THE YAKIMA RIVER IN WASHINGTON. 



25 



main body of water, is about nine miles long and 

 from one and one-half to two miles wide. On August 

 16, 1893, the outflow of the lake, as measured at a 

 point less than one-fourth of a mile below the outlet, 

 was 211 second feet. About two miles below, and a 

 half mile above Easton, this water joins that from 

 Lake Keechelus, the two streams being approximately 

 of the same size. The area drained by each of these 

 headwater streams above their junction, and includ- 

 ing the lake surfaces, is about 100 square miles. 



COURSE OP THE YAKIMA. 



The Yakima river, after receiving the waters of this 

 lake region, flows in a general southeasterly and 

 southerly course through the broad Kittitas valley, 

 and then cutting across a series of ridges enters 

 Selah valley, from which it escapes through a gap to 

 Moxee valley. Throughout this upper course its 

 flow is greatly increased by the creeks entering from 

 the north and west. On leaving the gap in Selah 

 ridge, and at a point seventy-five miles below Lake 

 Kachass and a mile above North Yakima, the Naches 

 river, one of the largest tributaries, comes in from the 

 west. This stream was measured on August 14, 1893, 

 at a point an eighth of a mile above its mouth. At that 

 time the height of water on the gauge rod at the 

 railroad ridge over the Naches was 100 feet, and the 

 discharge was 1,193 second feet. The area drained, 

 as measured from the Land Office map of Washington 

 is 1,000 square miles, of which 300 square miles is 

 within the catchmont area of Tiaton'river, the princi- 

 pal fork of the Naches river. The gauge rod at this 

 point is fastened to the crib on tne south side of the 

 river sixty feet west of the railroad bridge, the 12- 

 foot mark of the gauge being 9.97 feet below the top 

 of the rails. 



After passing along the west side of Moxee val- 

 ley, Yakima river cuts through Yakima ridge, form- 

 ing Union Gap, this point being seven miles below 

 Naches river and six miles from North Yakima. 

 Here the stream has been measured and gauge rods 

 established to obtain the fluctuations of water. The 

 principal rod is under the west end of the county 

 bridge which crosses at this point. The zero of this 

 gauge is 19.02 feet below the top of the rails on the 

 railroad, which lie about 40 feet away. The high- 

 water marks, presumably those of the spring flood 

 of 1893, were on a level with the readings 9.90 of 

 this gauge. On August 14, 1893, when the water 

 stood at 0.90, the discharge was 2,963, and on Sep- 

 tember 26, 1893, as measured by Engineers J. B. 

 Rogers and Samuel Storrow, the water standing -0.25, 

 the discharge was 1,186 second feet. By assuming 

 intermediate values for discharges between the 

 heights given, it has been computed that the average 

 discharge for October, 1893, was 2,662 second feet, or 

 for the whole month, a total of 163,713 acre-feet. 

 The total drainage area above this point, as measured 



from the Land Office map, is 3,300 square miles. 

 Comparing this with the discharge for October, the 

 average depth of run-off over the whole was 0.93 

 inches, or 0.81 second feet per square mile drained. 



. IRRIGATION ON THE YAKIMA. 



There are a number of irrigating ditches taking 

 water from Yakima river and its tributaries above 

 this gauging station, most of these being in the Kitti- 

 tas valley or in the vicinity of North Yakima. The 

 principal irrigating works of the country are, how- 

 ever, below this point, taking water out upon the 

 large valley in the vicinity and to the east of Tope- 

 nish, or farther down the river near Prosser and 

 Kiona. The largest canal in operation is that of the 

 Northern Pacific, Yakima & Kittitas Company, head- 

 ing a few miles below the gauging station at the 

 county bridge. Other canals under construction 

 heading near Prosser or at points below, cover strips 

 of land along the river, and when completed will 

 irrigate lands on the west side of the Columbia. 

 The question of water supply for all these systems is, 

 therefore, one of great importance. Comparing the 

 estimated October discharge of the Yakima with that 

 of other rivers, the remarkably large volume from 

 a relatively small water-shed is apparent. This is 

 best shown by the following table, which gives the 

 discharge of various streams for October, 1893, and 

 also in several cases for the same month in preceding 

 years. Opposite this, for comparison, is placed the 

 area drained, and in the third column the amount 

 drained by square mile of catchment. These last 

 figures bring out most strongly the large flow of the 

 stream. All quantities of water are given in second 

 feet (cubic feet per second of time), equaling about 

 fifty miner's inches, as commonly measured. 



COMPARISON OP RIVER DISCHARGES FOR OCTOBER. 



From the inspection of this table, which might be 

 extended to far greater length, it is apparent that the 

 canal owners taking water from this stream have far 

 less to fear as regards their water supply than have 

 irrigators in other parts of the arid region. 



