The Nant Dowlais - a tributary of the River Ely outside Cardiff – is currently failing to achieve ‘good’ status under the water framework because of phosphate and a lack of fish.
Ar hyn o bryd mae Nant Dowlais - un o lednentydd Afon Elái y tu allan i Gaerdydd - yn methu â chyflawni statws 'da' o dan y fframwaith dŵr oherwydd ffosffad a diffyg pysgod.