My Dad sent me this extract from a 1920s book he’s dug up when researching his local river with my old primary school headmaster!
This is the river he was born right next to the source of. Thought you might like it…

Kieran

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The River Alan (in early days Alun or Eilan) has its source some miles farther up near the farm of Llandigige Fach from whence it runs through the Common of Dowrog, past Gwrhyd, through the ‘Vale of Roses; finally emptying into the Creek of Porthclais. The rivulet has been described by Giraldus as being ‘muddy and unproductive’. This description however is wholly erroneous, as its waters besides being clear, are productive in a degree beyond the ordinary. The historian George Owen, speaking of the Alun Trout says, “For bigness, they exceed any in these parts and for tameness against nature, that they were not afeared at the sight of many people looking on them and approaching almost to mens handes, to receave anything that should be cast into the broke for foode”. Manby (1801) further writes “It is remarked for having the best and largest Trout in the Country”. Several good catches are frequently made, despite the fact that poachers practise anything but legitimate means. Trout varying from half a pound to one pound in weight are by no means uncommon, while fish of one and a quarter pounds and even exceeding one and a half pounds have been landed. At Pont Cerwyn Dewi (Davids Brewing Vat), the river divides at this spot – the upper portion supplying the historic ‘Dewiston Mill’ (Felin Isaf) half a mile below.