Scientific Investigations Report 2006–5212
U.S. GEOLOGICAL SURVEY
Scientific Investigations Report 2006–5212
Numerous smaller return and diversion flows enter or leave the Klamath River between the Link River at Klamath Falls and the Klamath River at Keno. These additional flows were not included in the water-balance equation because they were measured on an irregular basis, poorly documented, and/or considered insignificant in magnitude. Nonetheless, it was necessary to determine if changes in these flows over time could have had a significant effect on the water balance and been a factor in the flow inconsistency. A summary of the return and diversion flows is shown in table 6. Table 6 includes circa 2004 flow estimates in addition to how these estimates compare with probable flow conditions in the 1960s.
Most of the unmeasured or poorly measured diversions have been used for irrigated agriculture and the wood products industry. Historical water right permits granted by the Oregon Water Resources Department (OWRD) provide some insight into the magnitude of the diversions, although it cannot be assumed that a water user will use the full amount of water that they are allowed to use. In some years, a water right holder may not use the appropriated water at all. The water rights granted by OWRD in the water budget reach provided an estimate of the maximum potential uses in addition to the measured Klamath Project diversions and returns. An increase in undocumented surface-water diversions from the Klamath River would be inconsistent with changes in the water balance over the 44-year period from 1961 to 2004.
Some landowners adjacent to the Klamath River have surface-water withdrawal permits for agricultural use. Between the Link River and Keno Dams, the sum of these numerous small diversions has been estimated to be about 25,000 acre-ft/yr (PacifiCorp, 2005). Although this amount is significant, there is no available quantitative or anecdotal evidence of changes in irrigation practices over the 44-year study period that would explain the water-balance inconsistencies. Few new water rights have been granted to landowners on this stretch of the Klamath River since 1971. At the same time, these direct diversions for irrigated agriculture adjacent to the river have not likely decreased by a significant amount.
Some other water users in the study area include wood-products processing plants. In the 1960s, four major plants existed, which included Modoc Lumber, D.G. Shelter Products, Collins Products LLC (formerly Weyerhaeuser), and Columbia Plywood. As of water year 2004, only Columbia Plywood and Collins Products LLC existed. Historically, water has been used at these facilities for the manufacturing and processing of plywood, cardboard, and wood siding products, and for log sprinkling to reduce the potential for fire. However, the Collin Products LLC plant stopped using logs altogether in 1992 and now relies on wood chips. Columbia Plywood still uses logs; however, their logs are stored in the river and do not need to be kept wet using sprinklers (Ted Devore, Collins Products LLC, Klamath Falls, Oregon, oral commun., 2005).
A query of the OWRD water rights information data base found the combined total surface-water rights permits for the four plants to be about 1,600 acre-ft/yr. Historically, however, most of the water used by the plants has come from ground-water wells. The two remaining plants take very little water directly out of the river. The surface-water right permits are kept mostly for fire suppression (Ted Devore, Collins Products LLC, Klamath Falls, Oregon, oral commun., 2005).
Although difficult to quantify, overall water diversions for the wood products industry in the study area likely has decreased between 1961 and 2004, mainly because there are fewer plants in operation. A trend of less water diversion is consistent with the water-balance inconsistency; however, an amount of only 1,600 acre-ft/yr is too small to explain it.
Return flows to the Klamath River that are not included in the water-balance equation include outflows from wastewater-treatment and wood-products processing plants. An increase in undocumented surface-water return flows to the Klamath River would be consistent with changes in the water balance over the 44-year period from 1961 to 2004.
Return flows from irrigated agriculture on lands adjacent to the Klamath River were not measured. However, 25 to 50 percent of irrigation diversion flows is considered a reasonable estimate for return flows in the Upper Klamath Basin (Broad and Collins, 1996). Using a rate of 25 percent, return flows for water year 2004 were estimated at 6,250 acre-ft/yr. Return flows in the 1960s possibly were higher than in water year 2004 because of more flood irrigation and less sprinkler irrigation at that time. For many locations in the upper Klamath Basin, the transition from flood irrigation to sprinkler irrigation has reduced return flows (Burt and Freeman, 2003).
The study area is served by two main wastewater-treatment plants (WWTP). One is operated by the City of Klamath Falls and the other by the South Suburban Sanitation District. As a result of population growth, these flows have gradually increased. Between 1960 and 2000, the population of Klamath County increased from 47,475 to 63,775 (U.S. Census Bureau, 2005). Annual average effluent releases from the Klamath Falls WWTP have increased at a steady rate from about 2.2 Mgal/d (2,464 acre-ft/yr) in the early 1960s to about 3.0 Mgal/d (3,360 acre-ft/yr) in water year 2004. The Klamath Falls WWTP also currently (water year 2004) treats about 0.22 to 0.3 Mgal/d of urban storm and geothermal runoff, which when combined with effluent outflow is about 3.3 Mgal/d (3,696 acre-ft/yr) (Jeff Fritz, City of Klamath Falls, Oregon, oral commun., 2005). On an annual basis, this increase in quantity is insufficient to explain the water-balance inconsistency. Not all WWTP outflow is discharged to the Klamath River. Since 2001, the Klamath Cogeneration Project Power Plant has been using about two-thirds of the WWTP outflow for cooling purposes. About one-third of that amount (less than 1,000 acre-ft/yr), the portion that is not evaporated, is returned to the WWTP and then discharged to the Klamath River (Jeff Fritz, City of Klamath Falls, Oregon, oral commun., 2005). Total effluent discharged to the river is approximately 2,000 acre-ft/yr.
From the early 1990s to the mid-2000s, an annual average of about 2.5 Mgal/d (2,820 acre-ft/yr) of effluent was treated by the South Suburban Sanitation District WWTP. This rate is about three times what it was in 1961. In 2004, the total combined sewer outflow from this plant (which includes effluent, storm runoff from streets, and geothermal return flows) was about 6.8 Mgal/d (7,600 acre-ft/yr) (Sally Braton, South Suburban Sanitation District, Klamath Falls, Oregon, oral commun., 2005). PacifiCorp (2005) estimated an additional 4,000 acre-ft/yr of storm runoff from other locations in the study reach. Although flows are higher than in the early 1960s, the amount of increase is insufficient to explain the water-balance inconsistency.
The two remaining wood-products processing plants in the study area, Collins Products LLC and Columbia Plywood, discharge an average of 900 and 30 acre-ft/yr, respectively (Burt and Freeman, 2003). In the 1960s, when there were additional wood-products processing plants in operation, the total return flows would have been greater than the current total flows of 903 acre-ft/yr. However, a decrease in return flows from these plants would have been contrary to the trend in the water balance, in addition to being insignificant.
Changing ground-water levels in land adjacent to the river between the Link River and Keno Dams also could cause a water-balance inconsistency. Because the water balance shows a losing stream in the 1960s and 1970s and a gaining stream in the 1980s and 1990s, ground-water levels would have had to rise during the 44-year period; however, water-level data collected by the OWRD and the USGS from wells in or near the study reach do not show a rising ground-water-level trend (http://or.water.usgs.gov/projs_dir/or180/waterlevels/, accessed March 29, 2006).
The nearest long-term OWRD observation wells to the study area include KLAM 11950 and KLAM 12815. The record for KLAM 11950, a geothermal well located within the city limits of Klamath Falls, began in the late 1960s. From that time to the present, this record does not show an overall increase in water levels. The water level in KLAM 11950 declined by 15 ft between 1975 and 1990, followed by a recovery between 1990 and 1995. The observed decline was likely due to a combination of development of the geothermal aquifer and climate influences. The recovery of the water table is undoubtedly due to an increase in the practice of injecting spent geothermal water back into the aquifer that was mandated after July 1990 by city ordinance. As far as is known, this decline and recovery is limited to the geothermal aquifer in and around Klamath Falls. According to Sammuel (1980) the total discharge of the geothermal system in and around Klamath Falls is 2,868,000 gallons per day, or about 3,200 acre-ft/yr. On the basis of that volume, pumping and injection practices in the geothermal aquifer are unlikely to have a measurable effect on flow in the Klamath River. (Marshall Gannett, USGS, Portland, Oregon, oral commun., 2006). The record for KLAM 12815, located about 4 mi east of the river, shows an overall decline in water levels of about 8 ft between the early 1960s and the early 1990s. This decline, which is likely climatological in origin, is contrary to the water-balance inconsistency.
Closer to the river, below Klamath Falls and above the Keno flow-measurement site, the USGS has collected water-level data from seven observation wells (KLAM 10013, KLAM 10253, KLAM 11211, KLAM 13744, KLAM 13800, KLAM 50392, and KLAM 51231) since 1999 for the USGS upper Klamath Basin ground-water study. Because of drier than average conditions for most of the period since 1999, water levels generally declined in all seven wells. Although the period of record for these wells does not represent the longer period from 1961 to 2004, additional water-level measurements made at the time the wells were drilled are available. KLAM 13800 and KLAM 13744 were drilled in 1974 and 1988, respectively, and the other wells were drilled during the 1990s. The water levels in all seven wells at the time they were drilled are within the range of their measured water-levels over the past 7 years. Therefore, the possibility that there has been an overall rise in water levels over the period from 1961–2004 is not supported by the OWRD and USGS water-level data.
Precipitation data (fig. 7) also do not support a rise in ground-water levels. A long-term shift from drier to wetter weather would cause such a change, but although there are periods of wet and dry years, long-term precipitation did not significantly increase. Mean annual water year precipitation at Klamath Falls for 1961–82 and 1983–2004 was 13.3 and 13.8 in., respectively, which is a difference of less than 5 percent. Precipitation at other nearby sites also did not differ significantly between the two 22-year periods. Mean annual precipitation at Crater Lake for water years 1961–82 and 1983–2004 was 65.8 and 64.63 in., respectively.
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Department of the Interior | U.S. Geological
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