The sloping lands or mountainous areas, the floodplains with their reservoirs, the deltas with their large urbanization development, and the mangroves such as the last buffer between the continental area and the Ocean, respectively from the upstream to downstream. In a first step, the research activities will deal with the two large Vietnamese river basins settling the two megapoles of Vietnam, i.e. Hanoi and Ho Chi Minh City. The research goal is to provide remediation processes in rural and urban water compartments, based on a multidisciplinary approach focusing on hydrological, physical, chemical, biogeochemical and ecological processes. The strength of NUCOWS is to couple research activities on field and artificial worlds (i.e. microcosm) mixing ecological approach within biogeochemical researches to inter-cross the observation scales, a need for a sustainable water quality and an efficient watershed management.
Nutrients and contaminants transport via inland watersin river basins, from mountains to deltas, have been receiving increasing attention as their role in linking landwaters and seawaters. Within the human and economic development, the pollution frighten is rising and the demand forwastewater mitigation is increasing. Long regarded as a passive conduit between land and ocean, inland water systems (i.e. rivers within their ecological environment) are significantly more complex and influential than previously believed. Rivers do not only transport materials from land to sea,but they also store sediments in their banks, lakes, floodplains, with nutrients and contaminants internally. They also support food web of aquatic environment and promote naturallywater-cleaning regulation. What are the driven forces of such ecosystems?
The aim of NUCOWS is to characterize the nutrient and contaminant fluxes being associated with theecohydrological processes in different functional compartment of large populated river basin. Due to the lack of observed and measured multidisciplinary data in term of ecological services, the main concern of NUCOWS is firstly to search the pivotal role of sediment in regulating water and aquatic habitat quality. Indeed river systems receive very heavy sources of pollutants from agricultural practices and metropolis areas, increasing attention on establishing meaningful targets or thresholds for guiding remediationstrategies.Much on-going work is assessing the performance of targeted on-farm mitigation options for reducingexcessive sediment loss, but the in-channel restoration of streams has equally become an increasingly popular activity, which is requesting so large research demand. Then the project will aim also to develop scenarios based on expected demographic and land use changes in order to evaluate the resulting changes in nutrient and contaminant loading delivered to the coastal zone at the horizon 2050.
The NUCOWS project will be based on four main modern high-value methodologies:
- measurements and modelling of greenhouse gas through sediment/water columns (IMPMC, USTH, ICH, INPC);
- measurements of organic contaminants by passive samplers such as POCIS system (VNU-HCMC, EPOC, USTH, IET, ICH) or by dynamic in-situ sensors (ENSIACET, IET);
- simulationsof sediment/water/macrolife in microcosm environments (ECOLAB, iEES-Paris, IET, ICH, SFRI, ECOSYM);
- simulations through multidisciplinary distributed modelling platformsdealing with land-use change, economic change and climate change scenarios (iEES-Paris, INPC, ICH, SFRI, ECOLAB).
Each methodology will be applied sequentially in each identified hydrological compartment. In relationship with the other project funding sources, we suggest to implement NUCOWS studies within the mangroves during the first year. Then river streams and lakes,floodplains and deltas would be successively put in action over the next 4 years. The final objective would be to get a global image of the whole large river basin in term of nutrient cycles and contaminants transfers through the hydrological network in relationship with economic change, land use change and climate change forcing.