18. WATER CANNONS Description: A water cannon is a high-pressure pump system designed to propel a high- or low-velocity jet or spray of water at an individual or group of people. Water cannons are often mounted on armoured public order vehicles, but they can also be free-standing, building-mounted (for example at a checkpoint), or as mobile, “backpack” style devices. Intended purpose: Water cannons can be used to keep crowds at a distance, to assist in their dispersal and to support police cordons.122 The pressure of the water jet can be varied from low pressure (designed to soak, deter or demoralize), to high pressure, which can cause blunt trauma or knock a person to the ground. Many water cannon systems can propel a narrow, focussed jet, targeting an individual, but there is a high risk of also affecting others when the targeted person is in close proximity to them, such as in a public assembly. Substances are sometimes added to the water jet. These include chemical irritants (e.g., CS tear gas), malodourants and marker dye (for the later identification of people). Possible health and/or human rights implications of use in policing assemblies: In the context of a public gathering, any use of water cannons will likely affect multiple people, rather than just the targeted individuals, creating a high likelihood of cross contamination or affecting innocent bystanders. Even when targeting a person or group engaged in criminal activity, there is a risk of causing them disproportionate harm. 122 United Kingdom College of Policing, “Public Order: Tactical Options”, United Kingdom College of Policing website <https://www.app.college.police.uk/app-content/public-order/planning-and-deployment/ tactical-options/#water-cannon>.