DAM assesment for Xinyi River, China
DAM analysis provides a fast picture of the current strength of dikes lining the Xinyi River
Shuyang is a rapidly-growing city to the north of Shanghai and to the south of the Xinyi River. Because of the rise in the population and economic activity, it was thought necessary to check the adequacy of the surrounding flood defences. In 2014, a pilot study was conducted to assess the strength of the dike on the basis of the summary data available. The pilot study looked at the dikes on the southern side of the Xinyi River, from Shuyang to the Yellow Sea, over a distance of approximately 100 km. Deltares teamed up with Rijkswaterstaat to complete a fast assessment of the current strength of these flood defences. The Huaihe River Commission (HRC) supplied a number of cross-sections and information about the subsurface. Deltares developed a stochastic subsurface model that made an automated DAM analysis possible.
Fast data input
The largely automated analysis of dike strength is possible because the basic data from the HRC were ‘tailored’ for use in stability and piping calculations in a Geographical Information System (GIS). The basic data about the loads can include information about river water levels, but also actual measurements or water level forecasts. DAM can produce schematisations on that basis, which are then used as input for strength models to determine dike stability. The results are then entered in a GIS and displayed on maps, providing a picture of the overall situation and simplifying access to the data. On the basis of this initial, fast, overall test using summary, conservative assumptions, it can be concluded that the strength of the dike is more than satisfactory.
Link to FEWS
A follow-up study will be conducted in 2015. In addition to enriching the GIS system with more detailed data, a FEWS configuration will be set up for the area. DAM and FEWS will then be linked, allowing for real-time assessments of the dike strength.