Assessing human impacts on the Red River system, Vietnam, to enable sustainable management

The Red River in Vietnam is located in a rapidly developing area of the world's 13th most populous country. The area, which supports 20 million inhabitants, includes a major rice-growing region, the mega-city of Hanoi and a range of industries each of which have expanded in recent decades. The Red River Delta (RRD) delta area of the river which discharges water into the Bay of Tonkin provides crucial ecosystem services including the retention and removal of nutrients and pollutants for groundwater (drinking water) and marine resource protection, carbon processing, flood protection which is heavily managed through a series of agricultural dikes and sediment transport which governs erosion and deposition at the vulnerable coastal zones. However, hydropower dam installation, increasing agricultural fertilizer use, increases in urban wastewater and use of a range of toxic contaminants threaten these ecosystem services and the health and wellbeing of the people who live in this region. The delta region is a complex and highly modified hydrological network which is difficult to model using calibrations developed on more straightforward river basins from temperate regions. Therefore, this proposal aims to improve modelling capabilities through the application of the alternative approach of Materials Flow Analysis which is more suited to complex systems. The project focuses on filling in knowledge gaps in understanding on relationships between hydrology, nutrients, carbon and pollutants in the RRD region for improved model calibration using a combination of stable isotope and organic geochemistry techniques which have rarely been applied in this area. The first part of the project will use stable isotopes of oxygen and hydrogen to quantify precipitation-surface water- groundwater interactions and estimate the extent of saline intrusions upstream from the coastal zone. The second work package will focus on understanding how dam installation alters nutrient and carbon sequestration and removal from the downstream river in order to better inform reservoir management. The third work package will aim to better constrain nutrient cycling in the delta (including carbon, nitrogen, phosphorus and silicon) through the use of stable isotope techniques. The work will be supported by a PhD student project using more recently developed techniques of dual nitrogen isotope analysis (analysing N and O atoms in nitrates) and the application of Silicon-30 which can provide important information on silica cycling, shown to be important in rice paddy areas. The final work package will focus on providing an updated assessment of toxic contaminants from this region because systematic monitoring has not been conducted recently. A broad suite of persistent organic pollutants and heavy metals will be analysed, with a focus on some problem chemicals in this region such as the pesticide DDT and its derivatives which was banned in 1995 but has increased after that time indicating illegal usage, and the dioxin herbicide defoliant "Agent Orange" which was used extensively in the Vietnam War. For the first time we will measure pharmaceutical residues in river sediments and suspended particulates in order to evaluate the distribution and trends of these compounds across the delta. The project will also install facilities for "Microtox" analysis in Vietnam, allowing rapid screening for toxic pollutants in order to pilot the use of this technique for environmental monitoring agencies. The outputs from this project will deliver improved capabilities for MFA modelling of nutrients and hydrology, the carbon budget, the first measures of emerging pollutants (pharmaceuticals), updated measures of legacy and persistent contaminants and a newly establish national capability for toxic pollutant screening.

The beneficiaries of this research include:
1. Government ministries responsible for agriculture and the environment, and who have provided letters of support for the work in this project. These include:
(a) Institute of Agricultural Environment (IAE) within the Ministry of Agriculture and Rural Development (MARD) who require information on the interaction between water quality and paddy fields
(b) Environmental protection agencies such as the Center for Environmental Monitoring (CEM; http://quantracmoitruong.gov.vn), Vietnam Environment Administration (VEA) in the Ministry of Natural Resources and Environment (MONRE), who would like to assess the impact of anthropogenic activities (hydrology, agriculture, power production) to the river system
2. Hydro-meteorological agencies who require information for forecasting hydrological regime change especially during the dry season
3. Local farmers in the Red River Delta (RRD) who require sustainable and efficient solutions for agricultural management (e.g. fertilizer application, hydrological regimes).
4. Hydro-power companies (e.g. Hoa Binh Hydropower) who need to balance water reserves for power production and water supply downstream
5. Sand exploration and mining companies (such as Xian Truong Corporation) who need to understand the causes of sand loss and thresholds for resource use
6. Water abstraction companies who manage groundwater resources for domestic use in the RRD (e.g. Hanoi Water Limited)
7. The 20 million residents who live within the RRD and members of the general public in Vietnam who require information about possible scenarios under future climate change
8. Next-generation and early career scientists who are required for environmental and hydrological problem solving in Vietnam and the South East Asian region and require training in cutting edge analytical techniques and scientific approaches.

The impact plan outlined in detail in the Pathways to Impact document includes stakeholder engagement workshops and visits by key stakeholders to the UK to develop knowledge exchange among scientists and end users. The impact plan also focuses on developing effective ways of communicating the science to a diverse range of end user groups, including members of the public through the use of geospatial and e-technologies which can be accessed via mobile devices. Capacity building, for improvements in the scientific knowledge base, for improved environmental monitoring and modelling is also a major component of the impact plan, with training of early career researchers (including one postgraduate student) and Vietnamese investigators in the research team.