For the development of these sites to occur, significant infrastructure investment is required before making them available for development in the medium to long term.
Er mwyn i'r gwaith o ddatblygu'r safleoedd hyn fynd rhagddo, mae angen cryn fuddsoddi mewn seilwaith cyn eu gwneud ar gael i'w datblygu yn y tymor canolig i'r hirdymor.