Geological Survey Water-Supply Paper 1475-M Ground-Water Resources of the Bryce Canyon National Park, Utah

Bryce Canyon National Park lies at the east edge of the Paunsaugunt Plateau, one of the high plateaus of southern Utah, and includes part of the plateau, the rim, and the foothills bordering the plateau at a lower elevation. The altitude of the plateau top in the park ranges from about 7,600 to more than 9,000 feet. The climate of this part of the park is generally cold except in the summer months. The relief in the foothills below the rim is as great as 1,000 feet. The temperature below the rim is generally higher than that on the plateau, and the summers are longer. Figure 52 shows the annual precipitation and departure from normal at Bryce Canyon National Park from 1933 through September 1957. It also shows cumulative departure from normal precipitation. The weather station is at the headquarters, on the plateau.

FIGURE 52.—Annual precipitation and cumulative departure from normal at Bryce Canyon National Park, Utah. (click on image for an enlargement in a new window)

WATER USE

The principal water users in Bryce Canyon National Park and vicinity are the public and employees using the National Park Service and concessioner water systems, the town of Tropic, and the Tropic and East Fork Irrigation Co. Other water users in the area obtain small supplies from wells or springs. The town of Tropic is supplied from Bryce Spring through a pipeline about 2-1/2 miles long (pl. 24). The Tropic and East Fork Irrigation Co. obtains water from the East Fork of the Sevier River and transmits it by way of the Tropic Ditch across part of the plateau, down Water Canyon, and into the vicinity of the town of Tropic where it is used for irrigation. The diversions of the Tropic and East Fork Irrigation Co. for the last 7 years (1950-56) are listed in table 1. Water is used in Bryce Canyon National Park for general needs at the lodge, cafeteria, and campground and for domestic needs by the personnel of the Park Service and the employees of the Utah Parks Co.

TABLE 1.—Tropic Ditch diversions of the Tropic and East Fork Irrigation Co.
[U.S. Geological Survey gaging station 5 miles below Daves Hollow]

For many years some water has been supplied to the park facilities from Trough and Shaker Springs, but in 1956 and 1957 these springs were dry. For the past several decades some water has been obtained from springs in East Creek valley. In July 1955 the springs in that valley had so decreased in yield that it became evident that they would not supply water through the rest of the season, and in that month well 1 was drilled (fig. 53). This well was the sole source of water supply for the park from July 1955 to August 1957. It is reported that the springs dried up completely after the well pump was installed and that they did not flow in 1956. In May 1957 there was a small overflow from the spring collector sump (fig. 53), but by June of that year there was none. In February 1957 two additional wells were drilled in East Creek valley. Upon completion the wells were tested by personnel of the Utah Parks Co. to determine their yield. No measurements of water level were made during these tests. The results of each test are summarized as follows:

FIGURE 53.—Water-supply developments of the Utah Parks Co. in the East Creek valley showing wells 1, 2, and 3; a developed spring (4); the spring-collector sump (5); and the spring pumphouse (6). Note flat-floored valley bordered by bedrock side slopes. Photograph by H. A. Waite.

The average of 4 separate measurements of the discharge of well 1 made at the Utah Parks Co. storage tanks in May 1957 was 55 gpm. Three check measurements were made in July 1957, and still the average was 55 gpm. It should be emphasized that this was the water delivered at the tanks and available for use; it was not necessarily the same as the amount of water discharged by the well, because there may have been leaks in the 4 miles of pipeline between the pump and the tanks. In the parts of the pipeline seen by the writer, however, there were no leaks, and it is assumed in the rest of this report that 55 gpm was the discharge rate of well 1.

Water-level recording gages were installed on wells 2 and 3. The records from these wells show within 15 minutes when the pump on well 1 begins to operate. These recording gages, therefore, are valuable not only to record water-level fluctuations in the basin (fig. 54) but also to indicate the duration of pumping. Table 2 shows the total number of hours that the pump was in operation during each month from April through November 1957.

TABLE 2.—Monthly pumpage from Utah Parks Co. well field in East Creek valley during 1957 and the net decline in water level each month in well 3

FIGURE 54.—Hydrographs of two observation wells in the alluvium of East Creek valley, April to September 1957. Well 2 is 451 feet from the pumping well; well 3 is 245 feet from the pumping well.

On August 2, 1957, well 1 began to pump air, and from that date to the end of the season the amount of water pumped was not a true indication of the need for water in the park. The amount of water pumped in the first half of the tourist season may be used as a basis for estimating the need for water in the park. During the season, July and August are the months of maximum pumping and May and October the months of least pumping. The pump is started about May 1 and stopped about November 1. Assuming that the pumpage in August is about the same as in July, September the same as June, and October the same as May, it is estimated that the water need for one entire season (as of 1957) is about 1.3 million cubic feet. On the basis of the National Park Service's Mission 66 design of facilities for 500,000 visitors, a water need of about 5 million cubic feet per season has been selected as a basis for the comparison of various sources of water. A summary of these figures is given in table 3.

TABLE 3.—Summary of quantities of water available from selected sources compared to present water use and estimated water needs in Bryce Canyon National Park, Utah