Grwyne Fawr facts for kids
The Grwyne Fawr is a river in south Wales. It flows through the beautiful Brecon Beacons National Park. Part of this river forms a border. It separates areas like Powys and Monmouthshire. The Grwyne Fawr has a main smaller river that joins it. This is called the Grwyne Fechan. Both rivers eventually flow into the River Usk. They meet the Usk near a place called Glangrwyney.
The name Grwyne Fawr comes from old Welsh words. It probably means 'large river at the wet place'. This makes sense for a river in a green, often rainy, part of Wales!
Where the River Flows
The Grwyne Fawr starts high up in the Black Mountains. It begins on the southern slopes of a mountain called Rhos Dirion. From there, it flows mostly towards the southeast.
Along its path, the river's flow is slowed down. This happens because of the Grwyne Fawr Reservoir. This reservoir is the only large body of water in these hills. Below the reservoir, the valley sides are covered by Mynydd Du Forest. This forest is made up of many trees.
A public road goes into the valley. But the area around the river is very quiet. Not many people live there. The valley starts to look more like farmland closer to the small village of Partrishow. The river then turns west. It follows a natural weak spot in the ground. This spot is known as the Neath Disturbance.
The Grwyne Fechan
To the west, the Grwyne Fechan river flows. It runs in a similar direction to the Grwyne Fawr. The Grwyne Fechan starts on the southern slopes of Waun Fach. It collects water from many smaller streams. These streams flow from the wide ridge between it and the Grwyne Fawr.
The Grwyne Fechan valley has many conifer tree farms. But it feels more open than the Grwyne Fawr valley.
Joining Up
The two rivers, Grwyne Fawr and Grwyne Fechan, meet near the village of Llanbedr. From there, they continue south as the Grwyne Fawr. They pass through the small village of Llangenny. Finally, they join the larger River Usk at Glangrwyney.
River Rocks and Land
Both the Grwyne Fawr and Grwyne Fechan rivers flow through the Old Red Sandstone hills. These hills are part of the Black Mountains. The rocks here are called Brownstones and Senni Formations. They formed a very long time ago. This was during the Devonian period.
You can often see these rocks in the riverbeds. They are also sometimes visible on the steep sides of the valleys. These rocks are made of sandstone and mudstone. The lower parts of the river flow through an area covered in glacial till. This is a type of soil and rock left behind. It was left by glaciers during the last ice age.
A Bit of History
The valley of the Grwyne Fawr has a long history. In the year 1136, something important happened here. A Norman lord named Richard de Clare, 1st Earl of Hereford was killed. He was a powerful leader from Normandy. He was killed by Welsh fighters. These fighters were led by Iorwerth ab Owain and his brother Morgan. They were grandsons of Caradog ap Gruffydd.
This event led to a time of fighting. There was conflict between the Welsh and English people. This fighting happened in south Wales.
