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Pumping well on Spiekeroog
A construction site on an island in the heart of the UNESCO World Heritage Wadden Sea – our team constructed a new production well on the car-free island of Spiekeroog, surrounded by picturesque dunes. A challenging project in terms of schedule, technology and logistics, with nature conservation taking top priority throughout.
A project in the UNESCO World Heritage Wadden Sea
We supply our customers with a complete, bespoke production well, despite logistical and technical challenges and a tight schedule. From exploratory drilling through to well construction and the completion structure, including the valve assembly – Hölscher provides everything from a single source.
Services and technologies used
Exploratory borehole & groundwater monitoring well
To investigate the geological and hydrogeological conditions, we used our Rotomax XLB to drill a cored exploration borehole with a diameter of 324 mm to a depth of approximately 40 metres. As the exact depth of the freshwater lens and the salt/freshwater interface are of great importance for the subsequent operation of the well, the borehole was surveyed using geophysical methods.
The borehole was then completed as a DN 125 groundwater monitoring well using special NORIP pipes. In addition, monitoring equipment supplied by the customer was installed to enable continuous monitoring of the salt/freshwater interface during well operation.
Logistical challenges on a car-free island
The drilling rig had to be partially dismantled and transported to the island by ferry. All materials were delivered to the construction site by the island’s logistics provider using small electric carts. Our team travelled around the island on foot or by bicycle, as Spiekeroog is entirely car-free. As a result, every journey and transport operation had to be carefully planned and authorised. For the several-kilometre route to the construction site, the cable excavator travelled over ground-protection mats to avoid damaging the island’s sensitive clinker-paved roads.
Nature conservation comes first
The construction site was located within a strictly protected and highly sensitive dune area between the village and the beach. Under the close supervision of an ecological site inspector, every tuft of grass and each heather plant was carefully removed and stored for later replanting. The works were carried out to a strict schedule. To comply with the conservation requirements of the nature reserve and avoid disturbing the breeding and nesting seasons of the many bird species, all work had to be completed by early March.
Wellhead, valve assembly and wellhead chamber
In the final stage, the wellhead and bespoke stainless-steel valve assembly were installed, followed by the discreet glass-fibre-reinforced wellhead enclosure. The result is a new production well that will help secure the future water supply for both island residents and visitors.
The drilling rig had to be partially dismantled and transported to the island by ferry. The transport of our drilling equipment on the car-free island required individual approval.
Facts and figures
40
The well was drilled to a depth of 40 metres.
300
The well was completed in DN 300.
4
It took four months from the start of the project to the completion of the wellhead structure.
Equipment used
Sennebogen 640
Rotomax XLB
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