Assessment of particle deposition and accumulation in newly constructed wetlands receiving agricultural runoff
2015 (English)Manuscript (preprint) (Other academic)
This study analysed variations in sediment deposition and accumulation to improve understanding of retention processes in small wetlands constructed on clay soils. Sediment deposition (in traps) and accumulation (on plates) was measured in four wetlands in east-central Sweden.
Particle deposition generally exceeded (up to eight-fold) the total particle load to the wetlands, especially in the spring-summer period, suggesting that the settled particles in the traps were generated from internal processes. The particles probably originated from erosion of the bottom and sides of the wetlands, or from production of organic material which deposited in the traps.
Particle resuspension was evident in all wetlands and considered an important process. Only 13-23% of the deposited material in the traps remained on the plates in the wetlands. Both particle deposition and accumulation was very low in one wetland receiving high hydraulic load (HL, 400 m yr-1), suggesting that such high-loaded wetlands are not efficient as particle sinks in clay soil areas. In the other wetlands, more than 80% of the total sediment accumulation occurred in the initial parts of the wetlands (which represented the first 20% of the total wetland area), indicating the importance of designing wetlands with an initial wetland section that is easy accessed for sediment removal as maintenance.
The results from this study point to the importance of internal processes and resuspension for annual particle accumulation in constructed wetlands.
Place, publisher, year, edition, pages
Ecology Water Engineering Other Biological Topics
IdentifiersURN: urn:nbn:se:liu:diva-117970OAI: oai:DiVA.org:liu-117970DiVA: diva2:812523