A Record of a Portion of the Yuma/California Main Canal and the Yuma Valley Railroad

The Yuma Irrigation Project (YIP) was an early and essential Reclamation project in the Southwest, and the Yuma/California Main Canal and the Yuma Valley Railroad were important contributors to the success of the YIP and the early development of Yuma, Arizona. Construction on the YIP began shortly after a new federal agency - United States Reclamation Service - had been given authority to reclaim arid and semi-arid lands in the West in 1902. In only a couple of decades, the YIP infrastructure founded the transformation of desert into productive agricultural land as settlers, owners, and tenants realized the opportunities a stable water supply provided.

Engineers designed the YIP as a series of structures and facilities that aided in controlling and directing water from the Colorado River to project lands for cultivation. Originally the Laguna Dam diverted water from the Colorado River and two main canals - Yuma/California Main Canal and the Arizona Main Canal- conveyed it to laterals that then delivered the water to water users. Levees provided protective support of the newly created water works system as an elaborate network of berms constructed as important buffers to safeguard the nascent farmlands from flooding. Armoring the levees with rock riprap secured the soil-based levees and prevented water seepage during the flood season. Construction of the Yuma Valley Railroad atop the Yuma Valley Levee secured the berm with the placement of compacted riprap for the railroad bed. The railroad also transported project materials, passengers, and settlers' freight.

Reclamation completed the Yuma Valley Levee in 1911, finished the Yuma/California Main Canal in July 1912, and concluded construction on the Yuma Valley Railroad in 1916. By 1920, the Reclamation Service had produced a viable water project that encompassed the greater Yuma area. While the Yuma/California Main Canal and the Yuma Valley Railroad parallel one another in the project area, the structures were not constructed as the same project. Both aided in the operation of the YIP, but each provided a different function. The canal conveyed water to the East and West Main Canals that served the Valley Division, the Yuma Valley Levee protected the farmlands, and the Yuma Valley Railroad strengthened the Yuma Valley Levee with rock armament and provided transportation. Both the Yuma/California Main Canal and Yuma Valley Railroad were essential infrastructure to the YIP as a pivotal water project that laid the foundation for growth in the Yuma area.

尤马灌溉项目（Yuma Irrigation Project, YIP）是美国西南部早期且至关重要的垦务项目，尤马/加利福尼亚主运河与尤马谷铁路，是该项目成功以及亚利桑那州尤马地区早期发展的重要助力因素。1902年，美国联邦新机构——美国垦务局（United States Reclamation Service）获权治理西部干旱与半干旱土地后不久，尤马灌溉项目便启动了建设。仅数十年间，随着定居者、土地所有者与佃户们意识到稳定供水所带来的发展机遇，尤马灌溉项目的基础设施推动荒漠转型为高产农田的进程得以奠基。
工程人员将尤马灌溉项目设计为一系列结构与设施，用于管控并调配科罗拉多河（Colorado River）的水源，以输送至项目用地开展农业耕作。最初，拉古纳大坝（Laguna Dam）从科罗拉多河引水，经由尤马/加利福尼亚主运河与亚利桑那主运河两条主渠，将水输送至配水渠，再由配水渠送至用水户。防洪堤构成了这套新建水利系统的防护支撑：其由一系列精心构筑的土埂组成防护网络，作为关键缓冲带保护初创农田免受洪水侵袭。采用抛石护面（riprap）加固土制防洪堤，可在汛期防止堤体渗水。尤马谷铁路修筑于尤马谷防洪堤之上，通过为路基铺设压实的抛石护面加固了土埂；同时，该铁路还承担了项目物资、旅客与定居者货运的运输任务。
垦务部门于1911年完工尤马谷防洪堤，1912年7月建成尤马/加利福尼亚主运河，并于1916年完成尤马谷铁路的建设。至1920年，美国垦务局已打造出覆盖大尤马地区的成熟水利项目。尽管尤马/加利福尼亚主运河与尤马谷铁路在项目区内平行分布，但二者并非同一建设项目。二者均助力尤马灌溉项目的运行，但各自承担的功能各不相同。主运河将水源输送至服务于山谷分区的东、西主渠；尤马谷防洪堤负责保护农田；而尤马谷铁路则通过抛石加固强化了尤马谷防洪堤，并提供交通运输服务。作为奠定尤马地区发展根基的关键性水利项目，尤马/加利福尼亚主运河与尤马谷铁路均为尤马灌溉项目不可或缺的基础设施。