Types of Dams

Low head weir



Image - Types of Dams - Low Head Weir

(Photo: Courtesy of Toronto Region Conservation Authority)


A concrete or wooden wall type dam designed to hold back water to a specific elevation and allow additional water to spill over the weir. While this type of dam appears tranquil and serene, it poses many potential dangers. Persons falling on the slippery concrete can injure themselves, and the speed of the flowing water could easily carry away a small child or pet. The most serious danger however is posed by backwash current below the dam, often described as a 'drowning machine'. A person or pet caught in this revolving current would have great difficulty escaping, with drowning being the result.



Stop log dam


Image - Types of Dams - Stop Log dam


This type of dam has stop logs in a sluice gate that adjust or regulate the amount of water flowing through the dam. The number of gates in the dam may vary depending on the volume of water the dam is expected to pass. Note the boom and sign to warn people of dangers.



Hydro-electric power dam


Image - Types of Dams - Hydro-electric power dam

(Photo: Courtesy of Ontario Power Generation)


The Seymour Generating Station located on the Trent River near Campbellford. This type of dam is designed to generate electricity. Note the signs, boom, and fencing around the dams and powerhouse to protect the public from dangers associated with the dam.


Marine lock


Image - Types of Dams - Marine lock


Marine lock and dam constructed to regulate water levels and allow boats to navigate between lakes of different elevations. Booms, signs and dedicated walkways are in place to warn and protect the public.



Hydraulic wave of the 'drowning machine'


Image - Types of Dams - Hydraulic wave of the Drowning machine


This hydraulic circulating wave is often called a ‘drowning machine’ due to the force of water that can hold a person underwater long enough to possibly result in drowning. These hydraulic waves are frequently found below small weir dams.