Photos

Circular Canal by sunset
this circular canal is called The Purmerringvaart.
The Purmer is a polder for over 350 years.

text below from: http://www.onderzoekinformatie.nl/en/oi/nod/onderzoek/OND1288094/

The western and northern part of the Netherlands are typical Dutch polder landscapes with an altitude that is generally below sea level. They are characterised by numerous extended meadows separated by small ditches, shallow lakes, small rivers and small remnants of originally vast mesotrophic and oligotropic mires. The land is mainly used for agriculture, recreation and nature conservation. The western part of the Netherlands is also a densely populated area. Villages and smaller towns tend to claim the pastures in the polders for building suburban districts. Water management in polder landscapes can be characterised by pumping out any water surplus from the polders into the boezems as quickly as possible in periods of heavy rainfall and by letting (eutrophic) boezem water into the polders to avoid water shortages in the pastures and nature reserves in periods of drought. Some important water management problems of the regional water boards in the western and northern part of the Netherlands are: inundation of polders and pastures, flooding of greenhouses and villages in periods of heavy rainfall, drying out of pastures and nature reserves in periods of drought, and eutrophicaton of lakes and wetlands. These problems will gradually increase in time due to climate change, sea level rise and land subsidence. In order to solve these problems it is necessary to restore or increase the water storage capacity of the polder landscapes through a combination of measures, e.g.:
- temporary storage of a water surplus in artificial lakes and wetlands during the winter period, in order to keep the water surplus available for supplementary purposes in periods of droughts;
- temporary storage of a water surplus in a specific part of a polder in periods of heavy rainfall to avoid flooding of the entire polder or boezem system;
- temporary storage of water from the boezem system into specific polders during extremely wet periods to avoid high water levels in the boezem system
In order to achieve sustainable water management in polder landscapes, it is necessary to provide temporary storage for water in polders. However, these areas are also claimed for other land-use functions. This leads to the conclusion that multiple land-use may be a solution to these problems. A research project has been set-up to examine the possibility and feasibility of multiple land use, including temporary storage of water as one of the land-use functions.