Mae cam dylunio a datblygu gwerth £3 miliwn y drydedd bont yn rhan o'r gyllideb dros 2 flynedd a gytunwyd gan Lywodraeth Cymru a Plaid Cymru.
The £3m design and development stage of the third crossing is part of the 2-year budget agreed by the Welsh Government and Plaid Cymru.