Scientific Investigations Report 2006–5205
U.S. GEOLOGICAL SURVEY
Scientific Investigations Report 2006–5205
Ground-water pumpage was estimated for all water use categories. Depending on the pumpage category, the estimates are presented in either figures and (or) tables. PWS pumpage is not presented as a spatial distribution due to source-water security concerns. Unless stated otherwise, reported values are annual quantities. Pumpage estimates are presented as total annual quantities, such as irrigation pumpage in 2000, and the quantity of new pumpage in 1- or 5-year increments from 1960 to 2000. Annual pumpage also is presented as time series, at either 1- or 5-year time scales. Some category information is presented for earlier dates to more clearly highlight the growth in pumpage. When possible, pumpage estimates for the latest date, for example, 2004, are presented to provide a more current understanding of the total pumpage for selected categories. The presented estimates are those directly calculated using the methods described above, and thus, the estimates show significant figures to the ‘1’ place. It should be understood that this does not imply the accuracy of the estimates but only the result of the calculations. Rounding of values to higher places makes it more difficult to reproduce both the estimates and values derived from using the described methods. Summation of values in some tables will not always equal the total values due to rounding to the ‘1’ place. Pumpage for the frost protection category was assumed to be zero and is not described.
Pumpage from municipal (Group A) systems steadily increased from 1960 to 2000 (fig. 12; table 2), ranging from about 19,127 acre-ft (17.1 Mgal/d or 6.22 Bgal) in 1960 to about 37,273 acre-ft (33.3 Mgal/d or 12.2 Bgal) in 2000. Other Group A and B water systems also exhibited steadily increasing pumpage at proportionately similar rates. Estimated pumpage from Group A and Group B systems ranged from about 3,888 acre-ft (3.47 Mgal/d or 1.27 Bgal) and 858 acre-ft (0.77 Mgal/d or 0.28 Bgal), respectively, in 1960 to about 7,465 acre-ft (6.67 Mgal/d or 2.43 Bgal) and 1,650 acre-ft (1.47 Mgal/d or 0.54 Bgal), respectively, in 2000. Ground-water pumpage increases for the PWS systems mirrored population increases and the rates of increases are similar to the rates of increases for municipal systems that provided several years of data.
PWS pumpage distribution closely follows the population distribution shown in figure 11. In Kittitas County, most PWS systems are near Interstate 90 and in resort areas in the Cascade Range foothills. In Yakima and Benton Counties, most Group A and B wells are near Interstate 82 and to a lesser extent, along the Naches, Tieton, and Bumping Rivers.
The monthly distribution of total annual pumpage in 2000 (fig. 13) shows that the maximum pumpage was in July (about 6,430 acre-ft), closely followed by August at about 6,350 acre-ft. Together, these months account for nearly 30 percent of the annual pumpage. Minimum pumpage for PWS was in February (about 2,200 acre-ft) and the pumpage in December was about the same. Pumpage in July was nearly 3 times more than in February, primarily due to lawn and garden watering during the summer growing season. The shape of the curve is similar, including the slight upturn in January, to previously reported values for the study area (Kinnison and Sceva, 1963; Parker, 1971).
The self-supplied pumpage in Benton, Kittitas, and Yakima Counties, for domestic use increased by about 8,000 acre-ft from 1960 to 2000 (fig. 14, table 3). In 1960, pumpage totaled about 12,400 acre-ft (11.2 Mgal/d or 4.03 Bgal) and by 2000, had nearly doubled to about 20,000 acre-ft (17.9 Mgal/d or 6.52 Bgal), equivalent to a basin-wide average per capita rate of about 180 gal/d. However, pumpage decreased in Benton and Kittitas Counties during several 5-year intervals. The decreases for Kittitas and Benton Counties were due to decreases in population and the establishment of numerous PWS systems. Although some PWS systems may have been operating prior to a decreasing interval, the start year estimate is based on the “effective source date” obtained from the database provided by DOH.
Yakima County, the most populous county, had the most domestic pumpage in the study area, ranging from about 9,739 acre-ft (8.7 Mgal/d or 3.17 Bgal) in 1960 to about 14,957 acre-ft (13.4 Mgal/d or 4.89 Bgal) in 2000 (table 3). In 2000, pumpage in Yakima County accounted for some 75 percent of the total domestic pumpage. Pumpage in the least populated county, Kittitas County, ranged from about 1,250 acre-ft (1.12 Mgal/d or 0.41 Bgal) in 1960 to about 2,330 acre‑ft (2.08 Mgal/d or 0.76 Bgal) in 2000 (table 2). Pumpage in Benton County ranged from about 1,390 acre‑ft (1.24 Mgal/d or 0.45 Bgal) in 1960 to about 2,750 acre-ft (2.46 Mgal/d or 0.9 Bgal) in 2000. Nearly all of the domestic pumpage is accounted for by the exempt wells. It is estimated that, of the total estimated pumpage in 2000 of 20,036 acre‑ft, only about 31 acre-ft was for the 63 rights with a single PRU of DS. Self-supplied domestic pumpage for rights with additional PRUs was about 322 acre-ft, and this pumpage is included in either the irrigation, commercial and industrial, or livestock categories.
The spatial distribution of domestic pumpage for 2000 (fig. 15) is based on census block population and calculations described in Methods. Areas with the most pumpage are areas with the greatest number of people. There were 3,719 census blocks with 99,078 people who obtained water from exempt wells and from the 63 domestic wells with water rights. The census block population ranged from 1 to 540 per block. Based on the self-supplied population per block and the average number of people per household for each block, an estimate was derived of the number of houses per block served by exempt wells. The total number of houses indicates that about 43,100 wells supply water for domestic pumpage.
Irrigation rights typically are for withdrawals from April 1 to October 30. Pumpage for other PRUs associated with an irrigation right are assumed to be constant throughout the year. Excluding PWS rights for irrigation and irrigation pumpage for ground-water claims, the total estimated pumpage in 2000 for primary and standby/reserve rights was about 271,042 acre-ft (242 Mgal/d or 88.3 Bgal), of which about 188,230 acre-ft (168 Mgal/d or 61 Bgal) was estimated to be associated with primary rights (table 4). Other uses associated with irrigation rights account for only about 3 percent of the total or about 7,838 acre-ft (7.5 Mgal/d or 2.7 Bgal). However, as will be shown later, the total pumpage for these other uses is larger than both the self-supplied commercial and industrial uses and livestock uses.
The spatial distribution of irrigation pumpage (fig. 16) shows that pumpage tends to be concentrated in the mid-to-lower parts of the basin, especially in the Wenas Creek Valley, lower Naches River area, Moxee City area, and Ahtanum Creek Valley (fig. 1). Other pumpage was concentrated along the south slope of Rattlesnake Hills, the lower part of Benton County, and in valleys extending eastward from Moxee City.
About 75 percent (204,500 acre-ft) of the total estimated annual pumpage was in Yakima County and about 70 percent of the total was for primary rights. Pumpage in Benton County was about 60,200 acre-ft (about 23 percent of the total) and about 67 percent was for primary rights. In comparison, Kittitas County had the smallest allowable acreage (2,806 acres) and the smallest amount of estimated pumpage, about 6,310 acre-ft, 94 percent of which was for primary rights.
Annual pumpage increased inconsistently over time (fig. 17; table 5). Annual pumpage was about 42,000 acre-ft in 1959 and increased to about 271,042 acre-ft by 2000 (tables 4, 5). New pumpage added from 2000 to 2003 was estimated to be only 1,567 acre-ft. Since 2003 (excluding new pumpage during the 2005 drought), an additional small amount of pumpage was also added because ground water has been exchanged for surface water (a change in source for a water right) as part of projects for increasing instream flows in small streams. Except for 1975-79, total new pumpage (primary and standby/reserve) generally increased by about 10,000 to 29,000 acre-ft per 5 year increment from 1960 through 1994 (table 5). Between 1975 and 1979, the total estimated irrigation pumpage added was nearly 100,000 acre-ft due to the granting of new water-rights with large allowable annual quantities. However, about one-half of this new pumpage was due to standby/reserve pumpage associated with rights that started during the 1977 drought. After 1979, the amount of new primary pumpage added continually decreased through 2000. From 1995 through 2000, irrigation pumpage increased only by about 3,600 acre-ft (table 5), which is about the total increase from the l890s through 1919 and the increase in the 1930s (data not shown).
The generalized monthly distribution of irrigation pumpage for 2000 (fig. 18) shows a maximum in July and a minimum in October (November pumpage for a few vineyards is not included in the generalized distribution). More than 70 percent of the pumpage occurs June through August. If all standby/reserve rights were used in a dry year, then some 80,000 acre-ft may be withdrawn in July, and if no water was withdrawn for standby/reserve use, then the July total would be about 56,000 acre-ft.
Standby/reserve pumpage estimates are based on the crop-water duty and the appropriated right, that is, standby/reserve rights were treated the same as primary rights. The standby/reserve estimates are representative of the amount of water that can be withdrawn under the right with the identified crops, as if every year was an extreme drought year. These estimates are not actual withdrawal rates, but represent the amount of water that may be withdrawn. Total pumpage in any year is dependent on the prorated amount, if any, during an irrigation season. For years with no prorating, the total irrigation pumpage for standby/reserve rights would be zero and the irrigation pumpage estimate would be the primary pumpage. For years with prorating, standby/reserve pumpage would occur at some percentage of the estimated value; the percentage would depend on the prorated amount. Therefore, the actual pumpage for standby/reserve irrigation rights for prorating years is difficult to estimate. The type of standby/reserve right for each right would need to be identified, as well as the actual allowable quantity, not necessarily the listed value in WRTS. To obtain a potential pumpage estimate associated with standby/reserve rights in a prorating year, multiplication factors based on prorating levels were estimated. This information also is needed for other work elements.
For the 2001 drought, 64 emergency rights (a type of a standby/reserve right for emergency use) reported an actual use of 2,499 acre-ft with an authorized amount of 9,073 acre-ft (R. Dixon, Washington State Department of Ecology, written commun., 2003). The use was listed as zero for 32 wells because meters were missing or broken, wells were never completed or were being drilled, no data were provided, or no pump was installed. Using only actual usage information for the other 32 rights, yields an appropriated quantity of 4,702 acre-ft; on average, about 53 percent of the appropriated value was used. Based on water-right files, the allowable acres for 9 of these rights were determined. The water duty averaged about 1 acre-ft/acre and ranged from 0.2 to 2.8 acre-ft/acre. Assuming that the 53 percent value (compared to this study’s estimate that 79 percent of appropriated water is withdrawn) is a reasonable approximation for standby/reserve pumpage during drier years (1994, 2001, and 2005) with the most prorating, the pumpage estimates for the standby/reserve rights may be as much as 26 percent too large in drier years.
Pumpage in prorating years is similar to multiplying the estimated standby/reserve pumpage by the prorating appropriated percentage, that is, a 37 percent proratable entitlement yields 63 percent (a multiplication factor) of the estimated pumpage as an annual value. For example, the 37 percent prorating in 1994 suggests that the standby/reserve estimate of about 80,000 acre-ft would be reduced to about 50,400 acre-ft as the estimate of the standby/reserve pumpage for 1994. For years with the least prorating, the prorating ranged from 80 to 88 percent of appropriated surface-water value, and there was minimal standby/reserve pumpage. Therefore, a reasonable assumption is that at some base prorating level, say, 88 percent (the prorating in 1988), some small level of standby/reserve pumpage would be initiated, probably on the order of 5 percent, and would be zero for prorating percentages greater than 88. Between about 70 to 75 percent prorating (30 to 25 percent multiplication factors), multiplication factors would likely decrease linearly to about 5 percent at the 88 percent prorating level and would be zero after 88 percent.
The standby/reserve rights with a water duty on the order of 0.1 to nearly 1 acre-ft/acre would likely be completely used in most years with prorating levels of about 80 to 88 percent. The latter is especially true for perennial crops, such as orchards. For example, of the 32 rights with data, 9 had older existing standby/reserve rights, suggesting the full quantity of the older right was to be used and the application was for additional emergency water. Most of these 9 rights were for orchards, and the irrigation of such perennial crops is important. This suggests that standby/reserve pumpage values estimated using multiplication factors as described above may be conservatively low.
Pumpage for livestock uses, as defined in this report, is primarily for stock watering and dairy operations. Livestock pumpage associated with an irrigation right for irrigating pasture and (or) crop lands is included as part of the irrigation-pumpage estimates. Estimates presented principally are for wells with rights for livestock use (about 63 rights) and are based on the full appropriated quantity. In addition, 19 small dairies that pump water under an exempt status are accounted for.
The estimated pumpage for livestock in 2003 was 7,010 acre-ft (6.3 Mgal/d or 2.3 Bgal), table 6. About 1,840 acre-ft (0.6 Bgal) is for dairy operations based on the PRU of DY. However, several livestock rights without a PRU of DY also are for dairy use and total about 280 acre-ft; the PRU of DY was not established at the time of the right. The increasing pumpage is shown in figure 19. Early in 1960, about 222 acre-ft was pumped, and by 1969 this pumpage increased to only about 469 acre-ft (table 6). The largest increase in new livestock pumpage (about 3,189 acre-ft) was during 1970‑74 (table 6) and is associated with new water‑rights with large allowable annual quantities. By 1984, the pumpage had increased to 4,738 acre-ft, and there was a large increase during 1990-94; total pumpage by 1994 was about 6,726 acre‑ft. No increase occurred through 2000, with some increase in 2002 for dairy operations. Thus, the estimated pumpage increased from 222 acre-ft at the beginning of 1960 to 6,726 acre-ft in 2000, with an additional 284 acre-ft of pumpage added in 2002.
The spatial distribution of livestock pumpage (fig. 20) shows that most pumpage is concentrated on the south slope of the Rattlesnake Hills and along the stretch from Granger through Mabton and Prosser. Additional pumpage is in the Ahtanum Creek valley and the Moxee City area, and about 210 acre-ft of pumpage is in the Kittitas basin. Overall, total pumpage for livestock (without irrigation rights) and dairy operations accounts for less than 3 percent of total pumpage in the basin. However, livestock rights with another PRU of IR have about 5,166 acre-ft of pumpage accounted for in the irrigation pumpage category.
The commercial and industrial category includes pumpage for heat exchange, refrigeration, food and timber processing, railway, manufacturing, and other industrial uses. Pumpage was estimated for 151 ground-water rights with PRUs that are primarily associated with the above uses. Total estimated pumpage in 2000 was about 7,230 acre-ft (6.5 Mgal/ d or 2.3 Bgal) (table 7). However, actual pumpage probably decreased by some small amount. From the dates of rights and drilling of wells, estimated pumpage was about 14 percent (1,042 acre-ft) of the 2000 total prior to 1930, and by 1959, 3,093 acre-ft (about 43 percent of the 2000 total) was already being withdrawn for commercial and industrial uses. Since 1960, estimated pumpage increased by 4,137 acre-ft, with no new pumpage added after 1992. The largest pumpage increase was during 1965-69 and 1980-89, and the largest single year increase was in 1981 at 1,080 acre-ft (fig. 21).
The spatial distribution of commercial and industrial pumpage (fig. 20) shows that most pumpage is concentrated in the Ahtanum Creek valley and the Moxee City area (fig. 1). Other pumpage is concentrated near the Yakima River in the area between Toppenish and Prosser. Other pumping centers are in the lower part of the Naches River Basin and in the Kittitas basin near the City of Ellensburg.
A simplified method was developed to obtain a general understanding of the temporal distribution of pumpage. In this method, we assumed two basic pumpage categories: (1) food products and (2) all other uses. The first category represents about 76 percent of the total and the second category accounts for the remaining 24 percent. A monthly percentage of annual pumpage was calculated from information in Dion and Lum (1977) for the Standard Industrial Classification for Food and Kindred Products, which generally represent the first category. The monthly percentage of annual pumpage was assumed to be constant throughout the year for the second category. An effective monthly percentage of annual pumpage was then derived by weighting each monthly percentage by the percentage of total. Multiplying these percentages by the total estimated annual pumpage for 2000 yielded an estimated monthly distribution of pumpage (fig. 22). This distribution shows that the least pumpage was in April and July and the largest pumpage was in September (fig. 22).
The pumpage estimates for fish and wildlife propagation are for 9 rights represented by 15 POWs and 2 POWs for 2 other non-WRTS hatchery wells. Table 8 shows estimated pumpage in 2000 was about 9,369 acre-ft (8.4 Mgal/d or 3.1 Bgal) for fish and wildlife propagation. Hatchery operations in 2000 accounted for all but 65.5 acre-ft of the total and 3 hatcheries account for 71 percent (about 6,643 acre-ft) of the total. Pumpage estimates for single rights or wells ranged from 2 to 4,192 acre-ft. Total pumpage was about 64 acre-ft by 1979 (only 5 acre-ft of pumpage prior to 1974) and increased by 2,661 acre-ft during 1980-84 (table 8). Substantial new pumpage was added during 1990-94 (4,194 acre-ft) and 1995‑2000, (2,450 acre-ft).
Figure 23 shows the estimated average monthly distribution of annual pumpage in 2000 ranging from 653 acre-ft in February to 1,030 acre-ft in August. The curve was based on the monthly percentage of annual values calculated using monthly data provided by one of the hatcheries; pumpage for this hatchery accounts for about 23 percent of total pumpage. The shape of the monthly curve is influenced by hatchery needs for different life-history stages of salmonids in the Yakima River Basin and availability of surface-water supplies.
The estimates of the pumpage for ground-water claims are for 924 claims. As described in the methods section, it was assumed that the pumpage for other claims is included in other categories of pumpage. Annual pumpage values apply to all years for 1960 through 2000 because a claim is for ground-water use prior to July 1945.
Total estimated annual pumpage for the 924 claims is about 34,310 acre-ft (30.6 Mgal/d or 11.2 Bgal). Total annual pumpage for individual claims ranged from 2.5 to 638 acre-ft and averaged 37 acre-ft. Irrigation accounts for 32,431 acre-ft (28.9 Mgal/d or 10.6 Bgal) or about 95 percent of the total. Irrigation use for the claims ranged from 2.5 to 571 acre-ft and averaged 35 acre-ft. Commercial and industrial uses account for 1,695 acre-ft (1.5 Mgal/d or 0.55 Bgal) and averaged about 212 acre-ft. The water supply part of the claims (524 claims had a second PRU of DG) totaled only 185 acre-ft, or less than 0.2 Mgal/d.
The spatial distribution of the annual pumpage for the claims (fig. 24) shows that most claims are located in the lower part of the river basin because that was where most of the early development of ground water occurred. For example, more than 80 percent of total estimated annual pumpage for ground-water claims was in Yakima County, with about 10 percent estimated pumpage in each Benton and Kittitas Counties (about 3,300 acre-ft).
Pumpage estimates for each category are summarized and compared in this section. Unless otherwise stated, values exclude pumpage associated with standby/reserve rights. Total pumpage in the Yakima River Basin was about 115,776 acre-ft in 1960 and increased to 312,284 acre-ft by 2000 (fig. 25; table 9). The three largest increases in new pumpage were during 1975-79, 1980-84, and 1970-74, respectively. These increases were largely due to increased irrigation pumpage, and similar to most pumpage categories, were directly proportional to the amount of appropriated water in the rights issued during a 5-year period.
Irrigation pumpage accounted for about 60 percent or 188,230 acre-ft of the pumpage in 2000 (table 9) and if irrigation pumpage associated with claims is included, irrigation use in 2000 totaled 220,662 acre-ft (about 69 percent of the total). Excluding claims, irrigation pumpage ranged from 35 to 61 percent of total pumpage during 1960-2000. The next largest pumpage category was municipal use, which in 2000 accounted for about 12 percent (37,273 acre-ft) of the total. The third largest category was for the ground-water claims, with an annual quantity of 34,310 acre-ft (32,431 acre-ft was for irrigation). The claims were similar to municipal pumpage in 2000 and account for about 11 percent of the total pumpage. Domestic pumpage (principally from exempt wells) was about 6 percent of the total in 2000 (20,036 acre-ft). Pumpage estimates for the Group A systems, livestock, commercial and industrial, and fish and wildlife propagation categories were all relatively similar in 2000 and ranged from about 6,700 to 9,400 acre-ft. Together, these four categories totaled about 30,800 acre-ft of pumpage in 2000 and account for about 10 percent of the pumpage. The least amount of pumpage was for the PWS Group B systems category. In 2000, this category totaled only 1,647 acre-ft or less than 1 percent of the total estimated pumpage.
Estimated potential pumpage for standby/reserve rights was about 82,812 acre-ft in 2000, and was the second largest quantity of estimated pumpage (table 9). However, withdrawals for standby/reserve pumpage were only in years with surface-water prorating and are not shown on figure 25. During extreme prorating years, standby/reserve rights could account for as much as 21 percent of total pumpage. For example, if 2000 was an extreme prorating year, total pumpage in the basin could have been as much as 395,096 acre-ft with standby/reserve pumpage accounting for 21 percent of the total. In years when prorating is not large, for example, when junior surface-water users receive 80 percent of their appropriated water, standby/reserve pumpage would be much less than the estimated value, on the order of 16,600 acre-ft.
The spatial distribution of pumpage reflects the distribution of irrigated crop lands (fig. 2) and population in the basin (fig. 11). Excluding PWS pumpage, in 2000 about 75 percent of pumpage was in Yakima County. Benton County accounts for the next largest amount of pumpage (about 23 percent). Of the three counties in the study area, Kittitas County has the smallest number of acres of ground-water irrigated crops and the smallest population and thus, accounts for only about 3 percent of the pumpage. However, for the PWS category, about 60 percent of the pumpage occurs in Yakima County, a reduction of 15 percent compared to the total for the other 7 categories of pumpage; the reduction is due to the fact that the largest city in the study area (the City of Yakima with a population of about 72,000 in 2000) uses surface water as their primary source of water. About 25 percent of the PWS pumpage occurs in Benton County, followed by about 15 percent in Kittitas County.
The total pumpage in 2000 was about 11 percent of the appropriated quantity of surface water diverted for irrigation and PWS. Total pumpage in 2000 was about 430 ft3/s (0.31 million acre-ft) compared to mean annual precipitation of about 12,000 ft3/s (8.7 million acre-ft), mean annual unregulated streamflow of about 5,600 ft3/s (4.1 million acre-ft), mean annual regulated streamflow of about 3,600 ft3/s (2.6 million acre-ft), and the above diversions of about 3,900 ft3/s (2.8 million acre-ft). Maximum pumpage, about 100 ft3/s, is during the months of July and August. Calculating an average, basin-wide water duty based on the estimates for irrigation pumpage and using the total irrigated acreage of 64,308 acres for the outstanding ground-water applications for irrigation, yields about 185 ft3/s potential pumpage for the applications if all were approved.
U.S.
Department of the Interior | U.S. Geological
Survey
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