Lincolnshire, I am told, has a location problem. Despite being England’s second-biggest county, it remains somehow tucked away, hidden between the Humber and the Wash. “So there’s no reason to pass through,” Helen Gamble laments as she leads me from Bag Enderby’s church into freshly spring-sprung hills. As Lincolnshire Wolds Countryside Service project officer, one part of Helen’s role is raising awareness of this overlooked landscape. “It’s as good as Yorkshire,” she claims, “but without the tourists.”

When most people think of Lincolnshire, if they think of it at all, they think: flat. And true, the southern fenlands are steadfastly non-undulating. But the northerly Wolds are the highest ground in eastern England between Kent and Yorkshire itself. Here, farmland, woods, chalk streams, rock seams and pretty little villages fold, rise and ripple. Recognised as nationally important, the Lincolnshire Wolds were designated an area of outstanding natural beauty in 1973, so this year celebrates the 50th anniversary. Which is keeping Helen busy indeed.

To celebrate the golden jubilee, she came up with the idea of a “50 for 50” series of events, which began in April and runs until December. It has taken a lot of organising but promises to showcase all aspects of the Wolds landscape – to everyone.

Today, Helen is giving me a sneak preview of a walk scheduled for September, a five-mile stroll in Tennyson country, amid the scenes that inspired the Victorian poet. But the 50 events aren’t all walks. “I wanted the programme to be accessible, physically and financially,” says Helen. That’s why there’s a mix of everything from walks to talks, farm visits, bee bimbles, cross-country wheelchair try-outs, hedge-laying sessions and star-gazing nights. And that’s why it’s virtually all free. “Most events don’t require booking and don’t cost anything,” she says. Instead, participants are encouraged to make donations to the Lincs & Notts Air Ambulance.

Helen and I make a loop via the sleepy hamlet of Bag Enderby and Somersby village. Tennyson’s father was rector of both churches, and Alfred was born in Somersby rectory in 1809. At St Margaret’s, Somersby, we see the poet’s bust, his father’s grave and an array of Tennyson mugs and keyrings for sale. We edge around Holywell Wood, where he used to compose poems. And we cross a bridge over the River Lymn, the gentle trickle that sparked Tennyson’s much-loved poem, The Brook. “When we get to this point on the official event, we’ll stop and recite it,” Helen says.

That poem ends with the lines: “For men may come and men may go / But I go on for ever”. The brook outlives us all, concluded Tennyson when he wrote it in 1886. However, with many of our waterways in a perilous state, that’s no longer a given. England has about 85% of the world’s chalk streams, and the Lincolnshire Chalk Streams Project works to protect or restore these rare, vulnerable habitats. So for my next taster of the 50 for 50 programme I join project officers Will Bartle and Ruth Craig in the steep-sided Hubbard’s Hills valley for a bit of messing about in rivers.

It’s easy to spot them: standing amid the noisy bird-twitter, wearing wellies and wielding clipboards, they stare intently at the River Lud’s bottom. They’ve marked out a 10-metre stretch and are assessing every aspect of it on their complicated-looking forms, from the surrounding foliage to the speed of the flow.

Collecting detailed information is vital for the project. “We can compare data before and after we’ve made improvements to see how a river has changed,” Ruth explains. To help do this, they enlist volunteers and hold events, including several for this year’s celebrations. People can get hands-on with restoration, explore usually off-limits areas and learn about the importance of chalk streams for biodiversity, water quality and flood management.

I have a go, which involves wading into the river, placing a large net in the water facing upstream and kicking the bed in front of it for three minutes, hopefully churning up a good cross-section of local aquatic life. “Even from a brief moment of kick sampling, there’s quite a lot in there,” Will says as we peer at the spoils in the white tray. “We’re looking for diversity and amount. Species like freshwater shrimp, mayflies, cased caddis, signal crayfish.”

It’s like gazing into a whole other galaxy, all these small but perfectly formed invertebrates darting and dallying, wriggling strange bodies and searching antennae – aliens in miniature. Thanks to volunteers doing repeated counts of trays like these, estimating species’ abundance, Will and Ruth can determine whether numbers are dropping and whether there are problems. As Will says: “It’s about engaging with communities to help people take ownership of their local chalk streams.”

It has been a busy day, but I have one last facet of the Wolds to discover. The area, settled since prehistoric times, is acned with lost medieval villages. There are events in the 50th programme that will explore them; I manage a preview by checking in for a stay at Brackenborough Hall Coach House. On the eastern edge of the Wolds, this ancient farming estate has characterful apartments, fields of wheat and beans, a herd of cows and one of the best-preserved abandoned settlements – reduced to grassy bumps these days, but exceptionally well defined. Owner Paul Bennett walks me through the “village”, down the grid of sunken streets and on to one of the tofts, the raised plots on which tenants built their homes. Records show that, in 1332, 28 taxpayers lived here. But the Black Death and a breakdown in old farming systems led to its gradual decline. “Lincolnshire was once the most densely populated county,” Paul tells me as we stand in this abandoned piece of history, looking to Louth on the near-horizon, buffeted by the North Sea wind. “Now it’s the opposite.”

Lincolnshire may be “empty” now – and “on the way to nowhere” – but even from a short stay, it’s obviously there are far more than 50 stories to unearth.

Brackenborough Hall Coach House has three self-catering apartments (sleeping four to 12) from £270 for three nights. For Lincolnshire Wolds AONB 50 for 50 listings, see lincswolds.org.uk. Further information: lincolnshirechalkstreams.org and destinationlincolnshire.co.uk