🔍 Key Concepts

• Aids to Navigation on the Western Rivers (U.S. Aids to Navigation System) • How river miles (AHP – Above Head of Passes) are used on the Mississippi River • Color and shape conventions for lateral daymarks on the Western Rivers (upbound vs. downbound)

💭 Think About

• Think about whether you are considered upbound or downbound when you are at mile 385.2 AHP on the Mississippi River and how that affects which side of the river red or green aids are on. • Recall which shapes (square vs. diamond) are normally used with red vs. green lateral daymarks in the Western Rivers system. • Ask yourself: At a fixed lighted aid like Old Levee Light, would the charted aid normally be a federal lateral mark with a standard dayboard, or something like a private aid with no daymark at all?

✅ Before You Answer

• Verify on a river chart or Light List which side of the channel Old Levee Light is on for upbound traffic at that river mile. • Confirm from your notes which color and shape pairing matches that side of the channel on the Western Rivers (e.g., red/right/returning versus green/left). • Make sure you distinguish between a federal aid (with standard daymark shapes) and a private aid, which might not follow the same pattern.