The addendum documentation of the China Wash Flume was conducted by North Wind in under contract to the Bureau of Reclamation (Reclamation) and in accordance with a Memorandum of Agreement (MOA) among Reclamation, BIA, SCIP, the San Carlos Irrigation and Drainage District (SCIDD), GRIC, and the Arizona State Historic Preservation Office (SHPO), dated May 16, It is an expansion of the documentation for the SCIP completed by Pfaff in March The field team consisted of Architectural Historian Greta Rayle (North Wind), Photographer Aaron Rothman of ARBR Photography of Phoenix, and Bryan Jesse of Darling Geomatics (Darling) of Tucson. The written narrative was prepared by Ms.
Rayle, with the assistance of historian Helana Ruter and cultural resources specialist Caitlin Dichter, both of North Wind. It was edited by Reclamation Archaeologist Lauren Jelinek. The photographs and negatives were processed by Aaron Rothman of ARBR Photography of Phoenix. Information for the written narrative was primarily gathered through research materials housed at the Reclamation Phoenix Area Office, as well as the SCIP and SCIDD offices, both located in Coolidge, Arizona. A search for historic photographs, engineering drawings, and other primary sources on the physical development of the SCIP and its appurtenant features was also conducted at National Archives and Records Administration (NARA) Federal Records Center in Riverside, California.
Selected drawings were provided by Reclamation and George Cairo Engineering in Mesa, Arizona. Scans of original drawings from August and November are housed at the American Indian Records Repository (AIRR) in Lenexa, Kansas, and were photographed for this report. The available drawings include the as-built drawings, as well those depicting modifications to the structure that required a set of drawings (e.g., changes to the mechanical or electrical systems). Measured drawings showing the current conditions of the China Wash Flume were prepared on December 2, by Darling Geometrics of Tucson, Arizona, using three-dimensional laser scanning technology; copies of those drawings are included as data pages in the report.
The 3D scans of the flume were also used by LGM of Minturn, Colorado, to create a 3D scale model of the structure for display purposes. SAN CARLOS IRRIGATION PROJECT, CHINA WASH FLUME HAER No. AZ-50-F (Page 3) Part I. Historical Information A. Physical History: 1. Date of construction: The China Wash Flume was originally constructed by the BIA between October of and May of Subsequent rehabilitation efforts have occurred in the and in 2. Architect/Engineer: Charles Real Olberg and Herman Christopher (H. C.) Neuffer, engineers with the United States Indian Irrigation Service (USIIS), designed the China Wash Flume and oversaw its construction. 3. Builder: The structure was constructed by government labor. 4.
Original plans and construction: The original plans for the China Wash Flume date to August and included six sheets. Sheets labeled 1 through 5 of 6 are housed at the American Indian Records Repository in Lenexa, Kansas, and include a plan view drawing of the structure in its entirety as well as detail plans of the ribbed concrete arches, concrete barrels, and retaining walls. The bottom right corner of a sixth drawing, ostensibly sheet 6 of 6, was bent, obscuring the sheet label. Construction of the flume occurred between October and May The original structure included four 10-foot-high by 14-foot-wide concrete barrel structures and five reinforced concrete arches that stood 43 feet above the barrel structures at their apex.
Four reinforced concrete retaining walls, each roughly 28 feet long, were constructed on either side of the structure and wrap the banks of the China Wash. Forty-foot-long wing walls were constructed at either end of the flume along the north and south banks of the FCG Canal. 5. Alterations: The China Wash Flume has undergone minor alterations since its construction in In the shotcrete was applied to the structure, and in delaminated surfaces and cracks were repaired with concrete, a cathode coating was applied to retard corrosion, and exposed steel joints were refinished. B.
Historical Context: The Akimel O odham people had lived an agrarian lifestyle along the Gila River, in what would become the State of Arizona, for centuries prior to the arrival of Euro-American settlers to the region in the late and early The settlers soon harnessed the Gila River for their own agricultural enterprises and impacted the flow of water to the Akimel O odham and their SAN CARLOS IRRIGATION PROJECT, CHINA WASH FLUME HAER No.
AZ-50-F (Page 4) Pee-posh neighbors living on the newly designated Gila River Indian Reservation.1 In the early Arizona Congressional Representative Carl Hayden began formulating a strategy for providing water to indigenous agriculturalists living on the Gila River Indian Reservation, as well as to non-indigenous farmers living along the Gila River in the vicinity of Florence, Arizona. With the aid of fellow Arizonan Senator Henry Ashurst, Hayden was eventually successful in passing the Indian Appropriation Act of to develop the FCG Project.
The Sacaton and Florence diversion dams (the latter of which was later designated the Ashurst-Hayden Dam) were the keystones of this planned irrigation system which also called for the development of a canal distribution network.2 Construction of the FCG project s primary canal, the FCG Canal (also referred to as the Main Canal), had also actually begun as a private endeavor by the Casa Grande Water Users Association in however the irrigation association ran out of funds in and could not complete the canal as planned.
Following the passage of the FCG project the Federal government purchased the constructed portion of the canal and incorporated it into the larger project design.3 By the early the Federal government had invested more than million in water development in Pinal County, but the Gila River Indian Reservation was still not receiving an adequate supply of water. In response, Congress approved the San Carlos Act in which authorized the development of the SCIP.
The SCIP, which incorporated the existing and planned structures of the FCG Project, also allowed for the construction of the Coolidge Dam and an associated reservoir, which were completed in Also during that year, the FCG Canal was completed between the Ashurst-Hayden diversion dam and the Picacho Reservoir.5 The China Wash Flume was one of 23 features constructed along the FCG Canal. Herbert V. Clotts, supervising engineer for the Department of the Interior U. S. Indian Irrigation Service (USIIS), prepared a series of monthly and annual reports for Irrigation District No. 4 covering California and Southern Arizona during the years and These reports 1 The Gila River Indian Reservation was created in DeJong, An Equal Chance? The Pima Indians and the Florence-Casa Grande Irrigation Project.
The Journal of Arizona History Vol. 45 No. 1 (Spring 2 Paige B. Florie, Thomas E. Jones, Robert J. Stokes, and Glennda Gene Luhnow, Class I (Overview) Survey Update of the San Carlos Irrigation and Drainage District (SCIDD) Joint Works for the U.S. Bureau of Reclamation, Pinal County, Arizona (Tempe: Archaeological Consulting Services, 3 Christine Pfaff, San Carlos Irrigation Project, Lands North & South of the Gila River, Coolidge, Pinal County, Arizona: Written Historical and Descriptive Data Historical American Engineering Record (HAER) No. AZ-50 (San Francisco: National Park Service, Western Region, Department of the Interior, 4 David Intracaso, Coolidge Dam: Photographs, Written Historical and Descriptive Data, Reduced Copies of Drawings HAER No.
AZ-7 (San Francisco: National Park Service, Western Region, Department of the Interior, 53 55. 5 Pfaff, San Carlos Irrigation Project, SAN CARLOS IRRIGATION PROJECT, CHINA WASH FLUME HAER No. AZ-50-F (Page 5) chronicled the broader development of the San Carlos Project, and detailed the construction of the China Wash Flume between October and May It is interesting to note that while Clotts states that the final plans for the structure were designed by Major [Charles] Olberg, the construction plans for the flume, dated August attribute the flume s design to H. C. Neuffer6. Both Olberg and Neuffer served as engineers for the USIIS during construction of the SCIP. Charles Real Olberg was born in St.
Paul, Minnesota in He graduated from George Washington University with a degree in civil engineering in and became employed as an engineer by Reclamation in While working as an engineer for Reclamation, Olberg purportedly drafted the initial plans for Roosevelt Dam, as part of the Salt River Project, in Arizona and oversaw its construction between and In he married Eloise M. Oliver of Globe, Arizona. At the time, he was listed as residing in Livingston, Arizona, a town that was subsequently inundated by Roosevelt Lake upon completion of the dam.8 By Olberg took on the role of Superintendent of Irrigation for District No. 4 of the USIIS Service and was based out of Los Angeles.
In his role as superintendent, Olberg began investigating the proposed SCIP along the Gila River.9 In Olberg authored a report of his findings in which he recommended that reclamation activities on the Gila River begin with the construction of two diversion dams one above the Town of Florence and the other above the community of Sacaton rather than the construction of a single dam at San Carlos, which had been previously proposed10 In Congress appropriated funds for the construction of a diversion dam in Florence, and the following year a diversion dam above Sacaton was authorized.11 By Olberg had been named Assistant Chief Irrigation Engineer for the Office of Indian Affairs. While serving in this 6 Herbert V. Clotts, Annual Report Irrigation District No.
4 California & Southern Arizona Fiscal Year USIIS, Bureau of Indian Affairs Collection Record Group 75, box 17. (The report narrative was misplaced in the annual report folder 4 NARA was notified of the misplaced item); USIIS, Gila River Project Florence-Casa Grande China Wash Flume Plans and Details, USIIS, Bureau of Reclamation Office, Phoenix. 7 Franklin Harper, ed., Who s Who on the Pacific Coast. A Biographical Compilation of Notable Living Contemporaries West of the Rocky Mountains (Los Angeles: Harper Publishing Company, Christine Pfaff, San Carlos Irrigation Project, Lands North & South of the Gila River, Coolidge, Pinal County, Arizona: Written Historical and Descriptive Data HAER No.
AZ-50 (San Francisco: National Park Service, Western Region, Department of the Interior, 8 State of Arizona, Charles R. Olberg, License date 3 February Gila County. Arizona County Marriage Records http://ancestry.com. 9 U.S. Congress House, Report on the San Carlos Irrigation Project and the History of Irrigation Along the Gila River by Charles Real Olberg, contained in Committee on Indian Affairs. Indians of the United States, Appendixes A, B, and C, the Condition of Various Tribes of Indians. Hearings Before the Committee on Indian Affairs. Congress, 1st Session. 10 Ibid. 11 David M. Introcaso, Coolidge Dam: Photographs, Written Historical and Descriptive Data, Reduced Copies of Drawings. HAER No.
AZ-7 (San Francisco: National Park Service, Western Region, Department of the Interior, SAN CARLOS IRRIGATION PROJECT, CHINA WASH FLUME HAER No. AZ-50-F (Page 6) role, Olberg designed the diversion dam above Florence which, upon its completion in was dedicated as the Ashurst-Hayden Dam. The Ashurst-Hayden Dam was designed as a floating weir structure. The 396-foot-long, 212-foot-wide, by 10-foot-high concrete slab was developed to float upon the sand base of the river channel.12 The structure regulated water along the Gila River and diverted river water to the FCG Canal.
Olberg also supervised the design and construction of the subsequent Sacaton Dam, which was built between and The Sacaton Dam was also designed as a floating weir roughly 73-feet-wide with a weir crest height of 3 feet above the river bed.13 A bridge over the river was constructed in tandem with the weir and is roughly feet long. The dam was to provide water solely to the Gila River Reservation and channel water to both the Pima-Sacaton Branch Canal and the San Tan Canal.
For his role in the construction of the dam, the nearby town of Olberg was named in his honor.14 In the interim period, between the initial construction and completion of the Sacaton Dam, Olberg designed the China Wash Flume and Coolidge Dam, both of which were part of the original proposed SCIP.15 The completion of the Coolidge Dam in effectively blocked the flow of water to the Sacaton Dam and obviated the structure.16 Herman Christopher (H. C.) Neuffer (var. Nuffer) was born in Preston, Idaho in By Neuffer had moved to New Mexico and was working as an assistant engineer for the USIIS.17 In he married Virginia Simmons in El Paso, Texas. Sometime prior to Neuffer was transferred to the District No.
4 office of the USIIS and the couple relocated to Los Angeles, California where they had two children by The USIIS annual report from fiscal year notes that Mr. Herman C. Neuffer was appointed to the position of temporary field draftsman February 1st and was actively engaged in the design of structures for canal work throughout the year. He was reinstated as Assistant Engineer June and on June 3rd he was 12 Pfaff, 13 Pfaff, San Carlos Irrigation Project, 14 Casa Grande Dispatch, Death Takes Designer of Coolidge Dam, Casa Grande Dispatch (Casa Grande, AZ), April 8, 15 Introcaso, Coolidge Dam; Pfaff, San Carlos Irrigation Project,1996. 16 Pfaff, San Carlos Irrigation Project, 17 U.S.
Selective Service, Herman Christopher Nuffer, World War I Selective Service System Draft Registration Cards, U.S. Selective Service System, National Archives and Records Administration http://ancestry.com 18 State of Texas, Herman C. Nuffer, marriage date 2 April to Virginia Simmons, Texas, County Marriage Index, http://ancestry.com; U.S. Bureau of the Census, Fifteenth Census of the United States, National Archives and Records Administration (Washington D.C.:U.S. Government Printing Office, SAN CARLOS IRRIGATION PROJECT, CHINA WASH FLUME HAER No. AZ-50-F (Page 7) placed in charge (as the Superintendent Construction Engineer) during the detail of Mr. Southworth on other work. 19 Correspondence between Assistant Engineer John J. Hubbell and H. C.
Neuffer demonstrates the direct involvement of Neuffer with the design and construction of China Wash Flume. In a series of letters dating between October and March Hubbell, who was then working in Florence, sought advice from Neuffer regarding the construction specifications for the flume.20 Neuffer also assumed a supervisory role in the construction of the Coolidge Dam which, as previously noted, was designed by Charles Olberg, which further suggests the two worked in concert with one another. Supervisor Clotts monthly progress reports for Irrigation District No.
4 indicate that the initial construction work on the China Wash Flume began in October and consisted of hauling gravel to the site.21 The following month, excavation of the footings of the structure had been started, steel cut, and partial forms constructed.22 Work on the structure progressed rapidly the following month as the crew poured the concrete footings and placed steel reinforcing materials in the arch ribs, counter forts, abutments, and retaining walls.
23 In January, the crew completed the forms of the east and west abutments, poured concrete to a height of 13 feet, and then stripped the lumber from the dried poured sections to be re-used in the creation of new forms.24 By March the retaining walls were completed and it was noted that the forms had been completed for the arched ribs, steel placed and the concrete poured. Forms had also been constructed for the flume barrels but had not been placed.25 The following month, the flume barrel forms were placed and reinforcing steel placed.
Additionally, metal lath was placed on the webs between the arches and the barrels and the crew waited for the delivery of a cement gun to place concrete in the barrels and webs.26 In May, construction progress of the flume was documented in two photographs which were included in USIIS District No. 4 annual report for The first image depicts a cross section of the flume, taken from the wash, with support timbers along the flume ribs. The second image is taken from the FCG and depicts the concrete ribs and barrels. Laborers can be seen working in 19 USIIS, Annual Report Irrigation District No. 4 California& Southern Arizona Fiscal Year Volume I. Narrative and Photos. USIIS, Bureau of Indian Affairs Collection Record Group 75, box 17, 47. National Archives, Riverside.
20 USIIS, Gila River Project Florence-Casa Grande. 21 Herbert V. Clotts, Monthly Progress Report District 4, October U.S. Indian Irrigation Service, Bureau of Indian Affairs Collection Record Group 75, box 47, folder 4, National Archives, Riverside. 22 Ibid., Monthly Progress Report District 4, November box 47, folder 5. 23 Ibid., Monthly Progress Report District 4, December box 47, folder 6. 24 Ibid., Monthly Progress Report District 4, January box 47, folder 7. 25 Ibid., Monthly Progress Report District 4, March box 47, folder 9 26 Ibid., Monthly Progress Report District 4, April box 47, folder SAN CARLOS IRRIGATION PROJECT, CHINA WASH FLUME HAER No. AZ-50-F (Page 8) the second barrel from the left in the second of the two photographs.
In fact the monthly report from May notes that the gunite was applied to the structure on the day of that month.27 While the work on the flume was effectively finished in May, it is interesting to note that flaws were soon discovered which required work to recommence. Voids in the concrete were discovered adjacent to the steel reinforcements within the barrels which required additional gunite. A light rain caused water to collect in the canal and resulted in settlement of concrete paving and piers in the transition area between the flume and canal.
While the repairs were completed on the of May, the first test flow of the canal, on the resulted in additional concrete settling.28 Subsequent flooding in September of caused washouts along the FCG canal and required crews to reinforce the banks on either side of the China Wash Flume.29 A survey report on the conditions of Native Americans within the United States stated that Native Americans who benefited from federally funded irrigation projects were to partially reimburse the government for construction and maintenance. In regards to the Gila River Reservation, the report stated that tribal members should have free water rights for acres of land irrigated under the Coolidge Dam project. However, the cost of the diversion and distribution networks was to be reimbursed by tribal members.
Notably, however, the report stated .the excess cost of the China-Wash or Olberg flume over and above the cost of a type of approved structure suitable under good engineering practices for such conditions and portion of other works which are not useful in the final completed project shall not constitute a part of the construction costs to be used in calculating reimbursement.30 This statement suggests that the design of the China Wash Flume, with its four concrete arches and barrels, was perhaps excessive or not practicable for the location.
It is clear that the USIIS was concerned regarding the potential flow of the China Wash in planning for the flume structure as the annual USIIS report noted that while the wash was relatively small, it was subject to excessive runoff which could total between and second feet. In this regard, it was decided that an opening not less than sixty feet in width and six and one-half feet in depth was necessary to care for the possible runoff in the wash. 31 This, in turn, required a much larger structure to span the width and length of the wash and also encouraged a design that floated above the wash. However, it does not appear that the USIIS 27 Ibid., Monthly Progress Report District 4, May box 47, folder 11. 28 Ibid., Monthly Progress Report District 4, June, box 47, folder 7.
29 Ibid., Monthly Progress Report District 4, September box 47, folder 15. 30 The use of the term Olberg flume further suggests Olberg s role in the design of the structure.; United States Senate Committee on Indian Affairs, Survey of conditions of the Indians in the United States: hearings before a subcommittee of the Committee on Indian Affairs, United States Senate, Seventieth Congress, second session pursuant to S. Res. 79 (Washington: Government Printing Office, 31 Herbert V. Clotts, Annual Report Irrigation District No. 4 California & Southern Arizona Fiscal Year SAN CARLOS IRRIGATION PROJECT, CHINA WASH FLUME HAER No. AZ-50-F (Page 9) subsequently used this concrete arch/barrel design, which likely stemmed from the high construction costs. In consultant W.
Glenn Smoak prepared a condition assessment of the China Wash Flume and noted that shotcrete had been used in the past, possibly in the to patch areas where concrete had failed.32 However, these patches had in turn failed and required further repairs. Smoak outlined a number of material/structural issues with the flume including delamination of concrete, hairline and large cracks in the concrete barrels, corrosion of steel joints, delamination of stream abutments, as well as delamination of the lateral arch support beams and corrosion of the steal.33 In Reclamation contracted with TOPCOR Services, Inc. (TOPCOR) to make repairs to the China Wash Flume. The repairs included resurfacing the concrete barrels as well as reconditioning the steel bracing structures.
TOPCOR completed the repairs to the concrete surfaces and supporting steel structures in January of However, a subsequent investigation of the flume s condition, conducted in revealed that much of the concrete placed by TOPCOR in had delaminated and the protective cathodic coating had also failed.34 Part II. Structural/Design Information A. General Statement 1. Character: In the early twentieth century elevated flume construction was predominantly limited to wooden and steel flumes.35 A publication on irrigation engineering practices, dating to demonstrated that reinforced concrete was a relatively new and expensive form of elevated flume construction.
The author, Bernard Etcheverry noted limited use of reinforced concrete for elevated flumes is due largely to the high cost when compared to wooden or sheet metal flumes and to the difficulty in construction. The false work and forms used in the construction and the inaccessibility of most flume locations bring the cost per cubic yard of concrete in place higher than for any other type of irrigation structure. 36 The recommended supports for such concrete flumes included concrete trestles, columns, arches, or solid 32 Bureau of Reclamation, China Was Flume, San Carlos Irrigation Project: Appraisal-level Replacement Options and Damage Mediation Action Programs Recommendations Reclamation, Phoenix area office, A2. 33 Ibid.
34 Marc Rozman, project manager of the SCIP Rehabilitation to Chad Wegley, SCIDD, January 31, Draft Technical Memorandum No. 1. China Wash Structural Evaluation and Replacement Options, Reclamation, Phoenix area office. 35 Bernard Alfred Etcheverry, Irrigation Practice and Engineering: Conveyance of Water (New York: McGraw-Hill Books, 36 Etcheverry, SAN CARLOS IRRIGATION PROJECT, CHINA WASH FLUME HAER No. AZ-50-F (Page 10) piers. These substructures, however, were placed underneath the flume within the bed of the drainage the flume was to cross. A guide to water flow in flumes, prepared by the U.S. Department of Agriculture in also noted that the use of reinforced concrete flumes dated to the early twentieth century.
The technology by this point included cast-in-place as well as pre-cast structural members, but was still less utilized in comparison to other materials. A survey of Reclamation irrigation projects identified flumes which included concrete, metal, and wood structures. However, wood represented 62 percent of these flumes. For those flumes constructed in concrete, the most standard cross-section shape of the concrete flume was noted as rectangular with slightly dished bottoms, followed by trapezoidal shapes with steep sides. The document noted that semi-circle flume shapes were rarely used.37 Elevated flumes continued to be supported by substructures such as trestles or piers. The China Wash Flume is a distinctive form of flume engineering.
The flume was designed in a period when reinforced concrete was just coming into use in flume construction. The desert environment of the flume lent itself to the use of concrete over the more common flume material wood due to the damaging impacts of the sun and hot, dry climate on wood. However, it was the distinctive circular barrels, and use of ribbed concrete arches in lieu of a standard substructure placed underneath the flume, which set the structure apart from contemporary flumes. 2. Condition of fabric: Although not in danger of imminent collapse, the flume remains in a deteriorated state, with areas of delaminated concrete and corroded metal present on both the arches and barrels.
Additionally, the cathodic protective coating applied to the barrels as part of the rehabilitation efforts is failing. B. Description: Designed by USIIS engineers Charles Olberg and H. C. Neuffer, the structure was constructed in as part of the FCG Project later subsumed under the SCIP for the purpose of carrying irrigation water from the Ashurst-Hayden Diversion Dam (then known as the Gila River Diversion Dam) across the naturally existing China Wash a generally north to south trending desert arroyo. The 170-foot-long by 50-foot-wide structure consists of four semi-circular flume barrels suspended from a series of five reinforced concrete arches.
The barrels and arches are flanked by 40-feet-long by 45-feet-wide concrete inlets and outlets at the eastern and western ends that are warped (curved) from the channel of the canal to conform to the straight walls of the flume. 37 Fred C. Scobey, The Flow of Water in Flumes, Technical Bulletin No. (Washington United States Department of Agriculture, SAN CARLOS IRRIGATION PROJECT, CHINA WASH FLUME HAER No. AZ-50-F (Page 11) The barrels measure 12 feet in diameter and are constructed of 6-inch-thick concrete that has been reinforced with 4-inch square mesh steel and -inch diameter steel suspension rods. Each of the barrels has three expansion joints.
The expansion joints are 0.5 inches wide, with 6- inch-wide sheets of 12-gauge steel and copper sheets affixed adjacent to the joint with mastic to prevent leakage. The suspension arches rest on reinforced concrete abutments located along the eastern and western banks of China Wash. The abutments are built atop 14-foot-wide by 130-foot-long by 2- foot-thick reinforced concrete footings which extend 15 feet below the current wash bed. The width of the arches varies from 11 feet wide at the base of the footers to feet at the top center. The arches are reinforced with -inch diameter suspension rods encased in concrete, as well as exposed -inch square steel bars.
The area between the semi-circular flume barrels and crest of each arch was infilled with 4 inches of concrete to protect that reinforcing steel from corrosion. Lateral support for the arches is provided by a series of six 12-inch-wide reinforced concrete beams. Three of the beams connect the base of the arches, and the remaining three support the upper portions. Copper sheeting extending from the expansion joints of the barrels to the bottom of the arches and through the panel webs provides further waterproofing of the structure. In addition to contributing to the unique design of the flume, utilization of the arches also allowed the structure to functionally span the wash without extending into it, allowing flood runoff water to flow without restrictions.
Flow within the FCG Canal and beneath the flume is controlled by wing walls. The banks of FCG Canal are further supported by 40-foot-long stone masonry retaining walls which extend at a 45-degree angle between the arches and lower side of the barrels. C. Mechanicals/Operation: The China Wash Flume was constructed for the sole purpose of carrying irrigation water from the Ashurst-Hayden Diversion Dam over China Wash. The flume was designed to allow runoff water within the wash to flow unrestricted.
This was accomplished in part due to the placement of the barrels, abutments, and wing walls, which created a 60-foot- wide by 6.5-foot-deep opening for the wash channel, and also through incorporation of the suspension arches which allowed the structure to float above the wash rather than extend into it. The flume does not possess any mechanical or operational features; rather, the Parshall measuring flume a fixed hydraulic structure located immediately east of the China Wash Flume acts to control the flow of water through the China Wash Flume through contraction of its parallel sidewalls and a drop in the floor at its narrowest point or throat.
The Parshall flume also measures the volumetric flow rate of water within the canal using primary and secondary measurement points located in its inlet and throat. SAN CARLOS IRRIGATION PROJECT, CHINA WASH FLUME HAER No. AZ-50-F (Page 12) D. Site Information: The current flume site encompasses approximately acre within the City of Coolidge, Pinal County, Arizona. The site is bounded by East Diversion Dam Road and residential development to the north and agricultural fields and undeveloped private land to the south, west, and east. It is constructed over and perpendicular to the China Wash, a naturally flowing drainage that originates at the Gila River to the north.
Originally the site of the project headquarters, housed in a tent camp near China Wash, the site of the flume remains predominately rural, although three residences each with a number of associated outbuildings are located to the north, northeast, and northwest of the flume to the north of East Diversion Dam Road. The landscape is broad and flat with Sonoran desert vegetation such as creosote bush, white bursage, saguaro cactus, creosote, prickly pear, agave, and other native species present in areas that have not been cleared for cultivation. The flume is a structure of the FCG Canal, a 22-mile-long unlined canal that provides irrigation water to non-Indian lands between the Town of Florence and the Picacho Reservoir, located to the south of Coolidge.
It originates 2.5 miles northeast of the flume site at its heading at the Ashurst-Hayden Dam and flows in a southwesterly direction until it reaches the east side of Picacho Reservoir. From there, water is diverted through a Y connection into either the reservoir or the FCG Extension Canal. Five irrigation-related buildings and structures are located in the vicinity of the China Wash Flume and FCG Canal. These include a Parshall measuring flume, U.S. Geological Survey (USGS) gauging station, footbridge, a fish barrier, and a control building.
Archival research suggests that the Parshall measuring flume and gauging station were built to the east of the flume by the USGS and USIIS in and the fish barrier, fish barrier control building, and footbridge were constructed by SCIDD in These five resources are not included as part of AZ-50-F. Part III. Sources of Information A. Primary
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