable Nama Stations \0 2() 30 40 Median 60 70 80 90
J)isc\l!Irge, cfs 15 3.0 3.0 3.3 5.5 6.6 28.5 29.5 71.0 81.5 Total Sutl Solids 23 ,.. ,.. • 2.0 4.1l 5.0 8.5 10.0 11.8 Conductance, umho/clU 30 30.5 45.1 59.0, 115.0 210.5 260.0 300.0 400.0 602.5 Chloride, Tot 24 0.6 0.8 1.0 5.0 6.0 6.4 7.5 8.2 9.0 Sulfate, Tot 30 8 10 13 30 55 61 70 105 180 Fluoride, IHss 6 0.1 0.2 0.2 0.2 0.7 Fluoride, Tot 7 0.2 0.5 0.7 0.7 1.6 Calcium, CaC03 11 14 .0 l7 .5 34.7 37.6 40.5 56.0 65.0 66.5 10.8 Calcium, Ca 18 2.9 5.4 5.7 15.5 21 • I 23.1 26.0 31.5 55.5 td HagnellilllU, Diss 12 0.58 0.60 0.78 1.25 4.46 4.95 5.40 7.25 9.60 1 N Magnesilllll, Tot 16 2.0 3.5 4.3 4.4 5.0 5. 1 5.5 6.5 7.5 t-' Sad illlU, Tot 8 5.0 5.5 9.3 10.0 H.O 50dilllU, DillS 8 1.25 1.27 1. 31 2.13 7.00 I'otalllllum, Tot 4 2.73 Po t aB:lilllU, III tiS 8 0.11 0.90 0.91 0.92 2.00 ,.. I'hollphorus, Tot 21 ,.. o 0.008 0.051 0.1l55 0.060 0.105 0.160 Phosphorllll, DillS 5 • /l.001 Alktllinity, CaC03 22 7.5 8.0 12.5 32.0 42.8 44.0 45.5 54.0 81.5 lIardnelis. mg/l CaC03 •• 12 3B 48 69 77 129 158 177 265 289
·Uelo~detection limit. ,HCa 1clllaled froln calcium and magnesium. 1/ Concentrations are mg/l unless otherwise noted.
~/ The percentiles indicate the proportion of sampling sites whose medians are equal to or less than the indicated value for the variables. J/ Only stations for which three or more samples have been taken are included in this analysis. TABLEB.4
Summary of Water Chemistry Data 11 ~/ West Fork of Clear Creek and North Clear Creek
Pcrcentlles
Variable N 10 20 ]() ~O HeMan 60 70 80 'HI
\Jcst Fork 111scharge. eta 0 .. Tucal :lUll Solids ~5 .. 10 I~ 18
Condllctanee, umho/em ]8 84 140 210 2~0 260 310 350 380 ~I/l Chloride 0
SlIlfate ~4 20 28 48 50 61 66 74 82 90 Fluoride 0 Cal c !tuo, CaCO] 0 Hllgnellium 0 tJ:j Sodium 0 I N Photiphorus (Totsl) 42 ...... 060 .080 .120 N Alkalinity, CaCO] 36 24 32 36 60 67 76 84 94 100 lIardnelis 0 North Fork Discharge, efll 0 Total SIIS Solids 42 • 10 13 17 20 24 33 60 Conductance, umho/cm 37 100 180 20() 240 ]00 320 380 410 4411 Chloride 0 Sulfate 1,4 32 55 70 90 131 140 170 190 210 Fluoride 0 ea I cium, CaC03 0 Hagnesium 0 Sodium 0 Phosplioru8 (Total) 42 • .. .055 .060 .070 .100 .150 Alkalinity, CaC03 ]7 2 6 8 10 12.5 14 16 18 20 lIardnesli 0
*Delow detection limit.
1/ Concentrations are mg/1 unless otherwise noted. 2/ Source: Colorado Department of Health monitoring program. - - - •• - - - - .. ------.. ------.. TABLE8.5
Summary of Water Chemistry Data 11 ~I Clear Creek at Hidden Valley and Clear Creek above Golden
Percentiles
Variable N 10 20 30 40 Hedian 60 70 110 90
Clellr Creek at Il1dden Valley IHschaQle, cta 0 Total Sus Solida 85 9.9 ll. 14. 17. 25. Conduct lince, umho/cDl 72 91 120 11.0 180 210 250 270 290 310 Chloride. 15 4 5 6 8 Ii I 1 12 J) Sulf lite 42 16 20 33 40 60 62 67 75 89 Fluoride a ea 1ci um, clleo3 16 22 27 49 52 65 65 67 75 77 Hagnesium 16 2 3 5 6 7.5 8 9 10 tJ:1 , SodiulU 16 5 11 15 18 20 N • l.U Photlphorua (Total) 70 • • 0.001 .060 .070 .100 .120 .140 Alkalinity, CaC03 64 22 24 32 3B 42 50 56 60 72 lIardncsa 16 34 35 68 70 92 102 102 110 120 Clear Creek above Golden 01scharge, cfll 280 39 45 54 64 82 100 144 271 487 Total fius Salida 261 • 8 10 12 18 24 40 Conlluctance, Ilillho/cm 247 11) 154 187 220 250 271 299 )19 )49 Chloride 180 8 9 10 II 13 Sulfate 102 19 31 46 58 70 72" 77 85 93 Fluo ri de 37 0.4 0.5 0.6 0.7 0.7 0.8 0.9 1.0 Calcium, CaeO) 96 32 41 54 65 7 I 75 81 84 91 tiagnesium 96 4 5 6 7 8 9 iO 11 SodiulB 178 4 7 10 12 15 17 19 20 24 I'hosphorua (Total) 189 • 0 0.04 .060 .074 .090 .120 .180 Alkalinity, CaCO) 81 24 28 34 40 48 50 56 60 64 lIardneas 96 52 69 82 95 lOB 114 120 123 136
*Ilelow detection limit.
11 Concentrations are mg/1 unless otherwise noted.
21 Source: Colorado Department of Health monitoring program. I
Conductance, which indicates the concentration of ionic solids, is II moderately high for Clear Creek, but by no means extreme (some comparisons: L. Dillon, 150 micromhos per centimeter; Chatfield Reservoir 340 micromhos per II centimeter). Except for North Clear Creek, the major tributaries vary little in conductance. The conductance of North Clear Creek is somewhat higher than that of the other major tributaries or of the main stem. The survey of all I stations shows that a few stations on smaller tributaries reach median conductances that are three times as high as those observed on the main I stem. These areas of high conductance are associated generally with mine drainage. I Major cation chemistry has not been well characterized for North Clear I Creek or for the West Fork. For Clear Creek at Hidden Valley and Clear Creek just above Golden, neither the amounts nor ratios of major cations are particularly exceptional; there is no obvious distortion of the ion ratios by I exposure of ores. I Alkalinity, expressed as calcium carbonate, is within a normal range for waters of this elevation in Colorado. Weathering of pyrites in tailings piles I and mines releases sulfate and hydrogen ions (acidity), but the alkalinity data show that any major depression of pH or alkalinity by the hydrogen ion I release is very localized; acidity is typically offset by background alkalinity. However, the waters of the main stem are enriched in sulfate as a il result of the oxidation of sulfur from pyrite (Wentz 1914). Chloride seems to be slightly enriched, but this effect is not extreme. The survey across all stations (Table B.3) shows the greatest spatial variation in sulfate, as would I be expected since this component is most sensitive to the amount of mining in a given watershed. Even so, sulfate concentrations exceed the stream standard I of 250 milligrams per liter at only a very few locations, and are well below this level on the mainstem. I
Hardness, or alkalinity, which is closely related to hardness, is especially important because of its effect on the toxicity of metals to I I I B-24 I I
I aquatic life. On the main stem of Clear Creek, the hardnesses fall within a relatively narrow range with a median around 100 milligrams per liter I (Table B.5). In the tributaries and small streams, however, as shown by comparing Table B.3 to Table B.5, there is a much broader range of I hardnesses. This is to a large degree explained by natural trends toward lower amounts of divalent cations at higher elevations, and a consequent trend toward lower hardnesses at higher elevation. Table B. 3 shows that the· more I extreme stations at the lower end of the hardness scale may have median hardnesses in the vicinity of 40, whereas most stations have hardnesses I exeeeding 100.
I Phosphorus concentrations are relatively uniform for North Clear Creek and fOJr the main stem below Idaho Springs. Medians for these stations are in the I vicinity of 60 micrograms per liter and the gOth percentile falls near 150 micrograms per liter. The West Fork has lower concentrations of phosphorus. The phosphorus concentrations are not exceptional, and there is I no evidence of significant enrichment of the phosphorus load by mining.
I 2.5 OVERVIEW OF METALS CHEMISTRY IN CLEAR CREEK By statistical methods identical to those described for the general water I chemistry variables, two sets of tables were made for metals chemistry on the Clear Creek drainage. Table B.6 shows the frequency distributions of station I medians, expressed as percentiles for the stations at which three or more samples were taken. Tables B.1 and B.8 give information on the frequency distribution for metals at four major stations: West Fork, North Clear Creek, I Clear Creek at Hidden Valley, and Clear Creek above Golden. I I I I I I B-25 TABLEB.6
Clear Creek Metals Chemistry Summary 11 ~I~/
Percentiles
N of Variable Naloe Stations 10 20 30 40 Median 60 70 80 90
Alum! n!lln, 01ss 4/ 6 46.6 75.0 80.0 Aluminum, Tot Rec 10 '" '" 64.2 65.9 270.0 Arsenic, IHss 7 '" '"1.0 1.7 2.0 '" Arsenic, Tot 8 '" '" 8arl111O, Tot 4 '" '" '" 8erylilllO. Tot Rec 7 0.35 CadmillRl, Olss 7 0'" '"1.0 '"2.0 2.0'" 5.5 Cadmium, Tot 11 '" CadmiulO. Tot Rec 22 '" '"0.1 1.5 1.9 '"3.5 3.9 '" '" t.d ChrOlululR. IHlls 0 I N ChromiulD. lIexa 21 0\ Chrolllium, Tot Rec '" '" '" '" 12 '" '" Cobalt, Oiss 6 '"2.0 2.3 '"3.0 3.0 21.0 Cohalt. Tot 1 17 .5 Copper. Olss 7 2.0 11.0 10.0 1 SO Copper. Tot 11 ...... 15.0 30.0 50.0 105.0 215.0 '" Copper. Tot Rec 22 '" 4.8 6.3 8.0 13.8 20.5 39.5 56.3 95.5 Iroll, Dillll 12 25'" 35 40 4.1.8 48 63 130 400() Iroll, Tot 23 145 170 200 225 255 280 975 1199 4250 Iron, Tot Rec 10 200.5 247.0 307.0 535.0 1,296.4 Lead. DillS 7 0.6 0.5 3.0 '" Lead, Tot 11 ...... oil '" Ll:ad. Tot Rec 21 ... 0.0 0.5 60.3 0.8 2.S 4.5 6.5 Nunganelle. III liS 12 '" 6.0 9.0 1350 140(j 1500 4900 5900 '" '" Nunganelle, Tot 11 222 900 9U) 2417 2875 3440 6950 '" '" Manganese, Tot Rec 18 4 31 J7 .5 260.0 595.8 !.I{)O.O 1:100.0 1301.7 2945.0 Nercllry. DillS 7 0.3 0.3 Hercury. Tot 10 ...... '" ~lolyh"enlllU.011111 8 ...... '" 4.0 65.0 HolybdellulII, Tot 8 2.6 14 .4 61.0 '" '"
Continlled. next page ------TABLEB.6 (CONTINUED)
Clear Creek Metals Chemistry Summary 11 21 11
Percentiles
N of Vadable NWDe Stations 10 20 30 40 Hed lan 60 70 BO 90 HolybdenulD, Tot Rec 18 • • • 1.7 12.2 IB.3 40.0 45.3 89.0 Nickel, \litis 7 4~2 8.0 9.0 9.0 50.0 Nickel, Tot 6 • 12.5 l:!.5 25. (J Nickel, Tot Rec 8 • ...... 6.5 SeleniulD, niBs 3 2.5 SeleniulII, Tot 8 .. .. 0 0 Silver, niBil 7 0 Silver, Tot 4 .. .. b:J Silver, Tot Rec 14 II ...... II I N Vanadium, IHss 2 14.6 '-J Vanad iUIII, Tot 2 20.5 Zinc, Diss 7 29 385 610 610 B30 Zinc, Tot 11 .. 58 99 165 216 253 548 5115 640 Zinc, Tot Rec 22 16 25 60 170 2'.9 295 495 695 9'.l1l
.Be1o~detection limit.
11 Concentrations are ~g/lunless otherwise indicated.
~I The percentiles indicate the proportion of sample sites whose medians are equal to or less than the indicated value for the variable. JI Only stations for which three or more samples have been taken are included in the analysis.
~I Abbreviations: Tot Rec - Total Recoverable; Diss - Dissolved; Tot - Total. TABLEB.7
Clear Creek Metals Chemistry 11 ~I at Mouths of West Fork and North Clear Creek
PercentJles
Variable N 10 20 30 1.0 Nedta" 60 70 IJO 90
\-lest ~'ork Arsenic 0 eaclldilim 1.8 ... 0.4 0.7 2 2 ChromlulD IV 0 ChromiuflI, Total 26 .. .. Copper 1.7 8 10 11 14 15 20 29 Iron '10 .. 110 170 180 215 380 420 51.0 720 J.eat! 1.8 .. .. 0 5 Hanganese 1.8 610 790 890 1100 1300 1600 2700 3400 1800 to HolybdcllulQ 45 12 25 29 40 45 60 65 72 100 I N SeleniuRl 0 co Silver 0 Zinc 41l 33 60 90 110 170 220 240 10n 390 North Clear Creek Artienlc 0 CaJmium 46 0 2 3 4 ') 6 9 12 Chromillin IV 0 Chro1UIulU, Total 25 ...... 0 Copper 1.6 1.0 56 89 92 100 )30 170 220 260 I rOil 41 810 HOn 2100 2700 2908 3.100 4400 5000 6L.00 Lead 46 * 6 a 11 19 20 23 32 44 Hilnganese 46 520 840 9110 HOO 1600 200/} 25110 2aOO 36110 Hi) I ybdenllm 30 * * .. 0 Selenium II Sliver 0 Zinc 46 260 470 690 960 1105 11.00 1800 2200 2500
*Helo~detection limit.
1/ Concentrations are in pg/1 total recoverable solids except as noted.
2/ Source: Colorado Department of Health monitoring program. ------.. ------_.. ------TABLEB.B -
Clear Creek Metals Chemistry 1/ ~/ at Hidden Valley and above Golden
l'ercent 11 es
Variable N 10 20 30 t.O tled1an 60 70 80 90 Clear Creek, at Ilidden·Valley Arsenic () CadmiulO 60 0.9 I ·2 3 3 4 b Chromium III 0 Chromium, Total 25 ...... Copper 81 18 28 38 t.8 56 67 8t. 110 180 Iron 82 510 690 890 1000 1300 1400 1600 2000 3100 I.ead 8t. .. .. 0.3 5 6 .8 20 Hanganese 84 460 610 950 1000 1300 1480 1850 2000 2500 HolybdenUla 77 .. 0 12 14 16 18 21 tP I Se leni lUB 2 0 N .. 1.0 Stiver 7 0 Zinc 83 230 310 390 510 660 750 850 990 1100 Clear Creek. above Golden Arsenic 5t. • • Cadlof UIII 115 0 1 2 2 3 4 ChrolU11ll8 VI 30 0.2 8 ChroloilliD. 'l'otal 54 .. • 0 Copper 172 0 20 27 35 42 t.6 59 75 105 I ron 183 450 580 720 850 988 1080 1220 1410 22110 Lead 176 .. .. (). 1 0 6 9 21 Hanllanese 183 390 480 590 710 880 1000 1200 1380 1540 ~IoI yudenulII 151 • II 12 It. 17 20 30 110 SeleniulII t.2 • 0 I 511 ver 22 • • Zinc 182 190 260 3111 390 500 550 620 740 870 .8elow detection limit. 1/ Concentrations are in pg/1 total recoverable solids except as noted. 2/ Source: Colorado Department of Health monitoring program. I
Table B.9 provides a means of judging the significance of the statistical I resul ts summar ized in Tables B. 6 through B. 8. Table B. 9 shows the chronic exposure limits (Final Criterion Values, FCV) for coldwater aquatic life, I including trout, used by the State of Colorado (typically measured as total recoverable), and a set of parallel values that have been recommended by the Water Quality Control Commission Task Force on metals (proposed as soluble I rather than total recoverable; CDH 1986b). The latter will be used extensively here because they reflect a more recent overview of the literature I than the current State criteria. In addition, Table B.9 shows the percentile ranks corresponding to the recommended criterion values for the frequency I distributions of metals concentrations near the mouth of North Clear Creek and Clear Creek near Golden, because these two sites are closest to the locations I of possible impoundments.
The criterion values shown in Table B.9 differ from the stream standards I in that the stream standards may, for reasons already explained in the section on standards, be set above concentrations that are compatible with aquatic I life. Criterion values are set according to the requirements of aquatic life, and represent the concentrations that should not be exceeded. Exceedances are I judged from 3~-day averages by Colorado convention and from 4-day averages by the EPA. The criterion values provide a good basis for evaluating stream I chemistry with respect to aquatic life.
The relationship of Clear Creek water quality to aquatic life is I summarized in Table B.l0, which clusters the elements into five groups. The groupings are based on the relative sensitivity of aquatic life to the I elements and on the concentrations in relation to the criterion values. Group 1 consists of elements to which aquatic organisms are known to be highly I sensitive and for which the criterion values consistent with coldwater aquatic life are frequently and substantially exceeded within the drainage, including I the main stem. All four of the elements in this group are heavy metals: cadmium, copper, lead, and zinc. I I I 8-30 I I
I TABLE B.9
Metal Criterion Values ~1 I Frequency Distributions -
I Criterion V~}ues Percentiles 3/ Lowest ~/ (FCV)* North Clear Clear Creek Reportable I Present Recommended Creek at Golden Concentration Aluminum 100 150 1000 Arsenic 50 190 >90 10 Barium 500 I Baryllium 10 50 Cadmium 0.4 0.66 10 35 0.3*** Chromium III 100 120 >90 >90 I Chromium VI 25 11 >90 >90 10 Cobalt 100 Copper 5 6.5 <5 15 5*** I Iron (mg/1) 1 15 55 o. 1 Lead 4 1.5 15 65 5*** Manganese (mg/1) 1 30 60 0.05 Mercury .05 .01** 0.25 I Molybdenum 500 Nickel 50 56 100 Selenium 50 >90 2 I Silver O. 10 .02 >90 0.2*** Vanadium 1000 Zinc 50 45 <10 5 10
I * At a hardness of 50 mg/1 ** Final Residue Value (FRV); FCV is 1.3 I *** Assumes graphite furnace I I 1/ Concentrations are expressed as ug/l unless otherwise indicated. 2/ Final Criterion Values (FCV) - Average concentrations that should not be I exceeded over a 30-day interval by Colorado conventions or a 4-day interval by EPA conventions. I J/ ,Percent of measured values that fall below recommended criterion value.
I 4/ Compiled by Colorado Department of Health, Water Quality Control Division I on basis of commonly used methodology. I B-31 I TABLE B.10 I
Elements and Their Probable Relation to Aquatic Life in Clear Creek I
Characteristics Elements I Group 1 Concentrations exceed criterion Cadmium, Copper, Lead, values; aquatic life sensitivity Zinc high I
Group 2 Concentrations exceed criterion Iron, Manganese value; aquatic life sensitivity I low
Group 3 Little or no evidence of exceedances Mercury, Silver but worthy of further study I
Group 4 Of uncertain significance because Molybdenum, Cobalt, of poorly known sensitivity; probably Vanadium I not significant Group 5 Unlikely to affect aquatic life Aluminum, Arsenic, I adversely due to low concentrations Chromium, Nickel, present in relation to criterion Selenium, Barium, values Beryllium I I I I I I I I I B-32 I I
I Copper and zinc are both more extreme in their divergence from the crit;erion concentrations than cadmium or lead. Figure B.3 shows how the I concentrations of copper and zinc vary within the watershed. At Golden, copper exceeds the criterion concentrations by a factor of 3-4 as a median. I The concentrations are slightly higher at Hidden Valley on Clear Creek, and are considerably lower on the West Fork of Clear Creek where they only slightly exceed the criterion concentrations; the median for North Clear Creek I· is some eight t.imes greater than the criterion concentration.
I Zinc is the most extreme among the four metals of group in its exceedance of the criterion concentrations. As in the case of the other I metals, the concentrations are most extreme for North Clear Creek, least extreme for West Clear Creek, and intermediate for the main stem. At Golden, I the median concentration for zinc is approximately 11 times the criterion concentration for aquatic life. The survey of stations throughout the watershed shows that the highest concentrations of zinc are essentially I restricted to North Clear Creek, although the concentrations in other parts of I the watershed still exceed the criterion maximum. The concentrations of cadmium and of lead are least extreme in their I exceedance of the criterion concentrations. As shown by Table B.8, the median concentrations for cadmium along the main stem are approximately double the I criterion concentration, and the 90th percentile concentrations on Clear Creek above Golden are 3-4 times the criterion concentration. The concentrations of cadmium are higher in North Clear Creek than in other parts of the drainage. I However, as shown by Table B.6, the median cadmium concentrations at most of the stations that have been sampled for cadmium are below 1 microgram per I liter.
I The criterion value for lead is exceeded at about the 65th percentile of concentrations for Clear Creek above Golden. Higher up on Clear Creek, at I Hiddlen Valley, the concentrations are much lower. On the West Fork, the concentrations are even lower than on the main stem, whereas on North Clear Creek the concentrations are substantially higher, and the median exceeds the I criterion concentration by a factor of 4 to 5. The survey of all stations I (Table B.6) shows that only a few stations throughout the watershed have I B-33 I medians that exceed the criterion value. These stations are concentrated in I the North Clear Creek area.
Elements of group 2 as shown in Table 8.10 are those for which I concentrations exceed the criterion values for aquatic life, but to which aquatic life is known to have relatively low sensitivity. These elements are I iron and manganese. Aquatic organisms tolerate high concentrations of both iron and manganese. At concentrations above 1 milligram per liter, iron and I manganese may cause physical interferences with the gills of fishes and aquatic insects, or may coat surfaces where organisms grow and thus be I indirectly harmful. However, the strong tendency of these elements to form hydroxides at moderate pH is likely to render them much less harmful than they I would be at low pH in true solution. Consequently, these elements differ from the heavy metals of group 1, which can, in the dissolved state, harm aquatic organisms at quite low concentrations. I
Iron and manganese are very abundant throughout the watershed. The tables I show that Clear Creek above Golden has median iron and manganese concentrations very near the criterion maximum, and that concentrations are I slightly higher on the main stem of Clear Creek at Hidden Valley. Concentrations of manganese are similar to those for Clear Creek at Hidden I Valley on the West Fork and North Clear Creek. Concentrations of iron are considerably lower on the West Fork and considerably higher on North Clear Creek than on the main stem. As shown by the survey of all stations, most of I the iron is not in dissolved form except at a few extreme stations where there is localized high acidity that keeps iron in solution. Stations at which I dissolved manganese is present at high concentrations are more numerous because of the less extreme chemical conditions required to hold manganese in I solution. I Group 3 contains the elements mercury and silver. Silver in the dissolved state can be harmful to aquatic life in extremely small amounts. However, the limits of detection for most analyses exceed by a factor of ten or more the I criterion concentrations. Consequently, the analytical information on silver is probably not adequate to rule out silver as a potential problem for aquatic I life in Clear Creek drainage. What argues against the probable importance of I 8-34 I I
I silver in relation to aquatic life in the Clear Creek drainage is the survey of stations shown in Table B.6. This survey shows that none of the stations I for which silver has been analyzed has a median concentration of silver exceeding the detection limit, even for total recoverable silver. If silver I were a problem, it is likely that there would be at least a few stations where total recoverable silver could be detected on a routine basis.
I iMllch the same reasoning applies to the data on mercury. Mercury has been undl:!tectable at most stations. One station showed concentrations that were I detectable but near the analytical limit. Overall, there is no evidence that mercury is exceptionally abundant in the watershed, but more extensive study I might be warranted because of the relatively small number of samples and the problems with detection limits. I One special consideration applies to mercury. Because· of bioaccumulation . of mercury, the mercury criterion needs to take into account not only the I potential of mercury for directly damaging organisms, but also for bioaccumulation in the food chain. For this reason, the critical value for I mercury is set well below the criterion value consistent with chronic exposure. Because of detection problems, past measurements of mercury in the I Clear Creek watershed are not meaningful. I Group 4 contains three elements (molybdenum, cobalt, vanadium) for which there is some analytical information but to which the State of Colorado has not applied numeric standards. Given the concentrations that appear in the I tables, it seems unl ikely that these metals pose a problem for aqua tic life, but this cannot be stated with certainty because relatively little research I has been conducted on the sensitivity of aquatic organisms to them.
I Group 5 contains 1 elements that seem very unlikely, on the basis of what is known from the monitoring in Clear Creek watershed, to constitute a problem I for aquatic life.
In summary, the critical water quality variables for establishing the I characteristics of an impoundment on Clear Creek, and for which there is a I sufficient current background of information, include cadmium, lead, copper, I B-35 I zinc, phosphorus, and hardness. The first four of these variables are I important from the viewpoint of the general suitability of impounded waters for aquatic life. Because hardness (alkalinity) determines the sensitivity of aquatic organisms to metals, it also is important. Phosphorus is important as I a determinant of lake productivity, trophic status, and general aesthetic appeal. I
2.6 DISCHARGE-WEIGHTED CONCENTRATIONS FOR CRITICAL VARIABLES I For general water chemistry variables and for the six variables of special importance as identified in the previous section, it is desirable to compute I the discharge-weighted mean concentrations at stations near the points where impoundments may be situated. The discharge-weighted means may differ significantly from the medians or simple means. The simple means and medians I are of great interest with respect to stream water quality. However, the discharge-weighted means are a more appropriate basis for projecting the water I quality of an impoundment because the relative influence of a,given season's flow on the water chemistry of the impoundment is strongly influenced by the I amount of discharge occurring during that season. I Analysis of the relationship between discharge and concentration and the computation of discharge-weighted mean concentrations is complicated by the I low frequency of discharge measurements coincident with the stream sampling. However, there is a continuous gage record of stream discharges just above Golden, which is near the lower-most stream sampling point in the Upper Clear I Creek Basin. A second gage, for which there is also a good record, is located on Clear Creek just below the West Fork, but this gage is too high in the I watershed to be of great relevance to the calculation of discharge-weighted means in the lower portion of the watershed where an impoundment is likely to I be situated. Consequently, we first obtained the relationships between discharge and concentration for the site just above Golden, and then used I indirect approximations as a means of estimating discharge-weighted concentrations at a few other upstream locations that are important in relation to possible impoundment. I
Figures B.4 and B.5 show the relationship between discharge and I concentration for cadmium, lead, copper, and zinc. For cadmium, copper, and I B-36 I I
I zinc, there is an inverse and nearly linear relationship between discharge and concentration. This is the type of relationship that would be expected from I the dilution of a strong source of fixed volume (i.e., mine drainages) by a seasonally varying volume of dilution water (i.e., runoff). Such a I relationship is favorable for the reduction of metals concentrations in reservoirs because it indicates that the largest volume of flow occurs at times when the concentrations of .metals are lowest, and that the discharge I weighted means can be expected to be lower than the median concentrations for I these metals. For lead, there is a completely different relationship between I concentration and discharge. Concentrations of lead are negligible except during runoff, when the concentrations increase drastically. This pattern I indicates that lead is not associated with the base flow from the mine drainages, but rather with surface runoff that occurs in quantity only during I the seasonal snowmelt. Figure B. 6 shows the relationship between the hardness and discharge. I Hardness, like the concentrations of copper, zinc, and cadmium, is inversely related to discharge. This is a common relationship for Colorado streams and I it generally reflects the dilution of base flow by runoff during the season of snoll'lmelt. Because of this relationship, the discharge-weighted mean hardness I can be expected to be well below the median hardness. I 2.1 PROJECTED WATER QUALITY FOR IMPOUNDMENTS 2.1.1 Quality of Water Entering the Impoundment I From the discharge-weighted mean concentrations at two key locations (Clear Creek above Golden and North Clear Creek), it is possible to project I the quality of water that would enter impoundments at sites that are now being considered. These sites, which are shown in Figure B.l, fall into three I groups: off-channel impoundments, impoundment of North Clear Creek at its mouth, and impoundment of the main stem. The quality of water entering an off-channel impoundment would depend mainly on the quality of main stem water I used to fill it, because native flows would be insignificant in relation to I reservoir volume. Although a number of withdrawal points have been proposed I B-31 I for off-channel impoundments, they can be placed in two categories with I respect to water quality. Water for impoundments on Fall River and Soda Creek, which would be taken from the main stem just below the confluence with the West Fork, would be of relatively high quality. Water for all other off I channel sites, as well as all main stem sites, would be of lesser, bu t relatively uniform quality • Because water quality in the main s:tem changes I relatively little from Idaho Springs to Golden, the actual point of withdrawal within that segment would have little impact on projected water quality in an I impoundment. An impoundment at the mouth of North Clear Creek would have chemical characteristics intermediate between those of the main stem and those I of native flows, and would probably have the poorest water quality of the proposed sites. A more detailed ranking of sites on the basis of water quality is not warranted with the available data. I
Two scenarios have been selected for which water quality projections will I be provided. An impoundment filled only with North Clear Creek water will illustrate the "worst" case expected for any of the proposed sites, and an 'I impoundment filled with main stem water withdrawn above Golden represents the "most likely" situation. Projections cannot be made for the Fall River and I Soda Creek sites due to the lack of suitable chemical data. Water quality characteristics of off-channel impoundments can be expected to vary in relation to the seasonal timing of water diversion into the reservoir. I Filling primarily from peak flows is most likely, and this is well reflected by use of discharge-weighted means for estimating concentrations. I
The first two columns of Table B.11 show the projected quality of water I entering impoundments on the main stem of Clear Creek and on North Clear Creek. The prOjections assume that the reservoir would have large enough I storage volume that the retention time for water would average at least several months. Based on the anticipated size of the reservoir, the action of the wind should be sufficient to promote the mixing of water across different I seasons. Such an estimate could be refined on the basis' of more exact knowledge of retention times if these are known at a later stage of I planning. I I B-38 I I
I TABLE B.11
I Projected Quality of Reservoir Inflows Before and After I Corrections for Sedimentation
Reservoir Inflows I Discharge-Weighted Mean Corrected for Sedimentation Element North C.C. Main Stem North C.C. Main Stem I Metals Cadmium, llg/1 3. 0.90 1.2 0.31 Copper, Jlg/1 19. 24. 43 13 I Iron, Jlg/1 2450. 644. 490 129 Lead, Jlg/1 15. 2. 6 1 Manganese, Jlg/1 1013. 444. 203 89 I Zinc, llg/1 120. 239. 554 184 General Water Chemistr,Y
I Suspended solids, mg/1 19. 10. 2 1 Conductance, ~mho/cm 185. 121. 185 121 Chloride, mg/1 8.* 5. 8 5 I Sulfate, mg/1 63. 29. 63 29 Caleium (as CaC03), mg/1 40.* 36. 40 36 Magnesium, mg/1 5. 5. 5 5 I Sodium, mg/1 8.* 6. 8 6 Potassium, mg/1 1. .9 1 1 Phosphorus, mg/1 .05* .03 .025 .015 Alkalinity, CaC03, mg/1 13. 24. 13 24 I Hardness, CaC03 60.* 56. 60 56 I *MrulY missing values.
2.7 ..2 Correction for Sedimentation I For the major ionic solids (calcium, magnesium, sodium, potassium, sulfate, chloride, bicarbonate), the discharge-weighted mean concentration of I water entering a reservoir is likely to be a very close approximation of the concentration in the reservoir. The same is true of any derived variables I related to these substances, including alkalinity, hardness, and conductance. The major ionic solids are present almost entirely in dissolved form in the stream water, and are therefore not subject to significant I sedimentation after entry into the reservoir. Furthermore, these substances I are not subject to significant flocculation with organic matter or absorption I 8-39 I onto particulate material, and thus would not be expected to settle from the I water column.
Concentrations of heavy metals are much more subject to change after water I enters a reservoir. Large fractions of these metals are typically attached to particulate !IJClterial. Much of the particulate matter in a rapidly flowing I- stream settles quickly after the stream water enters a lake. For this reason, a sUbstantial fraction of the metals present in stream water can be expected I to settle from the water column after the stream water enters a reservoir (Hakanson and Jansson 1983). I
In principle there is little doubt that the concentrations of metals would decline substantially after stream water enters an impoundment. However, I -there is little specific information upon which to base an estimate of the amount of decrease that could be expected in this situation. Horan and Wentz I
(1974) showed for a small tri~utary of the Arkansas River below Independence Pass that the concentrations of metals were substantially reduced by a small I reservoir. The reductions varied widely between samplings and across the different metals, but the median reduction was in the vicinity of 50%. The I reduction could well be greater for a larger reservoir with higher retention times. Sedimentation of phosphorus, which behaves similarly to metals in this respect, frequently exceeds 50% in large reservoirs. I
Although the data base is by no means ideal for computing probable I sedimentation, some rough approximations can be made on the basis of a limited number of samples that were analyzed for multiple fractions of the same I metal. The analysis has been limited to cadmium, lead, copper, and zinc, which are the main heavy metals of interest with regard to aquatic life. In I making the approximations, a dual approach has been used. First, simultaneous analyses of total metals and of total recoverable metals are tabulated for individual samples. Linear regression is then used to obtain a relationship I between total recoverable and total metals. On the basis of the slope of the regression line, the total recoverable is expressed as a fraction of the total I for these samples. From the raw data set all instances are tabulated for which total and dissolved fractions were analyzed on the same sample. The I median is derived for ratios of dissolved to total for these samples. The I B-40 I I
I comparison of total recoverable and total by regression analysis is then used as a check on the validity of the median ratio obtained in comparing total and I dissolved fractions. The ratio of dissolved to total should be at least as low as the ratio of total recoverable to total, since total recoverable must I be equal to or greater than the dissolved fraction. One minus the ratio of dissolved to total is used as our estimate of the particulate fraction, unless this ratio is higher than the ratio of total recoverable to total as I detlermined by the regression analysis, in which case the slope of the I regression line is used. The results of the two-part estimation procedure are as follows. The I fraction of the total that is dissolved for lead is 0.41, for copper is 0.55, and for zinc is 0.77. For cadmium, the data base is insufficient to support I even this limited analysis, and we consequently set the proportion equal to that of lead. Assuming that the particulate fraction is equal to 1 minus the dissolved fraction, and that the particulate fraction will settle after the ·1 water enters the reservoir, we have corrected for sedimentation the discharge I weighted mean concentrations of the four metals as shown in Table B.11. For iron and manganese, estimates of sedimentation are even more difficult I because of the very strong tendency of these metals to form flocs in well oxygenated waters of moderately high pH, as would be expected in the upper I zone of a reservoir. Since it is likely that formation of these flocs would lead to precipitation of a very large fraction of iron and manganese, we have arbitrarily set the sedimentation for these metals at 80%. This is reflected I in Table B.11.
I We have corrected the suspended solids for sedimentation by allowing 90% sedimentation, and we have corrected phosphorus on the basis of 50% I sedimentation, which is a slightly conservative figure for most Colorado reservoirs. Other items in Table B.11 will show negligible sedimentation I because they are principally present in the dissolved phase.
2.7.3 Correction for Ligation and Flocculation in the Lake I Heavy metals are toxic to aquatic life typically only in the soluble I pha.se. Conditions in the upper water column of a lake favor the removal of I B-41 I dissol ved metals from solution. Floc formation by iron and manganese is I especially effective in removing heavy metals (Salomons and Forstner 1984). In addition, substantial amounts of organic carbon are produced in the upper water column of even a moderately productive lake. Exudates from planktonic I algae and decomposition of planktonic algae are responsible for the liberation of organic matter in the water column. Formation of flocs or colloids from I organic matter originating in this manner or from organic matter that has been transported into a lake along with the inflowing water may remove substantial I amounts of metals from true solution. It is expected that 50~ or more of the total metals in a quiet water column can be removed from solution by I filtration, even after sedimentation has occurred. This indicates that substantial amounts of these metals have become associated with organic matter that has an extremely low sedimentation rate. This flocculation process is I also favored by the development of higher pH in the upper water column of a reservoir. Rise in the pH is very likely to occur in an impoundment because I of photosynthesis by planktonic algae. Anticipati,ng this change, we should adjust the numbers in Table B. 11. This adjustment is not intrinsic in the I allowances that are already made for sedimentation. Even after allowances for sedimentation, an additional fraction of each metal will enter particulate or I colloidal form in the water column. We have no definite basis for making a correction for this fraction. However, general experience shows that 50~ is a reasonable approximation of the proportion of heavy metals that can be removed I by filtration following sedimentation. Consequently, we allow a 50~ reduction as an estimate of the dissolved metals concentrations. These numbers are I shown in Table B.12. I I I I I I B-42 I TABLE B.12
Projected Reservoir Water Quality 11
Corrected for Corrected for Corrected for lHement flocculation Diversions. Remedial Action Aquatic I.lfe North C.C. Uain Stem North C.C. Hai~Stem North C.C. Haill Stem Criturlon Values
CadmlulII, \lg/l n.6 0.2 0.6 0.2 0.6 0.1 0.66 Copper, ~/l 21.5 6.6 21. 5 6.1 21.5 2.4 6.5 I.ead, ~g/l 3.0 0.4 3.n 0.4 J.n 0.4 1.5 Zinc, }Jg/l 227. 92- 227. 83. 227. 1.2. 1.5 Total Phosphorus mg/l 0.025 0.015 0.025 .014 0.025 0.014 lIardneslI, CaCO], mgll 60 56 60 53. 60 53. tJ::j .AveraHe ~ateryear. 1 ~ W 11 Concentrations of impounded water with approximate corrections for various factors. I 2.7.4 Correction for Water Diversions I The most probable source of transbasin diversion water will be the Williams Fork drainage. Since this water would enter Clear Creek through the West Fork, it would potentially affect the chemistry of an impoundment on the I main stem of Clear Creek. In order to make rough projections of the effect of this diversion on the water quality of an impoundment, we have made estimates I of the amount and quality of the water that might be diverted. The water quality summary is given in Table B.13. The data shown in Table B.13 are from I the Colorado Department of Health Water Quality Monitoring Program for a station located on the Williams Fork at Sugarloaf Campground. Data for the I years 1980 and 1981 were used in constructing Table B.13. It is evident fr9m the table that the concentrations of metals are much lower in the Williams Fork than in the main stem of Clear Creek, and that the diversion would I therefore provide some dilution. In addition, phosphorus concentrations and hardness are somewhat lower than in the main stem of Clear Creek. I
Table B.14 shows the amounts of water that would probably be diverted to I Clear Creek, expressed as a percentage of the average flow of Clear Creek at the Golden gage (Cheryl Signs, personal communication). For a dry year, there I would be minimal diversion, and the effect on water chemistry in an impoundment on Clear Creek would be undetectable. In an average year, however, water originating from the Williams Fork drainage would augment the I volume entering an impoundment by 12.1%. Table B.12 shows the effect of this water on the concentrations in the main stem of Clear Creek. The numbers in I Table B.12 were derived from the concentrations in Table B.13, corrected for sedimentation and flocculation as described above (see Sections 2.7.2 and I 2.7.3), and weighted for average flows (Table B.14). The effect of diversion, although small, is beneficial for copper and zinc. I I I I I B-44 I I
I TABLE B.13
Metal Concentrations for Williams Fork I at Sugarloaf Campground
I Element N Concentration
Cadmium, pg/1 (Total Rec.) 20 1.0 I Copper, pg/1 (Total Rec.) -20 B.O Lead, pg/1 (Total Rec.) 20 0.0 Zinc, pg/1 (Total Rec.) 20 11.5 I Total Phosphorus mg/1 17 0.010 Hardness, mg/1 CaC03 20 32 I I I n I II I I I I I I I B-45 I TABLE B.14 I Potential Diversions from Williams Fork 11 I
Month I Condition ~/ May June July August Annual Average 3.3 25.0 17.0 0.0 12. 1 I Wet 8.8 32.3 33.5 2.8 18.9 Dry 0.0 1.6 0.0 0.0 0.5 I I I I I I I I I I I 11 Amount of water, as percent of average flow at Golden gage, potentially diverted from the Williams Fork to Clear Creek. I 21 Refer to Metropolitan Denver Water Supply ElS. I 8-46 I I
I 2.7.5 Correction for Remedial Action If the EPA Superfund program progresses to a remedial action stage, the I most likely action would be treatment of the discharge from the Argo Tunnel. Although we still lack fully satisfactory information on the Argo Tunnel, it I is possible to make some rough approximations of the effect of treatment of the Argo Tunnel discharge. We will assume for purposes of the approximation that the flow from the tunnel is steady at a rate of 0.5 cfs. We also assumed I that the treatment program would be 90% effective in removing heavy metals. On this basis, we show in Table 8.12 the projected concentrations that would I result from remedial action on the Argo Tunnel. Any further remedial action involving the other tunnels would enhance the improvements shown in I Table 8.12. Clearly these improvements are considerable, and would benefit the aquatic life potential of an impoundment on Clear Creek. I 2.8 ESTIMATED SUITABILITY OF AN IMPOUNDMENT FOR AQUATIC LIFE The information given in Table 8.12, although only approximate because of I the present limitations of the information base, suggests a range of pos:sibilities for water chemistry of an impoundment. If an impoundment were I to be constructed on North Clear Creek, and were to receive water only from the North Clear Creek drainage, the expected final concentrations of copper I and zinc in the water column would be several times the chronic criterion values for cold water aquatic life, and would be twice the criterion value for I lead. However, if an impoundment on North Clear Creek were to rece i ve substantial amounts of water from the main stem, which seems likely, the expected concentrations would be reduced in proportion to the amount of main I stem water diverted into the impoundment. If the water from the main stem were to be diverted in very large quantities, the chemistry of the water in I such an impoundment would approach that shown in Table 8.12 for an impoundment I on the main stem. An impoundment on the main stem of Clear Creek, or an impoundment off the I main stem but receiving large amounts of water from the main stem by diversion, would be very likely to fall below the chronic exposure criterion values for cold water aquatic life for all metals, assuming the implementation I of a remedial action plan on the discharge from the Argo Tunnel. Since these I criterion values for aquatic life are very stringent, it is anticipated that I B-41 I the water quality of an impoundment under these circumstances would be highly I suitable for all forms of aquatic life. For example, the projected concentration of zinc would be similar to that of Lake Superior or the Missouri River (30 micrograms per liter: Forstner and Wittman 1979), both of I which support extensive fisheries. I If an impoundment were to be constructed on the main stem of Clear Creek, or if an impoundment off the main stem of Clear Creek were to receive large I amounts of water from the main stem, but the Argo Tunnel remedial action plan did not come into .being, we would expect, as shown in Table B.12, that the I concentration of zinc would exceed the criterion value for cold water aquatic life by a factor of approximately 2. Because of the approximate nature of the calculation, it must be stressed that this may be an overestimate or an I underestimate that can be refined by further study. If this prOjection were to prove correct, it would still be quite likely that an excellent coldwater I biota could be established and maintained in the impoundment, for several reasons: (1) criterion values are based principally on metals in the ionic I state, whereas a substantial portion of the dissolved metals in a lake could be in a nonionic state, and thus would be less toxic, (2) the criterion values I contain intrinsic safety factors that often allow the development of a minimally affected aquatic life community, even though criterion values are somewhat exceeded, (3) physiological adaptation of local fish stocks can I frequently overcome initial detrimental effects when criterion values are moderately 'exceeded (e.g., Goettl and Davies 1975), and (4) the maintenance of I healthy fish stocks and recreational fishing in Georgetown Reservoir (Colorado Division of Wildlife, unpublished records) and in Standley Lake, which I receives almost all of its water from Clear Creek, suggests the suitability of impounded water for support of aquatic life. I.
In summary, with respect to metals toxicity, we conclude that the water quality of an impoundment on the main stem of Clear Creek receiving water by I diversion from the main stem of Clear Creek would be highly compatible with even the most sensitive forms of aquatic life, provided that remedial action I on the Argo Tunnel outflow is capable of reducing the metals loading from that source by 90% or more. Even in the absence of this remedial action plan, it I is very reasonable to expect that a full diverse and productive community of I B-48 I I
I aquatic life can be maintained in such an impoundment, although criterion I values for zinc are likely to be somewhat exceeded. The algal productivity of a reservoir on Clear Creek, its chlorophyll I coneentrations, and its general appearance can be judged from the phosphorus data. As with metals, additional information would be highly desirable, but the concentrations of total phosphorus shown in Table B.12 would suggest I mesotrophic or lower eutrophic status for the reservoir, which would imply grmiing-season chlorophyll averaging between 6 and 12 micrograms per liter in I the upper water column. This would put the appearance of the water and the productivity of the lake in the range between that of Lake Dillon and that of I Chatfield Reservoir. Experience with other lakes in Colorado shows that this range is probably quite acceptable given the location and reservoir. However if the productivity were to fall toward the upper end of this range, it would I be important to protect the lake and watershed against substantially augmented phosphorus transport that might occur as a result of upstream watershed I development in the future.
I Given the projected productivity of the reservoir, it is unlikely that severe depletion of oxygen would occur in deep water after the reservoir has I equilibrated following initial flooding. However, this matter should be studied more thoroughly on the basis of the shape and operating I characteristics of the proposed reservoir. Some oxygen depletion is not incompatible with coldwater aquatic life, but strong anoxia in deep water I would be undesirable for a reservoir of this type. Sedimentation of metals would cause enrichment of lake sediments with I heavy metals. This is a common phenomenon in Colorado and can be found, for example, in Lake Dillon. In general, aquatic life is far more tolerant of I heavy metals present in sediments than heavy metals dissolved in the water, and it is unlikely that notable problems would be associated with the I sedimentation of heavy metals in the lake basin.
2.9 POTENTIAL FOR AQUATIC LIFE AND FISHERIES I The information in this section was developed principally through I consultation with the Colorado Division of Wildlife, which manages the present I B-49 I fishery in the Clear Creek drainage and assesses both fishing success and fish I population sizes in selected portions of the Clear Creek drainage on a routine basis. The Division of Wildlife will play the key role in developing and managing any fishery that might result from an impoundment of Clear Creek, and I can draw extensive comparative experience in the management of other mountain reservoirs in Colorado. i
A number of specific management schemes are described in this section as a I result of discussions with the Colorado Division of Wildlife. These are not intended as commitments or predictioos for management, but rather as I indications of the scope of possibilities for an impoundment of Clear Creek. The management options described here presume the availability of suitable water quality for aquatic life and, downstream of the dam, the availability of I suitable minimum flow. Full use of the possible fishery potential resulting from an impoundment would also require development of facilities and access to I support recreation. I 2.9.1 The Present Fishery and its Management Many portions of Clear Creek and its tributaries currently support trout I populations and at least some of the associated aquatic life. To some extent, the trout populations are maintained by stocking that is conducted by the Division of Wildlife. However, as shown by the presence of brook trout, I cutthroat, and brown trout, which are not stocked by the Division of Wildlife, natural reproduction also occurs in the Clear Creek Drainage. I
Although reproduction of trout presently occurs in the Clear Creek I drainage, electroshocking stUdies conducted by the Division of Wildlife have shown that some of the areas where heavy metals pollution is most obvious have I very limited fish populations or, in some instances, are even devoid of fish (Colorado Division of Wildlife, unpublished records). In other areas where I fish are found, fish growth or reproduction may be impaired by the presence of heavy metals. The extent of this impairment is not known. I To the extent that fishermen are willing to capture freshly stocked trout, a self-sustaining fishery is not absolutely necessary for recreational I purposes. Stocking undoubtedly accounts for a significant precentage of the I B-50 I I
; rainbow trout that are available in the lower reaches of Clear Creek. Table B.15 shows the stocking records for the region of Clear Creek upstream I of Idaho Springs between 1979 and 1983, and between Silver Plume and Loveland I. Pass for the same interval. Some information on fish catch is also available for Clear Creek. As sho\Oll1 in Table B.15, which contains a summary of creel census information, I ther'e is fishing at several locations along Clear Creek. Fish catch, which varies considerably, falls generally in the range of 0.5 fish per hour. I Absolute estimates of fishing intensity have not been made; Table B.15 gives I, only qualitative information. ./uthough the present fishery on Clear Creek has some recreational value, Clear Creek has a number of shortcomings with respect to fishing. The total I fish yield of the stream has not been estimated, but is probably small by comparison with some of the better trout streams in the State. Quality I fishing is minimal due to the strong relationship between stocking and fish catch, and the stream is unlikely to produce significant numbers of large I fish. In addition, the distribution of fish and of other aquatic life is variable and is affected in unpredictable ways by heavy metal toxicity? the I effect of which changes with stream flow and with the amounts of water leaving the more potent source areas. Undoubtedly, this element of unpredictability I is frustrating for fishermen.
Clear Creek in many reaches also fails to provide optimum physical habitat I for trout. The current is swift and there is lack of pool habitat in many areas. The Colorado Division of Wildlife made some habitat improvements in I 1985 (log dams, boulder placements) in the upper part of the drainage, near I Bakerville. I I I I B-51 I TABLE B.15 I Stocking and Creel Census I Medians for 1919-1983 Clear Creek Stocking, Fish Fishermen Catch per ,I Stream Reach per y"ear Checked Man Hour
South Platte to 0 6 O. 11 Idaho Springs I Idaho Springs 1140 150 0.45 upward 1 miles I Clear Creek Ranch 0 12 0.10 to Georgetown I Silver Plume to 2905 Loveland Pass II North Fork 199 2 2.3 South Fork 1968 10 0.30 I I Source: Colorado Division of Wildlife records for 1979-1983 on Clear Creek. i I I I I I I I B-52 I I,
I Georgetown Reservoir, which was reconstructed in 1972 from a smaller impoundment, provides some direct evidence for possible success of a reservoir I fishery based on a major impoundment of Clear Creek (Colorado Division of Wildlife, unpublished sampling records). Even though this reservoir is upstream of some of the major sources of heavy metals, it receives water I containing significant amounts of heavy metals, and the Division of Wildlife I has had good success in establishing a fishery in the lake. 2.9.2 Potential for a Reservoir Fishery I It is likely that the Division of Wildlife would manage a large reservoir on the main stem of Clear Creek for intensive fishing. An important element I of such management would be immediate stocking with 8" rainbow at approximately 5 fish per acre to supply catchable fish in reasonable quantity. This would be subsequently followed by stocking of rainbow in the I range of 2-4" at a rate of 20-25 fish per acre. In addition, a strong possibility would be introduction of mackinaw (Salvelinus namaycush) at a I length of 4" (10 per acre) and 1" kokanee (Oncorhynchus nerka) at 100 per acre. The Division would probably not stock brown trout or brook trout, but I these would undoubtedly be present in the lake because of their entry from upper parts of the watershed. The kokanee would serve as forage base for the I mackinaw, and the general forage fish for the lake would be the naturally occurring western white sucker (Catostomus commersoni). This is judged to be a successful formula on the basis of management experience under similar I conditions elsewhere in the State.
S 2.9.3 Stream Fishery Potential An impoundment of Clear Creek could well lead to substantial improvement I of the upstream and the downstream fishery. An upstream fishery could benefit from the migration of fish upward from the reservoir, providing especially the I larger sizes that are not now available. A downstream fishery could be especially attractive, particularly if substantial minimum flow could be I provided for its support.
A philosophy that might be used by the Division of Wildlife in managing I the upstream and downstream fisheries would be to designate the upstream or I downstream area for quality fishing. The quality area would be protected by I B-53 ,I tackle restriction, catch-and-release, or some other combination of special I regulations designed to provide good sustained fishing for larger fish. Habitat improvement is also a possibility, and would probably be needed if the stream is to reach its full potential. Use potential for an improved stream I fishery below the dam might reach approximately half what it is below Cheesman .Dam at the present time. Producti vity of a stream of this type could reach I .200-300 pounds per acre. I 2.9.4 Other Considerations Aesthetic aspects of the reservoir surroundings at the quality fishing I areas upstream and downstream could be important in determining the ultimate value of the aquatic resource. Agencies capable of directing the planning and development of these areas include the Colorado Department of Parks and I Recreation and the U.S. Forest Service. I Planning for the development of recreational potential and fishery development in the Clear Creek drainage connected with an impoundment would I require additional detailed study. In particular, the flow characteristics of the stream need to be studied and modelled by U.S. Fish and Wildlife Service I IFIM (Instream Flow Incremental Methodology: Bovee 1982) methodology as a means of establishing the low flows consistent with good fishery potential. A I study of this type requires one full year of data collection on stream flow in relation to physical habitat characteristics. I Additional studies that would be useful in projecting the fishery potential would be comparison of species composition, management, yield, and I usage in other reservoirs and stream fishing areas that would have similar characteristics to those projected for the post-impoundment area of Clear I Creek. J I I I B-54 I ... - ..... _.-...... - ...- ---- ... I -l I
to I Vi Vi
• Gouge • Sampling Siles (wilh Code Number) - Possible Dam Siles • More than 25 Samples
I 1 r 5 N o miles
COLORADO WATER RESOURCES AND roWfR DfVElOPMENT AUTIIORITY
CLEAR CREEK PROJECT
CLEAR CREEK WATERSHED WATER QUALITY SAMPLING LOCATIONS TUDOR ENGINEERING COMPANY WESTERN E NVIRONMENTAL ANALYSTS, INC. DATE: DECEMBER 1986 FIGURE 8.1 to e Gauge I lJl • Sampling Siles 0'
I ' I 1 o miles 5 N
COI.ORo4OO WAHR RfSOUHCfS AND roW{R DfVHOPlAfNT AUTIIORIJ'(
CLEAR CREEK PROJECT
STATE OF COLORADO SEGMENTATION OF WATERSHED TUDOR ENGINEERING COMPANY WESTERN ENVIRONMENTAL ANALYSTS, INC. DATE: DECEMBER 1986 FIGURE B.2 ...... ~ .. -... ------,------~~~~------~--~~--
r~----~------. . . .---1
FORK ~llli I----...- ---
t:d I \J1 " 80 ..a ARGO TUNNEL 60 ~ 40 J 20 o.talo
CDLOIlADD WATfR Rt::SOUIICfS NOTE! AND .'OWER OfVHOPMEl1T AUIIIORITY
Copper and Zinc are the two heavy CLEAR CREEK PROJECT metals, most that consistently SPATIAL DISTRIBUTION exceed criteria COPPER AND ZINC CONCENTRATION TUDOR ENGINEERING COMPANY WESTERN ENVIRONMENTAL ANALYSTS, INC. DATE: DECEMBER 1986 FIGURE B.3 I
5 1000 I \I) 800 -<..l OJ- I 600 ...01 .Q 0 a. <..l a. --\I) i5 E3- ·E=:I - "C 0 0 II u 2 I I
0 J F M A M J J A S 0 N D I ,I 5 1000 \I) 800 -<..l I cu- 4 600 ...01 .c0 <..l .Q 400 \I) I a. a 0. 3 "C 200 0 cu I ...J 0 I I
0 i J F M A M J J A S 0 N 0 I
COLORADO WATER RESOURCES AND POWER DEVELOPMENT AUTHORITY I CLEAR CREEK PROJECT
RIVER DISCHARGE VS CONCENTRATION CADMIUM AND LEAD I TUDOR ENGINEERING COMPANY B-58 WESTERN ENVIRONMENTAL ANALYSTS, INC. DATE: DECEMBER 1986 FIGURE 8.4 I 100 1000 In 800 -u. I J F M AM J J A SON 0 I 1000 1000 In -CJ I QJ C1 800 'o .J:: U In I ..0 c.. a ~ 600 u I c: N a I 400 . 200 J F M AM J J A SON 0 I COLORADO WATER RESOURCES I AND POWER DEVELOPMENT AUTHORITY CLEAR CREEK PROJECT RIVER DISCHARGE VS CONCENTRATION I COPPER AND ZINC TUDOR ENGINEERING COMPANY B-59 WESTERN ENVIRONMENTAL ANALYSTS, INC. I DATE: DECEMBER 1986 FIGURE 8.5 I I 250 1000 -'"u J If') Q)- 0 ...en u 200 0 c .c. I U u .-a'" '"c I E 150 200 c. c. 0 I V)- Q) '"c:: "'0... I 0 :c I I J F M A M J J A S 0 N D I I I I I, I COLORADO WATER RESOURCES AND POWER DEVELOPMENT AUTHORITY CLEAR CREEK PROJECT RIVER DISCHARGE VS HARDNESS TUDOR ENGINEERING COMPANY B-60 WESTERN ENVIRONMENTAL ANALYSTS, INC DATE: DECEMBER 1986 FIGURE B.6 I I I I I . Appendix C I GROUND WATE.R HYDROLOGY I I I I I I I I I I I I I I I APPENDIX C I GROUND WATER HYDROLOGY I 1.1 GROUND WATER HYDROLOGY OF THE UPPER CLEAR CREEK BASIN 1. 1. 1 Introduction I The Clear Creek Drainage Basin is comprised of two distinct areas, the mountains and the plains. The mountains are characterized topographically by high relief mountains and valleys above 6,000 feet (ft) in elevation. The I plains are generally gently sloping areas below 6,000 ft in elevation. Geologically, the mountains are composed of crystalline rocks while the rock I fornmtions of the plains are sedimentary in origin. I. 1. 1 .2 Geology The geology of the mountains is characterized by Precambrian crystalline rocks that were formed from 1,800 to 1,600 million years before present. The I crystalline rocks are metamorphic gneisses and plutonic rocks. The gneisses are believed to have been formed from sedimentary rocks subjected to intense I heat and pressure which converted the sedimentry rocks to coarser cyrstalline I rocks, and intensely folded the sedi~entary layering. The plutonic rocks were formed when magma moved into the gneiss and cooled I slowly forming granite and similar rocks. During the Cretaceous and early Tertiary times (80 to 25 million years before present), the Rocky Mountains I were pushed upward and additonal magma moved into the existing rocks, forming younger rhyolite and granite masses which are sometimes associated with mineral deposits. As the mountains rose, faults originally of Precambrian age I were reactivated and the crystalling rocks were displaced upwards. I Soils in the mountains, other than the glacial deposits are generally highly varied residual deposits that are thin, except in highly fractured and I weathered areas where they may be thicker. I 1.1.3 Occurrence of Ground Water The upper watershed area in the mountains contains very few major alluvial I deposits, and this initial evaluation has not located any significant ground I C-1 I water supplies. There are approximately 1160 wells recorded with the State ,I Eengineer's office in this upper watershed, with the majority of these wells being located in overbank areas adjacent to existing streams. Due to the I geology of the area, the ground water storage is believed to be very limited. I 2.1 G~OUND WATER HYDROLOGY OF THE DENVER BASIN I 2.1.1 Introduction The location of the Denver basin and the Clear Creek study area are shown I on Figure 3.1. Generalized geologic sections through the basin are shown on Figure 3.2. Most of the geologic units in the basin are water bearing to some I degree. The important aquifers that yield significant amounts of water to wells in the Denver Metropolitan area include the bedrock aquifers of Dawson, Denver, Arapahoe, and the Laramie-Fox Hills formations, and alluvial and I terrace deposits along the South Platte River and its tributaries. The Dawson aquifer is not present in the Clear Creek basin. The location of the Clear I Creek study area is shown on Figure 3.1. I 2.1.2 Geology The Denver basin includes an area of approximately 6,700 square miles, I extending from Colorado Springs on the south to near Greeley on the north and from the hogbacks west of Denver to the western edge of the northern high plains on the east. The northern, eastern, and southeastern sections of the I basin are generally flat. On the west flank of the basin, steeply upturned sedimentary rocks, known as·the hogbacks, abut the crystalline rocks of the 'I mountains and dip to the east toward the synclinal axis of the basin. Hogback ridges west of Denver and along most of the western flank of the basin are I made up of the sedimentary rocks that comprise the Denver basin. I 2.1.2.1 Recharge, Discharge, and Occurrence of Ground Water in the Denver Basin I 2.1.2.1.1 Recharge and Discharge Recharge to the bedrock aquifers in the Denver basin occurs through I infiltration of precipitation that percolates down through the outcrop of the \1 C-2 I I I aquifers; from infiltration of surface water flows into the aquifers at the outcrop; and by slow vertical percolation of ground water from one aquifer to I the next. This latter effect is the main source of recharge to the deep aquifers in the Denver basin. A large percentage of the rainfall, which I averages between 15 and 17 inches per year, runs off and is not available to recharge the bedrock aquifers. Only a small percentage of the total annual I precipitation recharges the aquifers. The total quantity of natural recharge to the aquifers was estimated by I Romero (1916) to be approximately 120,000 af per year. Recently, the USGS estimated that under steady-state conditions, where inflow to the aquifers I equals outflow, the recharge to the aquifers in the basin is approximately 40,000 af per year. I Discharge from the aquifers occurs naturally through seepage and springs where the potentiometric surface lies above the elevation of the outcrop, and I by vertical leakage to underlying and/or overlying aquifers. Artificial discharge occurs when water is pumped from wells tapping the aquifer. In a I steady-state situation, discharge will equal recharge. In the Denver basin, however, discharge probably exceeds recharge because of well development I (artificial discharge). I 2. '1.2.1.2 Occurrence of Ground Water Most of the aquifers in the Denver basin contain ground water under artesian conditions. Along the edges of the basin, where the aquifer outcrop, I the ground water is under water table conditions. Storage coefficients 1/ under artesian conditions range from 0.0002 to 0.0008, and water table I conditions they generally range from 0.10 to 0.20 for the aquifers in the I Denver basin. I I 1/ The storage coefficient, which is usually expressed as a dimensionless dec:imal fraction, represents the quantity of water released from or added to I storage under a unit surface area of an aquifer per unit change in head. I C-3 I 2.1.2.2 Extent of Development I The extent of the ground water development in the Denver basin is difficult to accurately estimate. For the preparation of the SEIS a search I was made of the well permits and water right decrees filed with the State Engineers Office. This search showed that the amount of water that legally could be discharged from the Denver basin fee wells (wells used for purposes I other than stock or domestic. ~ater) is approximately 164,000 af per year. This estimate includes all absolute and conditional water rights and assumes I continuous pumping for 24 hours per day with no annual restriction of diversions from fee wells with decreed pumping rates only. I As reported in the SEIS, the USGS estimated that in 1978, 26,788 af per I year were pumped annually from the basin by wells. The amount of ground water pumping from the basin probably has increased since 1978; however, estimates of present-day pumpage cannot be made because the necessary data are not I available. Within the Denver Metropolitan area, as of 1982, about 126,000 af per year of absolute and conditional water rights existed. I Estimates of available supply were determined for the SEIS. These I estimates were made in accordance with Colorado law which allows withdrawal of that amount of non-tributary ground water which would deplete the aquifer in I 100 years, assuming no recharge. Based on the principle of annually producing 1 percent of the volume of recoverable water in that portion of the aquifer underlying the well field, the unappropriated ground water was computed I according to procedures for ground water administration under Colorado law. These estimates are based on specific yields; aquifer thicknesses, and I existing water rights. I Available ground water was determined for the areas under the future municipal boundaries as estimated by the Denver Regional Council of I Governments for the year 2000. Boundaries of several municipalities were extended beyond existing incorporated boundaries. A preliminary estimate of the annual ground water yield under future projected Denver metro municipal I boundaries is provided in Table C.l. I I C-4 I I I TABLE C.1 I Annual Yield of Unappropriated ftteJ Beneath Municipal Boundaries - ~ Annual Yield (acre feet) Arvada 12,546 Aurora 30,155 Broomfield 2,675 Castle Rock . 9,677 Denver 45,539 Glendale 175 Golden 1,671 It Lafayette 625 Lakewood }/ 9,358 Littleton 12,191 I~ Louisville 909 Sheridan 786 Thornton 6,642 Westminster 8,835 It Wheat Ridge 3,223 II Total 145,007 II Il II It I 1/ The tributary or nontributary status of water beneath each municipality must be determined by a detailed, site-by-site investigation. For purposes of II this report, all aquifers are considered nontributary. 21 Excerpted from Metropolitan Denver Water Supply ErS, Appendix 4C, If Volume 11. }/ Lakewood claims all unappropriated ground water beneath its 1980 I boundaries in Colorado Water Court Case No. 79CW368. Ii C-5 I 2.1.2.3 Description of Aquifers I The amount of water stored in the four aquifers in the Denver basin was estimated in the SEIS. The estimated amounts are provided in Table C.2. As I of 1982, approximately 7.2 percent of this total amount was decreed and permitted. 'I TABLE C.2 I Water in storage in Denver Basin Aquifers I Volume Water in Storage Aguifer (cubic feet) SQecific Yield 11 (af) I Dawson 6.42 x 10 12 0.20 29,500,000 Denver 1.27 x 10 13 0.15 43,700,000 Arapahoe 2. 1 x 10 13 0.15 72,300,000 ,I Laramie-Fox Hills 2;36 x 10 13 0.15 81 z300 z000 Total 226,800,000 I Most of this water is not available within or near the municipal boundaries where the greatest demand occurs. This water could either be developed as cities expand or by constructing satellite well fields. I The SEIS provides a detailed description of each of the Denver Basin I aquifers. The following aquifer descriptions were extracted from the SEIS. I 2.1.2.3.1 Laramie-Fox Hills Aquifer The Laramie-Fox Hills aquifer, the deepest of the major bedrock aquifers I within the Denver basin, is also the most extensive, covering the largest area of the basin. The sandstone layers of the aquifer are generally separated by I 5 to 20 ft of shale. In some areas, however, the aquifer consists of a relatively unbroken sequence of sandstones. I I .!I Specific yield, which is usually expressed as a dimensionless decimal fraction is the quantity of water that a unit volume of an aquifer will yield when drained by gravity. C-6 I The aquifer is artesian throughout most of the basin; however, water-table conditions exist near its outcrop. The upper and lower confining beds are the upper part of the Laramie Formation and the Pierre Shale, respectively. The thiekness of the aquifer ranges up to about 400 ft and averages about Ii 200 ft. Depth to the base of the aquifer ranges from 0 ft at the outcrop to about 3,200 ft near Larkspur, Colorado. I The hydraulic properties of the aquifer indicate that the aquifer is a good to excellent source of water. Transmissivity values 11 , a measure of how I much water an aquifer can transmit, range from 7,500 gallons per day (g.p.d.) per foot in the Englewood-Littleton areas to 75 g.p.d. per foot in the I northwestern part of the aquifer near Golden, Boulder, and Longmont. An average value of 525 g.p.d. per foot can be considered representative for most I of the aquifer. Storage coefficient values of 0.0002 to 0.0008 are representative of artesian conditions in the aquifer and specific yields II ranging from 0.15 to 0.20 are typical. The estimated amount of water stored in the Laramie-Fox Hills aquifer is I based on planimetric measurement of the saturated sandstones as presented in Robson et al. (1981). Using a specific yield of 0.15, approximately I 81,300,000 af of water are estimated to be stored in the aquifer. I The direction of ground water flow is genel"ally to the north in the northern sec"tion of the basin, but is southerly in the extreme southern section of the basin. Flow is away from the eastern and western edges of the I basin, indicating local recharge to the aquifer. At the southern and northern edges, local discharge occurs from the aquifer. Leakage from the overlying I aquifers contributes to water in the Laramie-Fox Hills aquifer. In the southern section of the basin, leakage is sufficient to cause a ground water II mound in the aquifer and a radiating ground water flow pattern. I 11 Transmissivity is the volume of water that will flow horizontally through a 1-foot-wide vertical strip of the full saturated thickness of an aquifer I under a unit flow gradient. It is usually expressed as gallons per day per foot and it relates closely to the rate at which water will be pumped from a I well at a given drawdown. II C-1 I Water quality information for water from the Laramie-Fox Hills aquifer I indicates that the water is more heavily mineralized than that from the other aquifers. Water from the aquifer is classified as a sodium bicarbonate type I because of the preponderance of sodium and bicarbonate ions. 2.1.2.3.2 Arapahoe Aquifer I The Arapahoe aquifer is generally 500 to 600 ft thick and is comp?sed predominantly of sandstones and congomerates with interbedded shales. Depth I to the base of the Arapahoe aquifer ranges from 0 ft at the outcrop to 2,600 ft southeast of Larkspur. Water obtained from the aquifer is of good to I excellent quality. I The Arapahoe aquifer is under artesian pressure except in its outcrop area. The lower confining layer is the upper part of the Laramie Formation and the upper confining layers are the shales of the upper part of the I Arapahoe Formation. Typical transmissivity values range from 375 g.p.d. per foot n~ar the margins of the aquifer to as much as 16,000 g.p.d. per foot in I the southern Denver metropolitan area. Storage coefficient values of 0.0002 to 0.0008 are representative for confined areas of the aquifer and specific I yields of the aquifer range from 0.15 to 0.20. I The amount of water stored in the Arapahoe aquifer was calculated using planimetric measurements from the sand thickness map in Robson et ale (1981a). Using a specific yield of 0.15, approximately 72,300,000 af of water I are calculated to be stored in the aquifer. I The direction of ground water flow in the Arapahoe aquifer is approximately the same as in the Laramie-Fox Hills aquifer. The general direction of flow is primarily toward the northern and secondarily toward the southern edges of the aquifer. Vertical leakage which, in part, controls the direction of ground water flow, contributes significant quantities of recharge water to the aquifer. 2.1.2.3.3 Denver Aquifer The best water-bearing strata in the Denver aquifer are located in the lower half of the aquifer. Where the permeable producing layers of the Denver c-8 I I aquifer are most developed, they comprise a 100- to 150-ft-thick series of I sandstones interbedded with thin shales. 'Transmissivity values reported by the USGS for the Denver aquifer range I from 400 g.p.d. per ft in areas near the aquifer margins to 3,000 g.p.d. per ft in the southern part of . the basin. The higher values occur in \ 0.1~5, with 0.15 being the usual value throughout the entire aquifer. The I amOllnt of water stored in the Denver aquifer was calculated using planimetric measurements of aquifer areas derived from the sand thickness map in Robson I and Romero (1981b). Using a specific yield of 0.15, 43,700,000 af of water are estimated to be stored in the Denver aquifer. I The general ground water flow direction is north but a small part of the aquifer has a southerly flow direction. Near the edges of the basin, the 'I aquifer is not completely saturated or has been drained. In some part of the I basin, streams are often in contact with the aquifer. 2.1.2.3.4 Dawson Aquifer I The principal water-bearing horizon of the Dawson aquifer occurs in the lowler part of the formation. Water-bearing sands in the upper part are not as Ii well developed as in the lower half, and are commonly drained and only partially saturated. Depths to' the base of the aquifer are as much as 1,000 ft in the south and southwest central portions of the basin. The I aquifer thins to the north and west and is absent in the north and west I portions of the Denver basin. USGS data indicate that transmissivity values for the Dawson aquifer can I be as high as 9,000 g. p. d . per foot in an area just north of the Black Forest. Near the margins of the aquifer, however, transmissivity values are I lower, and vary between 375 to 750 g.p.d. per foot. Transmissivity values range from 2,200 to 4,500.g.p.d. per ft throughout most of the aquifer. Storage coefficient values for the confined portions of the aquifer range from I 0.0002 to 0.0006, while a specific yield of 0.20 is considered I repr'esentative. Based on planimetric measurements for the aquifer from Robson I C-9 I and Romero (1981), and a specific yield of 0.20, approximately 29,500,000 af I of water are stored in the aquifer. I The direction of ground water flow is mostly to the north. There is a small southerly flow component in the southern part of the basin caused by a recharge mound in the aquifer. In parts of the basin where a stream or river I is in direct contact with the aquifer, ground water in the aquifer often flows toward the stream. I I I I I I I I I I I I I I C-10 I I I SOURCE: U.S.G.S. ATLAS HA-650 I I I I I I I I I I I I I o 25 50 75 100 MIL E S I LEGEND COLORADO WATER RESOURCES [JfiZJ DENVER BASIN AND POWER DEVELOPMENT AUTHORITY I .. CLEAR CREEK PROJECT ~ CLEAR CREEK BASIN LOCATION OF DEN VER BASIN I ~ STUDY AREA AND CLEAR CREEK BASIN TUDOR ENGINEERING COMPANY SOURCEi SEIS, APPE NO'IX 4 B CMIIIY&. ••••• '''1.1._ ... C-ll WOOO •••• -CL 'DI CO.,ULI ... r, WI" t •• ''''''.O_III, .. I&L...... , .... tltC, I DATE: DECEMBER 1986 FIGURE C.I ... II) A ~ A' ELEV. 0:: ELEV. LEAR CREEK ~ 7000' 7000!., STUDY AREA 0 III a. C .&: .><... 6000' o 600d ~ ~WOO' 5000' 4000' 4000' Fox-Hilla Sandatone Pierre Shale EOlt I 3000' 3000' W"d 8 CROSS SECTION A - A' 8' n ELEV. ELEV. I t-' 8000' N r8000' 7000' 6000' Greeley~ _ South Platte Rlve~ooo' ~ . 4000' Pierre Shale Fox-Hilla Sandstone South North CROSS SECTION 8 - 8' COLORADO WATER RESOURCES o 5 10 15 20 Miles I I I I I AtiD I'OW[R O[VELOf'MElH AUTIIORITY Vertical Exaggeration X32 CLEAR CREEK PROJECT Nat ional Geodet leVer Ileal Datum of 1929 GENERALIZED GEOLOGIC SECTIONS THROUGH DENVER BASIN TUDOR EIIGItIHRING COMPANY 'IItHH .. '1"'" '''''''''1111.... • ooO ...... O .. tL'I.I' ",1H,UI..)".I' SOURCE; SEIS, APPENDIX 4B •• "'~k .....II"U,...... L .... LI.II, tK. Appendix 0 PROJECTS ELIMINATED IN THE INITIAL SCREENING I I APPENDIX D I PROJECTS ELIMINATED IN THE INITIAL SCREENING 1.1 INTRODUCTION I Descriptions of the five projects eliminated in the initial project scrl~,ening _are included in this Appendix. These eliminated projects include: Nor'1:;1h Clear Creek, Guy Gulch, Soda Creek, Fall River, and Pine Ridge. "These I project descriptions include a geotechnical overview of each dam and reservoir site, a description of principal project features, and preliminary project I cost: estimate. I A general description of all twelve alternative storage sites, the basis for project layouts and cost estimates, a location map of the alternative I proJects, and descriptions of the seven projects which survived the initial screening are given in Section 8.0 of the Final Report. The project screening I process is described in Section 12.0 of the Final Report. I 1.2 NORTH CLEAR CREEK PROJECT 1 .2. 1 General I The North Clear Creek damsite is located on North Clear Creek applroximately one mile upstream from its confluence with Clear Creek. Major I features of this project include a concrete faced rockfill dam, a tunnel type spillway, a selective level outlet works, construction diversion works and the relocation of 6 miles of Route 119. A diversion dam on Clear Creek and a I 21,000 ft. long supply tunnel will be constructed to divert main stem Clear Creek water to the North Fork Reservoir. The location of the project I features is shown on Figure D.1. The dam layout and reservoir capacity data for the North Clear Creek Project are shown on Figure D.2. Physical features I of the project are summarized on Table D.1. I 1.2.2 Geotechnical Overview The rock units mapped at the North Clear Creek site are Precambrian crys talline rocks comprising fine- to coarse-grained, layered gneisses and I gran i te, which have been highly deformed. The layer ing generally str ikes east.-·west and dips to the north. Quaternary alluvium is mapped in the valley I bott.om. I D-1 I I The Blackhawk Fault zone trends northwest-southeast through the dam site and part of the reservoir area, as shown on Figure 7.1 of the Final Report. I The fault zone is mapped as a single trace to a zone about 200 feet wide of brecciated and altered rock. The Blackhawk Fault is not considered by the Colorado Geological Survey to be a potentially active fault. However, it may I provide a zone for migration of water downstream away from the site and should be considered in pre-feasibility designs since it extends not only beneath the '1 dam but extends along nearly the full length of the reservoir. The potential effects of the fault zone on the dam foundation and construction will require I significant additional study. Although concrete dams cannot be ruled out at this time, this site does I not appear as favorable for them as the other canyon sites since the valley walls are flatter, appear more weathered, and the Blackhawk Fault zone passes I through the damsite. The foundation at the site does however appear suitable for an earth or earth-rock dam. Since the abutments are generally soil I covered and the fault zone passes through the damsite, a moderate depth cutoff will be needed and the thin soil layer will need to be stripped from beneath I the dam. Blanket and curtain grouting may be needed beneath the dam and in the fault zone. I Fine-grained soils for earth or earth-rock dam core construction are likely not available in sufficient quantities locally. Weathered rock or rock I that breaks down to a fine-grained soil may be available from the fault zones. Rock for constructing an earth-rock dam could likely be quarried from I within the reservoir area, as could materials for upstream slope protection and processing into drain materials. I 1.2.3 Project Description I A concrete faced rockfill dam was selected for the basis of layouts and cost estimates. A concrete faced design was used in lieu of impervious core design because of the lack of information concerning availability of I impervious core borrow. A typical cross-section of the dam is shown on Figure 8.5 of the Final Report. I I D-2 I I I The outlet works is planned as a cut and cover conduit constructed at the right abutment of the dam. The intake structure will have selective level I reservoir withdrawal capabilities. A control house with the outlet works regulating gates will be constructed at the downstream toe of the dam. The I hydraulic capacity of the outlet works was sized to provide a minimum discharge of 1000 cfs at min~ pool elevation 7185. This hydraulic capacity. is sufficient to meet the State Engineer's reservoir. evacuation guidelines and I the maximum anticipated downstream demand requirements. I 'rhe spillway will be a tunnel-type structure located at the right abutment of the.dam, the control structure will be an ungated side channel spillway. I The inclined tunnel chute and the downstream portion of the diversion tunnel will be sized to 35 ft. diameter for use as the downstream portion of the I spillway tunnel. The tunnel spillway design at this site eliminates the need for large open cuts that would be required for an open chute type spillway. I This project will require a supply tunnel to divert water from the main stem of Clear Creek to the North Fork Reservoir. This tunnel will be I approximately four miles long and will have an inside diameter of 18 feet. A concrete dam and gate tunnel headworks will be constructed on the mainstem of I Clear Creek to divert water to the supply tunnel. The diversion dam will be appr.oximately 40 ft. high and will be an ungated concrete overflow I structure. The locations of principal project features are shown on Figure D.1. I I I I I I I D-3 I TABLE D.1 I North Clear Creek Project I Reservoir: I Maximum W.S. El. 7438 ft. Maximum Operating W.S. El. 7415 ft. Minimum Operating W.S. El. 7185 ft. Total Storage at Maximum Operating W.S. El. 65,000 af I Surface Area at Maximum Operating W.S. El. 450 ac. Dam: I Type Concrete Faced Rockfill I Crest Elevation 7445 ft. Crest Length 1850 ft. Maximum Height Above Streambed 445 ft. Dam Volume 10,500,000 yd3 I River Bed Elevation 7000 ft. Spillway: I Crest Elevation 7415 ft. Crest Length 200 ft. Capacity 85,000 cfs I Outlet Works: I Type Selective Level Withdrawal Conveyance Cut and Cover Conduit I Control Gates Jet-Flow Gates Diversion During Construction: Tunnel Left Abutment I Roads: I Road Relocation - Route 119 6 miles Clear Creek-North Clear Creek Tunnel: .1 Type Concrete Lined Length 21,000 ft. Diameter 18 ft. I Roads: I Road Relocation - Route 119 6 miles I D-4 I I I 1.2.,~ Relocations Required I 'TIhe North Clear Creek reservoir will require relocation of approximately 6 miles of Route 119. Replacement highway will be designed to meet state I requirements for road width, grade, and climbing lanes as discussed in Section 10.0 of the Final Report. Permanent aCGess to the dam will be provided from Route 6 by existing Route 119. The reservoir will inundate I several buildings and abandoned mining operations. I 1.2.5 Preliminary Cost Estimate The total construction cost of the North Clear Creek project was estimated I at $353,330,000. The project costs are at the January 1981 price level and include allowances for land, engineering and contract administration, and I contingencies. The total investment cost of the project was estimated to be $418,330,000 which includes allowance for interest during construction and financing expenses. The preliminary cost estimate is summarized in I Table D.2. I I I I I 'I I I I I D-5 I TABLE D.2 I Preliminary Cost Estimate North Clear Creek Project I Project Feature Cost I Land Acquisition $ 1,250,000 Diversion During Construction 2,890,000 Foundation Treatment 10,500,000 I Dam (including concrete facing) 99,250,000 Spillway 11,300,000 Outlet Works 4,610,000 I Clear Creek Diversion Dam 8,000,000 Clear Creek-North Fork Tunnel 33,650,000 Road Relocations 52,000,000 I Miscellaneous Items (5~) 22,340,000 Subtotal Construction Cost 245,790,000 I Contingencies (25~) 61 ,450,000 Direct Construction Cost 307,240,000 I Engineering and Administration (15~) 46,090,000 Total Construction Cost 353,330,000 I Interest During Construction (8~ over 5 yrs.) 77 z730 z000 I Total Capital Cost 431,060,000 Debt Service Reserve Fund 42,490,000 I Financing Expenses 4 z780 z000 Total Investment Cost 478,330,000 I Annual Costs I Debt Service 42,490,000 Annual O&M 4,780z000 I Total $ 47,270,000 I I I D-6 I I I 1.3 GUY GULCH PROJECT I 1. 3. 1 General The Guy Gulch damsite is located on Guy Gulch 1.5 miles upstream from its I confluencB with Clear Creek. Major features of this project include a roller compacted concrete gravity dam with ungated central overflow spillway, selective level withdrawal outlet works, and construction diversion works. I Approximately six miles of supply tunnel and pipeline will be required to - divert water from Clear Creek to the Guy Gulch Reservoir. The project plan is I shOlofn on Figure 0.3. The dam layout and reservoir capacity data for the Guy Gulch project are shown on Figure 0.4. Physical. features of the project are I summarized on Table 0.3. I 1.3.·2 Geotechnical Overview 'The lower Guy Gulch site is located in Precambrian gneiss bedrock. The foliation of the layers of quartz and feldspar, and mica and hornblende I strikes generally east-west and dips steeply to vertically. The site was not I visited during the site reconnaissance due to access limitations. The major geologic structure at the site is the Junction Ranch fault zone, I which is mapped as four distinct fault traces. The rocks at the damsite can be expected to be highly fractured, closely jointed and probably sheared I across a zone that may be 1500 feet wide. The fracturing could provide a zone where water could migrate away from the reservoir. This fracturing may also I affect the strength of the rock in the dam foundation area. Soils for earth dam construction or use in the core of an earth-rock dam I ate not likely available locally. Quarried and/or crushed rock from the reservoir area could likely be used for rock shells, concrete aggregate, or I upstream slope protection. I 1 .3.3 Project Description The site is located in a relatively wide canyon with foundation conditions suitable for the construction of either a concrete gravity, earthfill, or I rockfill dam. A roller-compacted concrete gravity dam was selected at this I level of study because of the local availability of construction material. I 0-7 I This selection will be reconsidered when more site specific geotechnical I information concerning borrow and foundations is obtained. The dam will be 500 ft. high and will have a crest length of 2000 ft. I The outlet works will have a hydraulic capacity of 1000 cfs at the minimum operating pool elevation 7020. This hydraulic capacity is sufficient to meet I the State Engineer's reservoir evacuation guidelines and meet anticipated downstream release demands. The outlet conduit will be a concrete encased I steel pipe. The outlet works intake structure will be capable of selective level reservoir withdrawals for water quality control. The outlet works I control house will be located downstream of the toe of the dam and will house the outlet works regulating gates and controls. I An ungated spillway will be located at the central portion of the dam. The spillway crest will be at elevation 7200 and the length of spillway crest I will be 300 feet. The spillway crest, chute, and walls will be constructed of conventional structural concrete. The spillway was sized to pass the PMF I while providing approximately two feet of freeboard to the dam crest. Freeboard from normal pool elevation 7200 to the dam crest is approximately 10 I feet. I Facilities for diversion of the river during construction will consist of upstream and downstream cofferdams on Guy Gulch and a concrete encased diver sion conduit located at the left abutment of the dam. I This project will require a supply tunnel to divert water from Clear Creek I to the Guy Gulch Reservoir. This tunnel will be approximately 30,000 feet long and will have an inside diameter of 18 feet and a pipe line crossing will I be required over North Clear Creek. A concrete dam and gate tunnel headworks will be constructed on Clear Creek to divert water to the supply tunnel. The I diversion dam will be approximately 40 ft. high and will be an ungated concrete overflow structure. The locations of principal project features are shown on Figure D.3. I I I D-8 I I I TABLE D.3 I Guy Gulch Project I Reservoir: Maximum W.S. El. 7208 ft. Maximum Operating W.S. El. 7200 ft. I Minimum Operating W.S. El. 7020 ft. Total Storage at Maximum Operating W.S. El. 35,000 af _ Surface Area at Maximum Operating W.S. El. 200 ac. I Dam: Type R.C.C. Gravity I Crest Elevation 7210 ft. Crest Length 2000 ft. Maximum Height Above Streambed 500 ft. I Dam Volume 2,800,000 yd3 River Bed Elevation 6710 ft. I Crest Elevation 7200 ft. Crest Length 300 ft. I Capacity 27,000 cfs I Outlet Works: Type Selective Level Withdrawal Conveyance Concrete Encased I Conduit Control Gates Jet-Flow Gates I Roads: Access road from Route 6 to dam 2 miles I Diversion During Construction: Concrete Encased Cut and Cover I Conduit Clear Creek-Guy Gulch Tunnel: Type Concrete Lined I Length 30,000 ft. Diameter 18 ft. I I I D-9 I 1.3.4 Relocations Required I This project will require minor relocation of Route 6 at the diversion dam. No other major relocations are anticipated for this project. I 1.3.5 Preliminary Cost Estimate The total construction cost of the Guy Gulch project was estimated at I $258,420,000. The project costs are at the January 1987 price level and include allowances for land, engineering and contract administration, and I contingencies., The total investment cost of the project was estimated to be $349,850,000 which includes allowance for interest during construction and I project financing costs. The preliminary cost estimate is summarized in Table D.4. I- I I I I I I I I I I I D-10 I I I TABLE D.4 I Preliminary Cost Estimate Guy Gulch Project I Project Feature Cost Land Acquisition $ 630,000 I Diversion During Construction 550,000 Foundation Treatment 4,300,000 Dam 96,120,000 I Spillway 3,500,000 Outlet Works 2,310,000 Clear Creek Diversion Dam 8,000,000 I Road Relocation 4,600,000 Clear Creek-Guy Gulch Tunnel 51,200,000 Miscellaneous Items (5%) 8,560,000 I Subtotal Construction Cost 179,170,000 I Contingencies (25%) 44,940,000 Direct Construction Cost 224,710,000 I Engineering and Administration (15%) 33 z710 z000 Total Construction Cost 258,420,000 I Interest During Construction (8% over 5 yrs.) 56 z850 z000 I Total Capital Cost 315,270,000 Debt Service Reserve Fund 31,080,000 I Financing Expenses 3 z500 z000 Total Investment Cost 349,850,000 I Annual Costs I Debt Service 31,080,000 Annual O&M 3z500,000 I Total $ 34,580,000 I I I D-11 I 1.4 SODA CREEK PROJECT I 1.4.1 General Soda Creek damsite is located on Soda Creek approximately one mile south I of Idaho Springs. The Indian Springs Resort hot springs is located along Soda Creek approximately 3/4 mile downstream of the proposed damsite. Major I features of this project include a 400 foot high roller compacted concrete dam with ungated central overflow spillway, selective level withdrawal outlet I works, and a supply tunnel to divert water from Clear Creek to the reservoir. The project layout is shown on Figure D.5. The dam layout and I reservoir capacity data for the project are shown on Figure D. 6. Physical features of the project are summarized on Table D.5. I 1.4.2 Geotechnical Overview The bedrock at the Soda Creek site is a Precambrian gneiss conSisting of I highly distorted layers of quartz and feldspar, and mica and hornblende. The bedrock visible at the surface has joint spacings varying from several inches I and about one foot. The Idaho Springs fault zone crosses the area just down stream (north) of the dam site and then trends up the Little Bear Creek Valley I as shown on Figure 7.1 of the Final Report. The geotechnical conditions along the faul t zone are unknown. I The exact location of the fault and its condition will be important in the dam siting. In addition, several adits are mapped in the reservoir area. I These mining activities and the fault may represent locations where water could exit the reservoir. The extent of the mining activity and faulting at I the site should be studied in further detail during later stages of planning and design. I The gneisses and granites should provide adequate foundation support for I any of the dam types being considered. Alluvial soils in the valley bottom should be thin. Rock is exposed over the majority of the abutments, weathering is therefore likely to moderate depth. The joints generally I appeared closed and tight; however, some joints in the canyon are making water. Assumptions for cost estimates assume blanket grouting will be I required for the entire dam foundation. A single line of deep curtain grouting was also assumed for the project cost estimates. I D-12 I I I Some soils may be available for earth dam construction or use in the core I of ill) earth-rock dam; however, it is not likely that there is enough material for either type structure. Therefore, these materials would have to be hauled I to the site. Quarried and/or crushed rock from the reservoir area could likely be used for rock shells, concrete aggregate, or upstream slope I protection. 1.4.3 Project Description I The site is located in a relatively wide canyon with foundation conditions suitable for the construction of either a concrete gravity dam, earthfill or I rockfill dam. A roller-compacted concrete gravity dam was selected at this level of study because of the local availability of construction materials for I the production of R.C.C. The proposed dam would be 400 ft. high with a crest length of 2100 ft. I The outlet works is sized to provide a hydraulic capacity of 1000 cfs at the minimum operating pool elevation 8000. This hydraulic capacity is I sufficient to meet the State Engineer's reservoir evacuation guidelines and meet anticipated downstream release demands. The outlet conduit will be a I concrete encased steel pipe. The outlet works intake structure will be capable of selective level reservoir withdrawals for use in water quality I control. The outlet works control house will be located downstream of the toe of the dam and will house the outlet works regulating gates and controls. I An ungated spillway will be located at the central portion of the dam. The spillway crest will be at elevation 8200 and the length of spillway crest I will be 150 feet. The spillway is capable of passing the PMF while providing approximately five feet of freeboard to the dam crest. Freeboard from maximum I operating surface elevation 8200 (spillway crest) to the dam crest is 20 feet. I This project will require a supply tunnel to divert water from Clear Creek I to the Soda Creek Reservoir. This tunnel will be approximately 7.4 miles long and will have an inside diameter of 15 feet. A concrete dam and gate tunnel I headworks will be constructed on Clear Creek to divert water to the supply I D-13 I tunnel. The diversion dam will be approximately 40 ft. high and will be an I ungated concrete overflow structure. The locations of principal project features are shown on Figure D.5. I Facilities for diversion of the river during construction will consist of upstream and downstream cofferdams on Soda Creek and concrete encased diver I sion conduit located at the right abutment of the dam. I I I I I I I I I I I I I I D-14 I I I TABLE D.5 I Soda Creek Project Project Data I Reservoir: ----Maximum W. S. El. 8215 ft. Maximum Operating W.S. El. 8200 ft. I Minimum Operating W.S. El. 8000 ft. Total Storage at Maximum Operating W.S. El. 35,000 af Surface Area at Maximum Operating W.S. El. 275 ac. I Dam: Type R.C.C. Gravity Crest Elevation 8220 ft. I Crest Length 2100 ft. Maximum Height Above Streambed 400 ft. Dam Volume 1,660,000 yd3 I River Bed Elevation 7820 ft. Spillway: Crest Elevation 8200 ft. I Crest Length 150 ft. Capacity 33,000 cfs I Outlet Works: Type Selective Level Withdrawal I Conveyance Concrete Encased Conduit Control Gates Jet Flow I Diversion During Construction: Concrete Encased Cut and Cover I Conduit Clear Creek-Soda Creek Tunnel: Type Concrete Lined I Length 39,000 ft. Diameter 15 ft. Roads: I Relocation of Soda Creek Road 3.3 miles I 1.4.4 Relocations Required Relocation will include 3.3 miles of Soda Creek Road, approximately ten I residences inundated by the proposed reservoir, and a municipal land fill. I I I 1.4.5 Preliminary Cost Estllnate I The total construction cost of the Soda Creek project was estllnated at $167,700,000. The project costs are at the January 1987 price level and include allowances for land, engineering and contract administration, and I contingencies. The total investment cost of the project was estimated to be $227,030,000 which includes an allowance for interest during construction and I financirig-expenses. A preliminary cost estllnate for the project is summarized in Table 0.6. I I I I I I I I I I I I I I D-16 I I I TABLE D.6 Preliminary Cost Estimate I Soda Creek Project I Project Feature Cost Land Acquisition $ 1,500,000 I Diversion During Construction 400,000 Foundation Treatment 3,320,000 Dam 58,030,000 Spillway 1,750,000 I Outlet Works 2,150,000 Road Relocations 2,900,000 West Fork Diversion Dam 8,000,000 I Clear Creek-Soda Creek Tunnel 33,050,000 Miscellaneous Items (5%) 5 1 560 1 000 I Subtotal Construction Cost 116,660,000 Contingencies (25%) 29 1 170,000 I Direct Construction Cost 145,830,000 I Engineering and Administration (15%) 21,870,000 Total Construction Cost 167,700,000 I Interest During Construction (8% over 5 yrs.) 36,890,000 Total Capital Cost 204,590,000 I Debt Service Reserve Fund 20,170,000 I Financing Expenses 2,270,000 Total Investment Cost 227,030,000 I Annual Costs Debt Service 20,170,000 I Annual O&M 2,270,000 I Total $ 22,440,000 I I I D-17 I L5 FALL RIVER PROJECT I L5.1 General The Fall River damsite is located approximately two miles west of Idaho I Springs and one-half mile upstream from Fall River's confluence with Clear Creek. Major features of this project include a roller compacted concrete I gravity dam with ungated central overflow spillway, selective level withdrawal outlet works, and a supply tunnel to divert water from Clear Creek to the Fall I River Reservoir. The project plan is shown on Figure D.7. The dam layout and reservoir capacity data for the Fall River project are shown on Figure D.8. I Physical features of the project are summarized on Table D.7. I 1.5.2 Geotechnical Overview The rock units mapped at the Fall River site are Precambrian gneisses and Tertiary granodiorite. All of the rock units are medium- to coarse-grained I crystalline rocks. The foliations of the layered gneisses strike northeast and dip 20° to 40° to the west. Young alluvium, including some reworked I glacial debris, occurs in the valley bottom. Numerous veins, which may be mineralized, are also mapped in the area. Mining activities may be associated I with the veins. I The Idaho Springs Fault is mapped downstream of the right abutment. The fault trends northwest away from the site as shown on Figure 7.1 of the Final Report. The Colorado Geological Survey does not consider the Idaho Springs I Fault to be potentially active. I The Lucania mine workings are located in the left abutment area of the dam site. The workings include a tailings pile and adits. Both the fault and the I mining may provide passageways for water away from the reservoir site. Specific studies to evaluate the mine workings will be necessary during later I stages of planning and design. The gneisses and granodiorite should provide adequate foundation support I for any of the dam type. Alluvial soils in the valley bottom should be thin. On the steep right abutment, the depth of significant weathering should I also be thin. The depth of weathering on the left abutment is also likely to I D-18 I I I be moderate. The joints generally appeared closed and tight; however, some joints in the canyon are making water, consequently for pre-feasibility grade I cost estimates, it was assumed that blanket grouting will be required over the entire dam foundation. A single line of deep curtain grouting was also I asslwed for the project cost estimates. Soils for earth dam construction or use in the core of an earth-rock dam are not likely available in the reservoir area. A source for this material may exist up Fall River Canyon approximately ten miles at glacial morraine and outl-wash deposits. Local quarried and/or crushed rock could likely be used for rock shells, concrete aggregate, or upstream slope protection. 1.5.3 Project Description The site is located in a relatively wide canyon with foundation conditions suitable for the construction of either a concrete gravity, earthfill, or rockfill dam. A roller-compacted concrete gravity dam was selected at this level of study because of the local availability of material for R.C.C. construction, the use of the center overflow spillway, and the favorable If foundation conditions. The dam would be 455 ft. high with a crest length of it 1800 ft. The outlet works will have a hydraulic capacity of 1000 cfs at the minimum II operating pool elevation 8023. The outlet works intake structure will be capable of selective level reservoir withdrawals for water quality control. The outlet conduit will be a concrete encased steel pipe. The outlet works I~ control house will be located downstream of the toe of the dam and will house II the outlet works regulating gates and controls. An ungated spillway will be located at the central portion of the dam. II The spillway crest will be at elevation 8215 and the length of spillway crest will be 150 feet. The spillway was sized to pass the PMF while providing II approximately one foot of freeboard to the dam crest. Freeboard from normal pool elevation 8215 (spillway crest) to the dam crest is 20 feet. II This project will require a supply tunnel to divert water from Clear Creek I to the Fall River Reservoir. This tunnel will be approximately five miles II D-19 I long and will have an inside diameter of 18 feet. A concrete dam and gate I tunnel headworks will be constructed on Clear Creek to divert water to the supply tunnel. The diversion dam will be approximately 40 ft. high and will be an ungated concrete overflow structure. Location of principal project I features are shown on Figure D.7. I Facilities for diversion of the river during construction will consist of upstream and downstream cofferdams on Fall River and a concrete encased diver I sion conduit located at the right abutment of the dam. I I I I, I I I I I I I I I D-20 I I I TABLE D.7 I Fall River Project ----Reservoir: I· Maximum W.S. El. 8234 ft~ Maximum Operating W.S. EI. 8215 ft. Minimum Operating W.S. EI. 8023 ft'. I Total Storage at Maximum Operating W.S. EI. 45,000 af Surface Area at Maximum Operating W.S. EI. 270 ac. Dam: Type R.C.C. Gravity Ii Crest Elevation 8235 ft. ,Crest Length 1800 ft. Maximum Height Above Streambed 455 ft. I Dam Volume 2,000,000 yd3 River Bed Elevation 7780 ft. I, Spillway: Crest Elevation 8215 ft. Crest Length 150 ft. I Capacity 47,000 cfs Outlet Works: Type Selective Level I Withdrawal Conveyance Concrete Encased Conduit I) Control Gates Jet Flow Diversion During Construction: Concrete Encased Cut and cover I Conduit Clear Creek-Fall River Tunnel: Type Concrete Lined I Length 27,000 ft. Diameter 18 ft. Roads: I Relocation of Fall River Road 5.5 miles I 1.5.4 Relocations Required Relocation will include 5.5 miles of Fall River Road. The reservoir I inundates approximately thirty residences and the abandoned Lucania Mine. I I I D-21 I 1.5.5 Preliminary Cost Estimate I The total construction cost of the Fall River project was estimated at $187,630,000. The project costs are at the January 1987 price level and include allowances for land, engineering and contract administration, and I contingencies. The total investment cost of the project was estimated to be $254,010, QOO which includes allowance for interest dur ing construction and I financing expenses. The preliminary cost estimate for the project. is summarized in Table D.8. I I I ,I I I II I I I I I I I D-22 I I I TABLE D.8 Preliminary Cost Estimate I Fall River Project I Project Feature Cost Land Acquisition $ 1,500,000 I Diversion During Construction 550,000 Foundation Treatment 3,450,000 Dam 69,890,000 Spillway 1,750,000 I Outlet Works 2,230,000 Road Relocations 3,900,000 Clear Creek Diversion Dam 8,000,000 It Clear Creek Fall River Tunnel 33,050,000 MisC!ellaneous Items (5%) 6,220,000 I Subtotal Construction Cost 130,530,000 Contingencies (25%) 32 z630 z000 If Direct Construction Cost 163,160,000 II Engineering and Administration (15%) 24 z410 1 000 Total Construction Cost 187,630,000 II Interest During Construction (8% over 5 yrs.) 41 1 280 1 000 Total Capital Cost 228,910,000 II Debt Service Reserve Fund 22,560,000 Financing Expenses II 2 1 540 1 000 Total Investment Cost 254,010,000 II Annual Costs II D€:bt Service 22,560,000 Annual O&M 2 1 540 z000 11 Total $ 25, 100, 000 II 11 II D-23 I 1.6 PINE RIDGE PROJECT I 1.6.1 General The Pine Ridge Project is located approximately two miles north of I Golden. The proposed reservoir will be located west of the Dakota hogback and will require three dams to retain the reservoir. One dam will be located at I Van Bibber Creek and will retain the reservoir to the west, another dam will be located on Cressmans Gulch and will retain the reservoir to the south and a I dike will be located on the northern end of the reservoir to retain the reservoir above the existing Ralston Reservoir. The project plan is shown on I Figure ·0.9. The dam layout and reservoir capacity data are shown on Figure 0.10. Water will be conveyed to the proposed reservoir from Clear I Creek by five miles of tunnels and pipelines. Physical features of the project are summarized on Table 0.9. I 1.6.2 Geotechnical Overview The Pine Ridge site is located in a small valley between the Dakota I hogback on the east and the foothills to the west. The rock units in the area, beginning on the west side include Precambrian gneiss, the Pennsylvanian I and Permian Fountain Formation, Permian Lyons Sandstone, Permian and Triassic Lykins Formation, Jurassic Ralston Creek and Morrison Formations, and the I Dakota Formation. The hornblende gneiss is a coarse crystalline rock composed of folded layers of mica and hornblende, and feldspar and quartz. The Foun tain and Dakota Formations and the Lyons Sandstone are sandstone units with I some conglomerate, siltstone, and mudstone. The Lykins, Ralston Creek, and Morrison Formations are claystone or mudstone with minor amounts of sandstone I and limestone. I The sedimentary rocks have been folded upward along the edge of the crystalline mountain front, and at the Pine Ridge site, dip nearly ver I tically. The beds strike along the axis of the valley. No faults are shown on published geologic maps along the main (south) dam axis. A one-mile long fault cutting the sedimentary rocks has been mapped in the northern part of I the site and crossing Van Bibber Creek and the saddle dam as shown on Figure 7.1 of the Final Report. This fault is not considered active by the I Colorado Geological Survey. I 0-24 I I I' Potential geologic concerns associated with the Pine Ridge site are the I permeability of the sandstones and faults, and the strength of the vertical Dakota Formation. Sandstones can be highly permeable and can provide a path I for water to exit the reservoir. Faults and fault zones can also provide pathways for water migration. The resistant sandstone of the Dakota Hogback is r.elatively thin and would need to be studied to evaluate its ability to I! retain the reservoir. In addition, there appears to be extensive mining actl.vity on the east side of the Dakota Hogback. The mining, could be flooded '1 by the reservoir and could. provide avenues for water to escape from the I reservoir. Since the foundation materials have highly variable engineering properties, earth' and rockfill dams have been estimated for this site. I Concrete dams could be subject to cracking caused by differential foundation movements resulting from claystone swelling or differential settlements of i. harder and softer foundation materials. I Soils for earth dam construction within the reservoir area are likely to be scarce. An earth or earth-rock dam can probably be constructed utilizing I' fine-grained soils and rock that breaks' down to a fine-grained soil during construction. This material may be available from within the reservoir area I for the core and soils and/or quarried rock for the shells. Sands and gravels for' drain construction do not appear to be available on-site. Also hard, durable rock for upstream slope protection will likely need to be obtained I off-site. I 1.6.3 Project Description The maximum reservoir elevation at this site is limited by the thin I hogback which forms the eastern side of the reservoir. Embankment type dams were selected for these initial layouts because of insufficient information I concerning the foundation rock. The dam on Van Bibber Creek would be 285 feet above streambed, the Cressman Gulch dam would be 185 feet above streambed, and a small saddle dike approximately 20 feet high would be located at the I northern side of the reservoir. The dam and reservoir configuration would be similar to Horsetooth Reservoir located behind the hogback ridge west of Fort I Collins. I D-25 I The outlet works will be combined with a low level spillway structure with I the capability of discharging floods up to the 100-year frequency. Floods in excess of the 100-year frequency will be discharged in conjunction wi th an emergency spillway located through the hogback and discharging into the Van I Bibber Creek drainage. The outlet works conveyance will be a cut and cover conduit and discharge into Van Bibber Creek. I Facilities for diversion of the existing streams around the proposed !I damsite, during construction will be minimal because of small tributary drainage of the reservoir. I This project will require a supply tunnel to divert water from Clear Creek I to the Pine Ridge Reservoir. This tunnel will be approximately five miles long and will have an inside diameter of 18 feet. A concrete dam and gate tunnel headworks will be constructed on Clear Creek to divert water to the I supply tunnel. The diversion dam will be approximately 40 ft. high and will be an ungated concrete overflow structure. The locations of principal project j features are shown on Figure D.9. I I I I I I I I I D-26 I TABLE D.9 Pine Ridge Project I Project Data ----Reservoir: Maximum W.S. El. 6321 ft. MaxUnum Operating W.S. El. 6310 ft. 'I Minimum Operating W.S. El. 6250 ft. Total Storage at MaxUnum Operating W.S. El. 25,000 af I Surface Area at MaxUnum Operating W.S. El. 400 ac. Dam:: (Cressmans Gulch) Type Rockfill I Crest Elevation 6335 ft. Crest Length 1800 ft. MaxUnum Height Above Streambed 185 ft. I Dam Volume 2,100,000 yd3 River Bed Elevation 6150 ft. Dam: (Van Bibber Creek) I Type Rockfill Crest Elevation 6335 ft. Crest Length 2250 ft. I Maximum Height Above Streambed 285 ft. Dam Volume 4,100,000 yd3 River Bed Elevation 6050 ft. I Saddle Dike: Type Rockfill Crest Elevation 6335 Crest Length 1000 ft. Maximum Height 15 ft. Dike Volume 35,000 c.y. Saddle Elevation 6320 ft. ~lllway: Crest Elevation 6310 ft. I Crest Length 100 ft. Capacity 21,000 cfs I Outlet Works: Type Selective Level Withdrawal Conveyance Concrete Encased I Conduit Control Valves Tainter Valves I Clear Creek-Pine Ridge Tunnel: Type Concrete Lined Length 21,000 ft. I: Diameter 18 ft. Diversion During Construction: Concrete Encased I Cut and Cover Conduit Roads: I Route 6 at diversion dam .5 miles I D-21 I 1.6.4 Relocations Required Relocation will include minor relocation of Route 6 at the diversion I dam. Approximately thirty residences, a quarry, and several abandoned mines will be inundated by the proposed reservoir. I 1.6.5 Preliminary Cost Estimate The total cons.truction cost of the Pine Ridge project was estimated at I $225,660,000. The project costs are at the January 1987 price level and include allowances for land, engineering and contract administration, and I contingencies. The total investment cost of the project was estimated to be $305,490,000 which includes allowance for interest during construction and I financing expenses. The preliminary cost estimate for the project is summarized in Table D.10. I I I .,II I I I I I I 0-28 I I I I TABLE D.10 Cost Estimate for Pine Ridge Project Project Feature Cost Land Acquisition $ 11,250,000 Hogback Dam Diversion During Construction 150,000 Foundation Treatment 6,100,000 Dam 38,200,000 Spillway 1,000,000 I Outlet Works 1,650,000 DikE! 350,000 Main Dam I FOWldation Treatment 5,800,000 Dam 22,100,000 Road Relocations (Route 6 at diversion dam) 4,400,000 Clear Creek Reregulating Dam 8,000,000 I Clear Creek-Pine Ridge Tunnel 43,950,000 Miscellaneous Items (5%) 1 2 480 2 000 I Subtotal Construction Cost 156,980,000 ,I Contingencies (25%) 39 1 250 1 000 Direct Construction Cost 196,230,000 I Engineering and Administration (15%) 29 2 430 2 000 I Total Construction Cost 225,660,000 Interest During Construction (8% over 5 yrs.) 49 2 640 1 000 I Tot.al Capital Cost 215,300,000 Debt Service Reserve Fund 21,140,000 Financing Expenses I 3 2 050 2 000 Total Investment Cost 305,490,000 I Annual Costs I Debt Service 21,140,000 Annual O&M 3 2 050 2 000 I Total $ 30,190,000 I I D-29 ) C'<~ -<;7-5> C'-5>~~-t- NORTH CLEAR CREEK RESERVOIR ___ ~NJ::LE..h------'. IDAHO SPRINGS ~ CLEAR CREEK t:.J I w o ~ o 3000 6000 9000 , I " I ! SCALE IN FEET COLORADO WATER H(SOuACES ANO POWER DEVELOPMENT AUTHORITY CLEAR CREEKPROJECT NORTH CLEAR CREEK PROJECT TUCOR EHGiNEERItW COMPAN'I' '''~''l II ...... ,., .. . • ""o.".o_u .11 (O"""~I"" r. _,UII .. 1 .... ''''Q...... fA~"."""U, .-C:, DATE FEBRUARY 1987 FIGURE 0.1 - -- .. ...-- - .. ------·es .. - - - - .. - --- .. .. ------ RESE RVOIR AREA (ACRE S) N 700 600 500 400 300 200 100 0 7600 7500 ...... j ...... " I- I"-r-.... - \J CREST u.. 7400 SPillWAY V ,- - El. 741~ z y , 0 7300 '- I- 7000. 1\ o 20 40 60 80 100 120 140 o RESERVOIR VOlUME(AF x 1000) I w I-' RESERVOIR ELEVATION vs STORAGE o 500 1000 ! ! SCALE IN FEET 7600 DAM CREST El.7445 z 7400 7400 o I JDIV ERSION/S PlllWAY COLORADO w~TER RESOuRces cf TUNNEL ANO PQwER OEV[LOPM[Nr AUTHORITY 7000 CLEAR CREEK PROJECT 7000 PROFILE A-A NORTH C LEAR CREEK PLAN AND PROFILE 400 o 200 TuDOR ENGINEERING COJotPANT I I! I I I I I", ("" ... I ..... I •• · ... 1 .... ~ .00 ...... "·.,.". CCI ... ""U.u SCALE IN FEET ..." ...... '., DATE FE9RlJARY 1987 FIGURE D.2 ~ \, ., ..I GUY GULCH RESERVOIR NOR~H' ~ .. , C'( ¢": '"" 4?> . -»", ~C'". ¢": €. -- ,-.r ~\~€.\..\~\\)~~€.~-- -- ~ r -- '"t~----- CI ~.,.~\\)~~~__...(.-f': I w -- :'--'\ N .. /;d--0 ' CLEAR DIVERSION DAM 9, ,3,000 .'2000 ,90.00 SCALE IN FEET COLORADO WATER R£SOURCES ANO POWER DEVELOPMENT AUTHORITY CLEAR CREEK PROJECT GUY GU LCH PROJECT TUOOR EtlGINEERmG COMPANl' C~I.· • • , .... __ ••••• _ .000.'.0-'.'''. '_,u~I"'" .'."~" 1 .... ""J...... u .. A"4'l!a, ,IOC.. DATE FEBRUARY 1987 FIGURE D.3 ------.. -- --- ... - -= ... - - .. - - .. ------ iii RESERVOIR AREA (ACRES) 400 350 300 250 200 150 100 :\0 o 7400 f- f- j 7300 r-. -- ...... -- ...... ~ ';:"L1AY- -CR ST lL ...... - "'"' 7200 \] !>< j EL 72 0 ==? ...... z /' ! 0 '-... , 7100 V I- <[ V > ~ • I III 7000 -/ l' -- "-. ...J / , w 6900 I "- I "\ 6800 1\ 6700 '------'--- -- 6 10 20 30 40 50 60 70 80 RESERVOIR VOLUME (AF x 1000) SITE PLAN t:! RESERVOIR ELEVATION vs STORAGE I 500 1000 W o I , I I W SCALE IN FEET DAM CREST SPILLWAY CREST EL.7210 EL. 7200 7200 7200 z 7000 7000 o l- e{ > W ...J W 6800 6800 DIVERSION CONDUIT COLORADO WATER RESOuRCES ANO POWER OEVELOPMEt4T AUTHORITY CLEAR CREEK PROJECT PROFILE A-A GUY GULCH DAM o 200 400 PLAN AND PROFILE I ! , " I ! I" I rUOOA ENGINEERING CQI.lPANl' SCALE IN FEET *Q.;;Ig.a.;·'"I'i, H.u~.la.', DATE F E B·AUARY··i987~u .... FIGURE 0.4 ~ \ \ '\.:..".('" . •..\;: ... ~~~ ...~~:\ ~ V \ EMPIRE WEST FORK CLEAR ) CREEK -:r-".~"''-''''______''~ -- DIVERSION DAM ------_UAlr Ale --'--- - ~ IDAHO SPRINGS ------GEORGETOWN ----/.... o RESERVOIR .' I (Existing) -- CREEK RESERVOIR w ...~. ./> ~f.~ ~ Gf\~.. ' ,,' ~~.,' ~ ",GO rP ( GEORGETOWN /1/ ~/ I If ( j(~ ) { o 3000 6000 9000 ! I " !. SCALE IN FEET COLORADO WATER RESOURCES AND POWER DEVELOPMENT AUrHORIT't CLEAR CREEK PROJECT SODA CREEK PROJECT ruDOR ENGINEERING COMPANY' .. OOO .... O·(l.OI Co-'''~I''''" .'Ir .... I .. ~'.O""I...... 11. flOC.. DATE FEBRUARY 1987 FIGURE 0.5 ------... ------.. RESERVOIR AREA (ACRES) 300 2!10 200 1!l0 100 !l0 0 8400 8300 .,..: i- .... 8200 I"---, l- I VI SPILLWAY CREST ...... ,./ ~ EL.8200 z r---.>< 0 ...... 8100 V _1 ~ RESERVOIR VOLUME (AF x 10(0) d I RESERVOIR ELEATION vs STORAGE W U1 SITE PLAN o !lOO 1000 8400 8400 SCALE IN FEET DAM CREST SPILLWAY CREST EL.8220 EL.8200 z 8200 8200 :> ~ CULCRADO WA T[R RESOURCES AND POWER DEVELOPMENT AUTHORITT 7800 I ~I V 7800 CLEAR CREEK PROJECT PROFIL E A-A SODA CREEK o 200 400 PLAN AND PROFILE TUOOR ENGINEERING COMPANY 1""1",, I <..... " ,., .. , ...... D·'••• '.;:..,.".I ... , •• SCALE IN FEET .... 1 •• , ..... " ..... u .. 4 .... ~ .... , ,K OATE FEBRUARY 19B7 FIGURE 0.6 ~ .•.~ AO, \. ••• C'-j> '. ~ ~<-j> ~+ "to- _-----~--1Jl!!!'f.L---.-:1,. FALL RIVER RESERVOIR EMPIRE WEST FOIII( CLEAR ..,r-- •.. -...... -... ,-- ...~" ~ IDAHO SPRINGS GEORGETOWN RESERVOIR t:1 I (Existing) w (j\ " GEORGETOWN 9, ,3,qOO, ,6000, 90.00 SCALE IN FEET COLORADO WATER RESOuRCES AND powER DEVELOPMENT AUTHORITY CLEAR CREEK PROJECT FALL RIVER PROJECT TUOOR ENGWEfRING COMPANY C.... ·l ... • ...... ·, •• '_ .ooo ... "O-Cl.D' CD'''UU'''', .1111'" , ..... j.O .. OI:I",.1...... , .... I-C. DATE FEBRUARY 1987 FIGURE 0.7 - --- .. ------.. ------.---~------ RfSE RVOIR AREA {ACRE 5) N 300 250 200 150 100 50 0 8300 r--... I" 8200 SPILLWAY CREST / EL.8215 / ~ "' / IL. 8100 " ~ -' z "" J 0 8000 /(] " l- , e:( If > ~ .... / ~ ...J 7900 .... ~ 7800 ,- ~. <::> <::> <::> a:> 7700 o 10 20 30 40 50 60 ~ DOWNSTREA!A COFFERDAM RESERVOIR VOLUME(AF xIOOO) t::l \\ \ \ \ \ \ \ \\\ \ \ \\ \ \ \ I RESERVOIR ELEVATION vs STORAGE w -....J SITE PLAN o 500 1000 I '" I 8400 SCALE IN FEET 8400 SPILLWAY CREST DA!A CREST EL.8215 EL.8235 z 8200 8200 o l- e:( > lJJ ...J .... 8000 r------~8000 COLCfUDO w.l.TER RESOuRCES 7800 7800 AND POwi -{ DEVELOPMENT AUTl10HITl CLEAR CREEK PROJECT PROFILE A-A FALL RIVER o 200 400 PLAN AND PROFILE 1""1,",, I TuDOR ENGINEERING COMP.\NT .",,~.... g.~ •• ~t ", ...... , •••• SCALE IN FEET ..... _. , ...... ,.0...... ". ,., DATE FEBRUARY 19B7 FIGURE 0.8 88 fR CRfJ! / .., VAN .J!-... ~ ..' . ~.) \ PINE RIDGE RESERVOIR .. "\ \ ) /, ...~ ) "-L{ /~.___\ ~>f'\.r-. ( ". y' ~ \ ""~... ~v- \""~ ....- >-···~VLCH., \ C "'--';;CKER ...\~c;. ..-"-T CI ~~ ./ I 'v' ./ w -( ... ~. ". ,?\'?~././ CIJ "~ \4~ ". ~. I "/ o 3000 6000 9000 ,. • I! I SCALE IN FEET COLORADO WAfER RESOURCES ANO powER O[VELOP".ENT AuTHORITY CLEAR CREEK PROJECT PINE RIDGE PROJECT TuDOR ENGINEERING COMPANY ' .. I .. l ...... ··tl·'_ .OOQ ••• D-Cl.O.CO ... ,,,., .... ,. _,'11'. l.w"U."I.'''~...... , I•.. ooc... DATE; FEBRUARY 1987 FIGURE 0.9 ------...- .. - - - - - .. ------.. - - .. RESERVOIR AREA (ACRES) ....: 500 400 300 200 100 0 LL 6500 SPILLW~YICREST z EL.6310 ~I- 6400 '" I...... r-... _f--:-'I- ru ~ 6300 ..J "..,. l,....-K UJ ~ T /BBER C I l; rr r- t-. V"~~···~EK 6200 , I 6100 o 10 20 30 40 50 RESERVOIR VOL UME (AF a 1000) t::l I RESERVOIR ELEVATION w z '" 0 6400 vs STORAGE I- 6200 LIMIT >'" UJ ..J UJ 6000 PROFILE A-A o 200 400 600 800 ~ SCALE IN FEET z DAM CREST 0 6400 EL.6335 SITE PLAN I- o 2000 4000 '"> 6200 UJ I" " I I I , ! j I COLORAOQ WA fER I'l[SOuRCES ..J AHO POW(R DEV[LOfW£NT AuTHORITY SCALE IN"FEET UJ 6000 CLEAR CREEK PROJ£CT PROFILE B - B o 200 400 600 800 SCALE IN FEET TUDOR ,~~~I~~..~ ~~'!.~u':~!"PANY ._ ..... ·'LI •• ' .. _I •• U ~ ...., ....._ ...... - DATE FEBRUARY 1987 FIGURE 0.10 I I I I I Appendix E I DATA COLLECTION I AND DOCUMENT REVIEW I I I I I I I, I I I I I I I APPENDIX E I DATA COLLECTION AND DOCUMENT REVIEW 1.1 PREVIOUS REPORTS II In addition to the hydrological data that were collected other data were collected that included topographic maps, aerial photos, geological maps, electric transmission line maps, and highway maps. The other significant I engineering projects that are planned in the basin were also identified, and the data related to the environmental issues were collected. The Authority's I recently completed Cache la Poudre Basin Study and the St. Vrain Basin.Study were also important sources of information. Sources of information for the 'I other data collection included the U.S. Geological Survey (USGS), the Denver Water Department, the Colorado Department of Natural Resources, the Colorado I State Highway Department, the U.S. Army Corps of Engineers (COE) , the U.S. Bureau of Land Management, the Environmental Protection Agency (EPA), and the I National Cardiographic Information Center (NCIC). The previous studies and reports that have been prepared for the Clear I Creek basin that were relevant to the Clear Creek project were also obtained and reviewed. Some of the sources of these documents include the Clear Creek II Water Users Alliance, the U.S. Bureau of Reclamation (USBR), the Colorado Water Conservation Board (CWCB), the State Engineers Office (SEO) , the Denver I Water Department (DWD) , the U.S. Army Corps of Engineers, Colorado State University (CSU), and other municipalities and industries in the basin. One of the most important documents that was reviewed and utilized in the study I was the U.S. Army Corps of Engineers' Metropolitan Denver Water Supply Systemwide EIS (SEIS). The various appendixes for the Systemwide EIS were I extremely useful for supplemental hydrological data in summarizing future water demands and for determining the ground water potential of the study I area. I A complete list of the prev ious reports referenced for this study is included in the bibliography. A brief description of the documents that were obtained and reviewed, and the application of this information for the I Phase I - Feasibility Study is contained in the following paragraphs. I I E-1 I The documents obtained from the USBR are related to the environmental I evaluation of the Upper South Platte Unit, the Narrows project, and the Upper South Platte River Basin studies. The information from these sources was used to estimate the effect of South Platte conditional decrees on the Clear Creek I project. The studies relate primarily to the effect of upper basin development on the migratory bird hatitat in Nebraska. I Documents collected from the CWCB are: the Cache La Poudre study, the I Hardin Dam report and the South Platte River Basin Assessment Summary. These were used to supplement the USBR's information on the conditional South Platte I decrees. Reports obtained from the DWD pertain to the Williams Fork system in its I' existing condition and future development of the system. These are reports from the mid-1910's and need some verification and updating. This will be I done in Step 2 of this study. The providers' and participants' agreements have also been obtained. I The COE's information pertains to the Metropolitan Denver Water Supply I Systemwide Environmental Impact Statement. This process is currently ongoing. All of the publications available to the public have been obtained I and reviewed. In addition, the vicinity hydrology, a six volume set not generally available to the public, was obtained. The information in this source was used to help determine the potential flows available to the project I from adjacent basins. I Data obtained from the USGS include statistical summaries for published stream gages, as well as the actual data from these gages. These data were I described in the Final Report. I The reports obtained from the Authority generally include basin studies for some of the South Platte tributaries. These reports include basin studies for the St Vrain and Cache La Poudre. I The information obtained from the SE~ includes decrees, diversion records, I and South Platte call records. These were used to update the Clear Creek I E-2 I I I yield model and verify its water balance. They were also used to develop the I native hydrology for Clear Creek at the Golden gage. A report obtained from CSU has useful information on the irrigated acreage I of some of the Clear Creek ditches. This information was used to determine water-use distributions for systems that have not yet gone through a change of I use proceeding in the water court. Geotechnical reports and maps obtained and reviewed concerning the I regional geology, local geology, and seismicity. These sources are listed in I the bibliography. Information from the EPA relating to water conservation was obtained to I supplement the technological developments portion of the plan of study. 2!1 OTHER DATA COLLECTION I This information included readily available and relevant data that are useful for the preliminary screening of potential reservoir sites. These data I generally included topographic maps, aerial photos, geologic maps, other I project data, and data related to possible environmental issues. 2.2 TOPOGRAPHIC MAPS I The following USGS 7.5-minute quadrangle maps were collected for: Englewood, 1965; Commerce City, 1965; Fort Logan, 1965; Arvada, 1965; Mor'rison, 1965; Golden, 1965; Evergreen, 1965; Ralston Buttes, 1965; Squaw I Pass, 1957; Black Hawk, 1972; Idaho Springs, 1957; Georgetown, 1957; Empire, 1958; Grays Peak, 1958; Berthoud, 1957; and Loveland Pass, 1958. Most of I these maps were photorevised in 1971, 1974, or 1980. The contour interval for these quadrangles is generally 40 feet in the mountainous areas and 10 feet in I the lower elevations. I The intermediate-scale base maps that have been collected include the 1 :50,000-scale county maps for Clear Creek, Gilpin, Jefferson and Denver counties, and 1: 100,000-scale metric topographic map of Denver West. The I contour interval for the 1 :50,000-scale maps is 20 feet and 50 feet, and for I the 1:100,000-scale it is 50 meters (15.24 ft.). I E-3 I Digitized topography is also available from the NCIC for the following I quadrangle maps: Evergreen, Squaw Pass, . Ralston Buttes, and Black Hawk. These topographic data may be obtained and utilized in an interactive CADD I program for finalizing the work in Step 2. 2.3 AERIAL PHOTOS I Aerial photos are available· from the NCIC for most areas in the wesfern United States. Black and white stereo pairs for scales of 1:25,600, 1:27,600, I 1:30,800, and 1:28,000 are available for the entire Clear Creek basin. These photos were taken in 1969, 1971, and 1974. Black and white aerial photos were I collected for each of the dam and reservoir sites investigated in the study. I Color photos (stereo pairs) are also available for the lower part of the Clear Creek basin. These photos were taken in 1978, and the scale is 1:28,000. The color photo coverage of the basin by USGS quadrangle sheets is I as follows: Evergreen, Morrison, Fort Logan, Englewood, Commerce City, Arvada, and Golden. I 2.4 GEOLOGICAL MAPS I USGS geological maps are available for most of the 7.5 quadrangle maps that cover the Clear Creek basin. USGS geological maps have been collected I for the following quadrangles: Golden, Evergreen, Ralston Buttes, Squaw Pass, Black Hawk, and Idaho Springs. In addition, the geological map for the State of Colorado was also obtained. I 2.5 OTHER MAPS I The other maps that were collected include the following Bureau of Land Management surface-minerals or surface management quads: Mount Evans, NW-24; I Boulder, NW-18; Dillon, NW-23; Hot Sulphur Springs, NW-17. All of these are planimetric maps, compiled to a scale 1: 126,720 (112 inch equals 1 mile), I which show the public land ownership status in and adjacent to the Clear Creek basin. I Typical land status descriptions on these maps are public lands (administered by the Bureau of Land Management), National Forest, Indian I Lands, Military Reservations, Wildlife Refuges, State Lands, Reclamation and Water Power Projects Withdrawal, and State Wildlife Areas. I E-4 I I I 3. 1 DATA RELATED TO ENVIRONMENTAL ISSUES I The data related to the environmental issues is provided in the bibliography. The agencies contacted include the State of Colorado, I Department of Natural Resources, and the EPA. The data collected include water quality data from EPA, reports from Clear Creek County Planning Office, I and reports from the Colorado Division of Wildlife. It 4.1 BIBLIOGRAPHY Anderson, Wengert, and Heil, May 1916. The Physical and Economic Effects on the Local Agricultural Economy of Water Transfer From Three Irrigation I Companies to Municipal Use in the Northern Denver Metropolitan Area, 1915. Environmental Resource Center, Colorado State University. I Bode and Bryson, June 1915. Williams Fork Project Phase I of a Definite Plan Report. Prepared for Denver Water Board. Bryson, Samuel, October 1915. Hydrologic Summary for the Williams Fork River I Basin. Prepared for Denver Water Board. Bureau of Reclamation, Lower Missouri Region, August 1912. Upper South Platte I Unit Mount Evans Division Pick-Sloan Missouri Basin Program Colorado. Department of Interior. I Bureau of Reclamation, October 1914. Upper South Platte Unit Mount Evans Division. Multiobjective Planning of Water and Related Land Resources, Field Draft Feasibility Report. I CH2M Hill, Inc., September 1916. Environmental Assessment of Completing Williams Fork Water Diversion System. Prepared for the Denver Water I Board. Cheryl Signs Engineering, 1983. Report on Standley Lake Water Quality Management. Prepared for Ci.ties of Westminster and Thornton and Adolph I Coors Company. Clear Creek County. Weaver, Bert - Planning Director; Haskins, Jeannette - I Planning Assistant. Personal Communication, March 1981. Clear Creek Water Users Alliance, August 1983. Clear Creek Project, Application for Feasibility Study Funding. Prepared for the Colorado I Water Resources and Power Development Authority .. Colorado Division of Wildlife, Central Region. Demarest, Kathi; Howard, Tom; I Yamashita, Steve - Personal Communication, March 1981. I Colorado Energy Research Center, 1981. Water and Energy in Colorado's Future. I E-5 I Colorado State Engineer's O~~ice. District 7 Diversion Records. 1912-1985. I Colorado State Engineer' s O~~ice, July 1, 1984. Division One Water Rights Tabulation. I Colorado Water Court, Division One. District 7 Water Decrees. Colorado Water Court, Division Five. Districts 36 and 51 Water Decrees. I Colorado Water Division Number 1. Division 1 call records, 1950 through 1984. I Dames & Moore, December 1982. Hardin Dam. Prepared ~or the Colorado Water Conservation Board. Denver Regional Council o~ Governments, January 1975. Metropolitan Water I Requirements and Resources 1975-2010. Volume I - Text. Denver Regional Council o~ Governments, January 1975. Metropoli tan Water I Requirements and Resources 1975-2010. Volume II - Primary Study Area Appendix. I Denver Regional Council o~ Governments, January 1975. Metropoli tan Water Requirements and Resources 1975-2010. Volume III - Secondary Study Area Appendix. I Denver Regional Council o~ Governments, November 1981. Land Use in the Denver Metropolitan Area. I Denver Water Department, 1979 and 1986. Correspondence on Jones Pass Tunnel Discharges to Clear Creek. Environmental Science Services Administration, 1966 through 1969. I Climatological Data - Colorado. U.S. Department o~ Commerce. EPA (U.S. Environmental Protection Agency), March 1981. Flow Reduction I Methods, Analysis Procedures, Examples. Facility Requirements Division, O~~ice o~ Water Programs Operations, Washington, D.C. I Fish and Wildli~e Service, Geological Survey and Bureau o~ Reclamation, September 1983. Summary Report Upper Platte River Study. Fish and Wildli~e Service, Region 6. Finley, Ronel; Carlson, Lee. Personal I Communication, March 1987. Foley, Miller, Garzonetti, May 1986. Reclaimed Cali~ornia Wastewater Provides I Drought Insurance, WATER/Engineering & Management. Gilpin County. Donnelly, Hal - County Engineer. Personal Communication, March 1987. I Green, Jim, Compliance Archaeologist - Colorado Historical Society. Personal II Communication, March 1987. I E-6 I I I Grief, July 1986. A Computerized Water System: From Pitfalls to Perfection, WATER/Engineering & Management. I HeYlliood, July 1986. SCADA Systems Today and Tomorrow, WATER/Engineering & Management. International Engineering Company, April 1913. Upper South Platte Unit Mount I' Evans Division. Environmental Study. International Engineering Company, May 1985. Engineering Analysis of Projects I of Others for Systemwide EIS, Clear Creek Project. Prepared for the Denver Board of Water Commissioners. I Jefferson County. Kortendick, Michael and Sledd, David Mapping Department. Personal Communication, March 1981. McKee, Terry, U.S. Army Corps of Engineers - Platte River Resident Office. I Personal Communication, March 1981. Miller, Brad, Environmental Protection Agency Region 8. Personal I Communication, March 1981. NOllA (National Oceanic and Atmospheric Administration), 1910 through 1982. I Climatological Data for Colorado. U.S. Department of Commerce. Patterson, J.W., August 18, 1980. Inspection of Vidler Tunnel Water I Collection System. Pringle, 1982. Water, The Next Great Resource Battle. I R.W. Beck and Associates and Dames and Moore, February 1986. Saint Vrain Basin Reconnaissance Study. Prepared for the Colorado Water Resources and Power Development Authority. I Radosevich, George, et ale 1915 (updated annually). Colorado Water Laws, A Compilation of Statutes, Regulations, Compacts, and Selected Cases. I Stockton, Charles W., 1915. Long-Term Streamflow Records Reconstructed from Tree Rings. The University of Arizona Press, Tucson, Arizona. I Stockton, Charles W., 1975. Long-Term Streamflow Reconstruction in the Upper Colorado River Basin Using Tree Rings. Laboratory of Tree-Ring Research, University of Arizona, Tucson, Arizona. I SQiH Conservation Service, U.S. Department of Agriculture, April 1967, revised September 1970. Irrigation Water Requirements. Technical Release No. 21 I (Rev. 2). TUdor Engineering Company, July 1983. Cache La Poudre Project Study. Prepared for the Colorado Water Conservation Board. I U.S. Army Corps of Engineers, February 1983. Metropolitan Denver Water Supply I Systemwide EIS, Final Work Plan. I E-7 I u.s. Army Corps of Engineers, December 1985. Metropolitan Denver Water Supply Systemwide/Site-Specific EIS, Additional Hydrologic Data, Frequency I Analysis. u.S. Army Corps of Engineers, December 1985. Metropolitan Denver Water Supply I Systemwide/Site-Specific EIS, Additional Hydrologic Data, Relationships Between Monthly Flow and Maximum/Minimum Daily Flow. u.S. Army Corps of Engineers, December 1985. Metropolitan Denver Water Supply I Systemwide/Site-Specific EIS, Additional Hydrologic Data, Historic Streamflow Data Mean, Maximum and Minimum Daily Flow For . Each Month (1941 - Present). I u.S. Army Corps of Engineers, December 1985. Metropolitan Denver Water Supply Systemwide/Site-Specific EIS, Additional Hydrologic Data, Post-Project I Monthly Flows at Additional Sites. u.S. Army Corps of Engineers, December 1985. Metropolitan Denver Water Supply Systemwide/Site-Specific EIS, Additional Hydrologic Data, Monthly Flows at I Additional Sites. u.S. Army Corps of Engineers, 1985. Metropolitan Denver Water Supply I Systemwide/Site Specific EIS, Development and Evaluation of Water Supply Scenarios. I u.S. Army Corps of Engineers, April 1, 1985. Metropolitan Denver Water Supply Systemwide/Site-Specific EIS, Operational Hydrology Stream Flow Regime Effects for Site-Specific Projects. I u.S. Army Corps of Engineers, October 1986. Metropolitan Denver Water Supply Systemwide/Site-Specific EIS, Appendix 4, Water Sources for Future Supply, Appendix 4B, Water Sources Selected for use in Alternative Scenarios, I Volume 1 - Introduction, Straight Creek Collection System. u.S. Army Corps of Engineers, October 1986. Metropolitan Denver Water Supply I Systemwide/Site-Specific EIS, Appendix 4, Water Sources for Future Supply, Appendix 4B, Water Sources Selected for use in Alternative Scenarios, Volume 2 - East Gore Collection. I u.S. Army Corps of Engineers, October 1986. Metropolitan Denver Water Supply Systemwide/Site-Specific EIS, Appendix 4, Water Sources for Future Supply, Appendix 48, Water Sources Selected for use in Alternative Scenarios, I Volume 3 - Green Mountain Pumping Collection System. u.S. Army Corps of Engineers, October 1986. Metropolitan Denver Water Supply Systemwide/Site-Specific EIS, Appendix 4, Water Sources for Future Supply, I Appendix 4B, Water Sources Selected for use in Alternative Scenarios, Volume 4 - Eagle-Piney/Eagle-Colorado Collection System. I u.S. Army Corps of Engineers, October 1986. Metropolitan Denver Water Supply Systemwide/Site-Specific EIS, Appendix 4, Water Sources for Future Supply, Appendix 4B, Water Sources Selected for use in Alternative Scenarios, I Volume 5 - Blue River Exchange/Joint Use Reservoir. I E-8 I I I u.s. Army Corps of Engineers, October 1986. Metropolitan Denver Water Supply Systemwide/Site-Specific EIS, Appendix 4, Water Sources for Future Supply, Appendix 4B, Water Sources Selected for use in Alternative Scenarios, I Volume 6 - Satellite Well Field, Projects of Other Water Providers. u.S. Army Corps of Engineers, October 1986. Metropolitan Denver Water Supply Systemwide/Site-Specific EIS, Appendix 4, Water Sources for Future Supply, I Appendix 4C, Water Sources Selected for Site-Specific Analysis, Volume 7 - Williams Fork Gravity. II u.S. Army Corps of Engineers, October 1986. Metropolitan Denver Water Supply Systemwide/Site-Specific ErS, Appendix 4, Water Sources for Future Supply, Appendix 4C, Water Sources Selected for Site-Specific Analysis, Volume 8 - I Williams Fork Pumping. U.S., Army Corps of Engineers, October 1986. Metropolitan Denver Water Supply Systemwide/Site-Specific EIS, Appendix 4, Water Sources for Future Supply, I Appendix 4C, Water Sources Selected for Site-Specific Analysis, Volume 11 - MFA - Ground Water Development. I U.S. Army Corps of Engineers, October 1986. Metropolitan Denver Water Supply Systemwide/Site-Specific ErS, Appendix 4, Water Sources for Future Supply, Appendix 4C, Water Sources Selected for Site-Specific Analysis, Volume 12 - Transmount Effluent Exchange Nonpotable Reuse Purchase or I Condemnation of Agricultural Rights. U. S. Army Corps of Eng ineers. Metropoli tan Denver Wa ter Supply I Systemwide/Site-Specific ErS, Appendix 2, Future Water Demands. U.s. Army Corps of Engineers. Metropolitan Denver Water Supply I Systemwide/Site-Specific ErS, Appendix 5, Development and Evaluation of Water Supply Scenarios. U.s. Army Corps of Engineers. Metropolitan Denver Water Supply I Systemwide/Site-Specific ErS, Appendix 3, Existing Water Supply. USGS (U.S. Geological Survey), May 1979. Streamflow Statistical Summaries for I Colorado Streams through September 30, 1975. Volume 1: Missouri River, Arkansas River, and Rio Grande Basins. Open-File Report 79-681. United I States Government Printing Office, Washington, D.C. USGS (U .S. Geological Survey). Surface Water Supply. Water Supply Papers 1310, 1730, 1918, 2118, 2121, 2124, 2125. United States Government I Printing Office, Washington, D.C. USGS (U.S. Geological Survey). Water Resources Data for Colorado. Water Data Reports 1961 through 1985. United States Government Printing Office, I Washington, D.C. Weather Bureau, 1925 through 1939. Climatological Data - Colorado Section. I U.S. Department of Agriculture. Weather Bureau, 1940 through 1965. Climatological Data - Colorado Section. I U.S. Department of Commerce. I E-9 I Widler, Mike, Park Manager - Golden Gate Canyon State Park. Personal I Communication, March 1987. Woodward-Clyde Consultants, August 1981. Interim Report South Platte River I Basin Assessment. Prepared for Colorado Water Conservation Board. Woodward-Clyde Consultants, December 15, 1981. Hydrologic Services, I Evaluation of Streamflows Available to a Junior Water Storage Right in the Clear Creek Basin, Colorado. Prepared for Adolph Coors Company. March 1985. Platte and Colorado River Storage Projects Participation I Agreement. I I I I I I I I I I I I I E-10 I I I I I I Appendix F I FERC LICENSING REQUIREMENTS I I I I I I I I I I I I I I I APPENDIX F I FERC LICENSING REQUIREMENTS The FERC's regulations for licensing hydroelectric projects are found in I three sections of Part 18 of the Code of Federal Regulations (18CFR). The Clear Creek Project would be a Major Unconstructed Project and FERC's regulations governing this type of project are formed in Sections 4.40 and I 4.41 of the FERC regulations. I The FERC's regulations require applicants to consult with the appropriate local, state and federal resource agencies in preparing their applications for I lIcense. With pre-application consultation, key environmental issues may be identified and addressed at an earlier point in the process and the I Commission's own required consultation with other agencies will be expedited. The applicant must allow at least 60 days for each agency consulted to respond to the applicant's request for documentation of the I consultation process. Letters and other documentation of the consultation are then included, as appropriate, within the application when it is filed with I the Commission. I The results of the consultation process provide a basis for analysis of the environmental and natural resource management aspects of a proposed I project, and identify problems that should be considered in the Commission's licensing procedures. The Commission requires the pre-application consultation process as an initial step in compliance with the Fish and I Wildlife Coordination Act, the Endangered Species Act, the National Historic I Preservation Act, and other Federal statutes. The pre-application consultation process is useful to an applicant in I budgeting application-related expenditures. For example, an applicant might firui, after discussions with appropriate agencies, that the project is wholly I or partly infeasible, or otherwise poses unforeseen environmental problems. Consultation helps to ensure the preparation of acceptable appliGations and expedites the final interagency consultation process as required by the Fish I and Wildlife Coordination Act (16 USC 662) and the Endangered Species Act (16 I USC 1536). I F-1 I Pre-application consultation must be complete and documented. Each I application must be a self-contained document so that the Commission's staff, other Federal, state and local agencies, and the interested members of the I public may fully understand the proposed project. The information contained in the application should be specific, accurate, and sufficiently quantified to convey a precise description of the project to include the environmental I resources to be effected, and the proposed protective, mitigative and enhancement plans. I A new section 4.38 was added to the resultations to consolidate the I Commission's consultation requirements for applicants for licenses and exemptions and to clarify the minimum steps that must be taken to consult I adequately with appropriate agencies, including the fish and wildlife agencies. I The consultation process consists of three stages. During the initial stage, applicants are required to contact all appropriate agencies and provide I each of them with specific, detailed information, to the extent available, concerning the project, including maps, engineering design, operational mode, I affected environmental and mitigation, and streamflow data. Applicants should seek the agencies' advice as to potential impacts and what studies may be I necessary to assess the effects of the project on the area's natural and socioeconomic resources. I During the second stage of consultation, applicants must perform any reasonable studies that are necessary for the Commission to make an informed I decision regarding the merits of the application. Studies must be conducted prior to filing an application if the results: (1) would influence the I economic or technical feasibility of the project; (2) are needed to determine the design or location of project feasibility; (3) are needed to determine the I impacts of the project on important natural or cultural resources; (4) are necessary to determine suitable mitigation, and (5) are necessary to minimize impacts to a significant resource. The results of any necessary studies must I be provided to each agency along with a draft application. Applicants must respond in the draft application to any comments and recommendations made by I agencies during the initial stage. Applicants are required to provide I F-2 I I I consulted agencies either 30 days or 60 days, depending on the type of application, in which to analyze and respond to the applicants' plans of I development. These time periods begin only after the applicant has informed the agencies of its general plans and submitted all the studies required by I the agencies. If an applicant strongly believes that particular studies are unnecessary, it can refuse to perform those studies and file its application with an explanation of why these studies were not conducted. The applicant I bears the burden of proving to the Commission that the omitted studies were I unnecessary. The third stage of consultation consists of the application being filed I with the Commission and served on each of the agencies consulted. Any subsequent revision, amendment, or supplement of an application also must be I provided to each consulted agency. Documentation that the requirements of all three stages of the consultation process have been satisfied must be included in the application, as well as any agency letters containing comments, I recommendations, or terms and conditions. I If the appropriate agencies waive compliance with any requirements, the applicant can omit compliance with that requirement provided that the III application includes an explanation of the circumstances of the waiver. I The FERC License Application will include an initial statement and the Following Exhibits: I A. Project Description B. Project Operation and Resource Utilization II C. Proposed Construction Schedule D. Project Costs and Financing I E. Environmental Report F. General Design Drawings 'II (Including Supporting Design Document) I II II F-3 I Exhibit E - Environmental Report will include the following reports: I 1. General Description of the Locale 2. Report on Water Use and Quality 3. Report on Fish, Wildlife, and Botanical Resources I 4. Report on Historic and Archeological Resources 5. Report on Socio-Economic Impacts I 6. Report on Geological and Soil Resources 7. Report on Recreational Resources I 8. Report on Aesthetic Resources 9. Report on Land Uses I I I I I I I I I I °1 I I F-4 I