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Home My WebLink About841176.tiff c1JT of ,;.:, . ,,,aF� DEPARTMENT OF THE ARMY 4 � t^ OMAHA DISTRICT CORPS OF ENGINEERS yv i Z 6O14 U.S. POST OFFICE AND COURTHOUSE O' Pn OMAHA, NEBRASKA 681O2 1,4o pM. pE PLY TO t`J 1 �� ATTENTION OF �y 1, 1984 Planning Division Dear Systemwide EIS Participants: The Metropolitan Denver Water Supply Systemwide Environmental Impact Statement (Systemwide EIS) is being rescoped to add site-specific detail for selected projects. The decision to rescope was made after lengthy evaluation and discussion with many interest groups. Enclosed is a fact sheet which discusses the events that led to the addition of site-specific studies to the Systemwide EIS. Rescoping was endorsed by the Governor's Metropolitan Water Roundtable on January 18, 1984. On February 24, 1984, the Denver Board of Water Commissioners (Board) submitted a letter of intent to apply for Federal permits (1) to construct a South Platte storage project and (2) to complete the Williams Fork Collection System. The Board's letter of intent requests that the emphasis of the South Platte storage project be on the Two Forks Dam and Reservoir. For the Williams Fork Collection System, the Board requested emphasis be on the extension of the gravity collection project. These water sources and their alternatives will receive the site-specific detailed studies. Water sources which could be evaluated in site-specific detail in the new combined EIS have been tentatively identified. An initial list of issues has also been identified for each of these water sources. Enclosed is a technical information summary which lists the possible water sources for site-specific evaluation, how they were selected, and the known critical issues for each. Other alternative water sources can be added if identified during the rescoping process. Then, all potential alternatives will be reevaluated and a final list of alternatives to be studied in site- specific detail will be developed. The summary also identifies other water sources that have been studied and explains why these are not proposed for site-specific evaluation at this time. Following completion of the combined systemwide and site-specific analyses, the Federal agencies will decide whether to permit the proposed South Platte storage and the Williams Fork projects. For those of you affected ¢y the alternatives. this will be your primary opportunity to make s ggestions the study scope far these alternatives. a ilia' he Your last opportunity to .suggest other alternatives for evaluation. 84117E -2- Nine rescoping meetings have been scheduled between May 21 and May 31 , 1984, to discuss the site-specific studies that will be added to the systemwide analysis. Please carefully read the enclosed fact sheet and technical information summary and attend one of the nine rescoping meetings listed in the fact sheet. Your suggestions will be summarized and mailed to all the addresses on our mailing list. If you cannot attend one of the meetings or have further suggestions, please send your comments to the following address no later than June 15, 1984. Planning Division U.S. Army Corps of Engineers, Omaha District 6014 U.S. Post Office and Courthouse Omaha, Nebraska 68102 This is the last majoi opportunity that you will have to determine the direction and scope of the Systemwide EIS. If you have any questions, please call the Systemwide EIS information number: (303) 393-7514. I need your participation. Sincerely, Qijantriqdr-Lg,0 Colonel, Corps of Engineers District Engineer Enclosures Fact US Army Corps Metro Water clo Entercom, Inc425 So. Cherry St. of Engineers Systemwide EIS Suite 200 Denver, Colorado 80222 Omaha District April 1984 303/3937514 Systemwide EIS Rescoped SUMMARY and Reservoir and extension of the Williams Fork gravity system. The Omaha District, U.S. Army Corps of Engineers (COE) is rescop- The combined EIS will include ing the Systemwide Environmental the systemwide cumulative impact Impact Statement for the Metropoli- analysis of water development scen- tan Denver Water Supply (Systemwide arios and site-specific evaluation EIS) to include site-specific evalu- of the Two Forks and Williams Fork ation of certain projects. The projects and their alternatives. site-specific analysis of projects The COE has issued a notice of in- will be included with the systemwide tent to prepare the combined Draft cumulative impact evaluations in a and Final EIS's. combined EIS. The need for rescop- ing became evident in the fall of 1983 after the COE conducted a mid- The site-specific evaluations term assessment of the progress of will focus on South Platte storage the Systemwide EIS. projects, the Williams Fork Collec— tion System, and the No Federal Action alternative. It is intended The proposal to proceed with that the site-specific evaluations rescoping to include site-specific and Final EIS will be sufficient for evaluation in a combined EIS was all Federal permit decisions and formalized in the Coordinating will assist in addressing State and Committee of the EIS Task Force to local issues. To ensure that all the Governor's Metropolitan Water significant concerns related to the Roundtable in December 1983 and site-specific projects are identi- January 1984. The actual imple- fled, nine scoping meetings have mentation of the rescoping was ini- been scheduled from May 21 to May tiated with a letter of intent dated 31, 1984. A detailed list of these February 24, 1984, from the Denver meetings is included in this fact Board of Water Commissioners (Board) sheet. to the COE. The Board indicated their desire to have the Systemwide EIS rescoped to include site- MIDTERM ASSESSMENT specific analysis of South Platte Storage and the Williams Fork sys- tem. The Board requested that the In October 1983, the COE began analysis focus on the Two Forks Dam a midterm assessment of the System— wide EIS. This assessment consisted Following many hours of dis- of interviews with the contractor's cussion and deliberation in December project team and representatives of 1983 and January 1974, the Coordi- the Governor's Metropolitan Water nating Committee, in conjunction Roundtable, including the Environ- with the COE, developed the concept mental Caucus, the Denver Water De- of a combined EIS which would broad- partment (DWD) , the Metropolitan en the scope of the Systemwide EIS Water Providers, West Slope leaders, to include both site-specific analy- and other involved parties. sis and systemwide cumulative effect evaluation. The combined EIS could result in long—term cost and time Several concerns were raised in savings in providing water to the these discussions regarding the con— Denver metropolitan area while also duct and progress of the Systemwide providing a greater opportunity for EIS. Some of the major concerns West Slope and environmental commun- were that the quality of the docu- ity involvement in the process. ments and level of analysis were insufficient; that there was not sufficient opportunity for public There was agreement that, by involvement in the process; that combining the Systemwide EIS and agencies, groups, and interested site-specific analysis, the concerns parties did not take the Systemwide expressed during the midterm assess- EIS as a serious process which was ment could be resolved. The Coordi- resulting in apathy about construe- nating Committee developed by con- tive involvement; that the System- sensus the concept of submitting a wide EIS was moving too quickly; and "letter of intent" in lieu of a per- that the time and costs expended mit application to initiate the would result in a product of limited site-specific analysis and combined utility. The COE felt that the EIS process. The COE will proceed overall credibility of the System- with the preparation of the combined wide EIS was in jeopardy and took EIS as though permit applications steps to remedy the problem. have been submitted for specific projects. FORMATION OF COORDINATING COMMITTEE The combined EIS will provide sufficient detail on site-specific The COE discussed the various alternatives to serve as the Nation- concerns of the interest groups with al Environmental Policy Act (NEPA) the Governor's Metropolitan Water document required for all Federal Roundtable EIS Task Force. As a permitting decisions for construe- result, it was mutually agreed that tion of additional storage in the an EIS Coordinating Committee would South Platte River drainage above be formed to work with the COE and Denver and for the completion of the its contractor to resolve the con- Williams Fork Collection System. cerns. The EIS Coordinating Commit- The combined EIS concept was pre- tee consists of two representatives sented to the full Governor's Metro- from each of the various interest politan Water Roundtable, and has groups: the West Slope, the Environ- since been endorsed by Colorado mental Caucus, the Water Providers, Governor Richard Lamm, Denver Mayor and the DWD. Federico Pena, the Environmental Caucus, the West Slope representa- tives, the Board, and the Metropoli- tan Water Providers. LETTER OF INTENT listing of projects in categories (1), (2), (3), and (4) will be de- veloped. This final listing will be On February 24, 1984, the Board distributed to the public. The submitted the letter of intent which water sources as initially categor- triggered the initiation of the re- ized are listed in table 1. The scoping process for preparation of technical information summary des- the combined EIS . The letter of cribes these projects. intent requested initiation of site- specific work on South Platte stor- age with a focus on the Two Forks CONTENT OF COMBINED EIS Dam and Reservoir and completion of the Williams Fork Collection System extension. The combined EIS will The primary change to the Sys- include all of the work originally temwide EIS approach that will re- planned for the Systemwide EIS in sult from combining the EIS's will addition to the site-specific evalu- be the reporting. The water sources ations. The combined EIS will also technical appendix (Task 4) will now include evaluation of the No Federal be more detailed to present site- Action alternative and reasonable specific information for those water alternatives to Two Forks and sources that will be evaluated in Williams Fork. site-specific detail. Also, the development and evaluation of alter- native scenarios to satisfy the ALTERNATIVE WATER SOURCES water demand of the Denver area for the next 50 years (Task 5) will now be reported in a new technical ap— The Systemwide EIS studies to pendix, rather than as the subject date have been used to classify all of the Draft Systemwide EIS. water sources into four categories for purposes of identifying candi— date water sources for evaluation in The combined Draft EIS will site—specific detail in the combined focus on the necessary information EIS. The four categories of classi- for Federal decision making on any fication are: (1) South Platte identified proposed actions. It is storage sources, (2) Williams Fork expected that the Board will submit sources, (3) No Federal Action sour- formal permit applications for se- ces, and (4) other water sources. lected projects prior to the distri- In response to the letter of intent, bution of the Draft EIS. These pro- the combined EIS will evaluate some posed actions will be identified in of the sources in categories (1) , the Draft EIS document. (2) , and (3) in site-specific de- tail. The sources in category (4) will continue to be evaluated as a RESCOPING MEETINGS part of the systemwide evaluations, but will not be evaluated in site- specific detail. To ensure that all significant concerns related to the proposed actions are identified, nine scoping Changes in the categorization meetings will be held to receive of these projects can be made during public input regarding the alterna- rescoping. Following the rescoping tives and issues which the public meetings, all potential alternatives feels should be addressed in the will be reevaluated and a final 3 Table 1 WATER SOURCE CATEGORIES Category (1) SOUTH PLATTE STORAGE1/ Two Forks Estabrook Ferndale Highline with Pipeline New Cheesman Wildcat Chatfield Operational Changes Category (2) WILLIAMS FORK SYSTEM Williams Fork Gravity Williams Fork Pumping Gross Reservoir-EnlargementZ/ Category (3) NO FEDERAL ACTION3/ Conservation Ground Water Development Under Municipally-Owned Land Nonpotable Reuse Sewage Exchange Purchase or Condemnation of Agricultural Rights Category (4) OTHER WATER SOURCES East Gore Eagle-Piney/Eagle-Colorado. Green Mountain Exchange Importation Potable Reuse Watershed Vegetation Management Weather Modification Straight Creek Ground Water Bear Creek Operational Changes Joint Use Reservoir Joint Use of Existing Systems 1/Further screening of Categories 1, 2, and 3 will occur following the rescoping meetings to reduce this list. 2/Not necessarily exclusive of development of Williams Fork project. Enlargement of Gross Reservoir could occur before., after, or in con- junction with a Williams Fork project. 3/Not exclusive to No Federal Action. Some conservation will occur under any action. 4 combined EIS. The meetings will be If you cannot attend one of the held at the following times and meetings or if you have further sug- locations: gestions, please send your comments to the following address no later Monday, May 21 at 7 p.m., than June 15, 1984: Middle Park High School Auditorium, Granby, Planning Division Colorado U.S. Army Corps of Engineers 6014 U.S. Post Office S Court- Tuesday, May 22 at 7 p.m. , house Battle Mountain High Omaha, Nebraska 68102 School, Avon, Colorado Wednesday, May 23 at 7 p.m. , Lake Dillon Lodge, Interstate 70, Exit 203 ( Breckenridge/Frisco exit), Frisco, Colorado Thursday, May 24 at 7 p.m. , City/County Auditorium, 520 Rood Avenue, Grand Junction, Colorado Tuesday, May 29 at 2 p.m., Denver Botanic Gardens, 909 York Street, Denver, Colorado Tuesday May 29 at 7 p.m. , Broomfield High School, 1000 Daphne, Broomfield, Colorado Wednesday, May 30 at 7 p.m. , Platte Canyon High School, Bailey, Colorado Thursday, May 31 at 2 p.m. , South Suburban Recreation Center, 6315 South University, Littleton, Colorado Thursday, May 31 at 7 p.m. , Fort Lupton High School, Fort Lupton, Colorado 5 TECHNICAL INFORMATION SUMMARY FOR RESCOPING OF THE SYSTEMWIDE EIS TECHNICAL INFORMATION SUMMARY FOR RESCOPING OF THE SYSTEMWIDE EIS INTRODUCTION The Denver Board of Water Commissioners has requested the Omaha District of the Corps of Engineers (COE) to rescope the Systemwide EIS to provide site-specific level of detail for South Platte storage, par- ticularly Two Forks Reservoir, and the Williams Fork System, particu- larly the Williams Fork gravity project. The site-specific analysis will include not only these two projects but also reasonable alterna- tives and the No Federal Action" alternative. The results of the Systemwide EIS studies to date have been used to classify all water sources into four categories for purposes of identifying candidate water sources for evaluation in site-specific detail in the combined EIS. The four categories of classification are: (1) South Platte storage sources, (2) Williams Fork sources, (3) No Federal Action sources, and (4) other water sources. In response to the letter of intent , the combined EIS will evaluate some of the sources in categories (1) , (2) , and (3) in site-specific detail. The sources in category (4) will continue to be evaluated as a part of the systemwide evaluations, but will not be evaluated in site-specific detail. Changes in the categorization of these projects can be made during rescoping. Following the rescoping meetings, all potential alterna- tives will be reevaluated and a final listing of projects in categories (1), (2), (3) , and (4) will be developed. This final listing will be distributed to the public. The water sources as initially categorized are listed in table 1. The following represents a summary of water sources information generated in the Systemwide EIS to date. All information should be treated as preliminary until the final Systemwide EIS technical appendix is available. SOUTH PLATTE STORAGE TWO FORKS RESERVOIR South Platte storage focuses on the development of Two Forks Reservoir. The South Platte storage project preferred by the Denver Water Department (DWD) would involve the construction of Two Forks Dam on the South Platte River, 1 mile downstream from the confluence of the North Fork and the main stem and about 2 miles upstream from Strontia Springs Dam (figure 1 ) . The DWD does have water rights , both conditional and absolute, as well as rights-of-way that would be utilized at Two Forks Dam and Reservoir. The reservoir would be located in Jefferson and Douglas Counties, approximately 24 miles 1 Table 1 Water Source Categories Category (1) SOUTH PLATTE STORAGE Two Forks Estabrook Ferndale Highline with Pipeline New Cheesman Wildcat Chatfield Operational Changes Category (2) WILLIAMS FORK SYSTEM Williams Fork Gravity Williams Fork Pumping Gross Reservoir Enlargement Category (3) NO FEDERAL ACTION3/ Conservation Ground Water Development Under Municipally-Owned Land Nonpotable Reuse Sewage Exchange Purchase or Condemnation of Agricultural Rights Category (4) OTHER WATER SOURCES East Gore Eagle-Piney/Eagle-Colorado Green Mountain Exchange Importation Potable Reuse Watershed Vegetation Management Weather Modification Straight Creek Ground Water Bear Creek Operational Changes Joint Use Reservoir Joint Use of Existing Systems 1/Further screening of the alternatives to reduce this list will occur following the rescoping meetings. 2/Not necessarily exclusive of development of Williams Fork project. Enlargement of Gross Reservoir could occur before, after, or in con- junction with a Williams Fork project. 3/Not exclusive to No Federal Action. Some conservation will occur under any action. 2 • LOCATION MAP ... C •N0RTH4..-. 1V/ r I: ",� LEGEND 0 1,2 12 l TWO FORKS DAM-ELEVATION 6550' SCALE IN MILES MAXIMUM POOL-ELEVATION 6550 X72 CONSTRUCTION AREA ACCESS ROAD ACCESS ROAD TO DAM $''+) _ - ALTERNATIVE ACCESS ROAD i I / � RELOCATED ROAD ll I II / POTENTIAL SPOIL AREA 41> CONSTRUCT ION ACCESS 4]F CC CONSTRUCTION CAMP AREA 111 ( A BORROW AREA EXIST.STRONTIA SPRINGS DAM EXIST.STRONTIA SPRINGS RESERVOIR N�'� SYSTEMWIDE EIS 1 - METROPOLITAN DENVER WATER SUPPLY Figure 1 TWO FORKS RESERVOIR - PROJECT FEATURES southwest of Denver. It would control a drainage area of 2,580 square miles and would increase the DWD safe yield by providing long-term carryover storage of natural flow from the South Platte River and from existing West Slope collection systems. Two Forks may provide storage capacity to be used in conjunction with development of new West Slope systems. The reservoir could also provide additional protection from floods and allow stored flood water to be available for future use. Potential secondary functions could include recreation and the genera- tion of hydropower as water supplies were delivered into the South Platte River. In addition to the DWD's use of Two Forks Reservoir, water could be stored for other water suppliers in the metropolitan area. An agreement has been reached under which other Denver metropolitan area suppliers will participate in a South Platte River storage project with the DWD. The agreement involves the construction of a Two Forks Dam that would be no smaller than 860,000 acre-feet of active water stor- age. Participants in the agreement can request the construction of additional storage capacity. Although the ultimate size of the reser- voir is uncertain, about 1.1 million acre-feet of active capacity would be adequate to control the DWD system flows. The maximum practical size is about 1.9 million acre-feet and would be limited by the toe of Cheesman Dam upstream on the main stem of the South Platte River. At the minimum practical operating level, the reservoir would cover an area of 300 acres, which would be increased to a surface area of 10,600 acres by the maximum operating level with the large dam. Water to be stored in Two Forks Reservoir could come from a number of sources. With the present DWD system, the largest increment of storable water would be from South Platte River basin storage rights, while the largest increment of safe yield would come from the existing Blue River and Fraser River basin systems. Two Forks Reservoir would have the capability of storing water from existing and future water sources on the West Slope and would increase their yield. It could also facilitate an increase in safe yield from effluent exchange. The safe yield of Two Forks Reservoir would be approximately 98,000 acre- feet per year. The volume of water that could be conveyed from Dillon Reservoir to Two Forks Reservoir could be limited by the capacity of the North Fork of the South Platte River. Roberts Tunnel has the capacity to carry about 1,000 cubic feet per second (c.f.s.), but the North Fork capacity is only about 700 c.f.s. Under present channel conditions, little water can be released from Roberts Tunnel during high runoff periods because of natural North Fork flows. Winter flows are also restricted because of icing. P The major issues to be analyzed would include wetlands, threatened and endangered species, the relocation of roads, the inundation of num- erous communities, fisheries and wildlife effects, cultural resources, recreation, impacts of additional transmountain diversions from the Blue River and Fraser River basins, how the sizing and operation of the Platte River will affect future system development, and impacts on rate payers. OTHER SOUTH PLATTE STORAGE DAM SITES Candidate alternatives to the Two Forks site have been identified in the South Platte River basin. Based on preliminary engineering characteristics and costs, the most feasible candidate alternative reservoir sites to be evaluated include, but are not necessarily limited to, Estabrook and Ferndale Reservoirs on the North Fork of the South Platte River and Wildcat, New Cheesman, and Highline Reservoirs on the main stem of the South Platte River (figure 2). The enlargement of Chatfield Lake is also potentially an alternative project. The major issues to be analyzed would include wetlands, threatened and endangered species, relocation of roads and railroads, displacement of communities and residents, cultural resources, fisheries and wild- life effects, recreation, additional diversions from the West Slope, impacts on rate payers, and the cumulative effects of multiple-project proposals. No water rights have been filed at any of these sites. Comparative storage capacities for the sites are shown in table 2. Although all of these projects are discussed here, further evaluation and screening will occur to reduce the number of projects for which site-specific analysis is considered. It is anticipated that two or three of these sites will be evaluated in site-specific detail. Estabrook Reservoir. The Estabrook site is located on the North Fork of the South Platte River in Park County, about 4 miles east of the town of Bailey. The storage capacity would range from 55,500 to 413,000 acre-feet. The issues unique to this project to be analyzed would include the effects of inundating the town of Bailey, wetlands, relocation of U.S. Highway 285, construction of access roads, cultural resources, fisheries and wildlife effects, and recreation. Ferndale Reservoir. The Ferndale site is located on the North Fork in Jefferson County, about 2 miles northeast of the town of Buffalo Creek. The storage capacity would range from 188,000 to 868,000 acre-feet. The issues unique to this project to be analyzed would include wetlands; the inundation of the communities of Ferndale, Pine, Buffalo Creek, and Riverview; relocation of roads and construc- tion of new access roads; cultural resources; and fisheries and wild- life effects. 5 Y a W W< O N Z < J V/ < a r 0 < WcoN W W G ' NC J 1-- x ° z N z < U a ♦O�R a i-4 0 Z W e ¢ � Lcc U W; V z Ln Q J 3 ¢ W < ilisi 7 S Z C V Wo O < N F a li ,n�- NeW . H Q yo W W W O cccc co f a oc F Fu.u. e m 2W� E m H 6;R 0 o J 4, to V G = J it W ' O = y �� m W a Wm V R , 1. e ,C m �'r + ib) m 0 Z p W 0 Q0�r oQ� m c 7 k. I Qt 0 m at ela J/ I. *St I 6 Table 2 Capacity Comparison Alternative South Platte Storage Alternate Dam Crest Storage Reservoir Elevation Capacity (feet) (acre-feet) North Fork Estabrook 7800 55,500 8000 413,000 Ferndale 6900 188,000 7000 453,000 7100 868,000 Main Stem Highline with pipeline Pipeline from 6650 596,000 Cliffdale Pipeline from Pine 6650 596,000 Pipeline from 6650 596,000 Buffalo Creek New Cheesman 7060 295,000 7160 605,000 Wildcat 7380 70,000 7480 175,000 7580 330,000 Highline Reservoir With Pipeline. The Highline damsite is located on the South Platte River, about 4.5 miles upstream from its confluence with the North Fork. The project would cover areas in both Jefferson and Douglas Counties and would store flows from the main stem of the South Platte River as well as water diverted from the North Fork. The North Fork-Highline diversion project would consist of a diversion dam on the North Fork and a gravity conveyance system to Highline Reser- voir. Three alternative diversion projects were considered for a reservoir with a dam crest elevation of 6650 feet and were designated as the Cliffdale, Pine, and Buffalo Creek diversion projects. The reservoir at this elevation would store 596,000 acre-feet. The unique issues to this project to be analyzed would include wetlands, fisheries and wildlife effects, the inundation of Trumbull, relocation of roads, and cultural resources. 7 New Cheesman Reservoir. The New Cheesman damsite would be located about 1,500 feet downstream from the existing Cheesman Dam on the South Platte River and approximately 35 miles southwest of Denver. The existing dam would be under water with the construction of the New Cheesman project. New Cheesman Reservoir could store additional water diverted from the North Fork of the South Platte River as an alterna- tive to the construction of a storage reservoir on the North Fork. The Estabrook-Cheesman diversion project would consist of an Estabrook diversion dam and an Estabrook-to-Cheesman diversion tunnel. The Estabrook diversion site would be located on the North Fork in Park County, about 4 miles west of the town of Bailey. Storage capacity would range from 295,000 to 605,000 acre-feet. The unique issues to this project to be analyzed would include the construction of access roads, wetlands, and fisheries and wildlife effects. Wildcat Reservoir. The Wildcat site is located near the common corner of Jefferson, Douglas, Park, and Teller Counties, about 6 miles upstream from the existing Cheesman Dam. Storage capacity would range from 70,000 to 330,000 acre-feet. The unique issues to this project to be analyzed would include wetlands, access road construction, and fisheries and wildlife effects. Chatfield Lake Operational Changes. Chatfield Lake is located on the South Platte River about 8 miles upstream from Denver (figure 3). The dam was completed by the COE in 1974 as a flood control facility with recreation as a secondary function. In return for water to fill the recreation pool, the DWD was granted 10,785 acre-feet of storage volume above the minimum pool. About 26,000 acre-feet of additional storage of water supply may be made available in Chatfield Lake. The project would not require any structural changes to the dam or asso- ciated flood control works. Relocation of recreational facilities would be necessary, however. The unique issues to be analyzed would include wetlands, fisheries and wildlife effects, recreation, and water quality. Determination of the yield from additional storage in the reservoir could be made only after determining the water rights, the system in which they would be used, and the operating criteria to be imposed. WILLIAMS FORK SYSTEM WILLIAMS FORK GRAVITY COLLECTION SYSTEM The analysis of the Williams Fork System focuses on the gravity system which is preferred by the DWD and would be located in Grand County in the headwaters of the Williams Fork basin (figure 4). The DWD owns a right-of-way for extension of the gravity system beyond Steelman Creek and the water rights required to develop this project. It would collect water from Darling Creek, the South Fork, Middle Fork, and main stem of the Williams Fork drainage. The entire area is within 8 Figure 3 CHATFIELD STATE RECREATION AREA EXISTING FACILITIES AND WATER SURFACE AREA . 1 Qv 8 . ...,.� m 7 \ o w u. (�@ 1 Fz ;, ) � , . i \ 30 28 �._.-N1 13/' \ oca 4. ( 2• 26 \ \ \ e ✓) •r. \ 1 \ • iu 22 ..; \ . IC 23 ` o • °o 21 /,� < • \\ 29 1/4.\-;\ 16 •\C.l 17 cc `� O \ m m 20 \x O1 cc v \ / 1el C! / LEGEND i / / `J ® SURFACE WATER I • a if ' CHATFIELD STATE PARK BOUNDARY '�/ �/ 1.Cottonwood Grove Picnic Area 2.Stevens' Grove Picnic Area 17. Fox Run Picnic Ares 31 •II ti 3. Owl Olen Picnic Arta 16.Kingfisher Perking Ana /Q �� ♦. Hatchery 19. Platte River Bridge 6 l 1 6. Chatfield Overlook 20.Platt*River Parking Area 6. North Boat Ramp 21.Heronry Overlook •L` \ 1. Massey Draw Parking Area 22. Perk Office 2, �\. B. Corp. Office 23. Model Airplane Field 2 ®/c4 1 -� a a. Visitor Center 24. Campground J / 10. Deer Creak Inlet 26. Lakeview Parking Area NORTH • 11. Deer Creek Picnic Area 26. Riverside Picnic Arse j 12. Bwlmgesch 27. Marine 13. Overflow/Balloon Launch 20. Plum Creek Picnic Area �j 0 1/2 1 1t. Jamison Picnic Area 29. Plum Creek Nature Area .......4— :/, I •1 H I t MILES 16. Catfish Flats Picnic Area 30. Suring Gulch J^;'--�' SCALE 10. Horse Corral/Livery 31. Dog Training Area V/ a. dd_ 2 W LI tti i YI-- o Ww O > ~ 003 ot — W 3 ~V' y Q 'oc a. S W • 2 W 2h = as- LL as _ O to. J CU V �,< o y 8 .• W W : J 3J '1 8 i is 0. w .- Id I' d J PP J s 4i r i . � . ,, N O :.. , , ` c _ , . • \J - 1 . N1 • ,, .,,,,,,,s,,t. e../ 4.4 •J �Y Y • • It N ° 2 = o N z 0 ° - o 'o _ G 0 •< Q , < o p LU 0 °< we a w w d a ° < ° w ° a i < r 3 O ° w G w i ° y La w ` 'o a 0 w w W 2 0 0 0 < ° o ° 0 0 g O a z a 3 o 0 < a O m CO 3 .- w J w a i HO ) ® { ; 114I > II 10 Arapaho National Forest. The Williams Fork Gravity Collection System would divert, collect, and convey surface water to the East Slope via Gumlick (Jones Pass) , Vasquez, and Moffat Tunnels beneath the Conti- nental Divide into Gross Reservoir and to the northern portion of the DWD system. Surface water from both overland sheet flow and discrete stream channels would be collected and conveyed in a buried conduit which would require no pumping. The system would operate throughout the year. The collection system has been partially completed and consists of about 5 miles of collection conduit that drain about 14 square miles. The project would have a safe yield of 11,000 to 17,000 acre-feet per year. The major issues to be analyzed would include wetlands, fisheries and wildlife effects, future potential forest management options, recreation, threatened and endangered species, additional transmountain diversions from the Williams Fork drainage, and impacts on rate payers. WILLIAMS FORK PUMPING COLLECTION SYSTEM The Williams Fork Pumping Collection System would be located in the Williams Fork drainage and would include a dam and reservoir, a pumping system, a gravity conduit, and replacement of existing water diversion facilities along the north sector of the gravity system (figure 5) . The project, as an alternative, would eliminate the need for the incomplete portions of the south sector of the Williams Fork Gravity Collection System. Water would be collected and stored in a reservoir located on the South Fork of the Williams Fork, approximately 1 mile upstream from its confluence with the Williams Fork. The reservoir would inundate a maximum of 160 acres and have a capacity ranging from 1,000 acre-feet at the minimum pool level to 13,000 acre-feet at the maximum pool. The impounded water would be released through the outlet works into a tunnel. The tunnel would connect directly to a buried conduit which would cross under the Williams Fork and enter a pump station. From the pump station, water would be conveyed upslope to the gravity pipeline. The gravity pipeline would carry water pumped from the reservoir, as well as collect water through diversion facilities in about 12 streams. Water would be collected year-round when available, but the major portion of the water would be diverted in May and June. The adjudicated water rights for the Williams Fork Gravity Collec- tion System would require legal action to obtain an alternate point of diversion and a new storage right for this alternative. This could affect the yield of these rights. The safe yield of the project may range from 13,000 to 20,000 acre-feet. 11 v .. f l W ° WWCC W YHA 0 cc W"• gLLyN Q ! w ii Q "` 3 `y Z =_ LL "qv 's WIt a .a ° 2 H o Ci OZ O ° 0a a W • • „ � .. Ni • a_ 2 W J V r • o . a i ,�` O 0 2 ° O ° O ¢ O ° O O_ ≤ < C < O • ¢• O ¢ 2 z .l ° W O W z p w v • m21 w o W a Ill a C v. 1 1 4 12 The major issues to be analyzed would include wetlands, threatened and endangered species, fisheries and wildlife effects, recreation, future potential forest management options, additional transmountain diversions from the Williams Fork drainage, and impacts on rate payers. GROSS RESERVOIR ENLARGEMENT • Gross Reservoir is located in Boulder County on South Boulder Creek, about 18 miles downstream from the Moffat Tunnel outfall and about 4.5 miles upstream from the town of Eldorado Springs (figure 6). The existing dam was constructed in the early 1950's to provide storage for the DWD's northern system, storing water diverted from the Williams Fork and Fraser River Collection Systems. Although it is discussed here as a candidate alternative to the Williams Fork gravity system, Gross Reservoir could be enlarged in addition to construction of either of the Williams Fork System alternatives. The timing of the enlarge- ment could be independent (before or after) of development of the Williams Fork System or in conjunction with that development. The reservoir at present has a maximum storage capacity of 43,000 acre-feet and a surface area of 440 acres. The enlarged dam would increase storage capacity to 113,000 acre-feet and the surface area to 800 acres. The normal maximum water level elevation would be 7400 feet. With the larger reservoir, the Fraser River and Williams Fork basins would contribute about 63 percent of the total inflow. Most South Boulder Creek water is passed through the reservoir to other water users. The enlarged reservoir would provide about 16,000 acre- feet of additional safe yield annually. The major issues to be analyzed would include wetlands, cultural resources, fisheries and wildlife effects,recreation, and threatened and endangered species. NO FEDERAL ACTION ALTERNATIVE The No Federal Action alternative assumes that no Federal permits would be granted for a water supply project. All water sources in this category, whether implemented individually or in combination, could provide water independent of Federal approvals or authorizations. Projects of this type include: water conservation, ground water developed under municipally-owned land, nonpotable water reuse, sewage exchange, and purchase or condemnation of agricultural rights. Many of these projects and actions are currently being implemented in the Denver metropolitan area. Some of the programs will be implemented whether Federal permits are granted or not because of the need for new water supplies. 13 W e Q. -- : e y = W i p O Y 1 0 rf.' J ; 3 W 7.W 2 W ; a ; 8 6 = LL we X 4°2 O W U a la < w E n 2 f.2 cc UJ • $ I '21 g 0 O' Q' CC V I y I ° LL Y. I 4 m 5 (I i c:• tom oho-N. h rt I Fa " R I y ye i / I' o. t- 1 s a s,'. a a % b ) H1 �T on�� / ie �i q 7 ov I r _ y ) - 4/ , ,-‘' ) r . ,c v Z 14 WATER CONSERVATION Water conservation measures which were considered to be potential- ly effective include: reduction of inside house water use, reduction of outside house water use, metering, and leak detection. Although these measures are categorized under No Federal Action, some of them will be implemented even if this is not the course followed. The issues to be analyzed for these measures would be socioeconomic• ▪ Retrofit. Retrofitting includes the installation of devices which reduce water used for bathing and toilet flushing. The conver- sion of existing shower heads and toilets to more water-efficient types would probably occur during normal replacement without the application of any conservation program because only low-flow toilets and shower heads are generally available. Water-saving devices have been installed in most new homes for some time. . Lawn Size Limitation. This option involves the limitation of the allowable size of irrigated areas for single-family dwellings. The amount of irrigated turf area would be limited based on a lot size to turf area formula. Local agencies would issue a permit prior to in- stallation of a lawn. The permit application would require submission of a landscape plan designating turf and nonturf areas. . Metering. The installation of water meters would provide a means to measure consumption. Water use would be reduced as a result of consumer awareness of use and the requirement to pay for the water used. . Leak Detection. A leak detection program similar to that currently used by the DWD would use electronic equipment to detect line leaks in the distribution systems of the other metropolitan area water providers. Corrective measures would reduce distribution system losses throughout the demand area. A summary of potential yields of the various water conservation measures is presented in table 3. It should be noted that the yields of these conservation practices are not necessarily additive. 15 Table 3 Summary of Yield Data for Water Conservation Lawn Size Universal Leak Retrofit Limitation Metering Detection Implementation 5 50 6 50 period (years) Potential safe 1070 — 11,600 290 (year 1) 12,500 (year 5,000 to yield (acre— to 14,500 6+) 6,000 feet per year) (year 50) GROUND WATER DEVELOPMENT UNDER MUNICIPALLY-OWNED LAND Ground water will continue to be developed independently by individuals and water providers. The water source could be both an alternative under No Federal Action and a major project that would be sponsored by a water provider. Project alternatives under this latter category are described under Other Water Sources. The four major Denver basin bedrock aquifers in the Systemwide EIS demand area, the Dawson, Denver, Arapahoe, and Laramie-Fox Hills, are considered to be nontributary in many or most areas to the surface waters of the South Platte River system. The actual status of ground water (tributary or nontributary) often can only be determined after a site-specific investigation. Under current State law, all of the nontributary ground water would be available for appropriation and 1 percent of the amount of water in storage could be withdrawn each year. As of 1982, production of approximately 164,000 acre-feet per year of water had been decreed or permitted. As much as 2,100,000 acre-feet per year may be available for development each year within the limits set by Senate Bill 213. The amount of nontributary ground water available in the four aquifers beneath municipally-owned lands is estimated for any lands approximately 50 acres or larger in area that are owned, or proposed to be owned, by the municipality. They include parks, golf courses, and designated open spaces. The amount of water potentially available from municipally-owned lands ranges from 19 acre-feet to 2,600 acre-feet. One percent of this could be withdrawn annually. NONPOTABLE WATER REUSE The parks, golf courses, greenbelts, and public areas that receive summertime irrigation water are considered potential uses of nonpotable reuse water as well as major industrial users who do not require potable-quality water. Wastewater treatment plants having a present flow rate of 2 million gallons per day (MGD), or 6 acre-feet per day, 16 (the Metropolitan Denver Sewage Disposal District No. 1 Central Plant (MDSDD No. 1) and the Littleton/Englewood plant) would be analyzed as sources of nonpotable reuse water. Nonpotable reuse may provide approximately 3,000 to 11,000 acre-feet of water every year. Implementation of a nonpotable reuse program would require con- struction of a filtration facility, a reservoir, pumping stations, and conveyance lines under different reuse programs. Public acceptance and water quality would be the major issues analyzed. SEWAGE EXCHANGE Sewage exchange would be accomplished using accounting methods in which transmountain raw water would be the source of the additional water yield. Under Colorado water law, transmountain water can be totally utilized by the water supplier within certain limitations. Sewage exchange opportunities could be possible with water diverted from the Colorado River basin to the South Platte River basin by the DWD, the city of Aurora, and the city of Englewood. Aurora and Engle- wood would have rights which would be junior to the DWD's and probably would not provide additional safe yield to the water supplies of the metropolitan area. The DWD exchange potential would involve the exchange of waste- water effuent at the MDSDD No. 1 for raw water at the DWD's Denver Intake. The DWD has the senior water rights for exchange on the South Platte River. This water source would be most functional during the summer, especially during drought periods when tributary South Platte River flows are low and water demand is high. The safe yield from sewage exchange could be between 12,000 and 14,000 acre-feet per year. It has been suggested that operational efficiences of a DWD exchange could be improved by the construction of a storage reservoir but studies have indicated that this may not be the case. PURCHASE OR CONDEMNATION OF AGRICULTURAL RIGHTS The potential for increasing safe yield through the purchase or condemnation of agricultural rights is based on the utilization of existing water supply systems without major structural additions. The only agricultural rights of value under these conditions would be those which are upstream from existing diversion points to water supply systems or those whose yield could be transferred to an existing diversion or storage facility. Agricultural water from the Williams Fork and the Fraser, Blue, and South Platte Rivers could meet these criteria. The only area which could yield significant amounts of water to most of the Denver metropolitan suppliers, however, would be the South Platte River basin from Denver downstream to Greeley. Enough agricul- tural water is used between Denver and Greeley that the investigation 17 of water further downstream would be unnecessary. The major water suppliers undoubtedly would continue to purchase water rights that would be useful to them as the rights come on the market, but the main advantage of such purchases would be to smaller providers for whom a relatively small increase in safe yield could be significant. Condem- nation is likely to occur if no action to develop other water resources is taken. OTHER WATER SOURCES EAST GORE COLLECTION SYSTEM The East Gore Collection system is considered to be a project that may be proposed in the long-term future because of institutional contraints. The water source would be located on the eastern slope of the Gore Range, paralleling the Blue River between Dillon and Green Mountain Reservoirs (figure 7) and would generally be within Arapaho National Forest , with parts of it extending into the Eagles Nest Wilderness. The system would divert water from tributaries of the Blue River and convey it to Dillon Reservoir by gravity. Assuming the water rights are adjudicated, the safe yield would be 30,000 acre-feet only if replacement water on the West Slope was available. If East Slope storage was available, the safe yield would be increased to about 58,000 acre-feet. If neither West Slope nor East Slope storage was available, there would be no safe yield. EAGLE—PINEY/EAGLE-COLORADO COLLECTION SYSTEM The Eagle-Piney/Eagle-Colorado Collection System is considered to be a potential future water source because of unresolved institutional issues, high cost, and its lengthy (31 years) construction time. The system would extend west from Dillon Reservoir. Water would be divert- ed from the Eagle, Piney, and Colorado Rivers into a pipeline and tunnel conveyance system which would terminate at Dillon Reservoir (figure 8). The water would be conveyed to Dillon Reservoir by a combination of gravity and pumping. The system would include Piney Reservoir, Eagle-Colorado Reser- voir, 39 stream diversion structures, 62 miles of tunnel, 22 miles of conduit, and pumping plants on the Eagle and Colorado Rivers and the outlet from Eagle-Colorado Reservoir. The safe yield of the Eagle- Piney/Eagle-Colorado system would range from 144,000 to 169,000 acre- feet. GREEN MOUNTAIN EXCHANGE The Green Mountain Exchange is considered a project that could be developed some time in the future because of the complex institutional issues and the lack of specific project definition, including engineer- ing and other technical data, which must be resolved and developed 18 Z • �.. O • - >f d « o w • c./ cr /� z i ro 1 0 0CC m E o O w g d W ~ d _ N Q A-- p --(-21-1---- U in h. OC J iiii�, 10 W 0A�!/ — Z > T- = 4 O �� H a W ti O O LJ.I CC ° J 1 al c LLO co WW a O ZU / CC - W 1 , p "" \ W i W CD 7 `yr, 3 N / / O m / q W W CC \ Z U. / H \N 1 Ca I CC / f .W \ W fikl toe. fon) 11.1 I 1. U. N 1 W N c 11- /2lNz` In T W Q o �, 1 y N C «Z d cc T C7 � W0 Ww UJ j- O_ O OH ZZ � �/ > d UV � CCa F VI > rn W u Q O d Q ci � E ° If)J U J D Q O E , n h O `..�. d N 9 W0 W CO E d Y a O T o I" / • w z l o elizQ� o \ / «eau f� , ,� \ �1 z 0 CC �/t -'�� I z LL/20 Z CC WO CC LU :<,.\\1<::„..._:,:wil (1:1,7/11- II` � _ ��- " - J /\ �,l�ln x • � v '��T �j, d��lll/glllli� / m - Q' ! � o VVmiiilP�lli w w� al _ <¢ '11 � /� °a I O¢ a HI z O� w 21 I �w -I 0 1i' w w 2 _ iii W 5 , Sr) H . O Y �, �� Q � ;�,iodiiiI °'III co-- Jy & , G. UU w $2 . I- , • WWW o\ 0 ILJJJ QQDV WWV E °'E u 20 '. prior to its further evaluation. A representative Green Mountain system could be located within the Eagle and Blue River basins in Eagle and Summit Counties (figure 9). This project would consist of two discrete, physically unconnected components: (1) a pressurized pipe- line to pump water from the existing Green Mountain Reservoir (a Bureau of Reclamation reservoir) to Dillon Reservoir and (2) a new downstream reservoir to replace the current functions of Green Mountain Reservoir. The project would pump water from Green Mountain Reservoir on the Blue River to the DWD Roberts Tunnel system in exchange for water from the Eagle River. Water could be diverted from the Eagle River to an off-channel reservoir and released to meet the water demands currently supplied by releases from Green Mountain Reservoir. The project may produce a safe yield of between 60,000 and 112,000 acre-feet per year. The DWD and the Colorado River Water Conservation District pres- ently have an application pending before the Colorado Water Resources and Power Development Authority for a reconnaissance study of the Green Mountain Exchange. IMPORTATION The importation of water from the Missouri River basin is con- sidered a potential future water source because of the lack of techni- cal detail and the institutional issues which would be involved. Two Missouri River importation concepts were identified. One would involve Denver water suppliers participating in a water pipeline that would convey Missouri River water for synthetic fuel (synfuel) production in Wyoming and Colorado. The other would be a single-purpose water supply pipeline from the Missouri River to Denver (figure 10). The synfuel water pipeline route would consist of a pipeline originating at Oahe Reservoir in central South Dakota and extending southwest through Nebraska, Wyoming, and into Colorado. The synfuel water pipeline would be about 550 miles long with a branch to Wyoming and a branch to Denver. The branch to Denver would be about 170 miles long. Three alternative routes for a single-purpose Denver water supply pipeline were considered, and a pipeline starting at Oahe Reservoir and running southwest to Denver, with a length of about 470 miles, appears to be the most feasible. The route from Oahe Reservoir to Denver had the lowest annual cost and was selected as the preferred single-purpose Denver water supply pipeline route. The yield of importation could range between 50,000 and 300,000 acre-feet per year. 21 cc z> P. = O¢ OJ W .-i J W z c OG z ❑ uz s< DJ 66 40110 , ` • d a 0 O �•� + m gilliffit:, saus ��f ,:0 °4%,41:' z •��7n k n�n W W tCC .'a — II rV : • p\� lli J i•-• NI• •' J a u z te of ti? 1,4 nil /' Q 0 w%l '� y W H W 4 °' MZ 4. m p Q Cr 044, W m CC F a z F Z x x do o I:— II CUJ C —1-/ W CC et Ill U.1 IX 22 Figure 10 WATER IMPORTATION r---- - SOUTH DAKOTA 0 s s - A I ill nuns • tt 4. °CITY . O WYOMING lry / -__ s i, -WATER IMPORTATION 4 k . # • ROUTE • • ?--- • 11 ■ M NEBRASKA • ♦ `'rr >1" ■ ft,r cericNEr NE 00 P. W , t v RC 68. i SOU" r DENVER 7 S� COLORADO NORTH o so too le O COLORADO V SPRINGS SCALE IN MILES e a 23 POTABLE REUSE A DWD. demonstration plant to produce 1 million gallons per day (MGD) , or approximately 1,120 acre-feet per year, of potable water is scheduled for implementation in 1984. Potable reuse has been classi- fied as a long-term water source pending test results from the demon- stration plant over a minimum of 7 years. If the pilot plant proves that it is a reliable water source from health and operational perspectives, the system may be expanded to 100 MGD, or 112,000 acre-feet per year. However, the function of the potable reuse plant would be to reduce some peaking requirements and normalize some of the seasonal demands. Therefore, continuous opera- tion at capacity is not contemplated and the potential available potable water is estimated to be about 40,000 acre-feet per year of safe yield. An expansion to 100 MGD assumes additional transmountain diversion because the existing volume does not provide this amount and Colorado water law does not allow the reuse of in-basin return flows. WATERSHED VEGETATION MANAGEMENT Watershed vegetation management is considered to be a future water source because of institutional issues which must be resolved prior to its implementation. The project would involve the removal of 40 percent of the timber above 9000 feet in elevation, with buffer zones along stream courses. The timber would be clearcut in patches. It is estimated that for every 640 acres (1 square mile) harvested, 4 miles of roads would be required for timber removal. Management and land owner- ship constraints would limit the possible use of watershed vegetation management by the DWD to the South Platte River basin where, it has been estimated, the cutting of 111,300 acres could result in an in- creased runoff of 1,900 acre-feet. The ownership of the water would, however, be constrained by minimum flow bypasses and the interplay of water rights and calls. WEATHER MODIFICATION Weather modification has been classified as a future water source because of unresolved institutional issues concerning the ownership of the water produced and the relatively experimental nature of the method. Use of weather modification would involve the injection of silver iodide or solidified carbon dioxide into clouds in order to increase precipitation. While it is feasible that weather modification could increase runoff by 10 percent in the areas where it is applied, there is no direct correlation to an increase in divertible yield because of minimum flow bypasses and the interplay of water rights and calls. The method could be utilized on both the East Slope and West Slope. 24 STRAIGHT CREEK COLLECTION SYSTEM The Straight Creek project would consist of an existing diversion dam in Straight Creek and an enclosed conveyance conduit from Straight Creek to Dillon Reservoir (figure 11), a distance of 1.8 miles. The project would be within the alignment of the Oro Grande No. 2 Canal, cross under U.S. Highway 6 , and then parallel U.S. Highway 6 and discharge into Dillon Reservoir. The outlet would be located below the normal maximum reservoir level. The project could provide a safe yield of 3,500 to 7,000 acre-feet annually. GROUND WATER The potential exists for the development of a major ground water program some time in the future. The development of ground water could require resolution of technical and institutional issues before a specific project can be defined. Currently none of the metropolitan water providers have proposed such a project. While ground water is currently a water source for some water providers, options for developing and using ground water under this category include: development of ground water under municipal boundaries, development of a satellite well field, utilization of ground water in dry years only, and deep well recharge. The following briefly describes these projects. . Ground Water Potentially Available Under Municipal Boundaries. Several municipalities in the Denver metropolitan area could utilize this ground water source. The total amount of potentially available water ranges from 130 acre-feet per year to 39,700 acre-feet per year. To appropriate the full amount of nontributary water available under city boundaries, the municipalities would have to obtain the rights to the ground water by owning the land or by obtaining the consent of the overlying land owners to develop the water. Presently, without the consent of the landowners, cities cannot develop the water in the aquifers beneath their city limits. . Satellite Well Field. To examine the feasibility of a large metropolitan water supplier utilizing ground water in the Denver basin aquifers as a source of water, a hypothetical, large-capacity well field is considered an alternative. The hypothetical well field is located in a 36-square mile area immediately east of the town of Parker. Ground water available from the four aquifers is estimated to range from 17,000 to 30,000 acre-feet annually, depending on the mode of operation of the well field. • Dry Year Alternative. This water source would incorporate ground water from existing wells of other Denver metropolitan area water distributors into the DWD distribution system. In return, the DWD would be responsible for providing a water supply to those con— sumers who had previously been receiving the well water. The DWD would 25 CO u_ wN Y W I Y o H . W y Wt g W : .. CC } °o� o W3 '' VN 4 a0= 0 • W . ` Z W Z <N= x c 3 2 9 = OU. m fOW 2 /'RR o a C7¢d - i F i - • Z o Z.O w 2 Y ° W W W R D N en t J / a m W 0 ' I Q r\ .1 N " a , { c. 2 i • J• e T s �6 • l; ' o t i Ii � a � l . • .-, e o _ • 11: -- - -- - u .l i i g I 2 4E . : .i G • 26 operate and maintain the wells. The DWD would supply the additional consumers from their surface water system during normal and wet periods when an excess of surface water would be available. The wells would be reactivated during drought periods and the additional consumers would be supplied from the wells that had been their original sources of water. Assuming that the physical operation was practicable, the DWD would simultaneously acquire an additional demand and the ground water supply that had previously met that demand. Thus, yield would be dependent on any well capacity excess over demand previously served. . Deep Well Recharge. Deep well recharge of the Denver basin aquifers would be one method of maintaining high ground water levels and replenishing depleted supplies. Recharge may provide the following benefits by retarding possible overdraft of a ground water basin: (1) lower operating costs for ground water suppliers by reducing pumping lifts; (2) extended useful life of the aquifer by decreasing the effects of "mining" the ground water; and (3) prevented or minimized land subsidence by sustaining pressure in aquifers' water levels. Also, storage of water in deep aquifers is relatively safe from contam— ination and less land area is required for ground water storage and recharge than for surface water storage. Although no specific data are available for the cost of artificial recharge to deep aquifers, it is believed to be relatively expensive and probably is not economical at this time. BEAR CREEK LAKE OPERATIONAL CHANGES Bear Creek Lake is located on Bear Creek about 8 miles upstream from its confluence with the South Platte River (figure 12). The enlargement of the reservoir would include an increase of 3 feet in the height of the embankment, an intake structure, and riprap. Determina- tion of the yield from additional storage in the reservoir could be made only after determining the water rights, the system in which they would be used, and the operating criteria to be imposed. JOINT USE RESERVOIR According to the draft Governor's Metropolitan Water Roundtable agreement of 15 April 1983, eastern Colorado will finance and construct a Joint Use Reservoir on the West Slope if a variety of conditions are met, including that the water from the reservoir will be available for eastern Colorado use prior to delivery of water from Two Forks Reser- voir, if constructed. The Joint Use Reservoir would be constructed at a mutually agreed-on location and would be utilized by eastern Colorado to produce water by exchange or replacement through Roberts Tunnel. The draft agreement contemplated that joint use storage would be constructed at a cost not to exceed $40 million and would yield at least 30,000 acre-feet per year. This water source would be utilized initially by the East Slope; however, upon completion of Two Forks, West Slope interests would have the option of purchasing up to half of 27 Figure 1 2 BEAR CREEK LAKE PARK EXISTING FACILITIES AND WATER SURFACE AREA /. \ � i > r l \ \ so \--- 4 �a ,, eor lee ~ ,__.f `' ✓ / \. ...... \ 7 l 2 / %� I I \ 1 t j4� \ 7 4,0f e I / Gee �. I-285 / ,_„.2:1______- / / t' /O LEGEND //;/ SURFACE WATER / � NORTH -- BEAR CREEK LAKE PARK BOUNDARY 1. CAMPGROUND / 2. SWIMBEACH 3. SHOOTING RANGE 0 1/2 1 L-L-_-1 '--+ ------ I MILES 4. BOAT RAMP / PARKING LOT SCALE 5. PICNIC SHELTER 28 the reservoir's yield. The draft agreement has not been ratified by all of the interested parties and until a fully negotiated agreement is accepted by all parties, the elements of the agreement are tentative. The DWD and the Colorado River Water Conservation District presently have an application pending before the Colorado Water Resources and Power Development Authority for a reconnaissance study of the Joint Use Reservoir. Preliminary examination has been given to eleven reservoir sites. These include Azure, DeBerard, Eagle-Colorado, Haypark, Iron Mountain, Lower Piney, Lower Rock Creek, Una, Upper Rock Creek, Ute Creek and Wolford Mountain. Other sites may exist, but have not been included in this analysis. All but Una are located upstream from the Shoshone diversion and could be used to help satisfy that call. Engineering features and storage capacity for each reservoir are presented in table 4. JOINT USE OF EXISTING SYSTEMS The joint use of existing systems consists of a review of the metropolitan water providers, the existing safe yield for dry year conditione;, and future water demand. Providers with surplus water are analyzed to determine whether it would be practical to incorporate any existing surplus water into the systems of other suppliers which do not have sufficient supplies to meet their demands. The joint use of existing systems is not a new water source in that it would utilize existing water resources and would not add water to the safe yield of the Denver metropolitan area supply. Joint use in some instances may increase the time before a water supplier would have to develop a major new water source. Joint use would only be feasible with the development of another source since increased demand could not be supplied without an increase in safe yield. 29 Table 4 Joint Use Reservoir Engineering Storage Reservoir Location Features Capacity (acre-feet) Azure Colorado River in Concrete arch dam 23,000 Gore Canyon, Grand and reservoir County, 9 miles southwest of Kremmling DeBerard Muddy -Creek, Grand Dam and reservoir 31,000 County, approximate- ly 20 miles north of Kremmling Eagle- Alkali Creek, Eagle Earth embankment dam, 230,000 to Colorado County, approximately reservoir, pumping 350,000 1 mile north of Wol- facilities (water cott would come from Eagle River) Haypark East Fork of Earthfilled dam 22,000 Troublesome Creek, . and reservoir Grand County, 12 miles north of _ Kremmling Iron Homestake Creek, Earthfilled, rock- 100,000 Mountain Eagle County, less filled, or concrete than 1 mile south gravity dam and of Redcliff reservoir and possi- ble hydroelectric facilities and Eagle River diversion Lower Piney River, Eagle Earthfilled dam and 35,000 Piney County, 1 mile reservoir upstream from Colorado River Lower Rock Creek, Routt Earthfilled dam and 110,000 Rock Creek County, 0.75 mile reservoir upstream from McCoy 30 Table 4 (continued) Joint Use Reservoir Engineering Storage Reservoir Location Features Capacity (acre-feet) Una Colorado River, Mesa Earthfill dam, reser- 189,000 and Garfield Counties, voir, and hydroelectric between DeBeque and facilities Parachute Upper Rock Rock Creek, Routt Dam and reservoir 50,000 Creek County, 11 miles north of McCoy Ute Creek Ute Creek, Eagle Dam and reservoir, 35,000 County, 0.5 mile diversion on Eagle upstream from River, pumps and pipe- Eagle River line Wolford Muddy Creek, Grand Earthfilled dam and 60,000 to Mountain County, 1 to 4 miles reservoir 117,000 north of Kremmling 31 Hello