"I read of chalk streams"
River Pang
Creative Commons Attribution Share AlikeRiver Pang - Credit: Shaun Ferguson

The term chalk stream refers to any river, small or large, which flows over a bed of chalk (soft white limestone). Such rivers have very specific characteristics, including exceptional water clarity and consistent temperatures. As a result, they support a wide variety of fish, including brown trout and Atlantic salmon, and are prized by the fly-fishing community.

Chalk stream springs have traditionally been the site of watercress production as they have clean, mineral-rich water at a constant temperature.

Examples of English chalk streams are the River Kennet which rises in Wiltshire, and the River Pang which rises in Berkshire. They areĀ  both tributaries of the Thames.