"The council were, and remain, extremely disappointed at the decision of the Planning Inspectorate... and have submitted a robust legal challenge."
The disruption to Affinity Water's road works is likely to delay long-awaited resurfacing of the A1250.
Councillor Linda Haysey, leader of East Herts Council, said: "It is fantastic that Three Rivers have now signed the memorandum of understanding."
This year's funding includes £8m for local roads, as the latest part of a five-year, £37m programme targeted on those smaller routes.
East Herts Council is clearing the way for construction of a six-storey, 546-space car park at Northgate End.
Councillors were critical of the SAWB4 development by Countryside Properties planned for Kecksy’s Farm.
Trustees want to knock down their building and a garage on the corner of London Road and Twyford Road and replace it with a nursery and day centre.
Bishop's Stortford Town Council, Chantry Community Association, East Herts district councillors and Herts highways are all opposed.
The partners at the Bishop's Stortford town centre practice have drawn up proposals for a state-of-the-art block.
The Uttlesford hub handled 1.9m passengers in January, 30,000 fewer than the same month in 2019 – a seventh consecutive month of decline.
The Twyford Road church has asked East Herts Council for planning permission to convert a redundant storage unit.