A GIS-Enabled Approach for Assessing Damage Potential of Levee Systems Based on Underlying Geology and River Morphology

Table 3

Underlying geology classification for the Sacramento River basin.

Deposit classification	Code	Short description	Geological epoch	Maximum thickness (m)
Alluvial deposits	Qa	Alluvium-unweathered gravel, sand, and silt	Holocene	10
Basin deposits	Qb	Basin deposits, undivided-Fine grained silt and clay	Holocene	60
Alluvial deposits	Qsc	Stream channel deposits of open, active stream channels (morphology constantly changing)	Holocene	25
Alluvial deposits	Qmu	Modesto formation—upper Member—unconsolidated, unweathered mix of gravel, sand, silt and clay	Pleistocene	120
Alluvial deposits	Qml	Modesto formation—lower Member—unconsolidated, slightly weathered gravel, sand, silt, and clay	Pleistocene	120
Alluvial deposits	Qru	Riverbank formation—upper Member—unconsolidated alluvium composed of gravel, sand, and silt	Pleistocene	120
Alluvial deposits	Qrl	Riverbank formation—lower Member—semiconsolidated gravel, sand, and silt	Pleistocene	120
Alluvial deposits	Qsc	Stream channel deposits of open, active stream channels (morphology constantly changing)	Holocene	250