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Cwm Brook

A stream near Rowlestone, County of Herefordshire. No gauge of its own: what the river map and the banked data say about it.

Cwm Brook is a stream on Ordnance Survey’s river map near Rowlestone, County of Herefordshire, with about 4.9 km of mapped channel. On the map it flows into Afon Mynwy (River Monnow), which flows on into Afon Gwy (River Wye), then Afon Hafren (River Severn) and out to the sea.

Next gauge downstream

Grosmont Rhosllwyn River Station on Afon Mynwy (River Monnow), about 5.3 km along the river below where Cwm Brook ends on the map.

0.50 m Normal · steady 15 min ago

After that, Skenfrith River Station, about 15 km along the river.

No gauge measures Cwm Brook itself. A gauge downstream shows water that has already passed it, mixed with everything else that has joined on the way, so it says nothing exact about this stream.

Water-sampling points on Cwm Brook

1 Environment Agency sampling point is placed on this stream. These are dated samples taken by hand, not live readings, and FloodRadar does not grade them.

CWM Brook at Vedw Farm
Last sampled 6 Sep 2024 · 2.1 years ago · 6 samples banked

A sample is taken on a date; it says nothing about the water today. A sample below an overflow does not by itself show where anything in it came from.

Water samples: Environment Agency Water Quality Archive, © Environment Agency and/or database right 2026, Open Government Licence v3.0.

Places along it

From its source towards its mouth, the settlements within a kilometre of it on the map: Rowlestone, Llangua, Monmouth Cap.

On the map

The map needs JavaScript. Everything it shows is listed on this page.

The blue line is Cwm Brook; grey lines are other mapped watercourses. Lines from OS Open Rivers (edition 2026-04).

Afon Mynwy (River Monnow), the river it joins →NP7 8HE, a postcode page near where it ends on the map (about 570 m away) →All rivers with gauges →

What this page can and cannot tell you

Its line, its name and where it flows come from Ordnance Survey’s river map (OS Open Rivers, edition 2026-04), which leaves out many small streams, ditches and culverts. “Flows into” is the map’s word: a channel that is not on the map is not shown here, which does not mean it is not there.
No gauge measures Cwm Brook itself, so its own level is not known here.
No storm overflow is placed on this stream on the river map. That is not the same as none: the map cannot place every overflow.
Water samples are England’s only (the Environment Agency’s archive), placed where the map can place their sampling point.
Nothing on this page says whether any place floods. For an address, see its postcode page.