river rising north of Luton in the county of Bedfordshire, England. It flows for 46 miles (74 km) east and then south to enter the River Thames (Thames, River) near Bromley-by-Bow, in the London borough of Tower Hamlets. In the 17th century an important aqueduct known as the New River was constructed in the valley of the Lea. Much of the valley has seen considerable industrial development, and many large reservoirs supplying water for London are located in the area. In 1967 a regional park authority was set up to provide recreational opportunities and public access along the natural corridor of the river.