Scientific Investigations Report 2006–5212
U.S. GEOLOGICAL SURVEY
Scientific Investigations Report 2006–5212
Trends in the four canal diversions (fig. 8A–D), the three canal returns (fig. 9A–C), and flow records for the Link River were visually evaluated to gain insights into water-management changes related to the Klamath Project and the National Wildlife Refuges over the 44-year period. Trends in these eight flow records cannot be used to explain the water-balance inconsistency because these same trends would be inherent in the downstream flow record (Klamath River at Keno), which also was used in the water-balance calculations and is assumed to be accurate. Nonetheless, the analysis of trends was included to determine whether known water-management changes are evident in the flow data. Also, the extent of possible error in the flow records could be assessed by noting how consistent or inconsistent the records were with each other.
With the exception of the Miller Hill Pumping Plant diversion on the Lost River Diversion Channel (fig. 8B), the records for the three other canal diversions show flow increases over time (figs. 8A, 8C, and 8D). The changes in flow rate can also be seen in a cumulative line plot of each of the canal diversions (fig. 10). The solid lines show cumulative measured flows. A change in the slope of these lines represents a change in the flow rate. The straight dotted trend lines show what the cumulative line plots would have looked like if there were no changes in the flow rate over time. By plotting the differences between the cumulative line plots and the trend lines (cumulative residuals) from figure 10, it is possible to more easily see changes, or breaks, in flow rates (fig. 11). Flow rates for both North and Ady Canals increased around 1984 and 1985. Flow rates for Station 48 increased around 1978 and again around 1991. Also, flow-rate changes for Station 48 and Ady Canal were greater and more abrupt than flow-rate changes for the North Canal. For Station 48, North Canal, and Ady Canal flow records, 1983–2004 mean annual diversion flows were about 16,000, 8,000, and 21,000 acre-ft/yr greater than their 1961–82 mean annual diversion flows (table 7).
The increase in diversion flows possibly can be explained by known water-management changes that occurred over the 44-year period. By the 1980s, many farms in the Klamath Project had converted from flood to sprinkler irrigation. If managed correctly, sprinkler irrigation can conserve water better than flood irrigation. However, total annual water use can increase when sprinkler irrigation is introduced because higher market value row crops (such as onions, potatoes, strawberries, and peppermint) that require more water are grown instead of nonrow crops (such as winter grain and annual hay) that require less water and were grown under flood irrigation. Conversion to sprinkler irrigation often changes overall farm management. Smaller, but more numerous, irrigation applications are applied to the crops. Applications are also made for frost control and preseason field preparation that would not have been made using flood irrigation (Mike Green, Bureau of Reclamation, Klamath Falls, Oregon, oral commun., 2005).
Diversions at Station 48 increased significantly in the 1990s (figs. 8A and 11) for two possible reasons. One could be related to increased sprinkler irrigation and increased row crop production in the Tulelake Irrigation District (Jerry Pyle, Tulelake Irrigation District, Tulelake, California, oral commun., 2005). More water was also needed for the Tule Lake Refuge. Flows from the Station 48 diversion flow to the refuge through the Lost River. As a result of an Endangered Species Act requirement, minimum water levels in Sump 1A and 1B were raised by 0.5 ft beginning in 1992 (Mike Green, Bureau of Reclamation, Klamath Falls, Oregon, oral commun., 2005).
The North and Ady Canals provide water to the KDD lands and the Lower Klamath Wildlife District. Flow diversions used for both winter (for mostly grain) and summer irrigation are shown in figures 8C and 8D. In the 1980s and 1990s, summer irrigation was higher than in the 1960s and 1970s. Some of the increased summer irrigation is likely a consequence of increased sprinkler irrigation and row crop production in farmlands served by these two canals (Mike Green, Bureau of Reclamation, Klamath Falls, Oregon, oral commun., 2005).
Not all increased flows in Ady Canal at U.S. Highway 97 were diverted to irrigation use. Ady Canal also provides water to the Lower Klamath Refuge. The flow record for the Ady Canal site located at Stateline Road (just upstream of the refuge) indicates that more autumn, winter, and spring water deliveries to the Lower Klamath Refuge in the 1990s than in earlier periods (fig. 12). These increased flows can also be seen in the Ady Canal at U.S. Highway 97 flow record (fig. 8D).
The most significant canal return flows in the water balance are the Lost River Diversion Channel at the Lost River Diversion Dam and Klamath Straits Drain at the F-FF Pumping Plant (figs. 9A and 9C). Return flow to the Lost River Diversion Channel at the Miller Hill Pumping Plant is insignificant by comparison (fig. 9B). Cumulative line and cumulative residual plots of the canal return flows are shown in figures 13 and 14, respectively. The Lost River Diversion Dam and, to a lesser extent, the F-FF Pumping Plant plots, show some correspondence to historical wet and dry periods in the upper Klamath Basin region. During wet periods (early 1970s, early 1980s, and late 1990s), a significant portion of the return flows included storm runoff. Likewise, during dry periods (late 1970s, late 1980s to early 1990s, early 2000s), return flows were lower. However, the F-FF Pumping Plant plots, and to a lesser extent the diversion at Lost River Diversion Dam plots, also show a definite overall change in water use over the 44-year period. For the period after the mid-1980s, flows at both sites were reduced compared with the previous period from 1961 to the mid-1980s. Flows at the Lost River Diversion Channel at Lost River Diversion Dam and the F-FF Pumping Plant decreased by about 31,000 and 27,000 acre-ft/yr, respectively, for the 1983–2004 period compared with the 1961–82 period (table 8).
Several of the decreased flows in the 1983–2004 record for the Lost River Diversion Channel at Lost River Diversion Dam (relative to flows in the 1961-82 record) occurred in summer and autumn (table 8). Many farms upstream of the Lost River Diversion Dam in the Poe and Langell valleys had converted from flood to sprinkler irrigation by the early 1980s. Flows in the Lost River into Lost River Diversion Dam would be expected to decrease during the summer-autumn irrigation season because return flows from sprinkler irrigated fields are significantly less than return flows from flood-irrigated fields (Jerry Pyle, Tulelake Irrigation District, Tulelake, California, oral commun., 2005).
Decreased summer and autumn flows mostly starting in the 1980s are also evident in the Straits Drain at F-FF Pumping Plant flow record (fig. 9C). After construction of the FF pumping plant in 1979, it was possible to control water levels in the Lower Klamath Wildlife Refuge in a more deliberative manner than in the past. More water was held in the refuge for autumn and winter flooding. As a result, autumn and winter flows decreased in the Straits Drain (John Hicks, Bureau of Reclamation, Klamath Falls, oral commun., 2005). Also, starting in 1992, more water was retained in the Tule Lake Wildlife Refuge as the water levels in Sump 1A and 1B were raised because of Endangered Species Act requirements, and less water was pumped over to the Lower Klamath Wildlife Refuge.
The cumulative monthly Link River flows for water years 1961–2004 are shown in figure 15. Similar to the cumulative canal return flows, trend fluctuations that mirror the historical wet and dry periods are apparent. A comparison of flows during the last 20 years with the first 24 years of the 1961-2004 period indicates an overall decrease in flows during the last 20 years (fig. 15). This is partly a consequence of flow data error discussed earlier. However, flow changes in the trend plot for the Link River also reflect changes in the management of the Upper Klamath Lake and releases from Link River Dam (Bureau of Reclamation, 2000; 2006). Prior to the 1990s, Link River Dam releases were made in the interest of maintaining sufficient supply for “A” Canal (located above Link River), Lost River Diversion Channel, North Canal, and Ady Canal irrigation diversions and downstream hydropower demands. By the 1990s, Link River releases were also made for the purposes of maintaining minimum lake level elevations and for ensuring sufficient spring and summer downstream flows. As a consequence, winter and early spring Link River Dam releases were significantly reduced in the 1990s compared with earlier decades. More water was held back in Upper Klamath Lake during this part of the year than had been in the past. Aside from Link River, the other main diversion from the lake is through the “A” Canal at Klamath Falls. Diversions through the “A” Canal have been generally constant over time. They were only slightly decreased, about 8 percent, during water years 1961–82 and 1983–2004 (table 9; fig. 16).
Another indication of water-management changes in the Klamath Project and the National Wildlife Refuges over the 44-year period can be seen in the USGS flow record for Klamath River at Keno, Oregon (table 10). Mean annual flows for the second 22-year period (water years 1983–2004) were about 109,000 acre-ft less than in the first 22-year period (water years 1961–82). This decrease is not likely an artifact of climate because the two 22-year climate periods were similar (fig. 7). Nor would the decrease be a consequence of flow record quality because this flow record had always been rated as “excellent” or “good.” Changes in the operation of Upper Klamath Lake and trends in the canal diversion and return flows would be the most likely explanation for the differences.
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Department of the Interior | U.S. Geological
Survey
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