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121. [Image] Farming practices and water quality in the Upper Klamath Basin : final report to the California State Water Resources Control Board : 205j program


	Summary The Upper Klamath Basin (UKB) is a high desert region straddling the California-Oregon border east of the Cascade Range. Irrigation and other agricultural practices in the U. S. Bureau of Reclamation's ...
	Citation Citation Citation Abstract Copy Title: Farming practices and water quality in the Upper Klamath Basin : final report to the California State Water Resources Control Board : 205j program Author: Danosky, Earl; Kaffka, Stephen Year: 2002, 2007, 2006 Summary The Upper Klamath Basin (UKB) is a high desert region straddling the California-Oregon border east of the Cascade Range. Irrigation and other agricultural practices in the U. S. Bureau of Reclamation's Klamath Project may result in impaired surface water quality, reducing its use for wildlife and fish in important national wildlife refuges that receive drainage water from farms, and in the Klamath River. By 2004, a system of total maximum daily loads (TMDL) for nutrients must be established for the Klamath River. To investigate the relationships among agricultural practices and surface water quality in the Upper Klamath Basin, a two year reconnaissance survey of surface water and agricultural tile drain locations, focusing on nitrogen and phosphorus concentrations and mass transfers was conducted. Data was collected at 18 surface locations and 10 tile drain locations. Triplicate samples were taken every ten days during the growing season (April through October) and one or two times a month during the remainder of the months, depending on opportunity. No samples were taken from tile drains during the winter months because there was no irrigation and drainage during that period. Water samples were analyzed for phosphorus (total P, soluble reactive P, total filterable P, and particulate P) and nitrogen (total N, soluble N, Soluble organic N, total filterable N, particulate N, and ammonia N), temperature, pH and electrical conductivity, a measure of salinity or total dissolved solids. Analyses of data, including data quality, estimates of the transfer of nutrients in surface waters in the region, and hypotheses about the relationship between agriculture and water quality are reported. 1. The salt and nutrient content of surface waters increases nearly threefold as water moves through the watershed from the Lost River and J canal diversion to the Klamath Straits Drain. Mean ECW levels in input waters at the J canal diversion were approximately 250 \iS cm1, while water sampled at the D pump increased to 600 ^S cm"1 on average over the sample period. By the time water reenters the Klamath River, salt concentrations have increased to approximately 700 jaS cm1. 2. The ECW values observed in subsurface tile drains were higher on average than in input waters and surface waters elsewhere in the region, especially in the Lease Lands area of the Tulelake Irrigation District (TID). ECW values averaged approximately 2,500 ^S cm"1 . Recycling irrigation water through soils in the TID increases the salinity of the water, especially by the time it reaches and is reused in the Lease Lands area of the Tulelake National Wildlife Refuge (TLNWR). Soils in this part of the Klamath Project area are naturally high in salt. 3. Water temperatures in agricultural subsurface tile drains were significantly lower than surface water temperatures during the growing season when tile drains were active. pH values in tile drains were lower than surface water values. The temperature and pH of tile drains does not influence surface water values. 1. 4. For total phosphorus (TP) input waters at the J canal irrigation diversion for the TED averaged approximately 0.27 mg L1 for the two years reported. Water leaving the Tulelake Sumps at the D pump increases to 0.33 mg L1. Water leaving the Lower Klamath National Wildlife Refuge (LKNWR) sampled at the start of the Klamath Straits Drain, averaged 0.33 mg L1, similar to those at the D pump. TP increased further to 0.40 mg L"1 a the end of the Klamath Straits Drain. The overall increase in P concentration in surface waters was much less than for salt, suggesting that processes other than simple enrichment are occurring, particularly those associated with the exchange of sedimentary P and aquatic plant species. TN increases from 2.3 mg L"1 to 4.0 mg L1 over the same pathway. Atomic ratios (TN:TP) of surface water samples remain constant at approximately 10:1 throughout the system, suggesting that the amount of sediment and other small particulate matter in surface waters affects the values observed. The amount of sediment is influenced in part by the agitation of surface water as it passes through pumps and over weirs. 5. The average seasonal TP value in tile drains beneath farm fields is approximately 0.34 mg L"1 . While average total P values in subsurface tile drains were not different from those found at the D pump and the LKNWR outlet, the range in values was great (0.1 to 0.8 mg L1). Similarly, high NO3 -N values were observed at times in tile drains. Very high values in tile drains lead to the inference that some fertilizer N and P is lost in drainage water, combined with nutrients derived from decaying soil organic matter. The amount estimated as lost is much less than the amount of surplus fertilizer P applied and the amount of P surmised to be mineralized from decaying soil organic matter. P from fertilizer and decaying organic matter appears to be accumulating in soils and lake sediments in the region. 6. Ammonia N concentrations are at or below the limit of detection in subsurface agricultural tile lines and one to two orders of magnitude below the values observed in surface soils. Un ionized ammonia increases with temperature. Values above 0.25 mg L1 were observed in late summer at several locations. 7. Some leaching of soluble salts and nutrients is unavoidable when crops are irrigated. P fertilizer is applied at rates higher than crop removal, while fertilizer n is applied at rates less than crop removal. Reduced fertilizer use can help bring P inputs and outputs into balance and may reduce further any avoidable losses of P. This objective should be the subject of an agronomic research program in the region. 8. Surface waters entering the TDD, the TLNWR, and the LKNWR are already enriched with N and P. It seems unlikely that reducing N and P losses from farming in the TID, if possible, would influence surface water quality sufficiently to make them significantly less eutrophic. For P, the hypothesized threshold concentration limiting algae growth in fresh waters is 5 to 25 times smaller than the values observed in waters entering the TID for irrigation use. The addition of 1. nutrients from agriculture probably does not influence significantly surface water quality in the region. Wetland sediments, large amounts of organic matter in soils, and water introduced for irrigation contain essentially unlimited amounts of nutrients for aquatic plant growth. It is not clear how this circumstance could be changed under any reasonable time frame, if ever. 9. Using a TMDL approach may not result in reduced amounts of nutrients returned to the Klamath River because wetlands and farming practices in the southern portion of the Klamath Project result in the net removal of nutrients from the waters diverted for irrigation on a yearly basis, compared to allowing the same amount of water simply to flow down the river unused. Because of large errors of estimation for the amounts of water transferred, combined with smaller errors associated with estimating nutrient concentrations in water samples, and with year to year climate variation, TMDLs may not be an effective or efficient means of reducing nutrients in return flows to the Klamath River. Rational confidence limits for TMDLs may have to be too broad to be effective. Recycling of some drainage water for irrigation would reduce the amount of nutrients returned to the river more effectively than implementing a TMDL program. Title: Farming practices and water quality in the Upper Klamath Basin : final report to the California State Water Resources Control Board : 205j program Author: Danosky, Earl; Kaffka, Stephen Year: 2002, 2007, 2006 Summary The Upper Klamath Basin (UKB) is a high desert region straddling the California-Oregon border east of the Cascade Range. Irrigation and other agricultural practices in the U. S. Bureau of Reclamation's Klamath Project may result in impaired surface water quality, reducing its use for wildlife and fish in important national wildlife refuges that receive drainage water from farms, and in the Klamath River. By 2004, a system of total maximum daily loads (TMDL) for nutrients must be established for the Klamath River. To investigate the relationships among agricultural practices and surface water quality in the Upper Klamath Basin, a two year reconnaissance survey of surface water and agricultural tile drain locations, focusing on nitrogen and phosphorus concentrations and mass transfers was conducted. Data was collected at 18 surface locations and 10 tile drain locations. Triplicate samples were taken every ten days during the growing season (April through October) and one or two times a month during the remainder of the months, depending on opportunity. No samples were taken from tile drains during the winter months because there was no irrigation and drainage during that period. Water samples were analyzed for phosphorus (total P, soluble reactive P, total filterable P, and particulate P) and nitrogen (total N, soluble N, Soluble organic N, total filterable N, particulate N, and ammonia N), temperature, pH and electrical conductivity, a measure of salinity or total dissolved solids. Analyses of data, including data quality, estimates of the transfer of nutrients in surface waters in the region, and hypotheses about the relationship between agriculture and water quality are reported. 1. The salt and nutrient content of surface waters increases nearly threefold as water moves through the watershed from the Lost River and J canal diversion to the Klamath Straits Drain. Mean ECW levels in input waters at the J canal diversion were approximately 250 \iS cm1, while water sampled at the D pump increased to 600 ^S cm"1 on average over the sample period. By the time water reenters the Klamath River, salt concentrations have increased to approximately 700 jaS cm1. 2. The ECW values observed in subsurface tile drains were higher on average than in input waters and surface waters elsewhere in the region, especially in the Lease Lands area of the Tulelake Irrigation District (TID). ECW values averaged approximately 2,500 ^S cm"1 . Recycling irrigation water through soils in the TID increases the salinity of the water, especially by the time it reaches and is reused in the Lease Lands area of the Tulelake National Wildlife Refuge (TLNWR). Soils in this part of the Klamath Project area are naturally high in salt. 3. Water temperatures in agricultural subsurface tile drains were significantly lower than surface water temperatures during the growing season when tile drains were active. pH values in tile drains were lower than surface water values. The temperature and pH of tile drains does not influence surface water values. 1. 4. For total phosphorus (TP) input waters at the J canal irrigation diversion for the TED averaged approximately 0.27 mg L1 for the two years reported. Water leaving the Tulelake Sumps at the D pump increases to 0.33 mg L1. Water leaving the Lower Klamath National Wildlife Refuge (LKNWR) sampled at the start of the Klamath Straits Drain, averaged 0.33 mg L1, similar to those at the D pump. TP increased further to 0.40 mg L"1 a the end of the Klamath Straits Drain. The overall increase in P concentration in surface waters was much less than for salt, suggesting that processes other than simple enrichment are occurring, particularly those associated with the exchange of sedimentary P and aquatic plant species. TN increases from 2.3 mg L"1 to 4.0 mg L1 over the same pathway. Atomic ratios (TN:TP) of surface water samples remain constant at approximately 10:1 throughout the system, suggesting that the amount of sediment and other small particulate matter in surface waters affects the values observed. The amount of sediment is influenced in part by the agitation of surface water as it passes through pumps and over weirs. 5. The average seasonal TP value in tile drains beneath farm fields is approximately 0.34 mg L"1 . While average total P values in subsurface tile drains were not different from those found at the D pump and the LKNWR outlet, the range in values was great (0.1 to 0.8 mg L1). Similarly, high NO3 -N values were observed at times in tile drains. Very high values in tile drains lead to the inference that some fertilizer N and P is lost in drainage water, combined with nutrients derived from decaying soil organic matter. The amount estimated as lost is much less than the amount of surplus fertilizer P applied and the amount of P surmised to be mineralized from decaying soil organic matter. P from fertilizer and decaying organic matter appears to be accumulating in soils and lake sediments in the region. 6. Ammonia N concentrations are at or below the limit of detection in subsurface agricultural tile lines and one to two orders of magnitude below the values observed in surface soils. Un ionized ammonia increases with temperature. Values above 0.25 mg L1 were observed in late summer at several locations. 7. Some leaching of soluble salts and nutrients is unavoidable when crops are irrigated. P fertilizer is applied at rates higher than crop removal, while fertilizer n is applied at rates less than crop removal. Reduced fertilizer use can help bring P inputs and outputs into balance and may reduce further any avoidable losses of P. This objective should be the subject of an agronomic research program in the region. 8. Surface waters entering the TDD, the TLNWR, and the LKNWR are already enriched with N and P. It seems unlikely that reducing N and P losses from farming in the TID, if possible, would influence surface water quality sufficiently to make them significantly less eutrophic. For P, the hypothesized threshold concentration limiting algae growth in fresh waters is 5 to 25 times smaller than the values observed in waters entering the TID for irrigation use. The addition of 1. nutrients from agriculture probably does not influence significantly surface water quality in the region. Wetland sediments, large amounts of organic matter in soils, and water introduced for irrigation contain essentially unlimited amounts of nutrients for aquatic plant growth. It is not clear how this circumstance could be changed under any reasonable time frame, if ever. 9. Using a TMDL approach may not result in reduced amounts of nutrients returned to the Klamath River because wetlands and farming practices in the southern portion of the Klamath Project result in the net removal of nutrients from the waters diverted for irrigation on a yearly basis, compared to allowing the same amount of water simply to flow down the river unused. Because of large errors of estimation for the amounts of water transferred, combined with smaller errors associated with estimating nutrient concentrations in water samples, and with year to year climate variation, TMDLs may not be an effective or efficient means of reducing nutrients in return flows to the Klamath River. Rational confidence limits for TMDLs may have to be too broad to be effective. Recycling of some drainage water for irrigation would reduce the amount of nutrients returned to the river more effectively than implementing a TMDL program.