Hydrogeologist & Water Resources Specialist

River Basin Assessment and Management:

Setting aside the social, economic, legal, and political considerations, effective water resources management begins with a comprehensive assessment of a river basin’s water balance, available resources, and the ways in which changes to one component of the balance affect other components and the environment, in terms of quantity, quality, and location.

Information compiled in databases and presented using ArcGIS maps provides an essential regional perspective for managing water resources. In general, four categories of data are required:

• Water resource development and use: These activities create significant “pressures” on available water resources and include demographic distribution, agricultural development, significant domestic water supplies, livestock demand, municipal, industrial and commercial use, wastewater treatment facilities, and other significant sources of pollution.

• Water resources monitoring. Monitoring data enable the quantity and chemical status of water resources to be assessed and trends to be identified. Key datasets include meteorological information, surface-water and spring flows, river ecology, groundwater and surface-water quality, and groundwater levels.

• Water resources assessment information. These are interpreted and analysed data, including rainfall patterns, mean annual and peak surface-water flows, evapotranspiration and recharge estimates, aquifer-system distribution and 3-D geometry, hydraulic properties, groundwater levels and flow directions, groundwater storage, water quality and potability, suitability for irrigated agriculture, and ecological status.

• Water management. These data and maps identify key water resources issues, including mean annual water balances, the overall water resources situation, water resources and environmental protection areas, flood-risk areas, dams, conservation and development schemes, resource-development constraints related to quality, quantity and risk, and development potential.

Expert services can be provided to collate and process water resources information from stakeholders, field inventories, pilot projects, and published and online sources, and to integrate these data into ArcGIS for assessment, management, reporting, and presentation.

Exploration:

Key datasets required for groundwater resource assessments are often missing or inadequate. In such cases, exploration boreholes, aquifer testing, and appropriate monitoring programmes may be required.

Associated services include facilitating remote-sensing investigations, including airborne, satellite and geophysical surveys; borehole design; preparation of tender documents and specifications; supervision of drilling and borehole construction; aquifer and borehole testing; and data analysis.

Development:

Effective groundwater management may require a range of different development options. Three common requirements are:

• Production Boreholes: To provide potable drinking water for rural or urban water supplies.

• Production Wells: To provide water for irrigated agriculture and livestock.

• Managed Aquifer Recharge (MAR): The controlled addition of water to an aquifer for later recovery, or to create a hydraulic barrier against seawater intrusion or other contaminants. Recharge can be achieved through methods including infiltration reservoirs, infiltration galleries, and injection wells.

Consulting services can be provided for the design, tendering, supervision, testing, construction, and management of these and other groundwater development schemes.

Evaluations:

Technical advice can be provided to assess the effectiveness of groundwater assessment, management, and development programmes.

Conflict Resolution:

Technical advice can be provided to help understand and resolve water-resource conflicts.

Groundwater models are valuable tools for analysing and predicting groundwater flow and contaminant transport in aquifers. Applications may include calculating the radius of influence of a well or wellfield, modelling the generation, movement, and attenuation of leachate, and assessing the impacts of large-scale groundwater abstraction on other users and available resources.

Both analytical and numerical models can be used. The most appropriate approach depends on the complexity and objectives of the problem.

Analytic Models

Analytical models such as LANDSIM, CONSIM, GFLOW, and BLUEBIRD can be used to simulate steady-state, two-dimensional groundwater flow systems using analytical functions. These programmes use libraries of specialised analytical elements to represent features such as heads and flow rates, engineered barriers, advective transport, contaminant concentrations, drains, slurry walls, wells, and reservoirs.

The functions associated with these elements satisfy Darcy’s law and mass-continuity requirements throughout the model domain. Some models, such as LANDSIM and CONSIM, are specifically designed to estimate potential contaminant concentrations using probabilistic assessment techniques.

Numerical Models

Numerical models such as the U.S. Geological Survey’s Modular Finite-Difference Flow Model (MODFLOW) provide numerical solutions for groundwater flow and contaminant transport problems in three dimensions.

Since MODFLOW was first developed in 1983, numerous codes and packages have been developed to extend its capabilities. These include advective transport modelling (MODPATH), solute transport modelling (MT3D), parameter estimation (PEST), solute transport modelling (MOC3D), inverse modelling (MODFLOWP), and seawater intrusion modelling (SEAWAT).

Commercial software such as the Groundwater Modelling System (GMS) integrates modelling packages with analysis, calibration, and 3-D visualisation tools in a single software environment.

Expert services can be provided to assist with Environmental Assessments and Remediation, including:

Field Investigations, Laboratory Analyses and Monitoring:

Sampling to identify and delineate sources of contamination; field investigations to characterise the extent of soil and groundwater contamination; laboratory testing to determine the properties of the soil, aquifer, and contaminants; and monitoring to assess whether contaminant concentrations meet acceptable levels.

Soil and Groundwater Risk Assessments:

Risk assessment of soil and groundwater contamination and vulnerability using a range of techniques, including UK Level 1–4 procedures, analytical and numerical groundwater models, and ArcGIS overlay and index methods, to support compliance with applicable environmental standards and regulatory requirements.