Henrike Hochmuth's research while affiliated with University of Greifswald and other places

This book depicts the results of a research project in northern China, where an international and interdisciplinary team of researchers from Italy, Germany and China has applied a broad range of methodology in order to answer basic and applied research questions and derive comprehensive recommendations for sustainable water management and wetland restoration. The project primarily focused on ecosystem services, e.g. the purification of water and biomass production. In particular, the ecosystem function and use of reed (Phragmites australis) and the perception as well as the value of water as a resource for Central Asia's multicultural societies was analysed.

To implement effective water resource management strategies, a sufficient data basis about the hydrologic situation must be available. An important parameter is the water consumption by the natural environment, e.g., evapotranspiration (ET). This study delivers actual evapotranspiration rates (ETa) computed on the basis of Landsat TM/ETM+ and MODIS data. Vegetation mappings recorded during a field work campaign in 2012 allowed the correlation of ET rates to certain units of vegetation. The study site is located in the Heihe river basin, Northwest China, where the landscape is characterized by extending land under cultivation along the middle reaches and ecologically valuable Tugai vegetation further downwards. Due to the arid climate, all agriculture depends on irrigation with water taken from the Heihe River. As a result of a massive expansion of irrigated land in the last decades, an imbalance with regard to water allocation has developed. It is characterized by an overexploitation of the water resources in the middle reaches and a strong degeneration of the natural Tugai vegetation along the lower reaches due to water shortage. As a response, a water distribution plan has been adopted to define target amounts of water that shall reach the lower parts of the river. Total values of the ETa over the whole vegetation period for corn, dates, orchards and grapes amount to 667.7, 762.2, 703.5 and 483.9 mm, respectively. For forest vegetation (ground coverage 80 %) and for shrub vegetation (80-100 % ground coverage), values of 496-530 mm and 177-233 mm were calculated, respectively. Areas with lower ground coverage show significantly lower ETa values. Spatially, ETa values decrease from the center towards the border of the oasis and from the middle towards the lower reaches. Agricultural land presents the largest water consumer. The total ETa values over the vegetation period amount to 2.15 km3 (middle reaches) and 0.28 km3 (lower reaches), respectively. On this basis, a minimum discharge of 0.34 km3 was calculated to maintain the natural vegetation downstream.