Estimation of Columbia River virgin flow: 1879 to 1928

Abstract

Abstract:The Columbia River is a major source of and conduit for Pacific Northwest economic activity, and is one of the more heavily modified rivers in North America. Understanding human and climate-induced changes in its hydrologic properties is, therefore, vital. Long streamflow records are essential to determining how runoff has changed over time, and Columbia River daily streamflow record at The Dalles began in 1878. To understand and separate anthropogenic and climate effects, however, it is also necessary to have a basin-scale estimate of virgin or naturalized flow. The United States Geological Survey has calculated a monthly averaged adjusted river flow at The Dalles for 1879-1999 that accounts for the effects of flow regulation. The Bonneville Power Administration has estimated the monthly averaged virgin flow at The Dalles, i.e. the flow in the absence of both flow regulation and irrigation depletion for 1929-89. We have estimated the monthly virgin flow of the Columbia River at The Dalles from records of irrigated area for the missing early years, i.e. for the period 1879-1928. In addition, to allow hindcasting of a virgin flow sediment transport for the system, a daily virgin flow index with realistic higher moments and spectral properties has been calculated. Examination of the virgin flow record shows that climate change since the late 19th century has decreased annual average flow volume by >7%; irrigation depletion has reduced the flow by another ¾7%.

Columbia River Estuary ecosystem classification—Concept and application

“…Most Columbia River discharge is the product of Pacific frontal systems moving east with the mid-latitude westerlies, with most precipitation falling as winter snowfall in the Rocky Mountains and in the Cascade Range. Mean annual river discharge at the mouth is about 6,970 m 3 /s) (Naik and Jay, 2005). Approximately 24 percent of this volume originates from west of the Cascade Range crest, despite a contributing area totaling only 8 percent of the river basin (Sherwood and others, 1990).…”

A Statistical Investigation of Lower Columbia River Water Temperature, 1915-2003

“…This change in the annual hydrograph shows the effects of storage dams, where water is held during periods of naturally high Q and released later in order to optimize hydroelectric power generation and decrease risk of flooding. It is possible that long-term cycles such as the Pacific decadal oscillation also affected Q during these periods (e.g., Naik and Jay, 2005;. when compared to the climatological average for that period ( Figure 9).…”

“…Decreases in summer Q are due in part to irrigation withdrawals and in part to storage reservoirs which hold water for later release (e.g., Naik and Jay, 2005;. Storing water in these reservoirs allows it to heat more than under natural flow conditions due to an increased residence time.…”

Historic Habitat Opportunities and Food-Web Linkages of Juvenile Salmon in the Columbia River Estuary and Their Implications for Managing River Flows and Restoring Estuarine Habitat, Physical Sciences Component, Progress Report.

“…(4) Estimated virgin flows for The Dalles, the Willamette at Portland and Beaver for 1878-date. The methodology and irrigation corrections for these calculations are described in Bureau of Reclamation (1999) and Naik and Jay (2005). (5) Used USGS flow and sediment transport data to develop rating curves for the Columbia at Vancouver and the Willamette at Portland for sand, fines, and total load.…”

“…Recently, all flow and sediment supply estimates were updated to 2004 (from 1999). The virgin flow methodology is further discussed in Naik and Jay (2005). Less detained estimates are available at Beaver and for the West-side tributaries (Cowlitz, Lewis, East Fork Lewis, and Kalama).…”