COLORADO This publication is authorized by the Secretary of the Army as required by PL 99-662

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-*/» ■** ■ * > ,< * . Partnership has changed the way we do business. It has committed us to pursue new strategies to deal with old problems. We are also finding that partnerships mean results.

With a civil works program of more than $3 billion annually, the Army Corps of Engineers is the largest water resources development and management agency in the Federal Government. The civil works program consists of water resources project activities — planning, design, construction, operation and maintenance, and regulatory program activities.

Numerous navigation and flood control projects serve additional purposes. The Corps produces nearly 30 percent of the Nation’s hydropower. The 115 Corps lakes store 275.2 million acre-feet of water for agricultural, municipal, and industrial use.

In the 1930’s and 1940’s, many of the Corps reservoirs were built for a host of benefits, including reducing flood stages on the Lower Mississippi River. Last year, the drought clearly illustrated the capability of Corps multiple-purpose reservoirs to respond in a water shortage situation. Undertakings such as the Pick-Sloan plan, with its six main stem dams on the Missouri River, bequeathed an unforeseen legacy to the Nation — stable, low-water flows on the Lower Mississippi.

We, in the Army, look forward to continuing this public service. The Corps of Engineers’ qualifications to provide construction management services to other military and civilian Federal agencies are greatly bolstered by our major new management initiatives. Commitment to efficient project management — making solid cost estimates, delivering projects on schedule and within the estimate, controlling costs — demonstrates our resolve to responsibly serve the Nation. We are counting on you, as partners, to help us make sure the Nation’s resources are put to good use.

ROBERT W. PAGE Assistant Secretary of the Army (Civil Works) 2 The U.S. Army Corps of Engineers entered a new era with the passage of the Water Resources Development Act of 1986. The act’s non-Federal cost-sharing provisions focused on an entirely different manner of doing business. With our cost-sharing partners, we are finding new and innovative ways to manage water resources projects and reduce costs to American taxpayers.

Our partners are paying not only large portions of the construction costs but also large portions of the study costs. Over the past 3 years, this partnership has completed a smooth transition that will provide a healthy water resources program for the future.

In the summer of 1988, a natural disaster brought home the importance of such a program. America was in the middle of a massive drought, one that rivaled the Dust Bowl days of the 1930’s. But, there was a difference. The Nation did not totally dry up. Aided by water resources projects built since the years of the Great Depression, the Corps was able to do a lot of things to aid navigation, water supply, and hydropower operation — even recreation.

If it were not for the massive reservoirs throughout the tributaries of the Mississippi River, navigation on the mightiest of rivers would have stopped in June — absolutely! During the summer and into the fall, some 65 percent of the flows into the Mississippi, past Memphis, came from Corps of Engineers reservoirs.

In addition, our lakes and dams enhance our national stewardship of the environment. Nine of the 191 finalists in last year’s “ Take Pride in America” awards program helped protect public lands at Corps of Engineers projects. These finalists were selected from 530 nominations representing 44 States, the District of Columbia, and Puerto Rico.

We are proud of our Take Pride in America finalists, and we are proud of our projects. But, most of all, we are proud of the new-found partnerships that will continue to build and operate our vital water resources for our future generations.

This booklet is one of a series detailing water resources programs in the 50 States and U.S. possessions. I hope you find it interesting and feel some pride of ownership.

H. J. HATCH Lieutenant General, USA Chief of Engineers US Army Corps of Engineers Missouri River Division

The address of each Corps of Engineers office in­ volved in the State is given below, and the area of 1989 responsibility of each is indicated on the map in Chapter I of this booklet. Inquiries regarding the work of the Corps should be addressed to the ap­ COLORADO propriate office. DIVISION ENGINEER DEPARTMENT OF THE ARMY WATER MISSOURI RIVER DIVISION Corps of Engineers P.O. Box 103, Downtown Station Omaha, Nebraska 68101-0103 RESOURCES DISTRICT ENGINEER DEPARTMENT OF THE ARMY Omaha District, Corps of Engineers 215 North 17th Street DEVELOPMENT Omaha, Nebraska 68102-4978 DISTRICT ENGINEER DEPARTMENT OF THE ARMY Kansas City District, Corps of Engineers 700 Federal Building Kansas City, Missouri 64106-2896 DIVISION ENGINEER DEPARTMENT OF THE ARMY SOUTHWESTERN DIVISION Corps of Engineers 1114 Commerce Street Dallas, Texas 75242-0216 DISTRICT ENGINEER DEPARTMENT OF THE ARMY Albuquerque District, Corps of Engineers P.O. Box 1580 Albuquerque, New Mexico 87103-1580 DIVISION ENGINEER DEPARTMENT OF THE ARMY SOUTH PACIFIC DIVISION Corps of Engineers 630 Sansome Street, Room 720 San Francisto, California 94111-2206 DISTRICT ENGINEER DEPARTMENT OF THE ARMY Sacramento District, Corps of Engineers 650 Capitol Mall Sacramento, California 95814-4794

4 Table of Contents Chapter I: Civil Works Overview Chapter III: Upper Colorado River Basin Introduction...... 7 Work Under the Continuing Authorities Program .. .25 Authorization and Planning Process Snagging and Clearing for Flood Control...... 25 for Water Resources Projects ...... 7 Emergency Bank Protection...... 26 Navigation...... 7 Work Under the Technical Assistance Program s---- 26 Flood Control and Flood Plain Management Services Program...... 26 Flood Plain Management...... 7 Flood Plain Information Reports ...... 26 Shore and Hurricane Protection...... 8 Special Flood Hazard Information Reports...... 27 Hydropower...... 8 Planning Assistance to States...... 27 Water Supply...... 8 Work Under Emergency Authorities ...... 27 Environmental Quality...... 8 Public Law 99, 84th Congress— Regulatory Programs...... 9 Flood-Associated Assistance...... 27 Recreation...... 9 Public Law 93-288—Major Disaster Recovery.. .27 Emergency Response and Recovery...... 9 Survey Investigations...... 27 Chapter II: Platte River and Kansas River Basins Chapter IV: Arkansas River, Rio Grande, and Completed Flood Control Projects...... 11 Cimarron River Basins Cherry Creek Dam and L ak e...... 11 Completed Multiple-Purpose Projects...... 29 Bear Creek Dam and L ake...... 12 John Martin Reservoir Project...... 29 Chat field Dam and Lake...... 12 Trinidad Lake...... 29 Multiple-Purpose Projects Underway...... 13 Completed Flood Control Projects...... 30 Comprehensive Plan, Missouri River Basin...... 13 Willow Creek Channel Improvement...... 30 Flood Control Projects Underway...... 15 Pueblo Floodway Levee Extension...... 30 Westerly Creek...... 15 Templeton Gap Floodway ...... 30 Associated Projects of Other Agencies...... 15 Las Animas Flood Control Project...... 30 Bonny Reservoir...... 15 Associated Projects of Other Agencies...... 31 Work Under the Continuing Authorities Program ... 16 Platoro Reservoir...... 31 Small Flood Control Projects...... 16 Fryingpan-Arkansas P roject...... 31 Emergency Bank Protection...... 16 Work Under the Continuing Authorities Program ... 31 Work Under the Technical Assistance Programs .... 17 Small Flood Control Projects...... 31 Flood Plain Management Services Program...... 17 Snagging and Clearing for Flood Control...... 31 Flood Plain Information Reports ...... 17 Emergency Bank Protection...... 32 Special Flood Hazard Information Reports...... 18 Work Under the Technical Assistance Program s___32 Planning Assistance to States...... 18 Flood Plain Management Services Program...... 32 Technical and Engineering Assistance on Flood Plain Information Reports ...... 32 Shore and Streambank Erosion...... 19 Special Flood Hazard Information Reports...... 32 Work Under Emergency Authorities ...... 19 / Planning Assistance to States...... 32 Public Law 99, 84th Congress— Work Under Emergency Authorities...... 32 Flood-Associated Assistance...... 19 Public Law 99, 84th Congress— Major Flood Emergency Operations...... 19 Flood-Associated Assistance...... 32 Survey Investigations...... 19 Survey Investigations...... 33 Urban Studies...... 23 In d e x ...... 34 Special Studies...... 23 Metropolitan Denver Water Supply G lo ssary ...... 36 Environmental Impact Statement...... 23

5 Chapter I Civil Works Overview

6 well as the need for the improvements. The desires of local Civil Works Overview interests and the views of Federal, State, and other agencies Introduction receive full consideration during the planning process. From 1775 to the present, the U.S. Army Corps of Engi­ Considerations which enter into recommendations for proj­ neers has served our Nation in peace and war. ect authorization to Congress include determinations that benefits will exceed costs and that the engineering design of Formed by General George Washington during the Revolu­ the project is sound, best serves the needs of the people con­ tionary War as the engineering and construction arm of the cerned, makes the wisest possible use of the natural re­ Continental Army, the Corps built fortifications and coastal sources involved, and adequately protects the environment. batteries to strengthen our country’s defenses and went on to develop our Nation’s water resources. Today, it is the A report, along with an environmental impact analysis, is largest engineering organization in the world. then submitted to higher authority for review and recom­ mendations. After review and coordination with all inter­ Although the mission of the Corps has always been to pro­ ested Federal agencies and Governors of affected States, the vide combat support to our fighting Army, the Nation over Chief of Engineers forwards the report which includes the the years has also needed roads, railroads, lighthouses, environmental impact analysis to the Secretary of the Army, bridges, and other engineering work. Consequently, since who obtains the view of the Office of Management and the period immediately following the Revolutionary War, Budget before transmitting the report to Congress. the Corps has carried out numerous civil works responsibil­ ities; and since the early 1800’s, it has been the Federal Gov­ If Congress includes the project in an authorization bill, en­ ernment’s principal developer of our Nation’s water re­ actment of the bill constitutes authorization of the project. sources. Once a project is authorized, further studies may be re­ quired to confirm the basic plan presented to Congress. The Corps is an Army Major Command, and the Assistant Secretary of the Army (Civil Works) directs and supervises Appropriation of money to build a particular project is the Corps’ civil works mission carried out by its 300 engineer usually included in the annual Energy and Water Develop­ officers and 28,000 civilian employees. ment Appropriations Bill, which must be approved by both Houses of the Congress and the President. Ever responsive to the changing needs and demands of the American people, the Corps has planned and executed Budget recommendations are based on evidence of support national programs for navigation, flood control and flood by the State and by the ability and willingness of non- plain management, shore and hurricane protection, hydro- Federal sponsors to provide their share of the project cost. power, water supply, environmental quality, regulatory pro­ grams, recreation, emergency response and recovery, and Navigation conservation. In its military role, the Corps plans, designs, Federal interest in navigation improvements stems from the and supervises the construction of modern facilities which Commerce Clause of the Constitution and from subsequent are necessary to ensure the combat readiness of our Army decisions of the Supreme Court to the effect that the Federal and Air Force. obligation to regulate navigation and commerce also in­ cludes the right to make necessary improvements. The Authorization and Planning Process Corps of Engineers was first assigned responsibility for im­ for Water Resources Projects proving rivers and harbors in 1824. Today, the Corps is re­ sponsible for construction of, as well as operation and main­ Water resources activities are initiated by local interests, tenance of, Federal river and harbor projects. authorized by Congress, funded by Federal and non-Federal The system of harbors and inland waterways remains one of sources, and constructed by the Corps under the Civil the most important parts of our Nation’s transportation sys­ Works Program. tem. Without constant supervision, rivers and other water­ The Water Resources Development Act of 1986 made nu­ ways collect soil, debris, and other types of obstacles which merous changes in the way potential new water resources lead to groundings and wrecks. New channels and cutoffs projects are studied, evaluated, and funded. The major appear frequently; they and the main traffic lanes require change is that the law now specifies non-Federal cost­ diligent patrolling. Where authorized to do so, the Corps sharing for most of the Corps’ water resources projects. maintains our Nation’s waterways in navigable condition When local interests feel that a need exists for improved for both business and recreational purposes, benefiting the navigation, flood protection, or other water resources devel­ economy and helping prevent the loss of lives. opment, they may petition their representatives in Congress, although technical assistance and some small projects can be Flood Control and Flood accomplished without congressional authorization under the Plain Management Continuing Authorities Program. A congressional com­ mittee resolution or an act of Congress may then authorize Federal interest in flood control began in the alluvial valley the Corps of Engineers to investigate the problem and of the Mississippi River in the 19th century when the interre­ submit a report. lationship of flood control and navigation became apparent. Corps authority for flood control work was extended in Water resources studies, except studies of the inland water­ 1936 to embrace the entire country. After a series of dis­ ways system, are conducted in partnership with a local spon­ astrous floods affecting wide areas, including transportation sor. The Corps and the sponsor jointly fund and manage the systems, it was recognized that the Federal Government study. should participate in the solution of problems affecting the Public meetings are held to determine the views of local in­ public interest when they are too large or cornolex |P hie han­ terests on the extent and types of improvements desired, as dled by State or local organizations. LIBRARY

mn"m 7 The purpose of flood control works is to regulate floodflows multiple-purpose dams. In a series of laws and resolutions and thus prevent flood damage. In addition, the Flood Con­ dating back to the River and Harbor Act of 1909, Congress trol Act of 1944 provided that “flood control” shall include has directed the Corps of Engineers to give consideration in channel and major drainage improvements. These objec­ its reports to various water uses, including hydroelectric tives are accomplished with structural measures* such as res­ power. ervoirs and local protection works, or with nonstructural The Corps continues to consider the potential for hydro­ measures which alter the way people would otherwise electric power development during the planning process for occupy or use the flood plain. all water resources projects involving dams and reservoirs. Reservoirs constructed for flood control storage often in­ In most instances, however, hydropower facilities at Corps clude additional storage capacity for multiple-purpose uses projects are now developed by non-Federal interests without such as water for municipal and industrial use, navigation, Federal assistance. The Corps becomes involved with plan­ irrigation, development of hydroelectric power, conserva­ ning, constructing, and operating hydropower projects only tion of fish and wildlife, and recreation. when it is impractical for non-Federal interests to do so. Local protection works are turned over to non-Federal authorities for maintenance, as are small reservoirs with a Water Supply local impact. Water supply is of vital interest to the economy and security The Corps fights our Nation’s flood problems not only by of our Nation. Full consideration is given to water supply in constructing and maintaining flood control structures but the planning, construction, and operation of river basin also by providing detailed technical information on flood works. Under Section 6 of the Flood Control Act of 1944, hazards. Under the Flood Plain Management Services Pro­ the Secretary of the Army is authorized to make contracts gram, the Corps provides (on request) flood hazard infor­ with States, municipalities, private concerns, or individuals mation, technical assistance, and planning guidance to other for domestic and industrial use of surplus water that may be Federal agencies, States, local governments, and private in­ available at Corps of Engineers reservoir projects. The dividuals. These items are designed to be an aid in planning Water Supply Act of 1958, as amended, establishes a policy for floods and providing for the regulation of flood plain of Federal participation and cooperation with States and areas, thus avoiding unwise development in flood-prone local interests in developing water supplies for domestic, areas. As an example, if community officials know what municipal, and industrial purposes in connection with Fed­ areas flood in their community and how often this could eral navigation, flood control, or multiple-purpose projects. occur, they then can take necessary action to prevent or Under this act, the Corps can include storage space for minimize damages to existing and new buildings and facil­ municipal and industrial water supply purposes in reser­ ities by adopting and enforcing zoning ordinances, building voirs, provided this is the best use of the resource and non- codes, and subdivision regulations. Federal interests assume the financial responsibility of the full costs. The most recent amendment to the 1958 act is in The Flood Plain Management Services Program also pro­ the Water Resources Development Act of 1986. vides assistance to other Federal agencies and to State agen­ cies in the same manner. Flood hazard data are developed Section 8 of the Flood Control Act of 1944 provides that and provided on request to the extent and detail needed so Corps dam and reservoir projects may be used for irrigation that those agencies can properly consider the flood hazards in the 17 Western States if recommended by the Secretary of in the execution of their programs. the Interior in conformance with the Reclamation Act of 1902. In other States, the Water Resources Development Act of 1986 permits the inclusion of agricultural water Shore and Hurricane Protection supply storage in Corps reservoir projects and establishes that non-Federal interests should pay 35 percent of the con­ The Corps’ work in shore protection began in 1930, when struction costs and 100 percent of the operation, mainte­ Congress directed the Corps to study ways to reduce erosion nance, and replacement costs. along U.S. seacoasts and the Great Lakes. Although each situation the Corps studies requires different considerations, Environmental Quality engineers look at each one with structural and nonstructural solutions in mind. Engineering feasibility and economic effi­ In conducting its Civil Works Program, the Corps must ciency are considered along with the environmental and comply with many environmental laws or Executive orders social impacts. and numerous regulations relating to the environment. Con­ Recommendation for Federal participation is based on sideration of the environmental impact of a Corps project shore ownership, use, and type and the incidence of bene­ begins in the early stages and continues through design, con­ fits. If there is no public use or benefit, Federal participation struction, and operation of the project. The Corps must also is not recommended. Maintenance of the restored shore is a comply with many of these environmental regulations in conducting its regulatory programs as discussed below. The non-Federal responsibility. National Environmental Policy Act (NEPA) of 1969 is the The Corps’ work in hurricane protection began in 1955, national charter for the protection of the environment, and when Congress directed the Corps to conduct general inves­ its procedures ensure that public officials and private citi­ tigations along the Atlantic and gulf coasts to identify prob­ zens may both obtain and provide environmental informa­ lem areas and determine the feasibility of protection. tion before Federal agencies make decisions concerning the environment. Corps of Engineers project planning proced­ ures under NEPA often point out the need for preparation Hydropower of more extensive environmental studies; namely, environ­ The Corps has played a significant role in meeting our mental impact statements. In selecting alternative project Nation’s electric power generation needs by building and designs, the Corps strives to choose options with minimal operating hydropower plants in connection with its large environmental impact. 8 Regulatory Programs to allow “the construction, maintenance, and operation of such facilities.” It also provides that the water areas of proj­ Under its regulatory program, the Corps of Engineers has ects shall be open to public use — generally for boating, regulatory authority for work on structures in navigable fishing, and other recreational purposes. waterways under Section 10 of the River and Harbor Act of 1899 and for the discharge of dredged or fill material into Emergency Response and Recovery “ waters of the United States,” which includes wetlands and other valuable aquatic areas. The standard permit evalua­ Corps assistance for emergency/disaster response and re­ tion process includes issuing a public notice, designating a covery is available under Corps authorities such as Public public comment period, and holding a public hearing before Law 99, 84th Congress (under the Flood Control and the Corps makes a permit decision. Coastal Emergencies appropriation), and under Public Law 93-288 and Executive Order 12148 in support of other agen­ The Corps’ regulatory program focuses primarily on weigh­ cies, particularly the Federal Emergency Management ing the economic and environmental benefits of develop­ Agency. Corps response activities under the Public Law 99, ment versus ecosystem preservation in deciding whether a 84th Congress, authority include the following: emergency permit for a proposed activity would be “ contrary to the operations (e.g., flood fight, search, and rescue and emer­ public interest.” When reviewing permit applications, the gency relief activities); emergency repair and restoration of Corps looks at all the relevant factors, including conserva­ flood control works which are threatened, damaged, or de­ tion, economics, esthetics, general environmental concerns, stroyed by flood; emergency protection, repair, or restora­ historic values, wetland values, fish and wildlife values, tion of Federal hurricane or shore protective structures flood damage prevention, land use classifications, naviga­ threatened, damaged, or destroyed by wind, wave, or water tion, recreation, water supply, water quality, energy needs, action of other than ordinary nature; preventive work done food production, and the general welfare of the public. before flooding when conditions pose a flood threat to life The Corps of Engineers has issued a number of nationwide or property; provision of emergency supplies of potable general permits for minor activities. These permits require water to any locality or individuals confronted with a source little or no processing. The separate Corps of Engineers Dis­ of contaminated drinking water that would or is likely to tricts have also issued regional general permits for certain cause a substantial threat to public health and welfare; and types of minor work in specific areas which also require only drought-related assistance, such as the construction, recon­ minimal processing. These general permits reduce the delays struction, or repair of wells and the transportation of water and paperwork burden involved with individual Department to farmers, ranchers, and political subdivisions in drought- of the Army permits while maintaining environmental safe­ distressed areas. guards. In support of FEMA’s disaster response and recovery activ­ ities, Corps mission assignments have included emergency Recreation debris removal, preliminary damage assessments, detailed The Flood Control Act of 1944, as amended, provides damage survey reports, temporary housing construction, authority “to construct, maintain, and operate public park emergency snow removal, contracting and construction and recreational facilities” at water resources development management, and other support which makes use of the projects under the control of the Secretary of the Army and Corps’ engineering, contracting, and construction expertise.

A u th o rize d sita» Corps of Engineers Projects Lal'e'^0 Completed Local Protection £ Under Construction \ u c \

Channel Improvements Not Sterted Levees

Other Improvements CHATFIELD DOWNSTREAM Other Projects IMPROVEMENTS © Reregulating Dam JttHiOOO SPRINGS Congressional Districts (

DENVER

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COLORADO SPRINGS

LAS ANIMAT I lM lI Hill I TEMPLETON GAP PUEBLO FLOODWAYo© PUEBLO FLOODWAY LEVEE EXTENSION© O GRANADA

PINON CANYON DAM © JOHN MARTIN 3URAK80 RESERVOIR O TRINIDAD emu @ LAKE © KANSAS

Chapter II Platte River and Kansas River Basins

10 Platte River and lican River. After flowing eastward through a portion of southern Nebraska, the Republican River dips sharply into Kansas River Basins Kansas to join the Kansas River in the east-central portion (Missouri River Division—Omaha and Kansas City Districts) of that State. The Colorado segment of the Kansas River The Platte River basin is the largest—86,300 square basin is arid, and irrigation is used extensively throughout miles—in the sprawling Missouri River basin. With Denver the region. No Corps of Engineers projects or studies are on the west, Lincoln, Nebraska, on the east, and a number currently authorized in the Colorado portion of the Kansas of other cities in between, the basin has more industry, ur­ River basin. banization, irrigated acreage, employment, and prospective growth in population and enterprise than any other basin tributary to the Missouri River. Completed Flood Control Projects The region is dominated by the Platte River, the largest trib­ Cherry Creek Dam and Lake (Omaha District) utary to the Missouri, and by its South and North forks, Cherry Creek Dam and Lake is located on the southeast each with an independent valley. Originating in Colorado, edge of Denver on the creek from which the project takes its the South Platte River basin encompasses the cities of Den­ name. The project was authorized by the Flood Control ver, Boulder, Greeley, and Fort Collins. Acts of 1941 and 1944 and is now an integral part of the pro­ Economic data show that the Colorado portion of the area gram for the Missouri River basin. is among the fastest growing in the Missouri River basin. Construction of the project was started in 1946 and com­ The surface waters have been heavily appropriated and ad­ pleted in 1953. The earthfill dam has a structural height of ditional supplies imported from the North Platte River basin 141 feet and is 14,300 feet long. Other features of the project and the Colorado River basin have also been heavily appro­ are the outlet works and a spillway. During extremely rare priated. Hence, this area is already critically short of water flood events, the spillway would discharge water into nearby and the supply will become more critical in the future. Fed­ Toll Gate Creek, thereby bypassing concentrated urban eral, State, and local agencies are working together to ex­ development along Cherry Creek. During floods, excess plore ways to meet the immediate and long-range water waters are stored temporarily in the reservoir and then needs of the region. One specific example is the Metropol­ released at rates consistent with the capacity of the channel itan Denver Water Supply Environmental Impact Statement through the city. study, which is discussed at the end of this chapter. The project was operated originally as a dry reservoir with a In 1953, the Corps of Engineers completed Cherry Creek total capacity of 94,000 acre-feet of water, but in 1958, at Dam and Lake. Located on the southeast edge of Denver on the request of the Governor of Colorado, 10,000 acre-feet of Cherry Creek, this project is one of three major flood con­ water was impounded for conservation purposes. Later, be­ trol projects which provide Metropolitan Denver and down­ cause of the growing popularity of the pool as a recreation stream rural areas a high degree of flood protection. Chat- area, storage was increased to 15,000 acre-feet, leaving a field Dam is located 8 miles south of Denver. In August capacity of 79,300 acre-feet for flood control storage. 1973, earthmoving equipment closed a gap in the dam to The primary purpose of the project is to protect Denver divert the South Platte River through the project’s outlet from flash floods that occur on Cherry Creek. More than tunnels. The dam was completed in April 1975 and began 5,000 homes, 5 railroads, and many industrial and business impounding water in May 1975. Chatfield Dam and Lake is establishments within the flood plain of the creek escaped the second major link in the three-dam system. Channel im­ disaster when the Cherry Creek project performed with provements downstream from Chatfield Dam to Denver, spectacular success during the June 1965 flood. This flood, which were authorized in conjunction with Chatfield Dam the most destructive in the history of Colorado, resulted and Lake, are complete. from torrential rains over the Plum, Sand, and Cherry Construction of the third and final link, Bear Creek Dam Creek basins. The floodflow on Cherry Creek reached an and Lake, was initiated in October 1973 and completed in estimated peak of 58,000 cubic feet per second, but Cherry September 1982. Bear Creek, a left-bank tributary to the Creek Lake absorbed the torrent as its level rose 15 feet South Platte River, originates west of Denver and follows an overnight. Without this control, a heavily populated area of easterly course through the city to its confluence with the Denver would have been severely damaged; instead, the South Platte. This project is located on Bear Creek 8 miles Corps’ Cherry Creek project prevented an estimated $130 upstream from its mouth. Bear Creek Lake, in combination million in additional damages. with Cherry Creek and Chatfield Lakes, provides the region Most of the project area is leased to the State and has been with a broad range of recreation opportunities. designated as a State Recreation Area. Trails and facilities In addition to the foregoing major projects, a small deten­ for camping, boating, fishing, swimming, and picnicking tion dam built by the Corps of Engineers in 1953 provides were developed extensively by the State with the Corps of flood protection for the suburban community of Aurora. Engineers providing access roads and planting trees. This Under its technical assistance programs, the Corps of Engi­ area receives more visitors than any other State Recreation neers has prepared a number of flood plain information re­ Area in the State. The City and County of Denver, the City ports for Denver and other cities in the State. These reports of Aurora, and the City of Greenwood Village also lease identify flood hazard areas and offer guidelines for min­ areas on which they have developed ball fields, tennis imizing future flood damages. courts, playgrounds, and a golf course. Project visitation Two rivers, the Arikaree and the South Fork of the Republi­ totaled 6,778,200 visitor-hours in 1988. can, originate in extreme northeastern Colorado. They tra­ The total Federal cost of the project was $15,220,000. The verse the northwestern corner of neighboring Kansas and project is credited with preventing $163,267,000 in flood join at the Kansas-Nebraska border to become the Repub­ damages through Fiscal Year 1988.

11 Cherry Creek Dam & Lake Bear Creek Dam and Lake (Omaha District) Construction of the project began in October 1973 and was Since 1876, 22 floods have hit the Bear Creek basin. These completed in September 1982. The City of Lakewood began floods were caused by rapid runoff of high-intensity rainfall managing most project lands for recreation in 1982. Phase I within the basin area. The most devastating flood occurred of recreation development, which was cost-shared with the on 2 September 1938. It caused damages of $648,000 and six City of Lakewood, began in the fall of 1982 and was com­ lives were lost. pleted in the fall of 1985. Visitation at the project totaled 308,600 visitor-hours in 1988. The Bear Creek project was authorized by the Flood Con­ trol Act of 1968. It is located on Bear Creek, a left-bank Total project costs as of October 1988 were $62,003,600. tributary to the South Platte River, 8 miles upstream from Flood damages prevented through Fiscal Year 1988 are its confluence with the South Platte River at Denver. The $450,000. project, in combination with the Cherry Creek and Chat- field projects, enhances the welfare and economic stability Chatfield Dam and Lake (Omaha District) of the area by providing a high degree of security against Since 1844, 20 floods occurred on the South Platte River at disastrous floods. Denver. Flood damages and flood damage potentials did The project consists of a rolled earth structure 179.5 feet not reach significant proportions until World War II, how­ high and 5,300 feet long, a reinforced concrete outlet struc­ ever, when Denver entered an era of extensive growth. From ture, a spillway, and a supplementary earthfill dike 65 feet 1940 to 1950 the city’s population increased by 155,000, and high and 2,100 feet long. The lake has a storage capacity of new suburban and commercial developments were con­ 30,800 acre-feet, including 28,800 acre-feet for flood control structed on the flood plains of the South Platte River and its and 2,000 acre-feet for sediment control. tributaries.

Bear Creek Dam & Lake

12 The Flood Control Act of 1950 authorized construction of ments and two rock drop structures, was begun in March the Chatfield project to provide flood protection for Metro­ 1984 and completed in May 1985. Work on the Union politan Denver and downstream rural areas. The project is Avenue Weir was begun in August 1984 and was substan­ located on the South Platte River just downstream from the tially complete in May 1985. This work consisted of a con­ mouth of Plum Creek 8 miles south of Denver. On 16 June crete bed grade control drop structure and a new water in­ 1965, torrential rains of up to 12 inches fell in the Plum take structure for Englewood. The City of Englewood con­ Creek basin. The resulting flood swept out of Plum Creek tributed funds for building the water intake structure. Stage and down the South Platte River through Denver. Colo­ II channel improvement work was started in February 1985 rado’s “mile-high” city sustained the most devastating and completed in July 1986. Stage III work—channel im­ flood in its history; 2,033 homes, 167 house trailers, 6 apart­ provements and three rock bed grade control structures— ment houses, and 612 business establishments were damaged was started in October 1986 and completed in late 1988. An or destroyed. Losses in the Metropolitan Denver area aquatics mitigation plan is scheduled for completion in totaled an estimated $325 million. 1990. The Chatfield project consists of a compacted earthfill dam The upper portion of the river reach has been left in an un­ 147 feet high and 13,136 feet long, a reinforced concrete disturbed state. The area has been designated as South outlet structure, a spillway, and related channel improve­ Platte Park by the City of Littleton. Cost-shared recreation ments on the South Platte River between the dam and the development with the South Suburban Metropolitan Rec­ existing improved channel in Denver. The lake has a storage reation and Park District and the City of Littleton is nearing capacity of 231,400 acre-feet, including 204,700 acre-feet completion. Similar development with the City of Engle­ for flood control and 26,692 acre-feet for sediment control. wood is still being planned. This development includes a Had Chatfield Lake existed prior to 1965, it would have hiking and biking path. contained the 1965 Plum Creek flood. Construction was initiated in August 1967. In August 1973, Multiple-Purpose Projects Underway a special ceremony was held to observe the closure of the Comprehensive Plan, Missouri River Basin earthfill embankment. With this accomplished, South Platte (Missouri River Division) River flows were diverted through the project’s outlet tun­ The Pick-Sloan Missouri Basin Program (Pick-Sloan plan) nels. The dam was completed and began impounding water began when the Flood Control Act of 1944 authorized a in May 1975. comprehensive basin plan formed from separate proposals In 1979, the multipurpose pool level raised from elevation recommended by the Bureau of Reclamation and the Corps 5430 feet mean sea level (m.s.l.) to 5432 feet m.s.l. In 1988, of Engineers. Projects in the plan included flood control, 3,036,600 visitor-hours were spent at the project. Recreation irrigation, hydroelectric power, improved navigation on the facility development and downstream channel works were lower Missouri River, water supply for cities and industry, completed in 1989. The Chatfield downstream channel im­ water quality control, conservation of fish and wildlife, provements are discussed further in following paragraphs. public recreation, and land treatment and enhancement. The project’s total cost is estimated to be $104,700,000 in­ At the start, the plan involved projects authorized in pre­ cluding $9,300,000 in non-Federal costs for rights-of-way vious acts. For example, the lakes at Fort Peck, Montana; and relocations associated with the channel work and for Harlan County, Nebraska; Tuttle Creek, Kansas; Pomme construction of cost-shared recreation facilities. Flood dam­ de Terre, Missouri; and Cherry Creek, Colorado, are parts ages prevented through Fiscal Year 1988 are $1,945,000. of the Pick-Sloan plan authorized before 1944. The Kansas Chatfield Downstream Improvements. Channel improve­ City levees and the Missouri River Bank Stabilization and ments on the South Platte River between Chatfield Dam and Navigation project are also part of the plan despite their Denver were authorized along with Chatfield Dam in the earlier authorizations. Flood Control Act of 1950, as amended by the Water Re­ Just as the Pick-Sloan plan has roots reaching back before sources Development Act of 1974. When completed, these 1944, it later grew beyond the first comprehensive plan de­ improvements will allow the channel to carry a 100-year scribed in the legislation. Some of the projects authorized in flood or maximum releases from Chatfield Dam. the Missouri River basin after 1944 bear the Pick-Sloan des­ For construction purposes/reasons, the project is divided ignation while other projects in the basin contribute to water into four stages: Stages I, II, and III and the Union Avenue resources development as independent units. In 1970, Con­ Weir. Stage I work, which consisted of channel improve­ gress enacted Public Law 95-576 which officially attached

13 the Pick-Sloan name to the comprehensive plan composed for State and Federal representatives and private interests to of all those projects that were part of either of the separate recommend goals for the plan that guides regulation of the plans merged in 1944. lakes through each year. The original blueprint for the basin featured 98 reservoirs Flood control projects in the Missouri River basin prevented storing about 85 million acre-feet of water for multiple uses. over $10.1 billion in flood damages through Fiscal Year The plan also provided for levees and floodwalls to protect 1988. Visitors spent almost 156 million hours at the lake municipalities and industrial areas plus levees on both banks projects in the Missouri River Division in 1988, including of the Missouri River from Sioux City, Iowa, to the mouth more than 43 million hours at the six main stem lakes. The near St. Louis, Missouri. The levees would protect hundreds main stem hydroelectric plants produced 8.8 billion kilo­ of thousands of acres of bottom land from floods. watt-hours in the same year. Cumulative power revenues While the Pick-Sloan plan is historic for its recognition of from the entire main stem system through 1988 amount to the role of tributary basins and comprehensive planning, the nearly $1.9 billion. Also in 1988, 2.5 million tons of com­ projects on the main stem of the Missouri River are the cen­ merce traveled on the Missouri River from Sioux City to the terpiece of the plan’s success. Six Corps of Engineers lakes on mouth. the main stem regulate the runoff from the entire upper half Storage in the main stem lakes assures continued service to of the basin. The system composed of Fort Peck Dam in all functions during droughts. For example, in 1985, inflow Montana; Garrison Dam in North Dakota; Oahe, Big Bend, to the lakes was about 74 percent of normal. The Corps re­ and Fort Randall Dams in South Dakota; and Gavins Point leased nearly 5 million acre-feet of water from multipurpose Dam in Nebraska and South Dakota can store 73.9 million storage before higher-than-normal 1986 runoff replenished acre-feet of water. Within that storage space, 16.3 million the pools. A more rigorous test began the following year. acre-feet is devoted to flood control. Other uses of storage In 1987, low mountain snowpack and sparse rainfall pro­ include irrigation, hydropower, and navigation downstream duced inflow into the upper basin only 85 percent of from Sioux City. In an average year, powerplants in the normal. The 1988 runoff of 12.5 million acre-feet was only main stem dams produce about 10 billion kilowatt-hours of about 50 percent of the normal 25 million acre-feet for the hydroelectric power. The control these lakes provide over same reasons. At the end of 1988, the Corps had withdrawn downstream flow is the key to dependable navigation. 12 million acre-feet from the main stem multipurpose stor­ The Reservoir Control Center at the Missouri River Division age to serve the project purposes downstream. Inflow to the office in Omaha coordinates the operation of the six main lakes has been below normal in 6 of the 22 years since the stem projects. Semiannual public meetings provide a forum system first filled to normal operating levels in 1967.

14 Chatfield Dam & Lake Besides meeting the project purposes mentioned in the Urban Drainage and Flood Control District, as the non-Fed- authorizing acts, the main stem lakes have a special relation­ eral sponsor of the project, will share the cost of construc­ ship with two species of birds. The least tern and piping tion. About 500 families in the Westerly Creek flood plain plover are federally listed as endangered and threatened downstream from Lowry Air Force Base will be protected species, respectively. Sandbars, which are exposed down­ from flooding. Construction was initiated in 1988. stream from some of the main stem dams when releases are low, attract these birds by providing nesting habitat. From Associated Projects of Other Agencies mid-May through August since 1986, the Corps has adjusted The Flood Control Act of 1944 assigned the Corps of Engi­ operations at Garrison, Fort Randall, and Gavins Point neers the responsibility of prescribing regulations for the use Dams in an effort not to disturb nests or inundate the sand­ of storage capacity allocated to flood control at reservoirs bars before chicks are fledged. constructed wholly or in part with Federal funds. The 1944 By the end of 1988, the Corps and the Bureau of Reclama­ act further provided that the Corps would be responsible for tion had 55 Pick-Sloan lakes either complete or under con­ determining flood control capacities in all reservoirs in­ struction. Considering other Missouri River basin projects cluded in the comprehensive plan for the Missouri River as well, the two agencies had more than 100 lake projects basin. The investigations and studies necessary to fulfill either complete or under construction. The Corps also com­ these responsibilities for both the Corps and the Bureau of pleted 76 local flood protection projects and 29 units of the Reclamation reservoirs are being actively pursued. Such reg­ Missouri River Levee system. Supplementing the planned ulations have been prescribed or are being considered for development, the Corps has completed about 145 small ero­ Bonny Reservoir. sion and flood control projects constructed under continu­ Bonny Reservoir ing authorities. Bonny Dam was authorized for construction as part of the Flood Control Acts of 1944 and 1946. The dam, which was Flood Control Projects Underway completed in 1951, is on the South Fork of the Republican River in Colorado. The reservoir has a total capacity of Westerly Creek (Omaha District) 170,160 acre-feet. Although the reservoir was originally au­ Construction of a dam and improvements to an existing thorized to include irrigation, the primary purpose is flood dam on Westerly Creek were authorized in the Water Re­ control. Conservation storage, however, was included for sources Development Act of 1986. The project will consist future development. In a report dated March 1977, the of constructing Westerly Creek Dam on Lowry Air Force Bureau of Reclamation concluded that an economically fea­ Base. The total estimated cost of the project is about $18.8 sible plan for a Federal irrigation project could not be for­ million, which includes $5.46 million credit for downstream mulated, and it recommended that alternative uses be channel work already completed by the local sponsor. The sought for this water supply.

15 A contract signed 24 June 1982 between the Bureau of Rec­ near Windsor. This project, initiated in May 1984 and com­ lamation and the State of Colorado authorized the sale of pleted in June 1985, provided for the construction of 850 storage capacity in Bonny Reservoir. Under the terms of this feet of stone revetment and 40 feet of stone windrow re­ contract, the State of Colorado has the right to use the reser­ fusal. Construction was completed in June 1985. The voir’s conservation capacity of 39,922 acre-feet of water for Federal cost was $49,800. recreation and fish and wildlife purposes. Flood damages South Platte River Near Platteville (Omaha District). Severe prevented by this project to date are $2,162,000. bankline erosion occurred along both banks of the South Platte River near Platteville threatening a county road and Work Under the Continuing Authorities bridge. The project, initiated in May 1984 and completed in Program August 1985, provided for construction of 100 feet of stone Work performed by the Corps of Engineers under the revetment and 250 feet of windrow refusal. The Federal cost Continuing Authorities Program in the South Platte River was $39,900. basin in Colorado is discussed in the following paragraphs. South Platte River Near Iliff (Omaha District). The project, initiated in June 1984, is located about 1 mile south of Iliff. Small Flood Control Projects Severe bankline erosion threatened a county road and Aurora (Omaha District). Storm runoff is carried by West­ several publicly owned power poles. Construction of 1,420 erly Creek through Aurora and has frequently caused sub­ feet of stone revetment and 131 feet of stone windrow re­ stantial damage in the community, which is located on the fusal was completed in August 1985 at a Federal cost of eastern edge of Denver. A feasible project was developed $135,900. under Section 205 authority. Big Thompson River Near Johnstown (Omaha District). Construction of the improvement, commonly referred to as The project is located 2 miles north of Johnstown on the left the Kelly Road detention dam and reservoir on Lowry Air bank of the Big Thompson River. Severe bankline erosion Force Base, was started in Fiscal Year 1953 and completed caused by periods of high flows in 1983 encroached upon the in Fiscal Year 1955 at a cost of $150,000 to the Federal Gov­ roadway and subsequently threatened not only the county ernment. Costs to local interests, chiefly for improvement of road, but also a natural gas pipeline located on the east side the waterway through town, were estimated to be $77,000. of the road. The project provided for construction of 36 feet The project is credited with having prevented $2,172,000 in of stone tieback. The project was initiated in June 1984 and flood damages through Fiscal Year 1988. construction was completed in September 1985. The Federal Accelerated urban development has taken place in the upper cost was $20,200. portion of the Westerly Creek basin since the project was South Platte River Near Merino (Omaha District). Bankline constructed. As a result, storm runoff from that area in­ erosion during June 1983 threatened a blacktop county road creased and the Kelly Road detention dam could no longer and power poles. This project, located along the right bank safely store the magnitude of floods for which it was de­ of the South Platte River three-fourths of a mile east of signed. Because of the extreme hazard posed by the possi­ Merino, was initiated in June 1984 and completed in Octo­ bility of the Kelly Road detention dam failing, the Chief of ber 1985. The project provided for construction of 500 feet Engineers approved rehabilitation of the dam under of stone revetment and 25 feet of windrow refusal. The Fed­ authority of Public Law 99, 84th Congress, as amended. eral cost was $48,500. This rehabilitation work was completed in Fiscal Year 1984 South Platte River Near Kersey (Omaha District). Construc­ at a Federal cost of $1,117,000. tion of 800 feet of stone revetment and 20 feet of windrow Emergency Bank Protection refusal was initiated in June 1984 and completed in Decem­ Plum Creek at Aurora (Omaha District). A Section 14 proj­ ber 1985. The project is located in Weld County, about 1.5 ect was constructed on the right bank of Plum Creek 4 miles miles northeast of Kersey. The Federal cost was $99,400. upstream from the confluence of Plum Creek with the South South Platte River in Morgan County (Omaha District). Site Platte River near Aurora to protect the city’s water supply 1 is located along both banks of the South Platte River line. The project, which consists of stone revetment and about three-fourths of a mile south of Goodrich. Erosion parallel wire fencing with rock toes, was initiated in May and scour threatened the Highway 39 bridge. Protection 1970 and completed in June 1970. The Federal cost was measures consisted of 40 feet of revetment, 80 feet of wind­ $39,000. row refusal, and 80 feet of stone blanket. Site 2 is located at North Washington Sanitation District, South Platte River the Highway 144 bridge in Morgan County. Construction Near Denver (Omaha District). A project to protect the included 205 feet of revetment and a 60-foot-long windrow water treatment plant of the North Washington Sanitation refusal to protect the State bridge, road, and public power District was initiated in June 1971 and completed in Septem­ poles from streambank erosion. Construction was initiated ber 1971 under Section 14 authority. The project, located on in July 1984 and completed in October 1986. The Federal the left bank of the South Platte River 3 miles north of cost was $146,600. Denver, consists of 800 feet of stone revetment. The Federal South Platte River Near Fort Lupton (Omaha District). A cost of the project was $26,000. study on the right bank of the South Platte River approx­ Cache la Poudre River at Fort Collins (Omaha District). imately 1.5 miles south of Fort Lupton was initiated in Two reaches of riprap, 415 feet and 535 feet long, were August 1985. The construction contract was awarded in No­ placed on the right bank of the Cache la Poudre River to vember 1986 and completed in January 1987. Bank protec­ protect the water treatment facilities for Fort Collins. The tion provided for construction of five hardpoints and 30 feet Section 14 work was initiated in October 1976 and com­ of windrow refusal. The Federal cost was $49,700. pleted in December 1976. The Federal cost was $46,000. South Platte River Near Weldona (Omaha District). The Cache la Poudre River Near Windsor (Omaha District). construction of 255 feet of stone revetment and 130 feet of Severe bankline erosion threatened a county road and bridge windrow refusal was initiated in October 1986 and com- 16 pleted in November 1986. The project is located in Morgan County, about 1 mile south of Weldona. The approximate Federal cost was $62,000. Work Under the Technical Assistance Programs Assistance provided to the State of Colorado under the Corps Technical Assistance Programs is described in the fol­ lowing paragraphs. Flood Plain Management Services Program The Flood Plain Management Services Program has pro­ vided for numerous services over the years to public and pri­ vate entities in an effort to achieve flood damage reduction. This effort has been in the form of published studies such as the flood plain information reports and special flood hazard information reports listed below and numerous unpublished studies and technical assistance. The Corps of Engineers has completed the following reports for streams in the Colorado portion of the South Platte

River basin. IBB

Flood Plain Information Reports

Locality Sponsoring Agency Status

Omaha District reports: Big Dry Creek; Little Dry Creek Denver Regional Council of Vol. IV, completed October 1968 (Arapahoe Co.); Greenwood, Weir, Governments Lakewood, South Lakewood, and McIntyre Gulches; Little Dry Creek (Adams Co.); and Grange Hall Creek

Left-hand Creek, Boulder County Denver Regional Council of Vol. I, completed January 1969 Governments

Boulder Creek and South Boulder Denver Regional Council of Vol. II, completed August 1969 Creek, Boulder Metropolitan Region Governments

Ralston, Leyden, and Van Bibber Denver Regional Council of Vol. V, completed November 1970 Creeks and Lena, Sanderson, and Governments North Sanderson Gulches

Goldsmith Gulch, Dutch Creek, Denver Regional Council of Vol. VI, completed October 1971 Lilley Gulch, and Coon Creek Governments and Urban Drainage and Flood Control District

Bear Creek and Mt. Vernon Creek, Town of Morrison and Urban Completed October 1971 Morrison Drainage and Flood Control District

Big Thompson River, Loveland City of Loveland Completed December 1971

Lower St. Vrain Creek, Boulder Urban Drainage and Flood Control Vol. Ill, completed June 1972 County District, City of Longmont, and Boulder County

Upper St. Vrain Creek, Boulder City of Longmont and Boulder Vol. IV, completed September 1972 County County

Cache la Poudre River, Fort Collins, Larimer-Weld Regional Planning Vol. I, completed October 1973 Larimer County Commission

17 Cache la Poudre River, Greeley, Larimer-Weld Regional Planning Vol. II, completed March 1974 Weld County Commission

Cache la Poudre River, Fort Collins- Larimer-Weld Regional Planning Vol. Ill, completed October 1975 Greeley, Larimer-Weld County Commission

Cherry Creek, Cherry Creek Lake Arapahoe County, Douglas County, Completed October 1976 through Franktown Urban Drainage and Flood Control District, and Colorado Water Conservation Board

Big Thompson River, Loveland to the Larimer County, Boulder County, Completed June 1977 Larimer-Weld County Line; Little Larimer-Weld Regional Council of Thompson River, Boulder and Governments, and Colorado Water Larimer Counties near Berthoud Conservation Board

Big Thompson River, Weld County Weld County, Larimer-Weld Regional Completed February 1978 Council of Governments, and Colorado Water Conservation Board

Dry Creek, Boulder County-Weld Boulder County and Weld County County and Colorado Water Conservation Completed June 1978 Board

South Platte River and Pawnee Logan County and Colorado Water Completed September 1978 Creek, Sterling Conservation Board

Kansas City District reports: North Fork Republican River at Wray Town of Wray June 1969 Special Flood Hazard Information Reports

Locality Sponsoring Agency Status Omaha District reports: Metropolitan Region, Denver; Sand, Denver Regional Council of Vol. II (revision), completed July 1971 Toll Gate, and Lower Cherry Creeks Governments and Urban Drainage and Flood Control District

Boulder Creek, City of Boulder City of Boulder and Urban Drainage Completed May 1972 and Flood Control District

Bear Creek, Denver Metropolitan Colorado Water Conservation Board Completed December 1972 Region

Upper Toll Gate Creek and City of Aurora Completed June 1973 Tributaries, Aurora

South Platte River, Vol. I, Weld Weld County and Colorado Water Completed April 1977 County Conservation Board

South Platte River, Vol. II, Morgan Morgan County-Washington County Completed May 1977 County-Washington County and Colorado Water Conservation Board

South Platte River, Vol. Ill, Logan Logan County-Sedgwick County and Completed June 1977 County-Sedgwick County Colorado Water Conservation Board

Planning Assistance to States Program The Planning Assistance to States Program was authorized gram was established by Congress to enable states to utilize by Section 22 of the Water Resources Development Act of Corps of Engineers’ planning expertise in the preparation of 1974 (Public Law 93-251), as amended. The Section 22 pro­ comprehensive plans for the development, utilization, and

18 conservation of the water and related land resources of mary of the expenditures for work performed under Public drainage basins located within the boundaries of a state. The Law 875, 81st Congress. assistance can be provided to any public entity as long as it is Stream Federal Cost Local Cost consistent with the state’s water resources planning objec­ tives. The priority of the work is established by the state. Kiowa Creek...... $ 38,900 $ 69,500 The Omaha, Kansas City, Albuquerque, and Sacramento Clear Creek...... 56,900 32,600 Districts serve the State of Colorado. The Omaha District Bijou Creek...... 18,700 0 has been designated as the lead District for the Section 22 Plum Creek...... 135,350 61,970 program in Colorado. South Platte River ...... 25,100 1,176,600 Studies underway during Fiscal Year 1989 in the Platte River basin include developing a cost estimate to rehabilitate T o ta l...... $274,950 $1,340,670 Bootleg and Klug Reservoirs located on Box Elder Creek, analyzing a flood plain on the Cache la Poudre River, and Big Thompson Canyon Flood (Omaha District). The Big formulating measures to reduce the limits of the 100-year Thompson Canyon is no stranger to floods. In 1962 and flood plain on the South Platte River at Sterling. Possible 1965, the area experienced serious flooding. Those events Fiscal Year 1990 studies include continuing the rehabilita­ were overshadowed by the devastating torrent that ravaged tion evaluation of Bootleg and Klug Reservoirs on Box the canyon on the last night of July 1976. Elder Creek, continuing the study of the South Platte River Storm centers over the Big Thompson River basin produced flood plain at Sterling, and developing hydraulic parameters from 10 to 12 inches of rain within a 3- to 4-hour period that for design of a flood warning station on Kiowa Creek in night. Numerous tributary streams exceeded their capacity Logan County. and deposited debris and huge amounts of water into the Technical and Engineering Assistance main stem of the Big Thompson River, which, confined by on Shore and Streambank Erosion high canyon walls, cut a swath of destruction from Estes In 1986, the Corps of Engineers completed two Section 55 Park to Loveland. Despite advance warnings of the impend­ Technical Assistance reports for the State of Colorado. The ing flood, many canyon residents and visitors lost their lives first addressed erosion sites on the Cache la Poudre River. in the debris-laden stream. Those who escaped or were The second was for the Castle Rock Greenway Foundation snatched from the flood’s grasp by rescuers counted them­ and provided erosion control assistance on Sellers Gulch selves fortunate to leave the canyon with nothing more than near Castle Rock. The Section 55 program of the Water Re­ the clothes they wore. sources Development Act of 1974 is currently inactive due to Homes, business places, mobile home and house trailers, the lack of funds. motels, and vacation cabins were destroyed—some disap­ peared without leaving a trace. U.S. Highway 34 between Work Under Emergency Authorities Loveland and Estes Park was extensively damaged and in The Corps of Engineers has given emergency assistance to some places was obliterated. the State of Colorado as described below. The following day, Sunday, men and women from the Public Law 99, 84th Congress—Flood-Associated Corps of Engineers Omaha District were on the scene to Assistance assess the extent of destruction. In the following days and weeks, Corps personnel carried out disaster recovery opera­ The costs for work performed under this emergency au­ tions assigned by the Federal Disaster Assistance Adminis­ thority in the South Platte River basin are listed below. tration (now the Federal Emergency Management Agency) Funds were expended for (1) levee repairs and bank protec­ under Public Law 93-288. Contracts amounting to more tion work along the South Platte River near the Adams- than $1,320,000 were awarded for the removal of flood Weld County line and near the mouth of Sand Creek, (2) debris. Damage surveys and other flood-related activities levee repairs along Kiowa Creek to protect the towns of brought the cost of this recovery phase to more than Elbert and Kiowa, and (3) bank stabilization work on Plum $1,535,000. Total economic and financial losses, including Creek near Denver. The $160,000 the Omaha District spent debris removal costs, were set at $35,498,100. The most in 1973 was for emergency levee repairs along the South tragic loss was in the toll of human lives—there were 139 Platte River in Adams and Weld Counties as a result of known dead and 7 counted as missing—and in the shock and major flooding in the spring of that year. misery of those who survived. Expenditures Fiscal Year $293,870 ...... 1948-1965 Survey Investigations 29,800 ...... 1970 Studies of flood and related water resources problems are 4,670 ...... 1971 conducted by the Corps of Engineers in response to direc­ 21,300 ...... 1972 tives by Congress or by the Senate or House Public Works 160,000 ...... 1973 Committee. These directives generally result from action taken by the people living in the affected areas. The study is Major Flood Emergency Operations assigned to the District Engineer concerned, who holds South Platte River Basin (Omaha District). During June public meetings at the beginning of, during, and at the con­ 1965, unprecedented rainfall caused severe flooding on the clusion of the investigation to ensure that the views and de­ South Platte River and several of its tributaries in the Den­ sires of the local interests are fully considered. Also, during ver region. The Corps of Engineers Omaha District office the course of each investigation, the Corps study is coordi­ directed flood fighting activities and supervised debris re­ nated with all interested state and Federal agencies as well as moval and repair of public facilities. Following is a sum­ with the local people. The findings and recommendations of the District Engineer Harbors, which may also hold public meetings in special are submitted to the Division Engineer. After successive re­ cases. The report of the Chief of Engineers is subjected to views by the Division Engineer, the Board of Engineers for further reviews by the affected states, other Federal agen­ Rivers and Harbors, and Headquarters, U.S. Army Corps cies, the Office of Management and Budget, and the Secre­ of Engineers, the report of the Chief of Engineers is tary of the Army before it is transmitted to Congress. prepared. The following studies were conducted in the North and The views and comments of local interests are again solicited South Platte River basins, which include areas within the during the review by the Board of Engineers for Rivers and State of Colorado.

Locality______Purpose______Status

North Platte River, Nebraska, To determine the advisability of Study reclassified from inactive to Wyoming, and Colorado developing a comprehensive plan for active status in February 1984. (Omaha District) the use and conservation of water and Study completed in 1989 as part of related land resources of the lower the Platte River Basin, Colorado, North Platte River basin Nebraska, and Wyoming study.

Platte River Basin, Colorado, To determine the feasibility of Reconnaissance phase of the study Nebraska, and Wyoming providing flood control measures in completed in Fiscal Year 1989. (Omaha District) the Platte River basin and to deter­ Several flood control studies mine the level of Federal interest in will be pursued as separate survey development of these measures investigations or Section 205 studies.

Ralston and Leyden Creeks, To determine the feasibility of Reconnaissance phase of the study Colorado (Omaha District) providing flood control measures for scheduled for completion in Janauary Ralston and Leyden Creeks in the 1990. Feasibility phase of the study Denver metropolitan area and to scheduled for completion in March conduct a more detailed evaluation of 1992. these measures

Goose Creek, Boulder, Colorado To evaluate an Urban Drainage and Reconnaissance phase of study (Omaha District) Flood Control District flood control scheduled for completion in plan and to identify and evaluate September 1991. other alternatives to resolve flood problems on the Goose Creek in Boulder

Box Elder Creek Basin, Colorado To determine the feasibility of Reconnaissance phase of study (Omaha District) providing flood control measures on scheduled for completion in March Box Elder Creek 1990.

Box Elder, Spring, and Dry Creeks To determine the feasibility of Reconnaissance phase of study at Fort Collins, Colorado providing flood control measures at scheduled for completion in March (Omaha District) Fort Collins, to evaluate a plan 1991. identified by Larimer County and the Colorado Water Conservation Board, and to evaluate other alternatives to resolve the flood problems

Dry Gulch, Colorado To determine feasibility of providing Reconnaissance study currently (Omaha District) flood control measures for the Dry unfunded. Gulch drainage basin in the Denver metropolitan area

20 15 Steps to a Civil Works Project Action by Local People if They Perceive 1 Water Resources Problems Local officials talk to Corps about available Federal programs. Tech­ nical assistance and some small projects can be accomplished with­ out congressional authorization. Local officials contact congressional delegation if study authorization is required. 2 Action by Congressional Delegation and Congress Member of Congress requests study authorization through Public Works Committees. Committee resolution adopted if report was previously prepared on water problems in area. Legislation normally required if no Corps report exists.

3 initial Funding of Study Study assigned to Corps District office. Funds to complete reconnaissance phase (12 months) included in President’s budget. Appropriations for reconnaissance phase provided in annual Energy and Water Development Appropriations Bill.

4 Accomplishing the Study District conducts reconnaissance phase. If study continues beyond reconnaissance phase, local sponsors will be required to share the costs of the feasibility phase. Public involvement is an integral part of planning process, including review of draft report and draft environmental impact statement (EIS). Study conducted under Federal Principles and Guidelines. Funds included annually in President’s budget; annual appropriations needed to continue study. Study results in feasibility report and EIS which are submitted to Corps Division (regional) office.

5 Division (Regional) Review Division office, which reviews District work during planning process, completes technical review of final District feasibility report and EIS. Division Engineer submits report to review board or commission and issues public notice inviting comments. Review by Board of Engineers for Rivers and Harbors (CEBRH) 6 and Washington Level Review Center (WLRC) CEBRH and WLRC conduct review of report and submit views and recommendations to Chief of Engineers. Comments from public fully considered in CEBRH action.

7 Preparation of Chief of Engineers Report Proposed report of Chief of Engineers and final EIS sent to heads of Federal agencies and Governors of affected states for comment. Final EIS filed with the Environmental Protection Agency and made available to public. Chief of Engineers considers comments on proposed report and EIS, prepares final report, and submits it to the Secretary of the Army.

Tne following >s a re p o rt o f tne Cn«et o * Engineers ^orvjtrot(\g dean-up and development o f Brown bottom O Administration Review T re e k n a a r A n yto w n .n th e coun+y of Square ftloeX The following report contains done of tt\e area and Chief of Engineers’ report reviewed by Assistant Secretary of the Army recommendations fo r creating a recreafIon area nsr use by * r d fx>r ttv* locdl jopjieripn and Surrounding persons to (Civil Works). whu.h nave applied! tor to C o n g r e s s ^nd h*ve oceo gr+'T+aJ th e r-gert to nv«, stvdj JttfC tor .mprour Office of Management and Budget comments on the report as it !p b f 1 i ri-i- i j -ir7~ee*» > r r> A 1.4 •hr / y f f r * relates to President’s programs. -*t ,4 rt VH- ("• s><- Assistant Secretary of the Army (Civil Works) transmits Chief of Engineers’ report to Congress.

21 Tr y fo llo w in g is •» rro o ri ot the CHiet o l Engineers ■ rjr\fgrf\,og th\e dM (\-u o «r*i development o^ Brown bottom Creek rvJAr Anytewn .n «he rounfy of Setuare ft loth. Michigan. The fo llo w in g report root¿ins **ud>rt done o f th e area an d «/ Preconstruction Engineering and Design (PED) rriom m rnditiom for ¿reefing a recrea+ioo & te * 6»r J t> t bj -»'vf for the lor el fjr.pi ie ripn and 9urrour*Jing person} to The Corps can continue planning and design pending congressional w h ■/ n rvw e a p p l e t fne t o C o r\g 'c v > and k»v«. ocen authorization of proposal. This process is called PED. Funds included g-r^rter) the <-*m to 'i«.e n\.*> stud/ XtfC fo r .mpro«jf ¡P tf>r»f iSy t r\\jf b tt.i ft rfc.1 ilof— ‘j Jr-7~te** ry r in President's budget, and Congress acts on each item in i> iJ h ^ w llr/ r4,iun, ,,Ai>y. f f f ■tt l>,'^r»t, iV ttV I'- n . 9 t •dJVi'l r h. • appropriations bill.

10 Congressional Authorization Feasibility reports referred to Committee on Public Works and Trans­ portation in House and Committee on Environment and Public Works in Senate. Civil works projects normally authorized by Water Resources Develop­ ment Act (Omnibus Bill) following committee hearings. Occasionally, Corps proposal Is authorized by separate legislation or as part of another bill or, in cases where estimated Federal cost Is $15 million or less, by committee resolutions.

11 Plans and Specifications for Project Implementation District completes enough engineering and design and develops plans and specifications for initiating project implementation.

12 Funding for Project Implementation New projects included in President’s budget based on national prior­ ities and anticipated completion of design, plans, and specifications so that construction contract can be awarded. Budget recommendations supported by evidence of support from state and other non-Federal sponsors responsible for sharing In cost of project. Congress appropriates funds for new starts; normally, this occurs in annual Energy and Water Development Appropriations Bill.

^ q Contract Between the Federal Government I O and Non-Federal Sponsors Secretary of the Army and appropriate non-Federal sponsors sign ^ ^?arty of the first Pari Agrees formal agreement once Congress has appropriated funds for project IT- :^Lith the Hirty of tiie Seciwd implementation to begin. ’ \wt furtdiiriit o: the Agreement obligates non-Federal sponsors to participate in Implement­ ing, operating, and maintaining project according to requirements established by Congress and the administration.

14 Project Implementation Engineering and design continue during implementation process; plans and specifications reviewed by Division offices and sometimes by Headquarters, U.S. Army Corps of Engineers. Funds included in President's annual budget; appropriations required to continue design and implementation. Construction managed by Corps but done by private contractors.

15 Operation and Maintenance For operating and maintaining a Federal project, funds are included in President’s annual budget based on project needs and available funding; congressional appropriations required to continue operation and maintenance. Local flood damage reduction, hurricane protection, and beach erosion projects normally operated and maintained by non-Federal sponsors as part of agreement signed prior to implementation. Corps periodically inspects projects after turning them over to non-Federal sponsors. 22 Urban Studies next 15 to 25 years. In February 1984, the DWB formally A brief discussion of a study conducted by the Omaha Dis­ notified the Corps of this request in a letter. Specifically, the trict in the South Platte River basin under the Urban Studies DWB indicated the desire to have the systemwide EIS ex­ Program is presented below. The study covered the Metro­ panded to include site-specific analysis of the upper South politan Denver area and other areas in the State of Platte River basin alternatives (with emphasis on the 1.1 Colorado. million acre-foot Two Forks project) and the completion of Metropolitan Denver and South Platte River and Trib­ the Williams Fork system (with emphasis on the Williams utaries, Colorado, Wyoming, and Nebraska (Omaha Dis­ Fork gravity system). In response, the Corps expanded the trict). This study was conducted to develop an integrated systemwide EIS effort to incorporate the aforementioned water and related land management program that would work. Thus, the expanded study includes the impact support and complement existing programs in the South analyses of both systemwide water development scenarios Platte River basin. Previously authorized studies of the and site-specific alternatives. South Platte River and its tributaries were reevaluated as The EIS is being developed in part under the Inter­ part of the study. The study was completed in January 1980 governmental Cooperation Act of 1968, as implemented by and the report was forwarded to Congress in September the Bureau of Budget Circular A-97, dated 29 August 1969, 1984. The study recommends modifications to the Kelly and Engineering Regulation 1140-2-303, “ Work for Road detention dam, beyond the rehabilitation work com­ Others,” which requires that the Corps be reimbursed for its pleted in 1980, to increase storage. It also recommends addi­ costs. The draft EIS was published in December 1986. The tional storage on Westerly Creek upstream from the Kelly final EIS was completed in March 1987. The District Engi­ Road dam. Both recommendations would ensure and pro­ neer notified all interests of his intent to issue a permit for vide increased flood protection and improved drainage in the 1.1 million acre-foot Two Forks project in March 1989. Aurora and Denver. This decision is currently being reviewed by the Environ­ mental Protection Agency. Special Studies Metropolitan Denver Water Supply Environmental Impact Statement The Foothills agreement of 1979 requires that, prior to any major Federal action on any of the Denver Water Board’s (DWB) future water development proposals, the site- specific and cumulative effects of all of the DWB’s foresee­ able future water development projects be evaluated. The Foothills settlement was reached after protracted contro­ versy and court action regarding construction of the Strontia Springs diversion dam and the Foothills treatment plant. The Corps of Engineers played an integral role in de­ veloping this agreement in conjunction with its Section 404 permitting activities. In 1981, the DWB began comtemplating future water proj­ ects in the upper South Platte River basin and determined that it was time to start a systemwide environmental impact statement (EIS) in accordance with the Foothills settlement. Because of the role played by the Corps in the Foothills set­ tlement, the DWB officially requested that the Corps as­ sume the role of lead agency on the systemwide EIS. The Corps accepted. The original approach was to prepare a systemwide EIS to be followed with site-specific EIS’s. Work on the system- wide EIS began in November 1982. It was half complete in 1983 when the Corps made a midterm assessment of the on­ going EIS process to determine if adjustments should be made in the basic approach on the EIS. Several serious con­ cerns with the ongoing EIS process were identified in this midterm assessment. A committee was formed to work with the Corps and its contractor to resolve these concerns. This committee, called the EIS Coordinating Committee, con­ sists of representatives from the West Slope, Environmental Caucus, Metropolitan Water Providers, and the Denver Water Department. In January 1984, the EIS Coordinating Committee recom­ mended that the systemwide EIS process be expanded to in­ clude the concurrent evaluation of certain site-specific alter­ natives that are candidates for implementation within the

23 UTAH W O ING YOM Upper Colorado River Basin River Colorado Upper Chapter III Chapter The basin features many important recreation areas. These Upper Colorado River Basin include national parks, national recreation areas, and (South Pacific Division—Sacramento District) national monuments. It includes such noted resort areas as The Upper Colorado River basin is in central southwestern Aspen and Vail as well as many popular smaller resorts on Colorado, southeastern Utah, northeastern Arizona, and both public and private lands. northwestern New Mexico. The basin comprises the drain­ The San Juan Mountains, known as the “American Alps,” age area upstream from Lees Ferry, Arizona, and encom­ are renowned for their scenic beauty and recreation oppor­ passes about 64,800 square miles. Principal tributaries to the tunities and attract vacationers from throughout the coun­ Upper Colorado River in Colorado are the Roaring Fork, try. The environmental quality of the Upper Colorado River Gunnison, and Dolores Rivers. The San Juan River, second basin is relatively uncontaminated. Very few regions in the largest tributary in the Colorado system, heads on the west­ conterminous 48 states can boast of this fact. ern slope of the Continental Divide in southwestern Colo­ rado and flows through northwestern New Mexico and At present there are no existing or authorized Corps of Engi­ southeastern Utah to join the Colorado River 80 miles up­ neers projects in the Upper Colorado River basin. Past ac­ stream from Lees Ferry. The Dirty Devil, Escalante, and tivities in the basin have included an extensive study of water resources development and related problems, cooperation in Paria Rivers drain the eastern side of the Wasatch Plateau the projects of other agencies, and participation in emer­ and join the Colorado River from the west. gency flood control work. Facilities are needed for flood The climate of the basin is arid to semiarid except in the high control and water supply. To provide the opportunity for elevations of headwater areas where precipitation is moder­ more people to enjoy the area, there is also a need for addi­ ately heavy. Wide ranges in precipitation, temperature, and tional recreation facilities and supporting services. wind movement are caused by differences in elevation, lati­ tude, and topography. Most precipitation occurs as snow Work Under the Continuing Authorities during the winter and early spring. In general the basin’s cli­ Program mate is characterized by short, warm summers and long, Work performed by the Corps of Engineers under the cold winters. Continuing Authorities Program in the Upper Colorado The principal urban centers in the Colorado portion of the River basin in Colorado is discussed in the following Upper Colorado River basin are Grand Junction, Montrose, paragraphs. Glenwood Springs, Durango, and Cortez. The 1980 popula­ Snagging and Clearing for Flood Control tion of the basin was 520,000, including approximately 270,000 within the Colorado portion of the basin. Under Section 208 authority the Sacramento District per­ formed snagging and clearing work in 1969 on Cornet Creek Livestock production, other agricultural activities, and min­ at Telluride at a cost of $9,600. ing form the economic base of the Upper Colorado River basin. It is the Nation’s chief source of molybdenum and is a In 1970, ice jams were causing high backup stages on the major source of vanadium, uranium, lead, zinc, and coal. Gunnison River in the vicinity of Gunnison. Emergency Oil and natural gas are also important, and there are vast re­ measures to relieve the ice jams were performed at a cost of serves of oil shale that offer potential for future develop­ $11,500. ment. Cropland is mostly devoted to the production of live­ In 1971, $52,500 was spent for emergency channel clearing stock feed to complement large areas of rangeland. In areas to permit passage of high flows on the Gunnison River at where frost damage is minimal, sugar beets, beans, po­ Gunnison. An additional $28,000 was spent in 1972 for tatoes, and a variety of fruit are produced. emergency channel clearing in the same area.

25 Emergency Bank Protection water treatment plant, with costs of about $38,500. Under Section 14 authority the Sacramento District pro­ Work Under the Technical Assistance vided emergency bank protection on the Colorado River near Rifle in 1972. Programs In May 1973, because of flooding, local interests reinforced Assistance provided to the State under the Corps Technical the right bank of the West Mancos River to protect the city Assistance Programs is discussed below. of Mancos’ water supply ponds; the Corps of Engineers pro­ Flood Plain Management Sevices Program vided bank protection and levee repair along the right bank The Flood Plain Management Services Program has pro­ of the Mancos River to protect the sewage treatment plant. vided for numerous services over the years to public and pri­ Federal costs amounted to approximately $22,000. In Sep­ vate entities in an effort to achieve flood damage reduction. tember 1973, high flows again made it necessary to reinforce This effort has been in the form of published studies such as these levees; the cost was $19,000. the flood plain information reports listed below and numer­ The snowmelt floods of April-May 1974 necessitated bank ous unpublished studies and technical assistance. protection work at two locations along the Yampa River—at The reports listed below have been prepared by the Sac­ Steamboat Springs to protect a sewage treatment plant, with ramento District for the Upper Colorado River basin in costs of approximately $21,500, and at Hayden to protect a Colorado. Flood Plain Information Reports L ocality Sponsoring Agency Status

Colorado and Gunnison Rivers at City of Grand Junction and Completed March 1973 Grand Junction Mesa County

Colorado River and Rifle, Govern­ ment, and Hubbard Gulch Creeks Town of Rifle and Garfield County Completed April 1973 at Rifle

Roaring Fork River at Aspen and City of Aspen and Pitkin County Completed June 1973 Castle and Hunter Creeks

Animas River and Lightner, Junction, City of Durango, La Plata County, Completed June 1974 and Dry Creeks at Durango and Animas Regional Planning Commission

Yampa River and Tributaries at City of Steamboat Springs and Completed February 1976 Steamboat Springs Routt County

Vallecito Creek Animas Regional Planning Completed April 1976 Commission

Colorado River at Fruita City of Fruita and Mesa County Completed November 1976

Colorado River and Tributaries at City of Grand Junction and Completed November 1976 Grand Junction Mesa County

Colorado River at Palisade Town of Palisade and Mesa County Completed November 1976

Animas River and Junction and Dry City of Durango and Animas Completed May 1977 Gulch Creeks at Durango Regional Planning Commission

Animas River and Hermosa Creek La Plata County and Animas Completed October 1977 at Hermosa Regional Planning Commission

Yampa River and Tributaries at Craig City of Craig and Moffat County Completed November 1977

Dolores River and Tributaries at Montelores Planning Group Completed September 1978 Dolores

Gunnison and Uncompahgre Rivers Delta County Completed February 1980 at Delta

North Fork Gunnison River, Delta and Gunnison Counties Completed February 1980 Hotchkiss to Somerset

Uncompahgre River at Montrose City of Montrose and Montrose Completed February 1980 County 26 The Sacramento District has developed flood plain informa­ tion as a part of flood insurance studies done for the Federal Emergency Management Agency at the following locations.. Special Flood Hazard Information Reports Locality Sponsoring Agency Status

Yampa River and Tributaries Steamboat Springs Completed 1 October 1976

Colorado and Roaring Fork Rivers; Garfield County Completed 1 October 1976 Alkali, Cattle, and East Elk Creeks

White River, Dragon and Rangely Completed 1 November 1976 St. Timothy Washes, and High School Ravine

Colorado River; Mesa, Roan, Mesa County Completed 1 May 1977 and West Creeks Planning Assistance to States Program nison, Olathe, and Delta (cost $19,300). The Planning Assistance to States Program is described in Public Law 93-288—Major Disaster Recovery the Platte River and Kansas River Basins chapter of this booklet. In the Upper Colorado River basin, Fiscal Year The following paragraphs describe activities of the Corps in 1989 work included an evaluation of the hydrologic and hy­ the Upper Colorado River basin for the Federal Emergency draulic characteristics on the Uncompahgre River. Possible Management Agency under this authority. studies for Fiscal Year 1990 include continuing the analysis After the floods of July 1965, the Corps of Engineers pre­ of the Uncompahgre River, beginning a hydrologic and hy­ pared an evaluation report recommending repayment of ap­ draulic analysis of the Colorado River in the vicinity of proximately $10,000 to local interests for emergency restora­ Grand Junction, and designing streambank erosion control tion work at Ouray. measures on the Animas River in La Plata County. Following the September 1970 floods in the Four Corners region, sanitation and water supply facilities at Silverton Work Under Emergency Authorities and Dove Creek were restored at a cost of $132,000. Other The Corps of Engineers has given emergency assistance to repair and restoration work costing $78,000 was done for 14 the State of Colorado as described below. local governmental agencies in Delta, Montrose, San Public Law 99, 84th Congress—Flood-Associated Miguel, Dolores, San Juan, Montezuma, La Plata, and Assistance Archuleta Counties. In addition, engineering services were provided in connection with 80 project applications for re­ Work accomplished under this authority is described in the imbursement of repair and restoration costs and 24 project following paragraphs. applications for removal of debris from public and private In 1949 and 1952, the Sacramento District spent $31,500 for lands. The services provided by the Office of Emergency emergency channel and levee work to protect the towns of Preparedness (now the Federal Emergency Management Craig, Dolores, Hayden, and Rico. The streams involved Agency) consisted of review of project eligibility, field in­ were Fortification Creek, the Dolores River, Dry Creek, and spection, preparation of cost estimates, and final inspection Silver Creek. of completed work. The Corps of Engineers, in cooperation with local interests, In the spring of 1984, the Sacramento District set up a flood repaired and extended existing flood control works at and operations office in Grand Junction to provide liaison with near Dolores in 1958 at an approximate cost of $14,000. State emergency operations personnel in reducing flood During the snowmelt flood of 1969, $27,000 was expended damage. Following the 1984 flood, the Sacramento District for channel rectification work, debris removal, and snag­ assisted the Federal Emergency Management Agency in ging and clearing on the Dolores River at Dolores. This making damage survey reports associated with a Federal dis­ project has prevented damages estimated to be in excess of aster declaration covering 15 counties of western Colorado. $20,000. Survey Investigations Following the September 1970 floods in the Four Corners Studies of flood and related water resources problems are region, levees along the Animas River at Durango were re­ conducted by the Corps of Engineers in response to direc­ paired at a cost of approximately $50,000. tives by Congress or by the Senate or House Public Works Following the spring floods of 1973, the left bank of Her- Committee. Additional information about the processing of mosa Creek immediately downstream from the town of Her- survey investigation reports is presented in the Platte River mosa was repaired and the channel was restored at a cost of and Kansas River basins section of this booklet under “ Sur­ $22,000. A levee along the right bank of the Animas River vey Investigations.” upstream from the town of Hermosa was restored and re­ A comprehensive study of the Colorado River and its trib­ paired at a cost of about $75,000. utaries upstream from Lees Ferry was authorized by the During the 1983 and 1984 snowmelt floods in the Upper Flood Control Act of 1938 to investigate the overall flood Colorado River basin of Colorado, the Sacramento District control and related water resources problems in the study provided technical assistance to local governments in their area and to develop plans to resolve the problems on both a efforts to construct advance measures projects, conduct local and a basin wide basis. The Upper Colorado River flood fights, and reduce the effects of flooding. Corps emer­ basin comprises a portion of the study area, which also in­ gency operations included helicopter support at Silt (cost cludes parts of Utah, Wyoming, New Mexico, and Arizona. $33,500); 100,000 sandbags to supplement State resources The study is inactive and completion is dependent on future (cost $32,000); and three small flood fight contracts at Gun- appropriation of funds. 27 Authorized Corps of Engineers Projects r- Ulke Completed N Local Protection Under Construction [ ¡ / ^ Channel tmpiavemente # COLORADO' Hot Stoned [ » ^ * DENVER

Other Improvements ^ Other Pro,«ts Reregulatiny 0.nn ■*■■■ 1__ , • lEADVIUt V

in « KANSAS

GRANADA Q

©JOHN MARTIN RESERVOIR

PINON CANYON DAM ©

© TRINIDAD LAKE

COLORADO NEW MEXICO

Chapter IV Arkansas River, Rio Grande and Cimarron River Basins Arkansas River, Rio Grande, Spillway at John Martin Dam and Cimarron River Basins (Southwestern Division—Albuquerque District) In Colorado the Arkansas River, the Rio Grande, and a short reach of the Cimarron River lie within the boundary of the Southwestern Division’s Albuquerque District. The Arkansas River rises high in the Rocky Mountains near the Continental Divide in central Colorado. The river flows 170 miles from near the historic mining town of Leadville through rugged mountains and foothills to Pueblo. At Pueblo the Arkansas enters the Great Plains region of the basin and continues eastward into neighboring Kansas. John Martin Reservoir is part of a comprehensive plan for Main stem flows of the Arkansas River cannot be used for flood control and the development of water resources in the most purposes without extensive treatment because of Arkansas River basin. The reservoir has a capacity for chloride contamination from natural sources. Some of its almost 619,000 acre-feet at maximum pool. The lake ex­ tributary flows, however, are suitable for domestic and in­ tends more than 14 miles up the valley from the dam. The dustrial use without treatment. Flood Control Act of 1965 authorized the Corps of Engi­ The Colorado reach of the Arkansas River basin is sparsely neers to use up to 10,000 acre-feet of the reservoir’s author­ populated and, with the exception of major concentrations ized flood control storage space for a permanent pool to en­ at Pueblo, Colorado Springs, and Trinidad, the population hance fish and wildlife resources and recreation in the area. is scattered in smaller communities throughout the region. This permanent pool is supplemented by water retained Water resources development includes projects at Colorado through the summer storage of irrigation water. Springs, at Pueblo, in the vicinity of Las Animas at the con­ Bent and Prowers Counties purchased the water to establish fluence of the Arkansas and Purgatoire Rivers, and on the the 10,000-acre-foot permanent pool. These counties are upstream reach of the Purgatoire in the vicinity of Trinidad. seeking reimbursement from the State of Colorado. The Rio Grande begins its 1,800-mile journey at an altitude Approximately 261,000 acre-feet of storage is reserved in the of 12,000 feet in the San Juan Mountains of southwestern reservoir for flood control and 357,000 acre-feet is used for Colorado. From its point of origin, the river flows 182 miles storage of irrigation water when it is available. Releases southeast through Colorado and, still a mountain stream, from the reservoir are made in accordance with terms of the crosses into New Mexico. The Rio Grande is a river of ex­ Arkansas River Compact and the requests of the Compact tremes, ranging from a narrow, shallow stream to a wide, Administration to supply irrigation water for lands down­ winding, and sometimes rushing river. In Colorado, the stream as far as Dodge City, Kansas. river courses through some of the most scenic country in all Completed at a cost of $15.25 million, John Martin Reser­ the continent. voir has more than paid for itself by preventing downstream The Rio Grande basin in Colorado is even more sparsely flood damages in Colorado and Kansas. In the 1965 flood populated than the Arkansas River basin. Creede, Del alone, the reservoir prevented more than $15 million in dam­ Norte, Monte Vista, Antonito, and Alamosa are the most ages in Colorado and $33 million in damages in Kansas. populated communities in the area. The Corps of Engineers Total savings by this project to date exceed $88 million. In has only one completed project in the Colorado segment of providing a more stable and supplemental water supply for the basin—at Creede. A study of the Rio Grande basin in downstream users, it has cumulative irrigation benefits in Colorado and New Mexico is scheduled for completion in excess of $19 million; about 60 percent of these benefits is 1989. The study will determine the need for additional water for Colorado users. resources improvements for flood control and allied During construction of the John Martin Reservoir project, purposes. some of the earthfill for the dam was obtained from a A short reach of the Cimarron River crosses the extreme 75-acre tract of land immediately downstream from the southeastern tip of Colorado. A study of the Cimarron dam. Averaging 12 feet deep, this excavation was filled with River basin by the Tulsa District has been combined with the water. Thus, Lake Hasty was formed and is the scene of study titled “Arkansas River and Tributaries, Great Bend, year-round fishing and swimming. The Corps of Engineers Kansas, to Tulsa, Oklahoma.” constructed camping, picnicking, and other recreation facil­ ities which are available to the public. Completed Multiple-Purpose Projects Trinidad Lake (Albuquerque District) John Martin Reservoir Project (Albuquerque District) Trinidad Lake is on the Purgatoire River, an Arkansas River The John Martin Reservoir project was the second dam con­ tributary, 4 miles upstream from Trinidad. It was author­ structed by the Corps of Engineers Albuquerque District. ized in the Flood Control Act of 1958. It is a multipurpose Authorized in the Flood Control Act of 1936, construction project, affording flood control protection for Trinidad and was started on Caddoa Dam early in 1940. By March 1943, the Purgatoire valley, irrigation water storage and regula­ however, the World War II demand for men, supplies, and tion, sedimentation control, and water-associated recrea­ materials caught up with the project and, with construction tion. The project was completed in June 1977. Relocations 85 percent complete, work ceased. Renamed for Colorado comprised a major portion of work on the project. These Congressman John A. Martin, who represented Colorado’s included the relocation of 6 miles of a State highway, 6 miles Third District, the project was completed in 1948. of a county road, 9 miles of railroad, two cemeteries, Jansen

29 Reservoir, and utilities. Water through the dam is controlled Pueblo Floodway Levee Extension by a 9-foot-diameter conduit. (Albuquerque District) Trinidad Lake inundated an area where four small mining Seventy-eight deaths and $10 million worth of property de­ communities once stood. Former occupants were reim­ stroyed by the 1921 flood on the Arkansas River at Pueblo bursed for their property and relocated to new homes. Two prompted formation of the Pueblo Conservancy District. cemeteries with 631 burial plots were relocated from the res­ This organization has sponsored construction of improve­ ervoir area to a consolidated cemetery on a hillside over­ ments for the city’s flood protection. One project sponsored looking the valley a mile downstream from the dam. by the conservancy district was a floodway on the Arkansas A unique feature of construction work on the Trinidad Lake River that extended through the city. Deficiencies of the project was the use of explosive cratering to cut two railroad backwater levee at the floodway’s lower end, however, passes through hills on the site for relocating the Colorado prompted city officials to request the Federal Government and Wyoming Railroad. The cratering was performed by the to investigate the adequacy of the floodway. Consequently, Corps of Engineers. Trinidad Dam is 200 feet high and in the Flood Control Act of 1950, Congress authorized the 6,610 feet long and contains about 8 million cubic yards of Corps of Engineers to extend the existing levee. earthfill. Irrigation water stored in the reservoir is used on The Corps Albuquerque District began construction in the approximately 20,000 acres. spring of 1952 and completed the job that fall. Work con­ Recreation facilities and a boat-launching ramp, managed sisted of raising and strengthening the existing levee and by the Colorado Division of Parks and Outdoor Recreation, building some new levees. The levee was extended 2,780 feet are located on the lake’s scenic and easily accessible north and is designed to convey a peak floodflow of 110,000 cubic shore. feet per second. This improvement protects an area contain­ ing important industrial and transportation facilities sub­ The total cost of Trinidad Lake was $45 million, of which jected to inundation by backwater from the Arkansas River. $39 million was a Federal cost. Federal cost of the project was $201,958. Pueblo local inter­ ests furnished lands and rights-of-way at an estimated cost of $4,950. They are also responsible for operation and main­ tenance of the project. The project’s average annual flood prevention benefits are estimated at $25,000. Templeton Gap Floodway (Albuquerque District) The Templeton Gap floodway project is in north Colorado Springs on an intermittent tributary to Monument Creek, a minor tributary in the Arkansas River basin. Construction of a floodway providing flood protection for Colorado Springs was authorized in the Flood Control Act of 1936, as amended by the Flood Control Act of 1944. The project was completed and put into operation in 1949. It consists of a 2-mile-long channel with a floodflow capacity of 14,000 cubic feet per second. The maximum Trinidad Lake flood experienced by the city was 9,700 cubic feet per second. The project’s upper reach is partially lined with rip­ Completed Flood Control Projects rap, and the downstream end is of reinforced concrete. The cost of the project was $1,171,633. Estimated annual Willow Creek Channel Improvement flood prevention benefits are $150,000. (Albuquerque District) Las Animas Flood Control Project Creede lies just east of the Continental Divide in southwest­ (Albuquerque District) ern Colorado. Until the fall of 1950, when the Corps of En­ gineers Albuquerque District completed the city’s flood pro­ The Las Animas flood control project was authorized by the tection project, Creede had been plagued by periodic flood­ Flood Control Act of 1965. Las Animas, the county seat of ing from Willow Creek which flows through the city. The Bent County, is on the right bank of the Arkansas River 75 project was approved by Congress in the Flood Control Act miles upstream from the Colorado-Kansas State line. of 1944, but funding and construction were delayed until The - flood threat to Las Animas and vicinity is from the after the war. Arkansas River. The aggrading riverbed reduced channel The channel improvement project consists of a grouted rip­ capacity to the point that overbank flows occurred at about rap channel on the alignment of Willow Creek. The channel 6,500 cubic feet per second (c.f.s.) and urban flooding is 5,527 feet long with a bottom width varying from 8 to 50 occurred at 10,000 c.f.s. feet; depths vary from 6 to 12 feet. The project extends ap­ The plan of improvement consists of a 9.6-mile-long levee proximately a mile from the mouth of Willow Creek on the right bank of the Arkansas River and a mile-long Canyon immediately above the town to a point just below levee on the left bank. Appurtenant works include levee pro­ the Denver and Rio Grande Western Railroad bridge. It ter­ tection measures, a sewage pumping plant, intake structures minates in a slightly flaring outlet structure which has a bot­ for irrigation canals, an interior drainage system, a ditch, tom width varying from 12 to 35 feet. The channel capacity and ponding areas. This project was completed in June is 1,800 cubic feet per second; this is equal to the maximum 1978. flood peak of record which occurred in 1911. The project cost $4,900,000, including $4,600,000 in Federal The project was completed at a cost of $277,500. To date funds. The average annual benefits are estimated to be this project has prevented $331,000 in flood damages. approximately $269,000. 30 Associated Projects of Other Agencies being overtopped and washed out by floodwaters, a spillway 75 feet wide was provided in the left abutment. The Flood Control Act of 1944 assigned the Corps of Engi­ neers the responsibility of prescribing regulations for the use The total Federal cost of the project was $130,400. In addi­ of storage capacity allocated to flood control at reservoirs tion, local interests furnished rights-of-way at an estimated constructed wholly or in part with Federal funds. Such reg­ cost of $25,000. Flood damages of $13,000 have been pre­ ulations have been prescribed or are being considered for the vented by the project since its completion. following Bureau of Reclamation projects. Holly (Albuquerque District), The town of Holly is at the Platoro Reservoir confluence of Wild Horse Creek, Two Butte Creek, and the Arkansas River. In 1965, their combined flows put the entire Platoro Reservoir is a dual-purpose project. It was com­ town under 8 feet of water and caused damage estimated at pleted in 1951 by the Bureau of Reclamation on the Conejos $1.5 million. River, a tributary to the Rio Grande in south-central Colo­ rado near the New Mexico State line. Storage capacity of To alleviate the problem, a levee system was completed by 54.000 acre-feet is allocated on a forecast basis for irrigation the Corps of Engineers in 1980 under Section 205 authority. and control of spring floods. The remaining 6,000 acre-feet The levee was constructed along the east bank of Wild is allocated for temporary storage of floodflows to provide Horse Creek to its junction with the Arkansas River and optimum flood control benefits on the Conejos River in then east along the north side of the main stem to the point Colorado and on the Rio Grande in New Mexico. It is esti­ of termination, east of Colorado State Highway 89. mated that the project has prevented flood damages of The flood control improvements provide standard project $629,000 since 1951. Included in that amount is an estimated flood protection for the town of Holly and adjacent lands. $466,000 in damages prevented in Colorado. The total Federal cost of the project was $1,990,000. In Fryingpan-Arkansas Project addition, local interests furnished rights-of-way at an esti­ Public Law 87-590 authorized the Fryingpan-Arkansas proj­ mated cost of $40,000. ect for construction, operation, and maintenance by the Wolf Creek, Granada (Albuquerque District), Granada, lo­ Bureau of Reclamation. The multiple-purpose project will cated in Prowers County, has long been exposed to serious provide supplemental water supplies for irrigation, munic­ threats from Wolf Creek, a right-bank tributary to the ipal and industrial uses, generation of power, flood and Arkansas River. The Corps of Engineers completed a Sec­ sediment control, and recreation. tion 205 flood control project at Granada in 1980 after a One element of the plan is the Pueblo Dam and Reservoir construction period of less than a year. which will be constructed for conservation and flood control The project consists of improvements to the existing channel purposes on the Arkansas River at approximately the same and levee system and an outfall channel to the Arkansas site as the existing Barrier Dam, 6 miles west of the city of River. These improvements provide Granada with protec­ Pueblo. The reservoir, as planned, will have a capacity of tion from the standard project flood of 41,000 cubic feet per 357.000 acre-feet, of which 93,000 acre-feet is allocated for second (c.f.s.) and the adjacent farmlands with protection flood control. The Corps of Engineers will be responsible from floods up to and including the 15-year flood of 9,200 for regulating the flood control storage. c.f.s. The total Federal cost of the project was $1.6 million. In Work Under the Continuing Authorities addition, local interests furnished rights-of-way costing Program $15,000. Work performed by the Corps of Engineers under the Con­ Snagging and Clearing for Flood Control tinuing Authorities Program in the Colorado portion of the The following work in the Arkansas River and Rio Grande Arkansas River basin is discussed in the following para­ basins has been accomplished by the Albuquerque District graphs. under Section 208 authority. Small Flood Control Projects Federal Year Pinon Canyon Dam (Albuquerque District), The Pinon Locality Cost Completed Canyon Dam protects a highly developed 40-acre area in the Arkansas River Basin: northwestern and central sections of Trinidad from floods Greenhorn Creek at Rye...... $11,660 1948 originating in the Pinon Canyon Arroyo, which drains a Eightmile Creek at Florence. .. . 21,328 1951 watershed of 1.4 square miles. Wild Horse Creek at Holly...... 21,222 1951 Construction of this Section 205 project was started in Jan­ uary 1954 and completed in August of the same year. The Arkansas River at Las Animas.. 35,818 1956 project consists of an earth dam 695 feet long with a maxi­ Arkansas River at La Ju n ta___ 66,609 1956 mum height of 73 feet above the arroyo bed. The reservoir Arkansas River at Canon City .. 74,609 1961 has a capacity of 406 acre-feet. An uncontrolled outlet was Arkansas River at Canon City .. 31,283 1977 installed at the bottom of the dam for releasing floodwater at a rate commensurate with the channel capacity down­ Rio Grande Basin: stream from the dam. As a safety measure against the dam Rio Grande at Alam osa___ 15,813 1949

31 Emergency Bank Protection Flood Plain Information Reports The following Section 14 work was accomplished in the Fountain Creek, Pueblo Arkansas River and Rio Grande basins by the Albuquerque Goodnight Arroyo, Dry Creek and District. Wild Horse-Dry Creek, Pueblo St. Charles River, Pueblo Federal Year Sixmile Creek, Pueblo Locality Cost Completed Salt Creek, Pueblo Arkansas River Basin: Monument Creek, Colorado Springs Arkansas River at Florence ..... $22,608 1950 Fountain Creek, Colorado Springs and Manitou Springs Arkansas River at Manzanola .. 32,175 1950 Fountain and Jimmy Camp Creeks, Colorado Springs Purgatoire River at Trinidad ... 3,880 1950 Fountain Creek, El Paso County Purgatoire River at Higbee...... 30,120 1950 Cottonwood Creek, El Paso County Arkansas River at Fowler...... 12,055 1951 Purgatoire River and Tributaries, Trinidad Arkansas River at Las Animas.. 25,614 1952 Rio Grande, Monte Vista Purgatoire River at Trinidad .... 43,034 1956 Cucharas River, Le Vet a Arkansas River at Rocky Ford.. 18,921 1958 Cucharas River, Walsenburg Arkansas River at Special flood hazard information reports have been pre­ 27,955 1959 North La J u n ta ...... pared for the following areas. Arkansas River at Canon City .. 46,380 1961 Special Flood Hazard Information Reports Purgatoire River at Trinidad ... 28,324 1968 Foundation Creek at Wolf Creek, Granada Pinon Branch...... 77,000 1981 Arkansas River and Tributaries, Holly Arkansas River at Arkansas River and Tributaries, Great Bend, Kansas, Reynolds Avenue...... 52,500 1983 to John Martin Dam, Colorado Smith Creek at Arkansas River, Anderson and King Arroyos, La Junta Pleasant View Estates...... 219,000 1983 Planning Assistance to States Program Purgatoire River The Planning Assistance to States Program is described in at Highway 1 2 ...... 108,000 1983 the Platte River and Kansas River basins chapter of this King Arroyo...... 62,500 1983 booklet. Studies being conducted during Fiscal Year 1989 in Fountain Creek at Fountain---- . 180,100 1983 the Arkansas River basin include a ground water investiga­ Purgatoire River at tion for the community of North La Junta and a hydrologic Highway 101 ...... 99,500 1983 analysis of Cheraw Lake in Otero County. Possible studies Fountain Creek for Fiscal Year 1990 include continued hydrologic analysis at Interstate 25...... 250,000 1984 of Cheraw Lake, a flood plain analysis on Fountain Creek Fountain Creek at Security----- . 198,500 1984 through Manitou Springs, and an evaluation of the effectiveness of the existing flood control channel at Fourmile Creek at Canon City. 90,000 1984 Florence. Fountain Creek at Stratmoor H ills...... 120,500 1984 Work Under Emergency Authorities Rio Grande Basin: The Corps of Engineers has given emergency assistance to Rio Grande at Alamosa...... 131,500 1983 the State of Colorado as described below. Public Law 99, 84th Congress—Flood-Associated Work Under the Technical Assistance Assistance Programs Work accomplished under this authority in the Arkansas Assistance provided to the State under the Corps Technical River and Rio Grande basins is described below. Assistance Programs is described in the following para­ Arkansas River Basin (Albuquerque District). Emergency graphs. repairs to levees, riverbanks, channels, and floodways and Flood Plain Management Services Program flood fighting operations on the Arkansas and Purgatoire The Flood Plain Management Services Program has pro­ Rivers and their tributaries involved the following ex­ vided for numerous services over the years to public and pri­ penditures. vate entities in an effort to achieve flood damage reduction. This effort has been in the form of published studies such as Expenditures Year the flood plain information reports and special flood hazard $ 13,270...... 1949 information reports listed below and numerous unpublished studies and technical assistance. 73,934...... 1950 15,562 ...... 1955 The following flood plain information reports have been prepared by the Albuquerque District for areas/commu- 181,797 ...... 1965 nities located in the Arkansas River and Rio Grande basins. 477,885 ...... 1966 11,306...... 1967

32 Rio Grande Basin (Albuquerque District). In 1948 a pilot channel was constructed and an existing flume repaired on. Willow Creek at Creede at a cost of $14,500. Survey Investigations Studies of flood and related water resources problems are conducted by the Corps of Engineers in response to direc­ tives by Congress or by the Senate or House Public Works Committee. Additional information about the processing of survey investigation reports is presented in the Platte River and Kansas River basins section of this booklet under ‘ ‘ Survey Investigations. ’ ’ Following is a list of studies by the Corps of Engineers in the Arkansas River, Rio Grande, and Cimarron River basins in Colorado.

Locality Purpose Status Arkansas River and Tributaries To determine the extent and The current study was initially downstream from John Martin Dam character of the flood and related divided into three interim studies— (Albuquerque District) problems of the basin and the the Lamar, Colorado, local pro­ feasibility of additional improvements tection project; Bear Creek; and the for water resources development remainder of the Arkansas River downstream from John Martin Dam to Great Bend, Kansas. Studies completed in 1977 and again in 1983 showed that the Lamar project was not economically feasible. The Main Stem, Kansas, and Bear Creek Interim studies were transferred from the Albuquerque District to the Tulsa District in 1983. In 1984, studies were completed for the remainder of the Arkansas River downstream from John Martin Dam to the Colorado- Kansas State line. Also, the feasibility study of providing a hydropower unit at John Martin Reservoir, which was initiated in 1982, was completed in 1984. The main stem flood control study and the John Martin hydro- power study were found to be not economically feasible.

Rio Grande and Tributaries, To determine the need for additional Flood control and related water Colorado and New Mexico improvements on the Rio Grande and resources studies are continuing in the (Albuquerque District) its tributaries in the interest of flood Rio Grande basin of Colorado and control and allied purposes New Mexico. Interim reports are scheduled for completion in 1988 for the Colorado portion of the Rio Grande basin and in 1989 for the New Mexico portion.

Cimarron River and Tributaries, To determine the feasibility of The study, scheduled for completion New Mexico, Colorado, Kansas, and developing improvements in the in 1988, was combined with the Oklahoma (Albuquerque District) interest of comprehensive develop­ survey on the Arkansas River and ment of the basin’s water resources Tributaries, Great Bend, Kansas, to Tulsa, Oklahoma.

33 Index Animas R iver...... 26, 27 Colorado Springs...... 29,30 Arkansas River...... 29, 33 Comprehensive Plan, Missouri River Basin...... 13 Arkansas River Basin ...... 29,32, 33 Congressional Authorization Process...... 21 Arkansas River and Tributaries Cornet Creek...... 25 Downstream from John Martin D am ...... 33 C raig...... 26,27 Aspen...... 25, 26 Creede...... 29,30 Aurora ...... 11,16,18, 23 Cucharas River...... 32 Bear C reek...... 11, 12,17, 18 D elta...... 26,27 Bear Creek Dam and L ake...... 11, 12 Denver...... 11,13,18 . Bear Creek and Mt. Vernon Creek...... 17 Dolores River...... 25, 26,27 Big Dry and Little Dry Creeks...... 17 Dry Creek...... 18, 26, 27, 32 Big Thompson Canyon Flood...... 19 Dry Gulch Creeks...... 20,26 Big Thompson River ...... 16,17,18, 19 Durango...... 25,26,27 Bijou Creek...... 19 Fort Collins...... 11,18,20 Bonny Reservoir...... 15 Fortification Creek...... 27 Boulder Creek...... 17, 18 Four Corners Region...... 27 Boulder Creek and South Boulder Creek...... 18 Fruita...... 26 Box Elder Creek ...... 19, 20 Fryingpan-Arkansas Project...... 31 Box Elder, Spring, and Dry Creeks...... 20 Goldsmith Gulch, Dutch Creek, Lilley Gulch, Cache la Poudre River...... 16,17,18, 19 and Coon Creek...... 17 Caddoa Dam ...... 29 Goose Creek, Boulder...... 20 Castle C reek...... 19, 26 Government Creek...... 26 Chatfield Dam and Lake...... 11,12, 13 Granada ...... 31,32 Chatfield Downstream Improvements...... 13 Grand Junction...... 25, 26, 27 Cheraw Lake...... 32 Grange Hall Creek...... 17 Cherry C reek...... 11,12, 18 Greeley ...... 11,18 Cherry Creek Dam and Lake ...... 11 Greenwood Village...... 11 Cimarron River B asin...... 29, 33 Gunnison ...... 25, 26,27 Cimarron River and Tributaries, New Mexico, Hayden...... 26,27 Colorado, Kansas, and Oklahoma...... 33 Hermosa...... 26,27 Clear Creek...... 19 Hermosa Creek...... 26,27 Colorado River...... 25,26, 27 H olly...... 31,32

34 Hubbard Gulch Creek...... 26 Platte River and Kansas River Basins...... 11 Hunter C reek...... 26 Plum Creek...... 11, 13,16, 19 Lightner...... 26 Pueblo Floodway Levee Extension ...... 30 John Martin Reservoir Project...... 29 Purgatoire River...... 29, 32 Junction Creek...... 26 Ralston and Leyden Creeks ...... 20 Kansas River Basin...... 11 Ralston, Leyden, and Van Bibber Creeks ...... 17 Kelley Road D am ...... 16, 23 Rangely...... 27 Kiowa Creek...... 19 Republican River ...... 11,15 Lake H a sty ...... 29 R ico...... 27 Las Animas Flood Control Project ...... 30 Rifle ...... 26 Left-hand Creek ...... 17 Rio Grande Basin...... 29, 31, 32, 33 Little Thompson River...... 17 Rio Grande and Tributaries, Colorado Loveland...... 18, 19 and New Mexico...... 33 Lower Cherry Creek...... 18 Roaring Fork R iver...... 25, 26, 27 Lower St. Vrain Creek...... 17 Sand C reek...... 11,15, 19 Mancos River...... 26 Sand and Toll Gate C reeks...... 18, 19 Manitou Springs ...... 32 Silver Creek...... 27 Metropolitan Denver and South Platte River South Platte Park ...... 13 and Tributaries, Colorado, Wyoming, South Platte River ...... ____ ... 11, 12, 13, 16-19, 23 and Nebraska ...... 23 South Platte River Basin...... 11, 16, 17, 19, 20, 23 Metropolitan Denver Water Supply South Platte River and Pawnee C reek...... 1 8 Environmental Impact Statement ...... 11, 23 Steamboat Springs...... 26, 27 Monte V ista ...... 29, 32 Sterling...... 18, 19 Montrose...... 25,26, 27 Telluride...... 25 Mt. Vernon Creek ...... 17 Templeton Gap Floodway...... 30 North Fork Republican River...... 18 Toll Gate Creek ...... n North La Junta...... 32 Trinidad Lake...... 29, 30 North Platte River, Nebraska, Wyoming, and Colorado ...... 20 Uncompahgre River...... 26, 27 North Washington Sanitation District___ 16 Upper Colorado River B asin ...... 25, 26, 27 Upper St. Vrain C reek...... 17 Palisade...... 26 Pinon Canyon D am ...... 31 Upper Toll Gate Creek ...... 18,19 Vallecito C reek...... 26 Platoro Reservoir...... 31 W eldona...... 16 Platte River...... 20 Platte River Basin, Colorado, Nebraska, Westerly Creek...... 15, 16, 23 and W yoming...... 20 White River ...... 27 Willow Creek Channel Improvement...... 30 Wolf Creek, Granada ...... 31,32 W ra y ...... 18 Yampa River...... 26, 27

35 GLOSSARY

Acre-foot: A volume of water equivalent to 1 acre of land covered to a depth of 1 Habitat: The total of the environmental conditions which affect the life of plants foot. and animals.

Headwaters: (1) The upper reaches of a stream near its source. (2) The region Advance engineering and design work: Work done by Corps of Engineers in where ground waters emerge to form a surface stream. (3) The water upstream preparation of a project for construction. from a structure.

Agricultural levee: A levee that protects agricultural areas where the degree of Hydraulic earthfill dam: An embankment built up from waterborne clay, sand, protection is usually less than that of a floocTcontrol levee. and gravel carried through a pipe or flume. Alluvial: Of, pertaining to, or composed of sediment deposited by flowing water, Ice jam: Accumulation of ice packed together and piled up, choking the stream as in a riverbed, flood plain, or delta. channel, and causing a rise in water level above the jam.

Appropriation: The setting aside of money by Congress, through legislation, for a Jetty: A structure similar to a groin built on a seashore or riverbank to prevent specific use. erosion due to currents and/or tide.

Arch-gravity structure: A structure which derives its resistance to the pressure Joint-use storage: Reservoir storage space which is used for more than one pur­ of water from both an arching effect and its own weight. pose. The operation may follow a fixed predetermined schedule or may be flexible and subject to adjustment, depending on particular hydrologic conditions. Authorization: House and Senate Public Works Committees resolutions or spe­ cific legislation which provides the legal basis for conducting studies or construct­ Left or right bank of river: The left-hand or right-hand bank of a stream when ing projects. The money necessary for accomplishing the work is not a part of the the observer faces downstream. authorization but must come from an appropriation by Congress. Levee: A dike or embankment, generally constructed close to the banks of the Bank and channel stabilization: A process to prevent bank erosion and stream, lake, or other body of water, intended to protect the landside from inunda­ channel degradation. tion or to confine the streamflow to its regular channel.

Basin: (1) Drainage area of a lake or stream, such as a river basin. (2) A naturally, Mouth of river: The exit or point of discharge of a stream into another stream, a or artificially enclosed harbor for small craft, such as a yacht basin. lake, or the sea.

Concrete gravity structure: A type of concrete structure in which resistance to Oxbow lake: A lake formed in the meander of a stream, resulting from the overturning is provided only by its own weight. abandonment of the meandering course due to the formation of a new channel course. Confluence: The place where streams meet. Paleontology: The study of fossils and ancient life forms. Control dam: A dam or structure with gates to control the discharge from the up­ stream reservoir or lake. Reach: A length, distance, or leg of a channel or other watercourse.

Crest length: The length of a dam along its top (crest). Refusal: An extension of revetment that runs back into a channel bank to prevent a revetment structure from being outflanked. Dam: A barrier constructed across a valley for impounding water or creating a reservoir. Reservoir: A pond, lake, tank, basin, or other space, either natural or created in whole or in part by the building of a structure such as a dam, which is used for Damages prevented: The difference between damages without the project and storage, regulation, and control of water. the damages with the project in place. Revetment: (1) A facing of stone, concrete, or sandbags to protect a bank of Degree of protection: The amount of protection that a flood control measure is earth from erosion. (2) A retaining wall. designed for, as determined by engineering feasibility; economic criteria; and social, environmental, and other considerations. Revetted levee: A stone- or concrete-faced embankment to prevent a river from overflowing. Dike: An embankment to confine or control water. Riprap: A layer, facing, or protective mound of randomly placed stones to prevent Diversion channel: (1) An artificial channel constructed around a town or other erosion, scour, or sloughing of a structure or embankment; also, the stone so point of high potential flood damages to divert fioodwater from the main channel to used. minimize flood damages. (2) A channel carrying water from a diversion dam. Rock dike: An embankment built principally of rock. Earthflll dam: A dam with its main section composed principally of earth, gravel, sand, silt, and clay. Sill: (1) A horizontal beam forming the bottom of the entrance to a lock. (2) A low, submerged dam-like structure built to control riverbed scour and current speeds. Flood capacity: (1) The flow carried by a stream or floodway at bankfull water level. (2) The storage capacity of the flood pool at a reservoir. Spillway: A waterway on a dam or other hydraulic structure used to discharge ex­ cess water to avoid overtopping of a dam. Flood plain: Valley land along the course of a stream which is subject to inunda­ tion during periods of high water that exceed normal bankfull elevation. Stage: The elevation of the water surface above or below an arbitrary datum.

Flood proofing: Techniques for preventing flood damage to the structure and Standard project flood: A flood that may be expected from the most severe com­ contents of buildings in a flood hazard area. bination of meteorological and hydrological conditions that are reasonably char­ acteristic of the geographical region involved, excluding extremely rare combina­ Floodwall: A wall, usually built of reinforced concrete, to confine a stream to pre­ tions. vent flooding. Tributary: A stream or other body of water that contributes its water to another Gilsonite: A natural black bitumen used in the manufacture of acid, alkali, and stream or body of water. waterproof coatings. Visitor-hour: The presence of one or more persons in an area of land or water for Groin: A wall-like structure built perpendicular to the bank to prevent beach the purpose of engaging in one or more recreation activities during continuous, erosion. intermittent, or simultaneous periods of time totaling 60 minutes.

36 tVU.S. GOVERNMENT PRINTING OFFICE 1990 755-590