The challenge: Overcoming excessive nutrient levels

摘要

Rising in chalk hills to the east of the village of Tit-tleshall, the Nar river flows South for 2.5km until it reaches Mileham, then predominately west for 39.5km through Litcham, Castle Acre, West Acre and Narborough until it reaches the tidal Ouse at King's Lynn. The river rises on chalk and in its course to Narborough flows over chalk formations. In its lower course the underlying geology is more complex and consists of a progression from Narborough downstream through a series of clays and greensands, making it one of only a few remaining fenland chalk streams.