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Restricted Areas Around Dams

The U.S. Army Corps of Engineers Walla Walla District has implemented restricted waterborne access to hazardous waters immediately upstream and downstream of all Corps-owned locks and dams, flood control dams and multi-purpose dams along the Columbia and Snake River in accordance to ER 1130-2-520, Chapter 10.  

Best described as industrial areas, the hazardous water areas above and below dams in the Walla Walla District pose a high level of risk for the public because of the Hydroelectric, spilling, sluicing and lock operations that are often present or begin with little or no notice.  Turbulent boils and powerful currents are capable of swamping, capsizing, and even trapping boats and people in turbulent waters. Also during instances of emergency boater distress, project employees are not always immediately available to respond.  This places emergency responders and other boaters at risk of a life-threatening situation during rescue attempts.  Lock, hydropower, spilling and sluicing operations are disrupted after and during any emergency response effort.  These incidents have far reaching impacts; the most important of which are families that have to deal with the loss of a loved one.

Life jacket wear has been ineffective in these areas, since all of the victims who drowned wore a life jacket. In order to increase public safety and address physical security issues, the Walla Walla District made the decision to fully implement the existing U.S. Army Corps of Engineers ER 1130-2-520, Chapter 10.

The restricted areas will be the minimum area allowed per Corps regulations upstream and downstream of locks, dams, and power plant facilities.  All forms of water access within the restricted areas are prohibited including boating, swimming and wading. 

Maps:

McNary Lock and Dam

Ice Harbor Lock and Dam

Lower Monumental Lock and Dam

Little Goose Lock and Dam

Lower Granite Lock and Dam

Dworshak Dam Reservoir

Lucky Peak Dam and Lake 

Cheatham Dam Fishing Accident Survivor Shares His Story

Boating Safety Demonstration

Historical Safety Video

Hazardous Conditions Near Dams

There are a number of factors that contribute to hazardous conditions for boaters that travel in close proximity to a dam.  These include multiple sources of water that can be discharged from a dam, the release of large volumes of water that result in the development of strong currents, rapidly changing conditions, the presence of highly turbulent water, and the presence of cold water that could lead to hypothermia and shock.  Any one of these factors can be problematic to boaters, and when experienced in combination can lead to catastrophic results.

· Conditions downstream of dams can be extremely hazardous to boaters due to large amounts of water that can be discharged through a dam. Because a significant increase in the flow of water can occur within a matter of only seconds, resulting turbulent waters and swift currents can capsize boats and render small boats uncontrollable.

· Turbine generation discharges directly below a dam can be extremely dangerous to boaters creating conditions that can capsize or overturn boats. When turbine generation begins, the release of water into the river below the dam can create turbulence and possible undertows. Boils or upwellings caused by the release of water through the turbine can flip boats.  Certain hydropower operations can lead to the sudden release of a large volume of air into the river downstream resulting in reduced buoyancy for boats in these areas.

· Spillway releases from a dam can create undertows, eddies and whirlpools resulting in very dangerous conditions for boaters.  Boats can be drawn into the spillway release and flooded.  While large spillway releases present obvious dangers, even a small release can be deadly.  The power of water should never be underestimated.

· Navigation locks may fill or empty at irregular intervals and the volumes of water involved are considerable.  Lock discharge locations may not be easily discerned and sudden discharges from lock chamber emptying can create turbulent boils and powerful currents capable of swamping a small boat.  In general, lock chambers should be given a wide berth in order to avoid these dangers.

· Sluice releases from dams cause extremely turbulent waters below dams.  Violent, irregular wave actions are common with sluice releases and can swamp or overturn boats.

· On the upstream side of dams, there is a strong undertow created by the flow of water through the gated section of the dam. Boats approaching too closely from the upstream side are in danger of being lodged against the dam or capsized by the undertow.