Expertise: Groundwater engineering, Hydrogeology, Modelling
Expertise Group: Engineering
Consultant Source: International
TOR Keywords: Groundwater, hydrogeology, contaminants
Objective and Purpose of the Assignment
Background:
Nepal has abundant renewable water resources. The annual rainfall varies from 500 mm/year insome western
areas to more than 4,000 mm/year on the southern slopes of the Himalayan range, with 70-80% occurring in
the summer monsoon and generating runoff to more than 6,000 watercourses. High rainfall generally gives
rise to abundant water supplies, at least seasonally, and surface water and groundwater are important
sources for domestic, industrial, and agricultural uses. Groundwater is abundant in the Terai and the
Kathmandu Valley aquifers, while groundwater is more limited in populated hill regions. In intra-
mountain valleys such as Kathmandu, groundwater occurs in well-defined and sometimes isolated basins. In
contrast, groundwater in the Terai plains south of the Himalayan Mountain ranges forms a part of the
larger system operating in theIndo-Gangetic plains.
Extensive groundwater development for irrigation in the Terai started in the 1960s, and today,
groundwater serves most of the area’s population for drinking and irrigation purposes. Groundwater
development was low-cost and initially did not lead to conflicts. Consequently, abstraction increased
without any specific plan or resource management, gradually leading to stress on the resource.
Today, almost half of Nepal’s population lives in the Terai and depends solely on groundwater for their
drinking needs. There are growing challenges facing groundwater security in the region, including issues
around year-round reliability, increasing instances of water insecurity, and growing concerns over its
quality. Data available on the quality of deep ground-waters in the Terai, show the presence of arsenic
as a major health contaminant apart from the prevalence of iron, manganese, and ammonium.
Given the strategic value of groundwater in the Terai and the significant risks associated with its
contamination and growing water stress, this study aims to support the Ministry of Water Supply, and
other relevant stakeholders in assessing groundwater potential, the risks due to contamination, and to
identify possible short- and medium-term solutions.
Objective of the assignment
The specific objectives of the assignment are to:
- Assess the current status of groundwater in the Terai region based on available data and field visit
and observations, including population exposure due to drinking water contamination, identify data gaps
and requirements, and suggest short-term mitigation measures. - Assess the quality and suitability of existing data sources for estimating groundwater contamination
by arsenic and other contaminants in the Terai region. - Validate findings through sampling to identify hotspot districts/areas.
- In priority areas, conduct a groundwater assessment and management plan based on groundwater uses and
future requirements.
Scope of Work
Summary scope of the assignment:
The scope of the work shall include but not limited to:
• Review existing reports and documents, including data on drinking water availability and contamination
(specifically on Arsenic concentrations, fecal coliform, etc) available with
different agencies and preparation of preliminary report.
• Mapping of the spatial distribution of tube wells, tube well discharge, and water quality
characteristics, specifically emphasizing arsenic concentration, fecal
coliform, etc and groundwater estimation.
• Draw up a sampling plan and field-testing program for existing wells ensuring representativeness at
the ground level and validate the field test results. Review of
existing arsenic removal practices.
• Ground water sampling and water quality tests in Laboratories. Validation of water quantity and
quality status in priority areas / hot spots, specifically for cluster
of villages and towns.
• Hydro-geological investigations and pump out tests in diverse geological settings and prepare sub-
surface lithology and water quality tests and monitoring of ground water.
• Development of a (pilot) simulated groundwater numerical flow and transport model.
• Development of ground water management plan (GWMP) for priority areas, emphasizing water stress,
ground water availability and quality.
• Recommend mitigation measures for arsenic and other contaminants including a program of measures for
the utilization and protection of groundwater resources utilizing effective
and cost-efficient water recharging models, with specific recommendations for managing arsenic
and other contamination (short, medium, and long-term).
• Prepare an investment plan for the medium to long run, including sustainable development, management,
and restoration/protection of the water sources, based on the local
authority’s plans, and in line with the national sector development plans.
• Undertake consultation and knowledge sharing discussion with Department of Water and Sewerage
Management (DWSSM), Ministry of Water Supply and other stakeholders.
Detailed Tasks and/or Expected Output
The consultant for this position will act as the International Ground Water Modelling Expert. The
consultant will carry out, but not limited to the following tasks:
- Coordinate and collaborate with Team Leader, Deputy Team Leader and Sr. Hydro-geologist and other
experts to identify the pilot study area for ground water modelling; - Review all available data and identify data gaps that required for developing ground water model. In
consultation with Team Leader, Hydro-geologists, and other team experts identify the need for field
survey and investigations and supervise Groundwater Modelling expert (national) and field engineers to
capture the data requirements. - Develop, together with the national groundwater modelling expert, a ground water numerical flow and
transport model, based on available data and data collected from field investigations, and provide high-
level expertise, introduce global best practices, and offer technical excellence on groundwater
modelling. - Prepare, with support from national groundwater modelling expert and other team members, a detailed
report on the simulated ground water model and its application on diverse hydro-geological setup. - Undertake field investigations, as maybe required to assess the field conditions.
- Assess aquifer stress for different ground water conditions (rainfall patterns, recharge conditions)
and also under different abstraction regimes. - Assess future scenarios (2050) concerning groundwater availability, climate change scenarios, and
contamination risk, including recharge zones and recharge potential in the pilot area. - Under the Team Leader and team of experts, conduct knowledge sessions on ground water modeling and
its applications to relevant government officials . - Other relevant tasks to be decided by the Team Leader and ADB.
Minimum Qualification Requirements
Preferably Master’s degree in hydrogeology, geology, groundwater engineering, environment engineering,
civil engineering, earth sciences or any other related discipline.
Relevant experience of groundwater modelling using software like MUDFLOW, FEFLOW or equivalent.
Minimum General Experience: 7 Years
Minimum Specific Experience (relevant to assignment): 5 Years
