Water Quality Modelling & Assessment Expert (Sediment, Nutrient and Salinity), Seconded to MRCS

Background and objectives of the position

The Mekong River Commission (MRC) is the intergovernmental organisation established under the 1995 Mekong Agreement, mandated to promote and coordinate the sustainable management and development of the Mekong River Basin’s water and related resources. The MRC facilitates dialogue and cooperation among its Member Countries, promotes joint planning and data sharing, and supports compliance with basin procedures to ensure equitable and sustainable development across the basin.

The Mekong River Basin is experiencing increasing pressures from land-use change, hydropower development, irrigation expansion, and climate variability. These drivers are altering sediment transport, nutrient dynamics, and salinity intrusion patterns, which in turn affect aquatic ecosystems, agricultural productivity, and the livelihoods of millions of people who depend on the river system. Addressing these challenges requires sound scientific evidence and improved analytical tools to assess basin-wide water quality and its response to natural and human-induced changes.

To support decision-making, the MRC has developed and recently upgraded the MRC’s Decision Support Framework (MRC-DSF), which integrates hydrological and hydrodynamic modelling and scenario-based simulations using the MIKE suite of models. While the upgraded DSF provides simulations of flows, reservoir operations, and flood and drought conditions, it currently does not include water quality or sediment processes, creating a gap in the assessment of sediment transport, nutrient dynamics, and salinity intrusion. In order to address this gap, the expert will focus on extending the MRC-DSF to include comprehensive water quality modelling, covering on sediment budgets, instream sediment, nutrient, and salinity intrusion.The expert will also conduct the sediment budget assessment based on this devlopped modules and training and capacity building to MRC and member countries to ensure effective use, interpretation and sustainable application of water quality models. Through these efforts, the expert will strengthen scientific evidence for transboundary water management, scenario analysis, policy formulation, and implementation of the MRC Strategic Plan 2026–2030.

Expected outcomes

The expert is expected to deliver the following outcomes:

· A harmonized and quality-assured basin-wide water quality (WQ) data, including sediment, nutrient, and salinity parameters, is established and maintained.

· Water quality modelling and simulation tools for the Mekong River Basin (e.g., MIKE+, ECOLab, or equivalent) are calibrated, validated, and integrated with hydrological and hydrodynamic models.

· Analytical reports and model-based assessments inform regional and national decision-making on sediment and nutrient management and salinity control.

· Enhanced capacity for both MRCS and MC national modelling and monitoring teams to operate and maintain WQ models.

· Technical inputs provided to basin indicators, the State of Basin Report (SOBR) and Basin Development Strategy (BDS).

Deliverables and responsibilities

Under the management direction of the Division Director and technical advice of the Chief Hydrologist, and in close collaboration with the other Modeller, the expert shall be responsible for delivering the indicative outputs and tasks. The final products shall be delivered within a reasonable timeframe following discussion and mutual agreement.

Deliverables

· Inception report with detailed work plan and capacity building roadmap for both basin and site-specific water quality and sediment assessment.

· Comprehensive basin-wide water quality database covering sediment, nutrient, and salinity, including metadata, quality assurance, harmonization of historical and current datasets, and integration of monitoring data.

· Sediment assessment outputs including:

• Basin-wide sediment budgets (source, transport, and deposition estimates).

• Instream sediment dynamics for key river segments and hydropower reservoirs.

• Identification of hotspot areas of sediment accumulation or erosion.

· Nutrient and salinity dynamics assessment including:

• Spatial and temporal distribution of key nutrients (N, P) across the basin and critical sites.

• Salinity intrusion mapping for Mekong Delta.

· Calibrated and validated water quality models (e.g., MIKE+, ECOLab, or equivalent) integrated with hydrological and hydrodynamic models, capable of supporting scenario analysis for development, land-use, and climate changes.

· Scenario analysis reports on sediment, nutrient, and salinity impacts under different development and climate conditions, including site-specific case studies for hydropower reservoirs, irrigation schemes, or other critical locations.

· Technical guidelines and QA/QC procedures for WQ monitoring and modelling.

· Training materials and workshops for national modeling and monitoring teams (at least one regional/national workshop per year).

· Final synthesis report summarizing basin-wide and site-specific assessments, model results, lessons learned, and recommendations for transboundary management and policy support.

Tasks and Responsibilities

1. Data Review and Harmonization

· Collect, review, and harmonize historical and current water quality datasets from Member Countries, hydropower monitoring, and research studies.

· Conduct QA/QC of sediment, nutrient, and salinity datasets, including filling gaps and ensuring metadata standards.

2. Sediment Modelling and Assessment

· Develop and calibrate sediment transport models for the basin, including instream dynamics, deposition patterns, and sediment budgets.

· Conduct site-specific sediment assessments for hydropower reservoirs and critical river segments.

· Analyze sediment connectivity, hotspot erosion/deposition areas, and cumulative sediment impacts from land-use changes and infrastructure.

3. Nutrient and Salinity Modelling

· Calibrate and validate nutrient transport and cycling models, considering point and non-point sources, land-use impacts, and hydrological variability.

· Model salinity intrusion and variations under low-flow and high-flow scenarios, including site-specific assessments for estuarine and upstream areas affected by infrastructure or water regulation.

4. Integration with Hydrological and Hydrodynamic Models

· Link water quality models with existing MRC-DSF models for scenario analysis and decision support.

· Develop model applications for both basin-wide and site-specific scenarios, supporting planning, development, and operational decision-making.

5. Scenario Analysis

· Conduct scenario simulations of sediment, nutrient, and salinity dynamics under key development plans (hydropower, irrigation, flood protection), climate variability, and land-use changes.

· Produce reports highlighting potential impacts, risks, and mitigation options for transboundary and site-specific water quality management.

6. Capacity Building and Knowledge Transfer

· Develop training materials and conduct workshops for national and regional technical teams on water quality monitoring, modelling, and interpretation of results.

· Provide ongoing technical support and advice to national experts to strengthen local capacity in water quality assessment.

7. Reporting and Documentation

· Maintain detailed documentation of models, input data, calibration procedures, and outputs.

· Contribute technical inputs to basin indicators, the State of Basin Report (SOBR), and other transboundary case studies.

· Prepare synthesis and technical reports summarizing findings and recommendations for the Technical Guidelines on the Implementation of the Procedures for Wate Quality (TGWQ).

Intellectual property rights

Intellectual property and copy rights – IPR: All the codes and scripts develop and use in developing the Mobile App, Information, data, database, knowledge resources in the forms of briefings, reports, proceedings, articles, essays, etc. issued by and for the MRCS will be the MRCS property. The expert may not share or use for personal gain in anyway.

Any utility, announcement and disclosure that are without MRCS highest levels of authority’ permission is considered illegal and will be charged by relevant local and international legal procedures.

Declaration of non-fraudulence and protection of personal data

The expert shall adhere to the MRC’s relevant rules and regulations of the MRC on personal data protection, business exclusion, and fraud prevention and anti-corruption principles, and shall be under strict disciplinary measures should any violation occurs.

Working arrangement

The secondment expert will be working under the overall guidance of the Director of Technical Support Division and technical advice of the Chief Hydrologist, and in close collaboration with the other Modeller and other relevant divisions.

Qualifications and requirements

Education

• Master’s degree (or higher) in Environmental Engineering, Water Resources, Hydrology, Environmental Science, or a related field (PhD preferred).

Experience & Skills

• Minimum 7 years of professional experience in water quality assessment and modelling.

• Proven expertise in sediment and nutrient dynamics, and/or salinity intrusion processes.

• Demonstrated experience in using modelling tools such as MIKE HYDRO Basin, MIKE+, MIKE 11, MIKE ECOLab, SWAT, or similar.

• Experience with large river basins or transboundary water management projects.

• Familiarity with MRC-DSF or comparable systems is an asset.

• Experience in capacity building and working with multi-country technical teams.

• Strong data analysis, QA/QC, and geospatial integration skills.

• Excellent communication and report writing in English.

• Proven ability to work in multidisciplinary and multicultural environments.

Duty station: MRC Secretariat, Vientiane, Lao PDR

Starting date and duration: Asap (or after mutual agreement) for 12 months

Swiss citizenship or a ‘C’ residence permit for Switzerland is mandatory.

Miscellaneous

For reasons of duty of care (increased risks due to other privileges and immunities) and to avoid conflicts of interest and potential bias, employees and their accompanying persons who hold dual or multiple citizenships shall, as a matter of principle, not be assigned to countries of which they are nationals.

Contact/Application:

Please submit your application by email no later than July 1, 2026 to Ms. Odette Mauron, odette.mauron@eda.admin.ch