Foudry Brook is a small stream in southern England. It rises from a number of springs near the Hampshire village of Baughurst, and flows to the east and then the north, to join the River Kennet to the south of Reading. The upper section is called Silchester Brook, and beyond that, Bishop's Wood Stream. The underlying geology is chalk, covered by a layer of clay, and so it has the characteristics of a clay stream, experiencing rapid increases in level after heavy rain due to run-off from the surrounding land. It passes a number of listed buildings and scheduled monuments, including the site of the Roman town of Calleva Atrebatum or Silchester. The natural flow of the river is supplemented by treated effluent from two major sewage treatment works, which contribute to the poor quality of the water. Water quality is also affected by physical modification of the channel, which restricts the free movement of fish around the system. Route Foudry Brook rises at springs between the small villages of Heath End and Baughurst, where it is known as Bishop's Wood Stream. It flows eastwards though Tadley, and is briefly culverted under housing on Elmhurst before emerging back on the surface and passing under the A340 Mulfords Hill road. It then enters a much longer culvert under Tadley Bottom, and emerges into open countryside on the east side of Bowmonts Bridge. It crosses the Pamber Forest nature reserve, becoming the Silchester Brook, and turns to the south, where Silchester Sewage Treatment Works is on the right bank. It then passes between two earthworks before Honeymill Brook joins it on the right bank. The linear earthworks were associated with a Late Iron Age town that developed into the Roman town called Calleva or Silchester. They are and long, with a gap of where the river passes through. Honeymill Brook rises at a pond near Browninghill Green, to the south of Baughurst, and at a series of springs to the east of the village near Church Brook Farm. The two sources join near Church Road, Tadley and flow eastwards to Honey Mill Bridge, which carries the A340 Aldermaston Road over the brook. The course of the Port Way Roman road also crosses at this point on the western boundary of Pamber Forest. On the far side of the woodland, it runs parallel to the earthworks and joins Silchester Brook as it turns