Research

Work Packages 1–9

Work Package 5

Natural Environment, Land Use and Carbon Dynamics - DEO, RUB, DGHM, ITT

The Overall goal of WP5 was to comprehensively analyze relevant aspects of the natural environment regarding ecosystem services (ESS) and carbon dynamics considering their spatial distribution and their temporal dynamics. The central unit of analysis has been the VGTB river basin; however there were strong linkages to the macro (regional and global) as well as to the micro (sub-basin and local) scales.
For the understanding of current patterns and processes in the landscape system and carbon dynamics, knowledge about historical human impacts were of outstanding importance. Human impacts were analyzed in a historical context, including historical deforestation and land use as well as related impacts on soils, water, climate and geomorphological processes.
The results served as the reference for the assessment of present and future processes in the landscape system. They were also required for the calibration of the carbon and hydrological models.

Different objectives have been achieved:

• At the current state of research, eE+E concentrates on the basin level and the low lands. For this historical maps and remote sensing data have been collected and pre-processed using Remote Sensing software (ERDAS Imagine) and ArcGIS (ESRI). Statistical data were digitized and several reports, studies and other documents as well as interviews and fieldtrips were used to fill data lacks in order to determine in a later stage the history of land and water use dynamics.
• The historical river system was digitized by using maps from 1920s, 1960s and LANDSAT images from the 1970s, 1990s and after 2000. Based on this pre-result, some present hydraulic problems can be understood more clearly.
• The land use of the Vu Gia Thu Bon (VGTB) for the year 2010 was characterized and mapped on the basis of satellite images, ancillary datasets and field data. The preliminary land use products obtained during the project year 2010 were significantly improved and the final Land Use Map of the VGTB river basin.
• A field campaign was carried out in June 2011 to acquire reference in situ data from which estimating the terrestrial carbon stock. The 2011 field campaign focused on measuring vegetation biomass in order to assess the aboveground carbon stock and its variability in the major land use classes. The field campaign was targeted to forest areas in the midlands and uplands of the VGTB basin and consisted on measuring plant and land cover parameters within pre-defined field plots (the Communes of Tra Bui, Song Thanh and Ma Cooi)
• A soil map has been created based on the Russian and Vietnamese soil classification which was translated into the FAO/WRB classification.
• The salinization of soils has been analyzed within an ITT MSc thesis by Melina Tenbrock for the ITT in May 2011. Soil samples were taken in three places between Da Nang and Hoi An. In order to be able to describe the possible effect of irrigation with saline water on the soils, the sodium absorption rate (SAR) has been calculated. It turned out that the salinity differs according to the land use. Soils used for rice paddy fields contain the highest amount of total dissolved solids (TDS), soils used for groundnut show lower values and unused soils show the lowest value.
• A field campaign was carried out in April/May 2011 to collect information about ecosystem dynamics and distribution patterns of indicator species. Distribution data was collected using a rapid assessment method which has been adapted to the topography of the study area. Data was collected only for plants, with a focus on tree species.
  Characterization of the hydrological system and water infrastructure: During the field trip in February 2011 26 samples have been taken and analyzed to get an impression of the regional distribution of the water quality. Furthermore, WMUs have been created for the whole river basin.
• A combined DEM was produced and used for the creation of the hydrological and erosion dynamics modeling. But as the modeling was far ahead of the project schedule, therefore the parameters for soil and land use have been very preliminary and under development.
• The analysis of the vulnerability of land use to floods, salt water intrusion and droughts for which field visits were done to the low-, the mid- and the highlands and statistical data analyzed. At Tu Cau pump station, one of the most seriously affected stations by salt water intrusion, together with the Irrigation Management Company Quang Nam, a monitoring station was installed by eE+E. Aiming to survey more detailed data about the salinity intrusion and the interaction between SWI and irrigation. Focusing on the analysis of the vulnerability of agriculture to salt water intrusion, a preliminary river network and boundaries for the MIKE11 model for the dry season were identified.