Rising from tiny headwaters in Lower Bodham and Baconsthorpe, the main river begins just below Selbrigg Pond where three streams combine at the outfall. The Glaven then winds its way through one of the most beautiful valleys in England for 17km (10.5 miles) before discharging into Blakeney Harbour at Cley. Mostly gently flowing, it falls just 50 metres from source to sea.
The Glaven’s sub-surface geology is predominantly chalk and in parts of the lower valley the river runs over chalk beds. Chalk is permeable and acts as a sponge: absorbing rainfall, filtering the water and releasing it though springs and fissures. This means that the Glaven has a constant supply of clean, mineral-rich water, and is not naturally prone to the floods and droughts associated with less permeable bedrocks and steeper river valleys. The chalk extends from eastern England to Normandy, but is found nowhere else in the world, making Norfolk’s ‘chalk rivers’ unique.
Although relatively clean and healthy, the Glaven is affected by nutrient enrichment from treated sewage and especially by the run-off of silt from fields and roads; after heavy rain it can be very cloudy.
At the time of the Domesday Book the River Glaven had 19 watermills. Today there are six and you may notice that the river can be very low and then soon after very high again; this is due to the operation of Letheringsett mill, the only working watermill in Norfolk.
The River Glaven attracts a wide variety of wildlife, but both luck and patiance are required to see some of the more exciting creatures. Otters, for example, are regular visitors, but mostly pass through at night (although some visitors do see Otters, often at close range, during the day). We regularly site an automatic ‘trail-cam’ along the river, and our Glaven-cam takes pictures of whatever passes, sometimes with unexpected results.