The new Water and Environment Management Frameworks will use fewer firms with just six contractors expected to sit on the national panel of companies carrying out fresh water and coastal protection work.
The agency said the new set up would help it achieve greater focus on outcome and performance specifications.
While using fewer main contractors, the agency has also pledged to retain access to small and medium sized companies who deliver specialist services.
Its procurement shake-up mirrors that of the Defence Infrastructure Organisation and is expected to see the use of project bank accounts to secure supply chain payments.
Spending through the four WEM Frameworks is forecast to run at £150-£220m a year, depending on government and other funding sources.
New contracts will be introduced from April 2013 that will run for four to six years delivering local projects across England and Wales
The asset delivery partner contractors will be worth up to £750m in total. It will cover inland and coastal flood defence work, water resources, river restoration, habitat creation and mechanical, electrical, instrumentation control.
The agency’s other Water and Environment Management Frameworks includes opportunities for firms offering modelling, mapping and data services, worth £48m; a separate environmental services panel of up to 10 firms covering £30m of fee work and up to six engineering consultancy carrying out fee work worth £180m.