The team learned that the irrigation of hayfields in the valley was carried out in a far less uniform manner than haying, representing every stage in technology from the mid-nineteenth to the late twentieth century. Hayfields were irrigated on the Ninety-Six by flooding, with the water directed through a system of ditches by wooden and metal headgates. This older approach was also seen on the DH and Fred Miller's ranch. Flood irrigation often employed what were still called "canvas" dams (actually coated fiberglass), typically secured by a mixture of manure and mud.
In contrast, some fields on the Mill Ranch had an elaborate system of arrow-straight ditches to control the water and rancher Bob Cassinelli used a land leveler to level some fields for more even water distribution. At Henry Taylor's Triple-T Ranch, water was carried to the fields in plastic pipes to reduce losses by evaporation and absorption. Other ranches, like Jim Wallace's and Frank Loveland's, operated elaborate and expensive pumping systems that dispensed water through rolling pipes or pivots. Keith Thomas's 7HL Ranch had a spring high enough on a hillside to push water through a pivot without an electric pump.
Four factors accounted for this wide disparity of method. The first factor was the size of the ranch. The production of hay from lower-yielding fields of native grasses demands more acreage and a small operation could not depend upon native meadows and would have to plant alfalfa, which requires a higher level of irrigation control. The second factor was the distance and terrain separating hayfields from stream or springs. The Little Humboldt River and its tributaries, chiefly Martin Creek, water the upper valley. Some ranches literally straddle the main system of streams, while others are on small creeks with much less water flow. The third factor was the ranch's water right. Like other arid parts of the West, water is dispensed from streams according to a strict order of precedence. Water rights are awarded more or less by order of establishment and the oldest ranches tend to have rights that provide the most reliable water supply. And, the fourth factor was the capital investment new equipment requires. All irrigation systems are costly, especially new, mechanized ones. In 1978, rancher Loui Cerri estimated that it would cost $50,000 to install an electric pump system and $4,000 per month to operate it.
Les Stewart explained in more detail why the Ninety-Six Ranch maintained meadows of native grasses in a relatively unimproved state and irrigated them by flooding. Native grasses, he said, are more resistant to natural disasters than alfalfa and will survive a three- to five-year drought without the need to re-seed. When there is excessive water from melting snow or rain, once again the native grasses will fare better than alfalfa. In addition, flood irrigation is cheaper than pumping, although more land is needed to produce the same yield. A rancher ought to make judicious improvements, Stewart counseled, but take care that the costs of large-scale improvements do not bring a ranch to the point of economic ruin.