Virtually all Dutch rivers and water systems are channeled and strengthened by means of groynes and/or breakwaters. As a result, the water column is uniform and shown little variation. Many aquatic organisms benefit from more diverse conditions such as structures in the water. Structues such as sand and gravel banks act as spawning areas for fish and the presence of dead wood provides shelter and habitat for macrofauna and fish.

Recently, there has been more importance put on creating varied habitats within rivers and waterways, which is good news for biodiversity and ecosystem functioning. The Dutch river authority (Rijkswaterstaat) has started restoring woody areas to rivers by anchoring dead trees in suitable channels.

The complex structures of trees and branches are difficult to sample with traditional macrofauna nets. Therefore, we developed the macrozoobenthos suction sampler. With its small suction nozzle, even previously hard to reach locations can now be sampled. The Dutch authorities (Rijkswaterstaat) have even recognised the macrozoobenthos suction sampler as the standard sampling method for these situations.

The device works like a vacuum cleaner. Organisms are effectively sucked into the sampler. Combined with diving and snorkeling, we can sample entire underwater structures. We can also search deep sandy bottoms for the rare yellow-legged dragonfly and European river lamprey.