▀ Columbia River Overview▀ Superfund Process

▀ Conceptual Site Models▀ Data Gap Analysis

Columbia River Surface Water Hydrology Plays a Critical Role in Sedimentation

▀ Flow rates ▀ High flows within

the Hanford section results in minimum sedimentation

▀ Major river confluences ▀ Yakima▀ Snake ▀ Walla Walla

S S

S SS

S

SS

S

S

S

The Majority of the Hanford Reach is a Non-Depositional Area

S S

S SS

S

SS

S

S

S

The Majority of the Hanford Reach is a Non-Depositional Area

USGS Annual Statistics

Average Flow (cfs)

Suspended Load (Kg/m3)River

0.063,512Yakima

0.01654,830Snake

0.00375117,480Columbia (Priest Rapids Dam)

568

2366

1188

EstimatedSuspended

Sediment Load (tons/day)

Yakima

Snake

Walla Walla

Columbia

Flow average 117,480 cfs (1188 tons/day)

Columbia

Yakima

Walla WallaFlow average 54,830 cfs

(2,366 tons/day)

Snake

Snake

Columbia

Walla Walla

Flow average 13,512 cfs (568 tons/day)

Yakima

Yakima

Snake

Columbia

Flow average 568 cfs

Walla Walla

McNary Dam currently has approximately 30ft of sediment

▀ Average Annual Deposit Rate is 2 to 7 in/yr

200019901980197019601950

Est. 30 ftSediment}

90 ftWater

Conceptual

Exposure Model

Primary Sources

Medium of Concern

Exposure Point

Potential Exposure Route

Potential Receptors

Rural Residents

Native American

Industrial Worker

Monument Worker

Avid Angler

Casual User

Ecological Receptors

Area 100/300

Sediment Near shore and islands

Ingestion

Dermal Contact

Surface water

River water Ingestion

Dermal Contact

What is a CEM? ▀ Sources ▀ Migration pathways ▀ Receptors ▀ Exposures

Sources of Contaminants to the River

▀ Upriver Sources ▀ Hanford Reach Sources▀ Downriver Sources

Generic Hanford Conceptual Site Model

Historic coolingwater discharge

GW seepsReactors/OperationalAreas

Conceptual Site Model – Cross Section

Cross section illustrates:▀ Sources ▀ Migration pathways ▀ Receptors: people, benthic, fish, etc.▀ Potential Exposure Points

Receptors Source

Cooling water

Columbia River

Site Conceptual Model – Recreational IslandsReceptors Source

Cooling water

Columbia RiverColumbia River

Conceptual Site Model – Richland Area

Agriculture Beach

Industry HouseIndustrial discharge

Water IntakeStructure

Water supplyWater supplyColumbia River

Irrigation discharge

Columbia River

West East

CRC Study Area

Study Area Cross-Section

Hanford Site

100/300 Study Areaand Inter-Area

Green line