Lower Yakima River: Difference between revisions
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The tributaries to the Lower Yakima River all drain arid watersheds and are thought to have been intermittent prior to widespread irrigation; today they have perennial flows supported by both surface and subsurface irrigation return flows. Water quality issues are significant, with some of the highest levels of toxic contaminants found in the basin DOUBLE CHECK; significant work has been done by the irrigation districts and partners to reduce delivery of fine sediment and associated legacy toxins (DDT etc) to the Yakima from these creeks. , with ; these tributaries do support resident fish and limited numbers of anadromous fish but have generally not been considered priorities for anadromous fish restoration | The tributaries to the Lower Yakima River all drain arid watersheds and are thought to have been intermittent prior to widespread irrigation; today they have perennial flows supported by both surface and subsurface irrigation return flows. Water quality issues are significant, with some of the highest levels of toxic contaminants found in the basin DOUBLE CHECK; significant work has been done by the irrigation districts and partners to reduce delivery of fine sediment and associated legacy toxins (DDT etc) to the Yakima from these creeks. , with ; these tributaries do support resident fish and limited numbers of anadromous fish but have generally not been considered priorities for anadromous fish restoration | ||
# [[Spring and Snipes Creeks]] enters from North | # [[Spring and Snipes Creeks]] enters from North on the left bank at river mile 41.8 of the Yakima River; drains a mix of ag and rural residential | ||
# [[Corral Creek]] | # [[Corral Creek]] a left bank tributary that at river mile 33.5 of the Yakima River. | ||
# [[Amon Creek Wasteway]] drains a rapidly | # [[Amon Creek Wasteway]] a right bank tributary at river mile 2.7 of the Yakima River; drains a rapidly urbanizing watershed in the Tri Cities; lots of work to conserve Amon Creek and adjacent lands as open space | ||
# [[Cold Creek (Lower Yakima)|Cold Creek]] is an intermittent creek that drains a large arid area | # [[Cold Creek (Lower Yakima)|Cold Creek]] is an intermittent creek that drains a large arid area | ||
Revision as of 16:38, 3 September 2025
The Lower Yakima River is approximately 51 river miles long beginning near the Yakima County/Benton County border and ending at the Columbia River.
There have been numerous studies and reports detailing the Lower Yakima River with one of the more comprehensive being the Assessment of the Lower Yakima River in Benton County, Washington by the Benton County Conservation District in 2011[1].
The Lower Yakima River is a critical corridor for many species of fish including numerous salmonid species.
Geography
Mainstem Reaches in this Geographic Unit
The Lower Yakima River below Prosser Diversion Dam is generally considered a high-gradient, bedrock controlled segment with a narrow alluvial floodplain with approximately 2 miles of backwater influence on the Lower Yakima River from the McNary Dam Reservoir.
Tributaries to the Lower Yakima River in this Geographic Unit
The tributaries to the Lower Yakima River all drain arid watersheds and are thought to have been intermittent prior to widespread irrigation; today they have perennial flows supported by both surface and subsurface irrigation return flows. Water quality issues are significant, with some of the highest levels of toxic contaminants found in the basin DOUBLE CHECK; significant work has been done by the irrigation districts and partners to reduce delivery of fine sediment and associated legacy toxins (DDT etc) to the Yakima from these creeks. , with ; these tributaries do support resident fish and limited numbers of anadromous fish but have generally not been considered priorities for anadromous fish restoration
- Spring and Snipes Creeks enters from North on the left bank at river mile 41.8 of the Yakima River; drains a mix of ag and rural residential
- Corral Creek a left bank tributary that at river mile 33.5 of the Yakima River.
- Amon Creek Wasteway a right bank tributary at river mile 2.7 of the Yakima River; drains a rapidly urbanizing watershed in the Tri Cities; lots of work to conserve Amon Creek and adjacent lands as open space
- Cold Creek is an intermittent creek that drains a large arid area
Lower River Flow/Hydrology
There is one gage in the Lower Yakima River, USGS stream flow monitoring at Kiona, located at river mile 30, see USGS Gage.
See Yakima Basin combined stream flow monitoring links page
Facilities
Chandler Canal
Prosser Hatchery and Enumeration Facility
Wanawish Dam (Horn Rapids Dam)
- Columbia Irrigation District
- Barker Ranch
Lewis and Clark Irrigation District
Badger Mountain Irrigation District
Water Stargrass (Heteranthera dubia)
Water stargrass is a perennial plant that has become well established in the lower 43 miles of the Yakima River, below Prosser Dam.
See separate page on Water stargrass
Yakima Delta
The Yakima delta and confluence is a critical link to the entire Yakima River both historically and today. The confluence was an important tribal fishing ground as noted in the Lewis and Clark Journals.
It provides an important link for fish as an adult and juvenile migration corridor.
However, much of the original floodplain/delta has been significantly developed, altered, or submerged as a result of the construction of McNary Dam downstream in the Columbia River. The reservoir now formed by McNary Dam extends nearly 2 miles up the Yakima River, changing flow and sediment deposition patterns in the delta.
The construction of the Bateman Island Causeway around 1940 further constrained the flow patterns of both the Yakima River and Columbia River in the delta.
For more info see the Yakima Delta page.
Water Quality
Water quality concerns in the lower Yakima River include high water temperature, low dissolved oxygen, high pH, high suspended sediments, high turbidity, and high levels of toxic substances.
Stream Temperature
The lower Yakima River is known to reach levels nearing 85°F (30°C) in the summer, creating a migration barrier for salmonids.
The primary causes of high stream temperatures in the Lower Yakima River are: 1) hot air temperatures, 2) a wide, shallow river with little riparian vegetation to provide shade, 3) loss of floodplain and riparian functions due to channelization and development, and 4) low flows due to water diversions.
Sediment
Habitat Quality
The Lower Yakima River below Prosser Diversion Dam is generally considered a high-gradient, bedrock controlled segment with a narrow alluvial floodplain.
Channel Complexity
Large Wood
Vegetation
Refuge Habitat
Fish Use
Salmon and Steelhead
Bull Trout
Non-Natives
Predation (Piscivore and Avian)
Citations
- ↑ Appel, M., R. Little, H. Wendt, and M. Nielson. Assessment of the Lower Yakima River in Benton County, Washington. Benton Conservation District, 2011. http://www.ybfwrb.org/Assets/Documents/Assessments/Lower_Yakima_Assessment.pdf.