The main sources of water were Free Mosedale Beck (now known as Sticks Gill East), which ran through the upper valley beneath Green Side, and then became Swart Beck as it ran more steeply down to the lower valley of Glenridding. Glenridding Beck was the other source, fed by Red Tarn, Brown Cove and Keppelcove Tarn. Over the years a series of reservoirs were created to regulate the flow of water in these becks.