Navigable rivers, locks, and dams

Orientation only. Verify current rules with the managing agency before launching. See Waterway Rules hub for jurisdiction overview.

• A navigable waterway carries federal authority regardless of the surrounding land ownership. If a river is navigable in the traditional legal sense (used or capable of use in interstate commerce), the federal government has jurisdiction over navigation. The USCG has authority there, COLREGs and Inland Rules apply, and the Army Corps of Engineers has permit authority over structures and work in those waters.
• State boating laws still apply on navigable rivers. Federal authority does not displace state boating law on navigable rivers within a state's borders. Registration, PFD requirements, speed restrictions, and state no-wake rules all apply simultaneously with federal navigation rules. The layers stack; they don't cancel each other out.
• The public has the right of navigation on navigable waterways. Even where the riverbed is privately owned, the public has the right to navigate the channel. This is a longstanding principle of federal law; access to the water itself cannot be blocked by a private landowner on a navigable river. However, access to the banks and adjacent land is a separate question governed by state law and property rights.

• Navigable-in-law rivers: federal jurisdiction for navigation. USCG authority, COLREGs/Inland Rules, and Corps permit authority all apply regardless of surrounding land ownership.
• State boating law (registration, PFDs, speed, wake) still applies on navigable rivers within state borders; layers stack, don't cancel.
• Public right of navigation: passage through the channel is protected even where riverbed is privately owned. Bank access is a separate state-law question.

• Recreational vessels generally have lockage rights but commercial traffic has priority. At river locks operated by the Army Corps of Engineers, commercial vessels (towboats, barge tows, and vessels of commerce) have priority over recreational craft. You may wait significantly at a lock while commercial traffic processes. This is not a malfunction or a courtesy failure; it is how locks operate by law.
• Signal for lockage using the proper procedure. At most Army Corps locks, recreational boaters signal for lockage by sounding one long blast followed by one short blast on a horn, or by using the VHF radio on Channel 16 or the lock's working channel (posted at the approach). Wait for the lockmaster's signal before approaching the lock gates. Do not approach the lock until you receive a positive signal to enter.
• Follow the lockmaster's instructions exactly. Once inside the lock chamber, follow the lockmaster's directions for where to tie up or hold. Most recreational boaters use a lock wall rope or a floating bollard; you hold the bow and stern lines manually as the chamber fills or empties. The current in a filling lock can be significant. Keep a light but steady grip: don't let the boat bang against the wall, but don't wrap lines around your hand.
• Maintain a safe distance from lock gates at all times. Current near open lock gates can be powerful and unpredictable. Stay well back from closed gates on approach. Never touch or push against lock gate hardware.

• Commercial traffic has priority at Army Corps locks. Wait for lockmaster's clearance; recreational queue can be long during peak commercial traffic.
• Signal for lockage: one long + one short blast on horn, or VHF Ch 16 / posted working channel. Do not approach gates until positive lockmaster signal.
• Inside lock chamber: follow lockmaster instructions for tie-up position. Manual hold on lock wall rope or floating bollard. Don't wrap lines around hands. Filling current can be significant.
• Maintain safe distance from gates at all times. Never touch lock gate hardware.

• Exclusion zones around dams are strictly enforced on federally managed rivers. Buoys and signs mark the upstream exclusion zone; you must remain outside this zone at all times. The zone is upstream of the dam face, not at it. Current accelerates toward the intake grates and spillways well before the structure is visible. A boat that enters the exclusion zone has little time to reverse course under power.
• Lowhead dams are among the most dangerous structures on inland rivers. A lowhead dam (a low, broad dam that allows water to spill evenly across the full width) creates a recirculating hydraulic below the spillway called a "hydraulic" or "hole." Water flowing over the dam recirculates back upstream at the base, forming a powerful, continuously cycling current that traps and holds boats, kayaks, and swimmers. Lowhead dams are often not visible until you're too close to avoid them. Portage around lowhead dams. Never run them.
• Identify lowhead dams before your trip on any unfamiliar river. USGS topographic maps, National Inventory of Dams (NID) data, and local paddling clubs all publish locations of lowhead dams on commonly used rivers. The "perfectly smooth horizon line" across a river is the classic warning sign of a lowhead dam ahead. If you see or hear a horizon line on a moving river: stop, get to shore, and portage.

• Federal dam exclusion zones: buoy-marked upstream of the dam face. Current accelerates into intakes/spillways well before the visible structure. Do not enter.
• Lowhead dam hydraulic (recirculating hole): continuous recirculating current at the base of the spillway; holds boats, kayaks, and swimmers. Portage around. Never run a lowhead dam.
• Pre-trip planning: USGS topo maps, National Inventory of Dams (NID), and local paddling clubs for dam locations on unfamiliar rivers. Horizon line across a moving river = stop and scout.

• River current affects everything about how a boat handles. Powerboats operating upriver against a strong current need more throttle to maintain steerage. Going downriver with the current, a small reduction in throttle can result in loss of steering. Always account for current direction and speed when maneuvering near docks, other vessels, or fixed structures.
• Strainers are fixed objects that allow water through but trap larger items. A strainer is any object that lets current pass through but stops a boat or person: bridge pilings, downed trees partially submerged in the channel, rocky formations. Strainers kill paddlers and small boat operators every season. On a fast river, being pinned against a strainer by current is nearly impossible to escape without outside assistance. Scout the river ahead and maintain enough distance to maneuver clear.
• Flood stage dramatically changes the character of a river. A river at or above flood stage has unpredictable currents, debris in the water (logs, fuel tanks, fencing, large limbs), and submerged hazards that are normally on the bank. River channels migrate during floods. Operating a recreational vessel at flood stage is a serious risk even for experienced boaters. Check river gauge levels through USGS WaterNow or NOAA before launching on any river after significant rain.

• Current direction and speed affect steerage in both directions. Account for current when maneuvering near docks and structures; upriver requires more throttle, downriver requires less before losing steerage.
• Strainers: bridge pilings, submerged logs, rocky formations. Allow current through but trap boats and people. Maintain maneuvering distance. Scout unfamiliar channels before committing.
• Flood stage: unpredictable currents, floating debris, submerged bank hazards, shifting channel. Check USGS WaterNow or NOAA river gauge before launching after rain. Avoid rivers at or above flood stage.

• Rivers are primary transmission vectors for invasive species. Connected river systems allow invasive species to spread rapidly between water bodies. A vessel that has been on the Mississippi River system, any tributary connected to it, or the Columbia River system carries a different contamination risk profile than one used only on isolated lakes. Asian carp, zebra and quagga mussels, and invasive aquatic plants all spread along river corridors.
• State inspection requirements apply on navigable rivers within state borders. Even though a river may be under federal navigation jurisdiction, state invasive species law applies on waters within the state's borders. If your state requires Clean-Drain-Dry or a formal inspection, that requirement applies on navigable rivers as well as state lakes. Requirements can change at state boundaries on rivers that cross state lines.
• USCG and Army Corps do not operate invasive species inspection stations on rivers. River invasive species programs are state-managed. Check your state's fish and wildlife or natural resources agency for the specific rivers where inspection or decontamination requirements are in effect. For multi-state rivers, check each state's rules for the segment you'll be on.
• Drain all water systems before moving between river segments or water bodies. Live wells, bait wells, bilge, and any onboard water storage should be drained and dried when transporting a vessel between water bodies. This applies even when moving between arms of the same river system; different segments may have different invasive species present.

• Rivers as transmission vectors: connected systems (Mississippi, Columbia basins) carry high spread risk. Contamination risk profile differs from isolated lakes. Treat all connected systems as potentially infested.
• State AIS law applies on navigable rivers within state borders despite federal navigation jurisdiction. Requirements change at state boundaries on multi-state rivers.
• USCG and Corps don't operate river inspection stations; programs are state-managed. Check each state's requirements for the segment you'll be on.
• Drain live wells, bait wells, bilge, and ballast before transport between river segments or water bodies.

• USGS NWIS Real-Time Data (waterdata.usgs.gov): River gauge heights, flow rates, and flood stage thresholds, pre-launch safety check for any river trip
• Army Corps Lock Status (ndc.ops.usace.army.mil): Lock operating status, closures, and navigation conditions on Corps-operated river systems
• National Inventory of Dams (nid.sec.usace.army.mil): 90,000+ dams mapped. Use to identify lowhead dams and other structures on any unfamiliar river reach