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• 81. [Article] Summer Steelhead Creel Surveys on the Grande Ronde, Wallowa, and Imnaha Rivers for the 2005-06 Run Year

  Abstract -- Summer steelhead (Oncorhynchus mykiss) fisheries in the Grande Ronde and Imnaha river basins were closed in 1974. This closure was prompted by declining adult returns, as indicated by adult ...

  Citation × Citation Citation Abstract Copy Title: Summer Steelhead Creel Surveys on the Grande Ronde, Wallowa, and Imnaha Rivers for the 2005-06 Run Year Abstract -- Summer steelhead (Oncorhynchus mykiss) fisheries in the Grande Ronde and Imnaha river basins were closed in 1974. This closure was prompted by declining adult returns, as indicated by adult counts at Ice Harbor Dam on the Snake River (U.S. Army Corps of Engineers 1996), and low steelhead redd counts on index streams in the Grande Ronde and Imnaha river basins (Oregon Department of Fish and Wildlife District Annual Reports 1949-1974). The Lower Snake River Compensation Plan (LSRCP), initiated by Congress in 1976, was developed to compensate for losses of anadromous salmonids in the Snake River Basin from construction of the four lower Snake River Dams built between 1962 and 1976. Thus, the focus of the LSRCP is the Snake River above Lower Granite Dam (Rkm 173), the uppermost of these four dams. One of the primary objectives of the LSRCP in Oregon is to restore historic recreational and tribal fisheries for summer steelhead in the Grande Ronde and Imnaha river basins (Carmichael 1989). Approximately 1.68 million steelhead smolts were targeted for release in Oregon each year during April and May in the Grande Ronde and Imnaha river basins between 1984 and 1999. In 2000, we reduced releases to approximately 1.2 million smolts in response to the National Marine Fisheries Service’s recommendation to help reduce straying of Wallowa hatchery stock steelhead, primarily into the Deschutes River (mid-Columbia tributary). These fish provide hatchery adult returns that contribute to recreational fisheries and may supplement natural spawning populations in northeast Oregon. Consumptive recreational fisheries for summer steelhead re-opened in 1986, in part as a result of increases in hatchery adult returns. Lower Snake River Compensation Plan (LSRCP) ODFW- Eastern Oregon Fish Research (EOFR) Title: Summer Steelhead Creel Surveys on the Grande Ronde, Wallowa, and Imnaha Rivers for the 2005-06 Run Year Abstract -- Summer steelhead (Oncorhynchus mykiss) fisheries in the Grande Ronde and Imnaha river basins were closed in 1974. This closure was prompted by declining adult returns, as indicated by adult counts at Ice Harbor Dam on the Snake River (U.S. Army Corps of Engineers 1996), and low steelhead redd counts on index streams in the Grande Ronde and Imnaha river basins (Oregon Department of Fish and Wildlife District Annual Reports 1949-1974). The Lower Snake River Compensation Plan (LSRCP), initiated by Congress in 1976, was developed to compensate for losses of anadromous salmonids in the Snake River Basin from construction of the four lower Snake River Dams built between 1962 and 1976. Thus, the focus of the LSRCP is the Snake River above Lower Granite Dam (Rkm 173), the uppermost of these four dams. One of the primary objectives of the LSRCP in Oregon is to restore historic recreational and tribal fisheries for summer steelhead in the Grande Ronde and Imnaha river basins (Carmichael 1989). Approximately 1.68 million steelhead smolts were targeted for release in Oregon each year during April and May in the Grande Ronde and Imnaha river basins between 1984 and 1999. In 2000, we reduced releases to approximately 1.2 million smolts in response to the National Marine Fisheries Service’s recommendation to help reduce straying of Wallowa hatchery stock steelhead, primarily into the Deschutes River (mid-Columbia tributary). These fish provide hatchery adult returns that contribute to recreational fisheries and may supplement natural spawning populations in northeast Oregon. Consumptive recreational fisheries for summer steelhead re-opened in 1986, in part as a result of increases in hatchery adult returns. Lower Snake River Compensation Plan (LSRCP) ODFW- Eastern Oregon Fish Research (EOFR) Close

• 82. [Article] Summer Steelhead Creel Surveys on the Grande Ronde, Wallowa, and Imnaha Rivers for the 2006-07 Run Year

  Abstract -- Summer steelhead (Oncorhynchus mykiss) fisheries in the Grande Ronde and Imnaha river basins were closed in 1974. This closure was prompted by declining adult returns, as indicated by adult ...

  Citation × Citation Citation Abstract Copy Title: Summer Steelhead Creel Surveys on the Grande Ronde, Wallowa, and Imnaha Rivers for the 2006-07 Run Year Abstract -- Summer steelhead (Oncorhynchus mykiss) fisheries in the Grande Ronde and Imnaha river basins were closed in 1974. This closure was prompted by declining adult returns, as indicated by adult counts at Ice Harbor Dam on the Snake River (USACOE 1996), and low steelhead redd counts on index streams in the Grande Ronde and Imnaha river basins (Oregon Department of Fish and Wildlife District Annual Reports 1949-1974). The Lower Snake River Compensation Plan (LSRCP), initiated by Congress in 1976, was developed to compensate for losses of anadromous salmonids in the Snake River basin from construction of the four lower Snake River dams built between 1962 and 1976. Thus, the focus of the LSRCP is the Snake River above Lower Granite Dam (Rkm 173), the uppermost of these four dams. One of the primary objectives of the LSRCP in Oregon is to restore historic recreational and tribal fisheries for summer steelhead in the Grande Ronde and Imnaha river basins (Carmichael 1989). Approximately 1.68 million steelhead smolts were targeted for release in Oregon each year during April and May in the Grande Ronde and Imnaha river basins between 1984 and 1999. In 2000, we reduced releases to approximately 1.2 million smolts in response to the National Marine Fisheries Service’s recommendation to help reduce straying of Wallowa hatchery stock steelhead, primarily into the Deschutes River (midColumbia tributary). In 2006, we further reduced smolt releases to approximately 1.065 million, partly due to an increased release size from five to four fish per pound (fpp) for Wallowa stock which increased smolt-to-adult survival, and a reduction of Imnaha stock Big Sheep direct stream releases. These fish provide hatchery adult returns that contribute to recreational fisheries and may supplement natural spawning populations in northeast Oregon. Consumptive recreational fisheries for summer steelhead re-opened in 1986, in part as a result of increases in hatchery adult returns. Lower Snake River Compensation Plan (LSRCP) ODFW- Eastern Oregon Fish Research (EOFR) Title: Summer Steelhead Creel Surveys on the Grande Ronde, Wallowa, and Imnaha Rivers for the 2006-07 Run Year Abstract -- Summer steelhead (Oncorhynchus mykiss) fisheries in the Grande Ronde and Imnaha river basins were closed in 1974. This closure was prompted by declining adult returns, as indicated by adult counts at Ice Harbor Dam on the Snake River (USACOE 1996), and low steelhead redd counts on index streams in the Grande Ronde and Imnaha river basins (Oregon Department of Fish and Wildlife District Annual Reports 1949-1974). The Lower Snake River Compensation Plan (LSRCP), initiated by Congress in 1976, was developed to compensate for losses of anadromous salmonids in the Snake River basin from construction of the four lower Snake River dams built between 1962 and 1976. Thus, the focus of the LSRCP is the Snake River above Lower Granite Dam (Rkm 173), the uppermost of these four dams. One of the primary objectives of the LSRCP in Oregon is to restore historic recreational and tribal fisheries for summer steelhead in the Grande Ronde and Imnaha river basins (Carmichael 1989). Approximately 1.68 million steelhead smolts were targeted for release in Oregon each year during April and May in the Grande Ronde and Imnaha river basins between 1984 and 1999. In 2000, we reduced releases to approximately 1.2 million smolts in response to the National Marine Fisheries Service’s recommendation to help reduce straying of Wallowa hatchery stock steelhead, primarily into the Deschutes River (midColumbia tributary). In 2006, we further reduced smolt releases to approximately 1.065 million, partly due to an increased release size from five to four fish per pound (fpp) for Wallowa stock which increased smolt-to-adult survival, and a reduction of Imnaha stock Big Sheep direct stream releases. These fish provide hatchery adult returns that contribute to recreational fisheries and may supplement natural spawning populations in northeast Oregon. Consumptive recreational fisheries for summer steelhead re-opened in 1986, in part as a result of increases in hatchery adult returns. Lower Snake River Compensation Plan (LSRCP) ODFW- Eastern Oregon Fish Research (EOFR) Close

• 83. [Article] Summer Steelhead Creel Surveys on the Grande Ronde, Wallowa, and Imnaha Rivers for the 2007-08 Run Year

  Abstract -- Summer steelhead (Oncorhynchus mykiss) fisheries in the Grande Ronde and Imnaha river basins were closed in 1974. This closure was prompted by declining adult returns, as indicated by adult ...

  Citation × Citation Citation Abstract Copy Title: Summer Steelhead Creel Surveys on the Grande Ronde, Wallowa, and Imnaha Rivers for the 2007-08 Run Year Abstract -- Summer steelhead (Oncorhynchus mykiss) fisheries in the Grande Ronde and Imnaha river basins were closed in 1974. This closure was prompted by declining adult returns, as indicated by adult counts at Ice Harbor Dam on the Snake River (USACOE 1996), and low steelhead redd counts on index streams in the Grande Ronde and Imnaha river basins (Oregon Department of Fish and Wildlife District Annual Reports 1949-1974). The Lower Snake River Compensation Plan (LSRCP), initiated by congress in 1976, was developed to compensate for losses of anadromous salmonids in the Snake River basin from construction of the four lower Snake River dams built between 1962 and 1976. Thus, the focus of the LSRCP is the Snake River above Lower Granite Dam (Rkm 173), the uppermost of these four dams. One of the primary objectives of the LSRCP in Oregon is to restore historic recreational and tribal fisheries for summer steelhead in the Grande Ronde and Imnaha river basins (Carmichael 1989). Approximately 1.68 million steelhead smolts were targeted for release in Oregon each year during April and May in the Grande Ronde and Imnaha river basins between 1984 and 1999. In 2000, we reduced releases to approximately 1.2 million smolts in response to the National Marine Fisheries Service’s recommendation to help reduce straying of Wallowa hatchery stock steelhead, primarily into the Deschutes River (midColumbia tributary). In 2007, we further reduced smolt releases to approximately 1.065 million, partly due to an increased release size from five to four fish per pound (fpp) for Wallowa stock which increased smolt-to-adult survival, and a reduction of Imnaha stock Big Sheep direct stream releases. In 2009, smolt releases were reduced again to approximately 1.015 million, due to reductions in releases of Imnaha stock into Big Sheep Creek. These fish provide hatchery adult returns that contribute to recreational fisheries and may supplement natural spawning populations in northeast Oregon. Consumptive recreational fisheries for summer steelhead re-opened in 1986, in part as a result of increases in hatchery adult returns. Lower Snake River Compensation Plan (LSRCP) ODFW- Eastern Oregon Fish Research (EOFR) Title: Summer Steelhead Creel Surveys on the Grande Ronde, Wallowa, and Imnaha Rivers for the 2007-08 Run Year Abstract -- Summer steelhead (Oncorhynchus mykiss) fisheries in the Grande Ronde and Imnaha river basins were closed in 1974. This closure was prompted by declining adult returns, as indicated by adult counts at Ice Harbor Dam on the Snake River (USACOE 1996), and low steelhead redd counts on index streams in the Grande Ronde and Imnaha river basins (Oregon Department of Fish and Wildlife District Annual Reports 1949-1974). The Lower Snake River Compensation Plan (LSRCP), initiated by congress in 1976, was developed to compensate for losses of anadromous salmonids in the Snake River basin from construction of the four lower Snake River dams built between 1962 and 1976. Thus, the focus of the LSRCP is the Snake River above Lower Granite Dam (Rkm 173), the uppermost of these four dams. One of the primary objectives of the LSRCP in Oregon is to restore historic recreational and tribal fisheries for summer steelhead in the Grande Ronde and Imnaha river basins (Carmichael 1989). Approximately 1.68 million steelhead smolts were targeted for release in Oregon each year during April and May in the Grande Ronde and Imnaha river basins between 1984 and 1999. In 2000, we reduced releases to approximately 1.2 million smolts in response to the National Marine Fisheries Service’s recommendation to help reduce straying of Wallowa hatchery stock steelhead, primarily into the Deschutes River (midColumbia tributary). In 2007, we further reduced smolt releases to approximately 1.065 million, partly due to an increased release size from five to four fish per pound (fpp) for Wallowa stock which increased smolt-to-adult survival, and a reduction of Imnaha stock Big Sheep direct stream releases. In 2009, smolt releases were reduced again to approximately 1.015 million, due to reductions in releases of Imnaha stock into Big Sheep Creek. These fish provide hatchery adult returns that contribute to recreational fisheries and may supplement natural spawning populations in northeast Oregon. Consumptive recreational fisheries for summer steelhead re-opened in 1986, in part as a result of increases in hatchery adult returns. Lower Snake River Compensation Plan (LSRCP) ODFW- Eastern Oregon Fish Research (EOFR) Close

• 84. [Article] From the Willamette to the Coast Range

  Citation × Citation Citation Abstract Copy Title: From the Willamette to the Coast Range Author: Adams, James Davis (J.D.) Title: From the Willamette to the Coast Range Author: Adams, James Davis (J.D.) Close

• 85. [Article] Lower Snake River Compensation Plan; Oregon Spring Chinook Salmon Evaluation Studies - 2008 Annual Progress Report

  Abstract -- This annual progress report summarizes spring Chinook salmon monitoring data collected by ODFW for the Lower Snake River Compensation Plan (LSRCP) facilities in 2008. Also summarized are the ...

  Citation × Citation Citation Abstract Copy Title: Lower Snake River Compensation Plan; Oregon Spring Chinook Salmon Evaluation Studies - 2008 Annual Progress Report Abstract -- This annual progress report summarizes spring Chinook salmon monitoring data collected by ODFW for the Lower Snake River Compensation Plan (LSRCP) facilities in 2008. Also summarized are the associated adult broodstock monitoring data collected in the Grande Ronde Basin by our co-managers, Nez Perce Tribe (NPT) and Confederated Tribes of the Umatilla Indian Reservation (CTUIR). The main objectives of this report are to document and evaluate spring Chinook salmon culture performance for hatchery programs and achievement of management objectives in the Imnaha and Grande Ronde river basins. Our co-managers, CTUIR and NPT, have specific program goals for Chinook returns to Catherine Creek, the Upper Grande Ronde River, Lookingglass Creek, and the Lostine River, that are discussed and evaluated in reports prepared by each co-management agency. Overall, these data are used to modify culture practices as needed in order to optimize the egg-to-smolt survival, smolt quality, smolt-to-adult survival rate, and to track spawning in nature by hatchery-reared adults. This report provides information on rearing and release operations for the 2006 brood year of juvenile Chinook salmon smolts, the collection of eggs for the 2008 brood year, Chinook spawning in nature, numbers and characteristics of adult Chinook salmon in the 2008 return year, recruit summary and age composition of the 2003 brood year, and bacterial kidney disease (BKD) monitoring. Lower Snake River Compensation Plan (LSRCP) ODFW- Eastern Oregon Fish Research (EOFR) Title: Lower Snake River Compensation Plan; Oregon Spring Chinook Salmon Evaluation Studies - 2008 Annual Progress Report Abstract -- This annual progress report summarizes spring Chinook salmon monitoring data collected by ODFW for the Lower Snake River Compensation Plan (LSRCP) facilities in 2008. Also summarized are the associated adult broodstock monitoring data collected in the Grande Ronde Basin by our co-managers, Nez Perce Tribe (NPT) and Confederated Tribes of the Umatilla Indian Reservation (CTUIR). The main objectives of this report are to document and evaluate spring Chinook salmon culture performance for hatchery programs and achievement of management objectives in the Imnaha and Grande Ronde river basins. Our co-managers, CTUIR and NPT, have specific program goals for Chinook returns to Catherine Creek, the Upper Grande Ronde River, Lookingglass Creek, and the Lostine River, that are discussed and evaluated in reports prepared by each co-management agency. Overall, these data are used to modify culture practices as needed in order to optimize the egg-to-smolt survival, smolt quality, smolt-to-adult survival rate, and to track spawning in nature by hatchery-reared adults. This report provides information on rearing and release operations for the 2006 brood year of juvenile Chinook salmon smolts, the collection of eggs for the 2008 brood year, Chinook spawning in nature, numbers and characteristics of adult Chinook salmon in the 2008 return year, recruit summary and age composition of the 2003 brood year, and bacterial kidney disease (BKD) monitoring. Lower Snake River Compensation Plan (LSRCP) ODFW- Eastern Oregon Fish Research (EOFR) Close

• 86. [Article] Lower Snake River Compensation Plan; Oregon Spring Chinook Salmon Evaluation Studies - 2009 Annual Progress Report

  Abstract -- This annual progress report summarizes spring Chinook salmon monitoring data collected by ODFW for the Lower Snake River Compensation Plan (LSRCP) facilities in 2009. Also summarized are the ...

  Citation × Citation Citation Abstract Copy Title: Lower Snake River Compensation Plan; Oregon Spring Chinook Salmon Evaluation Studies - 2009 Annual Progress Report Abstract -- This annual progress report summarizes spring Chinook salmon monitoring data collected by ODFW for the Lower Snake River Compensation Plan (LSRCP) facilities in 2009. Also summarized are the associated adult broodstock monitoring data collected in the Grande Ronde Basin by our co-managers, the Nez Perce Tribe (NPT) and Confederated Tribes of the Umatilla Indian Reservation (CTUIR). The main objectives of this report are to document and evaluate spring Chinook salmon culture performance for hatchery programs and achievement of management objectives in the Imnaha and Grande Ronde river basins. Our co-managers, CTUIR and NPT, have specific program goals for Chinook returns to Catherine Creek, the Upper Grande Ronde River, Lookingglass Creek, and the Lostine River, that are discussed and evaluated in reports prepared by each co-management agency. Overall, these data are used to modify culture practices, as needed, in order to optimize the egg-to-smolt survival, smolt quality, and smolt-toadult survival rate, and track spawning in nature by hatchery-reared adults. This report provides information on rearing and release operations for the 2007 brood year of juvenile Chinook salmon smolts, the collection of eggs for the 2009 brood year, numbers and characteristics of adult Chinook salmon in the 2009 return year, spawning at Lookingglass Fish Hatchery and in nature, recruit summary and age composition of the 2004 brood year, and bacterial kidney disease (BKD) monitoring. Lower Snake River Compensation Plan (LSRCP) ODFW- Eastern Oregon Fish Research (EOFR) Title: Lower Snake River Compensation Plan; Oregon Spring Chinook Salmon Evaluation Studies - 2009 Annual Progress Report Abstract -- This annual progress report summarizes spring Chinook salmon monitoring data collected by ODFW for the Lower Snake River Compensation Plan (LSRCP) facilities in 2009. Also summarized are the associated adult broodstock monitoring data collected in the Grande Ronde Basin by our co-managers, the Nez Perce Tribe (NPT) and Confederated Tribes of the Umatilla Indian Reservation (CTUIR). The main objectives of this report are to document and evaluate spring Chinook salmon culture performance for hatchery programs and achievement of management objectives in the Imnaha and Grande Ronde river basins. Our co-managers, CTUIR and NPT, have specific program goals for Chinook returns to Catherine Creek, the Upper Grande Ronde River, Lookingglass Creek, and the Lostine River, that are discussed and evaluated in reports prepared by each co-management agency. Overall, these data are used to modify culture practices, as needed, in order to optimize the egg-to-smolt survival, smolt quality, and smolt-toadult survival rate, and track spawning in nature by hatchery-reared adults. This report provides information on rearing and release operations for the 2007 brood year of juvenile Chinook salmon smolts, the collection of eggs for the 2009 brood year, numbers and characteristics of adult Chinook salmon in the 2009 return year, spawning at Lookingglass Fish Hatchery and in nature, recruit summary and age composition of the 2004 brood year, and bacterial kidney disease (BKD) monitoring. Lower Snake River Compensation Plan (LSRCP) ODFW- Eastern Oregon Fish Research (EOFR) Close

• 87. [Article] Lower Snake River Compensation Plan; Oregon Spring Chinook Salmon Evaluation Studies - 2010 Annual Progress Report

  Abstract -- This annual progress report summarizes spring Chinook salmon monitoring data collected by ODFW for the Lower Snake River Compensation Plan (LSRCP) facilities in 2010. Also summarized are the ...

  Citation × Citation Citation Abstract Copy Title: Lower Snake River Compensation Plan; Oregon Spring Chinook Salmon Evaluation Studies - 2010 Annual Progress Report Abstract -- This annual progress report summarizes spring Chinook salmon monitoring data collected by ODFW for the Lower Snake River Compensation Plan (LSRCP) facilities in 2010. Also summarized are the associated adult broodstock monitoring data collected in the Grande Ronde Basin by our co-managers, the Nez Perce Tribe (NPT) and Confederated Tribes of the Umatilla Indian Reservation (CTUIR). The main objectives of this report are to document and evaluate spring Chinook salmon culture performance for hatchery programs and achievement of management objectives in the Imnaha and Grande Ronde river basins (Our co-managers, CTUIR and NPT, have specific program goals for Chinook returns to Catherine Creek, the Upper Grande Ronde River, Lookingglass Creek, and the Lostine River, that are discussed and evaluated in reports prepared by each co-management agency). Overall, these data are used to modify culture practices, as needed, in order to optimize egg-to-smolt survival, smolt quality, and smolt-to-adult survival rate, and track spawning in nature by hatchery-reared adults. This report provides information on rearing and release operations for the 2008 brood year of juvenile Chinook salmon smolts, the collection of eggs for the 2010 brood year, numbers and characteristics of adult Chinook salmon in the 2010 return year, the 2010 spawning year at Lookingglass Fish Hatchery and in nature, recruit summary and age composition of the 2005 brood year, and bacterial kidney disease (BKD) monitoring. Lower Snake River Compensation Plan (LSRCP) ODFW- Eastern Oregon Fish Research (EOFR) Title: Lower Snake River Compensation Plan; Oregon Spring Chinook Salmon Evaluation Studies - 2010 Annual Progress Report Abstract -- This annual progress report summarizes spring Chinook salmon monitoring data collected by ODFW for the Lower Snake River Compensation Plan (LSRCP) facilities in 2010. Also summarized are the associated adult broodstock monitoring data collected in the Grande Ronde Basin by our co-managers, the Nez Perce Tribe (NPT) and Confederated Tribes of the Umatilla Indian Reservation (CTUIR). The main objectives of this report are to document and evaluate spring Chinook salmon culture performance for hatchery programs and achievement of management objectives in the Imnaha and Grande Ronde river basins (Our co-managers, CTUIR and NPT, have specific program goals for Chinook returns to Catherine Creek, the Upper Grande Ronde River, Lookingglass Creek, and the Lostine River, that are discussed and evaluated in reports prepared by each co-management agency). Overall, these data are used to modify culture practices, as needed, in order to optimize egg-to-smolt survival, smolt quality, and smolt-to-adult survival rate, and track spawning in nature by hatchery-reared adults. This report provides information on rearing and release operations for the 2008 brood year of juvenile Chinook salmon smolts, the collection of eggs for the 2010 brood year, numbers and characteristics of adult Chinook salmon in the 2010 return year, the 2010 spawning year at Lookingglass Fish Hatchery and in nature, recruit summary and age composition of the 2005 brood year, and bacterial kidney disease (BKD) monitoring. Lower Snake River Compensation Plan (LSRCP) ODFW- Eastern Oregon Fish Research (EOFR) Close

• 88. [Article] End Creek - Rice Fish Habitat and Wetland Restoration Project, OWEB #204-434

  Abstract -- The summer of 2006 culminated in the successful implementation of three consecutive phases of the End Creek Restoration Project located in the northwest Grande Ronde Valley within the Grande ...

  Citation × Citation Citation Abstract Copy Title: End Creek - Rice Fish Habitat and Wetland Restoration Project, OWEB #204-434 Abstract -- The summer of 2006 culminated in the successful implementation of three consecutive phases of the End Creek Restoration Project located in the northwest Grande Ronde Valley within the Grande Ronde Subbasin of eastern Oregon. The End Creek Project complex encompasses approximately 776 acres within three contiguous private land parcels, 1.13 miles of End Creek, 1.06 miles of the South Fork Willow Creek, 0.65 miles of McDonald Creek, and several spring-fed tributaries in the Willow Creek Watershed. This 39 page report details the many aspects of this project and includes photos, figures, and references. Title: End Creek - Rice Fish Habitat and Wetland Restoration Project, OWEB #204-434 Abstract -- The summer of 2006 culminated in the successful implementation of three consecutive phases of the End Creek Restoration Project located in the northwest Grande Ronde Valley within the Grande Ronde Subbasin of eastern Oregon. The End Creek Project complex encompasses approximately 776 acres within three contiguous private land parcels, 1.13 miles of End Creek, 1.06 miles of the South Fork Willow Creek, 0.65 miles of McDonald Creek, and several spring-fed tributaries in the Willow Creek Watershed. This 39 page report details the many aspects of this project and includes photos, figures, and references. Close

• 89. [Article] The Littlefield Rhyolite, Eastern Oregon: Distinct Flow Units and Their Constraints on Age and Storage Sites of Grande Ronde Basalt Magmas

  The Littlefield Rhyolite consists of widespread, high-temperature, hotspot-related rhyolitic lavas that erupted in eastern Oregon contemporaneous to late-stage Grande Ronde Basalt lavas. The estimated ...

  Citation × Citation Citation Abstract Copy Title: The Littlefield Rhyolite, Eastern Oregon: Distinct Flow Units and Their Constraints on Age and Storage Sites of Grande Ronde Basalt Magmas Author: Webb, Brian McCulloch Year: 2017 The Littlefield Rhyolite consists of widespread, high-temperature, hotspot-related rhyolitic lavas that erupted in eastern Oregon contemporaneous to late-stage Grande Ronde Basalt lavas. The estimated total volume of erupted rhyolites is ~100 km3 covering ~850 km2. The focus of this study has been to investigate the stratigraphy and petrology of the Littlefield Rhyolite and whether field and geochemical relationships exist to help constrain the timing and storage sites of Grande Ronde Basalt magmas. Although often indistinguishable in the field, our data reveal that the Littlefield Rhyolite consists of two geochemically distinct rhyolite flow packages that are designated here as lower and upper Littlefield Rhyolite, according to stratigraphic relationships in the Malheur River Gorge. Rarely viewed in sequence, these rhyolites are distinguished by Zr, Ba, Nb, TiO2 and FeO contents and 40Ar/39Ar ages (16.12±0.04 and 16.16±0.10 Ma versus 16.01±0.06 and 16.05±0.04 Ma). Rhyolites known either as ‘rhyolite of Cottonwood Mountain’ or ‘rhyolite of Bully Creek Canyon’, and which are exposed around Cottonwood Mountain, northwest of Vale, have compositions similar to samples of lower Littlefield Rhyolite. Additionally, single crystal 40Ar/39Ar ages of two samples (16.12±0.07, 16.20±0.08) are statistically indistinguishable. Among units sandwiched between the lower and upper Littlefield Rhyolite are several lava flows and a one-meter thick agglutinated spatter deposit of Hunter Creek Basalt. The spatter deposit thickens to 10s of meters over a distance of 800 m where the deposit is strongly welded. We recognize this as a venting site of Hunter Creek Basalt, and that Hunter Creek Basalt is geochemically and petrographically similar to, and contemporaneous with, late-stage Grande Ronde Basalt. Ages of Littlefield Rhyolite flow units constrain the timing of eruption of Hunter Creek Basalt to an age span of ~100k years, between 16.05 – 16.12 Ma. One local variant of late-stage Grand Ronde Basalt is icelanditic (~62 wt. % SiO2) and is found at a number of places including a location near the southern extent of the upper Littlefield Rhyolite. Geochemical modeling strongly suggests that icelandite lavas resulted from mixing of Grande Ronde and upper Littlefield Rhyolite magmas, thereby tying a Grande Ronde magma storage site to within the greater Malheur River Gorge area, and indicating contemporaneity of rhyolitic and Grande Ronde magma reservoirs. Title: The Littlefield Rhyolite, Eastern Oregon: Distinct Flow Units and Their Constraints on Age and Storage Sites of Grande Ronde Basalt Magmas Author: Webb, Brian McCulloch Year: 2017 The Littlefield Rhyolite consists of widespread, high-temperature, hotspot-related rhyolitic lavas that erupted in eastern Oregon contemporaneous to late-stage Grande Ronde Basalt lavas. The estimated total volume of erupted rhyolites is ~100 km3 covering ~850 km2. The focus of this study has been to investigate the stratigraphy and petrology of the Littlefield Rhyolite and whether field and geochemical relationships exist to help constrain the timing and storage sites of Grande Ronde Basalt magmas. Although often indistinguishable in the field, our data reveal that the Littlefield Rhyolite consists of two geochemically distinct rhyolite flow packages that are designated here as lower and upper Littlefield Rhyolite, according to stratigraphic relationships in the Malheur River Gorge. Rarely viewed in sequence, these rhyolites are distinguished by Zr, Ba, Nb, TiO2 and FeO contents and 40Ar/39Ar ages (16.12±0.04 and 16.16±0.10 Ma versus 16.01±0.06 and 16.05±0.04 Ma). Rhyolites known either as ‘rhyolite of Cottonwood Mountain’ or ‘rhyolite of Bully Creek Canyon’, and which are exposed around Cottonwood Mountain, northwest of Vale, have compositions similar to samples of lower Littlefield Rhyolite. Additionally, single crystal 40Ar/39Ar ages of two samples (16.12±0.07, 16.20±0.08) are statistically indistinguishable. Among units sandwiched between the lower and upper Littlefield Rhyolite are several lava flows and a one-meter thick agglutinated spatter deposit of Hunter Creek Basalt. The spatter deposit thickens to 10s of meters over a distance of 800 m where the deposit is strongly welded. We recognize this as a venting site of Hunter Creek Basalt, and that Hunter Creek Basalt is geochemically and petrographically similar to, and contemporaneous with, late-stage Grande Ronde Basalt. Ages of Littlefield Rhyolite flow units constrain the timing of eruption of Hunter Creek Basalt to an age span of ~100k years, between 16.05 – 16.12 Ma. One local variant of late-stage Grand Ronde Basalt is icelanditic (~62 wt. % SiO2) and is found at a number of places including a location near the southern extent of the upper Littlefield Rhyolite. Geochemical modeling strongly suggests that icelandite lavas resulted from mixing of Grande Ronde and upper Littlefield Rhyolite magmas, thereby tying a Grande Ronde magma storage site to within the greater Malheur River Gorge area, and indicating contemporaneity of rhyolitic and Grande Ronde magma reservoirs. Close

• 90. [Article] Ecological characteristics of montane floodplain plant communities in the Upper Grande Ronde basin, Oregon

  Citation × Citation Citation Abstract Copy Title: Ecological characteristics of montane floodplain plant communities in the Upper Grande Ronde basin, Oregon Author: Otting, Nicholas J. Title: Ecological characteristics of montane floodplain plant communities in the Upper Grande Ronde basin, Oregon Author: Otting, Nicholas J. Close