Sediment transport and water quality in Máchovo Lake (Czech Republic)

摘要

Máchovo Lake is a historical reservoir founded by Czech King Charles IV. in 14th century. Located in northern part of central Bohemia it has been widely used for recreation purposes for many decades (or even centuries). Its catchments (ca 100 sq km) consist of intensively used agricultural land (ca 25% of area) and of large forested area under nature protection. Several other lakes (ponds) are chained on the two reservoir's inlets. Irrespective of its great recreation potential Máchovo Lake is one of the Bohemian lakes known for its problems with eutrophication and water quality. The project was set up to point out sources of nutrients and to search for proper solutions. Sediment loads in every lake within the catchments were measured and sampled in order to quantify the nutrients and other pollution. Point and non point sources of phosphorus and other nutrients were searched. Sediment transport within catchments was modelled using WaTEM/SEDEM model. Interestingly, the water quality in the particular ponds varies significantly even though each one of several hundred years old ponds is heavily silted. Soil erosion protection measures within catchments were proposed altogether with flood protection measures in the stream valleys and waste water treatment facilities in surrounding villages. Setting up water quality sampling devices in selected stream profiles was tested and designed. The continual proper management should lead to water quality improvement.