Groundworks have been taking place at RSPB Frampton Marsh in preparation for the modular building that is to be attached to the current visitor centre.
The structure will house a new café, capable of seating up to 50 people and serving a range of snacks and light meals.
In addition, a new toilet, one with 24-hour access, is to be added to the site as part of the project.
The investment is based on feedback gained during a public consultation.
Dr Chris Andrews, visitor experience manager, said: “We have always listened to what our visitors have told us, and strived to make Frampton Marsh a great place to visit – both for nature lovers, and for those who just fancy a breath of fresh air. Two of the most common recurring comments we heard were that it would be good to have more food available, so people could have a light lunch with us, and that it would be good to have toilet facilities that were available outside the usual visitor centre opening hours. This redevelopment project will deliver both of those.”
The current visitor centre has been in place since 2009.
The foundations are now in place for the upgraded model. The next step in the process will be the installation of the modules that will form the extension.
"There will be some disruption to the site whilst the work is going on, but we do intend to stay open for business as much as possible,” Dr Andrews said.
It is hoped that the re-vamped centre will launch in the autumn.
Speaking of the hoped-for impact of the new facilities, Dr Andrews said: “With the improved facilities this investment will deliver, we hope to make Frampton Marsh a better place for people to visit, both from across the country and from the local area.
"The income generated by the café will also be very important in our work continuing to maintain and improve the reserve for the fantastic Lincolnshire wildlife. From wintering flocks of thousands of ducks, to rare breeding birds, and not forgetting our resident otters and water voles, Frampton Marsh is a special place that deserves care.”