Fundamentals of Conceptual and Numerical Groundwater Modelling: CEG8527

Coursework 2024/25

Overview

You are an independent hydrogeological consultant undertaking an assessment on behalf of a housing developer.  You have been engaged to determine whether there is sufficient groundwater in the area to supply a new housing development. You will need to generate a conceptual model, implement a numerical model to assess feasibility, and present a report of your findings to the developer.

You have been provided with;

•    A numerical model for the Stringside surface water catchment (Norfolk, UK) in which the planned groundwater abstraction is to be located.

•    A river flow time series for the Stringside catchment outfall at Whitebridge (NRFA 33029).

•    Groundwater levels from an observational borehole at Great Thorn Farm (SHETRAN grid square 133).

•    The location of a proposed water supply borehole at Lat/Lon = 52.636148, 0.607272

Assignment

Task 1 - Create a Hydrogeological Conceptual Model (40 marks) Approximately 5 pages long including figures

The conceptual model should include (but is not limited to);

1.    Geology overview - including any superficial and bedrock geology.

2.    Hydrology overview - including river flow, baseflow, recharge, and rainfall.

3.    Aquifer characteristics - including key parameters and information on flow direction/water quality.

4.    Summary of what the information tells you about the hydrogeological setting.

The conceptual model should begin with a glossary of key terms and any acronyms used in the report and use a range of literature to derive the conceptual model. Include appropriately labelled figures and plots where necessary. State any data gaps and propose ways to address those.

Task 2 - Multicriteria Calibration (20 Marks) approximately 3 pages

You have been provided with a SHETRAN model for the catchment. Perform. a multi-criteria calibration considering two of the SHETRAN model parameters: the saturated hydraulic conductivity of the chalk layer and its saturated porosity. Assume the chalk aquifer is homogenous and isotropic. Steps to complete;

1.    Prepare (and present) a calibration plan.

2.    Determine appropriate calibration metrics (objective functions) for the river flow and water level data and interpretation within a multi-criteria calibration strategy and physically plausible parameter limits and parameter sampling strategies.

3.    Perform. ~10 calibration runs.

4.    Choose the best simulation based on years 2-5 of the simulation (1981-1984).

5.    Run your best model for a 20-year period to provide a baseline against which the impacts of abstraction may be assessed.

6.   Justify of your choice of “best model” in the context of providing a baseline against which abstraction impacts can be assessed.

Task 3 - Groundwater Abstraction Assessment (20 Marks) approximately 4 pages

The developer proposes a borehole (located Element 112 in the SHETRAN model) to supply water to the new housing development for 100,000 people. The development itself will be located outside the catchment. It is expected that water consumption will be 130 litres/day per person. It is possible that the abstraction will not meet the needs the total number of residents.

1.    Estimate groundwater recharge and choose an appropriate abstraction rate for supply to the new development based on sustainable hydrological considerations.

2.    Adjust the SHETRAN model appropriately to include the chosen abstraction rate and perform a 20-year impact assessment simulation (1980-1999 inclusive; 1980 is the spin-up year).

3.    Discuss and quantify the hydrological impacts of the abstraction on the water table and surface hydrology considering both wet and dry years.

4.    State in the report if you recommend that the development can be totally, partially, or not supplied from the borehole.

Task 4 – Discussion, Conclusions, Limitations and Further Work (20 Marks) approximately 2 pages

You should provide a summary of your findings from the hydrogeological assessment process including your final recommendation to the housing developer. This should include a discussion of sources of uncertainty in both the conceptual and numerical modelling you have completed. You should critically assess the limitations of your approach and provide a considered review of how you could improve the assessment, including characterisation of geology, additional datasets and modelling enhancements.

Marking criteria and submission details

To pass this assessment you must be able to demonstrate that you can:

•    apply, interpret and critically evaluate hydrogeological data;

•    create, evaluate and update conceptual groundwater models;

•    understand the process for numerical groundwater modelling, and describe and implement numerical modelling software and techniques for water resource management;

•    use numerical models to test understanding of groundwater systems.

The standard faculty marking criteria as provided on Canvas will be applied, with marks assigned to the sections as indicated. Presentation and accurate citation will be considered as part of the marking process. The maximum length of the submission is 14 pages (assuming single spacing, 11pt text, not including title information and references).  You do not have to include screen shots or lengthy descriptions of the modelling process as you will principally be marked for demonstrating understanding and interpretation of the outputs.

Submission: 2pm on Monday 28th  April.

Modelling resources

SHETRANexe.zip: the SHETRAN executable code.

SHETRANmodel.zip: the SHETRAN model of the Stringside catchment.

SHETran-Results-Viewer-1.6.3.zip: Graphical interface to view SHETRAN model results.

Shetran Viewer Guide.ppt: Guide to the graphical user interface

CalibrationDatasets.xls: observed river flow and water table elevations, plus corresponding simulation data from an uncalibrated SHETRAN model.

CR04236N.pdf: Ander, E.L.; Shand, P.; Griffiths, Kate; Lawrence, A.; Hart, P.; Pawley, J.. 2004 Baseline report series. 13, the Great Ouse chalk aquifer, East Anglia. Environment Agency, 48pp. (CR/04/236N)

Table 1 Summary ofSHETRAN simulations