Naturpark Nordals: A Protected Landscape Defined by Glacial History and Fjord Restoration

The deeper history of Naturpark Nordals begins at the end of the last Ice Age, when the retreating Young Baltic Glacier left behind the ridges, basins, and tunnel valleys that still define the island of Als. The glacial shaping of the terrain around 18,000 years ago created the long east-west lowlands that would later become the park's corridors of lakes, marshes, and fjord arms.

Following deglaciation, marine incursion flooded these valleys, producing a fjord landscape similar in form to today's North Als coast. Beginning in the medieval period and culminating around the end of the 15th century, the inner sections of the fjord were progressively cut off from the open sea and diked into enclosed freshwater lakes. This transformation altered hydrology, shoreline, and land use, converting former marine inlets into the lake system around Bundsø, Mjels Sø, Farresdam, Dyvig, Oldenor, and Nordborg Sø.

A modern chapter opened with the expansion of Danish nature park policy. Local stakeholders and Sønderborg Municipality developed the idea for a nature park covering northern Als, and on 16 December 2020 Naturpark Nordals was formally approved as one of Denmark's official nature parks. The designation built on existing protected areas along the lakes and coast, alongside the larger effort to restore former fjord sections through the recreation of Mjels Sø and Bundsø, framing the park as an integrated project of landscape memory, ecological restoration, and rural identity.

The landscape of Naturpark Nordals is dominated by a hilly, glacially shaped terrain that drops into two long, low-lying valley corridors. Small knolls and ridges of glacial till contrast with deep former meltwater channels, producing a varied topography within a relatively small coastal setting. The overall impression is one of an undulating agricultural landscape interlaced with elongated lakes, ponds, and wetland basins.

The western valley runs inland from Stegsvig along a chain of basins and inlets: Stegsvig itself, Farresdam, Dyvig, Oldenor, Mjelsvig, and then the inland lakes Mjels Sø and Bundsø. The eastern valley is anchored by Nordborg Sø and extends westward along Nordborg Bæk. These two valley corridors are linked by a smaller north-south meltwater channel passing Gammeldam, continuing under the Nordborg road and past Luffes Plads toward Nordborg Slot.

The coast itself forms an important third element of the park's landscape character. Where the glacial valleys meet the sea, the result is a fringe of sheltered inlets, embayments, and shoreline transitions that blend marine influence with freshwater lakes and terrestrial habitats inland. The combination of reclaimed former fjord basins, active coastal edges, and glacial uplands gives the park its layered, transitional feel: simultaneously coastal, lacustrine, and terrestrial.

The ecological identity of Naturpark Nordals is built around the interface between water and land. Within the park's roughly 1,008 hectares of registered natural area, the most prominent habitats are the lake and former fjord systems of Nordborg Sø, Bundsø, Mjels Sø, and the connected basins, along with their fringing wetlands.

The shoreline zones, lake margins, and scattered inland patches classified as section 3 protected natural habitat form the core of the park's biodiversity value. Soft transitions between open water, reedbeds, wet meadows, grazed shoreline, scrub, and woodland create a habitat mosaic that supports aquatic, wetland, and terrestrial species in close proximity. The park also contains small remnant patches of more terrestrial habitats, including hedgerows, woodland fragments, and rough vegetation on slopes and field margins, embedded in a working agricultural matrix.

Sønderborg Municipality has undertaken comprehensive habitat surveys inside the park, recording both section 3 protected natural areas and neighboring natural areas with high ecological value. This dual mapping of strict protection status and broader ecological quality has shaped the park's conservation planning and reflects an approach that integrates protected habitat networks with the surrounding farmland.

The wildlife character of Naturpark Nordals is closely tied to its lake, wetland, and coastal habitats. Open water surfaces and fringing reedbeds provide feeding and resting environments for waterbirds, while the surrounding mosaic of meadows, scrub, and small woodland fragments supports a varied community of farmland, woodland, and edge species.

The recovery of Mjels Sø and Bundsø has been particularly important for the park's wildlife profile, as the return of larger freshwater bodies has expanded the spatial extent and quality of aquatic and shoreline habitat. The combination of restored lake basins, intact protected shoreline, and historic water bodies such as Nordborg Sø gives the park a continuous chain of wetland environments that benefit species associated with calm, sheltered, nutrient-rich inland waters.

Inland, the park's mixed agricultural and natural land mosaic also supports more typical countryside species associated with hedgerows, field margins, woodland patches, and small inland water features. While the park is not characterized by large charismatic mammal populations, its ecological value lies in the connectivity and diversity of smaller habitats across a compact coastal setting.

Naturpark Nordals represents a deliberate conservation framework that links landscape-scale restoration, statutory habitat protection, and regional identity. Although much of the park remains productive agricultural land, the protected natural areas within its boundaries form a meaningful ecological backbone. Section 3 protected natural habitats line the lakes and coast and appear in additional small patches inland, creating a dispersed but ecologically significant network.

The park's conservation strategy places particular weight on water and wetland recovery. The recreation of Mjels Sø and Bundsø is explicitly framed as ecological restoration, returning substantial stretches of former fjord basin to open water and shoreline habitat after centuries of reclamation. This restoration reconnects the western valley corridor with its earlier hydrological and ecological character and strengthens the park's functional value for aquatic and water-associated species.

Sønderborg Municipality's habitat surveys have mapped both formally protected natural areas and adjacent zones with high ecological value, integrating the strict protected-area layer with the broader landscape context. This combination makes Naturpark Nordals a notable example of a Danish nature park that operates as both a regional identity project and a coordinated conservation platform, balancing agriculture, settlement, and natural habitat rehabilitation.

Naturpark Nordals is inseparable from the cultural and historical fabric of northern Als. Nordborg Slot, which gives its name to the eastern lake and the surrounding town, anchors the landscape in centuries of Danish aristocratic and regional history. The castle and its associated estate have long influenced settlement patterns, land ownership, and the visual character of the park's eastern corridor.

The park also preserves a layered history of human transformation of the landscape. The 15th-century severance of the inner fjord arms from the sea was a major cultural and economic event, reflecting the growing importance of agriculture, freshwater management, and inland settlement. Hedgerows, estate landscapes, old roads, and small village cores scattered across the park continue to reflect this long history of land shaping.

As a designated nature park, Naturpark Nordals also plays a contemporary cultural role, providing a regional platform for outdoor recreation, environmental education, and local identity. Its status as one of Denmark's officially approved nature parks ties the island's historic landscapes to a national framework of nature park planning, giving northern Als a recognized place within the broader Danish system of protected landscapes.

Two large east-west glacial tunnel valleys, now expressed as long chains of lakes and former fjord arms, define the spine of the park and provide its strongest sense of landscape identity. The restoration of Mjels Sø and Bundsø, reviving a fjord landscape lost since the late 15th century, is a defining conservation achievement and a key reason the park was established.

The juxtaposition of protected shoreline habitats along lakes and coast with surrounding agricultural land gives the park a distinctive character as a working coastal countryside rather than a remote wilderness. Combined with the cultural anchoring provided by Nordborg Slot, the historic lake of Nordborg Sø, and the surrounding settlement landscape, Naturpark Nordals offers a layered experience of glacial geology, hydrological history, and contemporary Danish rural life.

Naturpark Nordals has a mild, temperate Danish coastal climate, and its landscape character shifts gradually across the seasons rather than dramatically between them. Late spring and summer generally offer the richest experience for visitors interested in the full habitat palette, with active vegetation along lake margins, accessible trails, and at their most expressive, the reedbeds, meadows, and small woodland patches typical of the park.

Autumn brings softer light across the lake surfaces and an active birdlife along the shoreline as waterbirds use the park's basins. Winter scenes emphasize the park's glacial skeleton: exposed ridges, calm frozen or open water surfaces, and stark contrasts between agricultural land and lake margins. For visitors focused on the restored fjord landscape of Mjels Sø and Bundsø, late spring through early autumn typically provides the most rewarding conditions for observing both water and shoreline habitats together.