gwh

Class Project: Municipal Water Supply Design

Modified from Finkel, M. (2008), Environmental Modelling 1 Lecture Notes, University of Tuebingen, Tuebingen.

1. Data

1.1 Hydrogeological Settings

The investigated aquifer is situated within the alluvial complex of a river catchment. The sediments consist of sandy silts and locally of old buried river channels. The aquifer is unconfined throughout the catchment and lays on top of an aquitard (elevation of aquifer base: 90 m above sea level). Fig. 1 depicts the situation. The head in the river (width = 40 m) can be assumed to be constantly hriv = 100 m in along the area of interest. A groundwater flow model shall be set up in order to support the planning of different facilities (water supply well, industrial area, landfill).

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Fig. 1 Plan view and cross section of the area of investigation. (Remark: isolines are only schematically correct!)

1.2 Model Setup

The model shall span an area of 4500 m x 1500 m as is indicated in Fig. 1. The suggested spatial gridding is Δx = Δy = 50 m. The aquifer can be represented by a single model layer.

1.3 Recharge

The recharge rate of 0.8 mm/day in the model domain can be assumed constant.

1.4 River

The elevation of the riverbed bottom is 95 m. Thickness of riverbed sediments is 20 cm and the conductivity of riverbed sediments is 0.02 m/day.

1.5 Electrical Resistivity Profiling

Geophysical survey as shown in Fig. 2 is available.

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Fig. 2 Results of electrical resistivity profiling showing resistivity values in ohm-meter [Ω.m].

The resistivity logs give qualitative hints where sandy material and gravel can be expected. Based on our understanding the geology of the area, buried river sediments are expected to be present in the subsurface. In general, river sediments are often composed of coarser and more permeable materials such as sand and gravel, which can have higher hydraulic conductivity than finer-grained materials such as clay and silt. These river sediments can act as a preferential flow pathway for groundwater. Resistivity logs can be used to identify buried river sediments by analyzing the variations in resistivity values. Variations in resistivity values can be used to identify boundaries between different types of sediments. Identifying areas with lower resistivity values and sudden changes in resistivity values could be indicative of buried river sediments. When an electrical current is applied to the subsurface through electrodes and the resulting voltage is measured, the resistivity of the subsurface materials can be determined. Resistivity [Ω.m], which is a fundamental specific property of a material, is a measure the electrical resistance of the material. In general, sandy and gravelly materials have higher electric resistivity than finer-grained materials such as clay and silt that have charged particles that conducts electricity. Thus, if resistivity logs indicate higher resistivity values in certain areas, it may suggest the presence of sandy or gravelly materials with higher hydraulic conductivity values.

1.6 Hydraulic Head Measurements

12 observation wells have been drilled. Table 1 shows the locations and head measurements. Tab. 1 Observation wells and head measurements

Observation Well X (m) Y (m) Head Measurements (m)
B1 450 1250 107.98
B2 1650 1050 105.93
B3 750 250 107.42
B4 1950 550 105.59
B5 2550 650 104.36
B6 2850 250 103.96
B7 4050 150 101.39
B8 3450 750 102.66
B9 3450 1350 102.72
B10 3450 950 102.60
B11 3150 850 103.18
B12 2850 1150 103.70

1.7 Pumping Test

Results from aquifer tests provide ranges of K values at each observation wells (Table 2). Table 2. Pumping test results

Well Low K High K
B1 3 12
B2 15 25
B3 18 25
B4 16 21
B5 16 20
B6 38 50
B7 35 47
B8 34 44
B9 39 44
B10 550 750
B11 250 320
B12 280 370

Note that no aquifer test could be made in vicinity to the river due to missing wells in this area. However, it can be assumed that highly permeable river sediments can be found along the river and beside it up to a distance of approximately 200 to 300 m.

2. Design Problem

2.1 Model Setup (120 points)

Setup groundwater flow model in a steady-state. Follow the suggestions concerning the spatial extension and gridding that are made above. Remark: Make sure that the elevation of the top of the layer is large enough to guarantee unconfined conditions (i.e. the simulated hydraulic heads should not exceed the model’s top elevation

2.2 Model Calibration (50 points)

Calibrate the groundwater flow model such that the heads simulated at the 12 observation wells do not deviate from the measured head values more than 0.3 m. Remark: As all model parameters except the hydraulic conductivity K are given, the task is to find the appropriate spatial K distribution. First, inspect the given data/information carefully. Then consider possible zonation to start with based on the given data. Once the model is calibrated, you can proceed dealing with the problem described below

2.3 Model Application (10 points)

Do any of the following two design problems.

2.3.1 Municipal Water Supply Design: Nature-based Infrastructure for Mitigating the Impacts of a Planned Industrial Area

It is planned to install a municipal water supply well half way between observation well B10 and the river. Also, a new industrial area is planned in the study area as show in Fig. 3 resulting in a complete sealing of the surface. For each of the following scenarios, what is the maximum rate of water than can be pumped if the drawdown of the water table should not exceed 1 m at any of the observation wells?

For each scenario:

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Fig. 3 Plan view of the model domain including the location of observation wells (B1 to B10), and the location of the planned industrial area.

Bonus Points: Discuss your results given the information provided in Elshall et al. 2020.

2.3.2 Municipal Water Supply Design: Capture Zone Delineation

It is planned to install a water supply well half way between observation well B10 and the river.

2.3.3 Municipal Water Supply Design: Landfill Site Selection

It is planned to install a water supply well half way between observation well B10 and the river.

3. Modeling report (20 points)

3.1 Objective

Prepare a modeling report to document your model and results. The report is the primary grading basis. Model files can be optionally submitted but are not required. Therefore, ensure the report includes all comprehensive information on model setup, calibration, and problem-solving. Describe and discuss all data; avoid figures and tables without context; aim for publication-quality visuals

3.2 Outline

Here’s a polished and more professional version of your outline and figures section. I’ve streamlined the language, improved consistency, and emphasized clarity while keeping it concise and actionable.

3.2 Report Outline

Suggested Structure and Content

  1. Title
  2. Abstract
  3. Introduction
    • Provide background and objectives of the study.
    • Present the groundwater flow equation with explanations of terms and relevance to your work.
  4. Hydrological Setting and Conceptual Model
    • Summarize available data and information (e.g., hydrogeology, recharge, pumping, boundary conditions).
    • Present the conceptual model developed from the data, including key assumptions and simplifications.
  5. Numerical Model
    • Describe the setup of the flow model (domain, discretization, boundaries, initial conditions).
    • Explain the calibration process: objectives, calibration parameters, methods, and evaluation criteria.
    • Present calibration results, including fit to observed data and overall model performance.
  6. Model Application
    • Define the problem(s) addressed using the model.
    • Describe modifications made for scenario analysis.
    • Present and discuss results for each scenario.
    • Provide actionable recommendations based on findings.
  7. Conclusions and Limitations
    • Summarize key results.
    • Discuss limitations of the model and implications for interpretation.
  8. References Cited
    • Use a consistent citation style.
    • Refer to exemplary reports (e.g., Oki, 2005; Swain et al., 2019).

Note: While Oki (2005) and Swain et al. (2019) provide detailed examples, your report should remain concise, well-structured, and focused on clear analysis with practical recommendations.

3.3 Required Figures (Minimum)

General

Model Application

These are the minimum required figures. Include additional figures where needed to better illustrate your design effectiveness and results.

4. Rubric

This rubric outlines the criteria for evaluating your modeling report and the underlying analysis. Your grade will be based on the successful completion of the modeling tasks and the clarity, professionalism, and completeness of your final report.

4.1 Model Setup (120 points)

This section evaluates the correct construction of the numerical groundwater flow model based on the provided hydrogeological data.

Criteria Excellent (100-90%) Proficient (89-75%) Developing (74-60%) Unsatisfactory (<60%)
Domain, Grid, and Layers (40 Points) Model domain, grid spacing (Δx=Δy=50 m) and (Δx=10 m) and (Δy=50 m) at the river, and single-layer unconfined aquifer are all implemented correctly. Minor errors in domain size or grid spacing. Aquifer setup is mostly correct. Significant errors in model domain or grid setup, or incorrect layer type used. Model domain, grid, and layer setup are fundamentally incorrect or missing.
Boundary Conditions (10 Points) All boundary conditions (Groundwater Divide as a no-flow boundary, River using river package boundary) are correctly identified and implemented based on the conceptual model. Boundary conditions are correctly identified, but there are minor errors in their numerical implementation. One or more boundary conditions are incorrectly identified or poorly implemented. Boundary conditions are not implemented or are completely incorrect.
Aquifer Properties and Recharge (10 Points) Aquifer base elevation and recharge rate are correctly and uniformly applied. [cite_start]River parameters (bed elevation, thickness, conductivity) are correctly assigned. Aquifer properties and recharge are mostly correct with minor input errors. River parameters are correct. Significant errors in assigning base elevation, recharge rates, or river properties. Aquifer parameters, recharge, or river properties are missing or grossly incorrect.
Initial Hydraulic Conductivity (K) Zonation (30 Points) A clear, logical initial K-zonation is developed and justified by thoughtfully integrating all available data, including pumping tests, geophysical logs, and geological descriptions with all required figures Initial K-zonation is reasonable but may not fully integrate all available data sources, the justification is incomplete, or some required figures missing K-zonation is attempted but is simplistic, arbitrary, or does not reflect the provided data. No attempt is made to create a rational K-field; a uniform value is used without justification.
Hyraulic Head Simulation (30 Points) Successful model run with all the required figures and tables shown Successful model run with all most the required figures and tables shown Successful model run with only a few figures shown Unscessful model run.

4.2 Model Calibration (50 points)

This section assesses the process and result of calibrating the model to match observed field data.

Criteria Excellent (100-90%) Proficient (89-75%) Developing (74-60%) Unsatisfactory (<60%)
Calibration Target Achievement (40 Points) The final calibrated model successfully meets the required target: simulated heads at all 12 observation wells are within 0.3 m of the measured values and all required figures and tables included. The model is calibrated, but a few wells slightly exceed the 0.3 m deviation target and most of required figures and tables included. Calibration is attempted, but deviations from measured heads are significant and widespread. The model is not calibrated, or the calibration results do not meet the project requirements.
Calibration Process Documentation (10 Points) The report clearly documents the iterative calibration process, showing adjustment of the K values to achieve the target. The calibration process is described but lacks some detail or clear justification for the changes made to the K-field. The report mentions calibration but does not describe the process used to achieve it. No evidence or description of a calibration process is provided.

4.3 Model Application (10 points)

This section evaluates the successful application of the calibrated model to solve one of the three specified design problems.

Criteria Excellent (100-90%) Proficient (89-75%) Developing (74-60%) Unsatisfactory (<60%)
Scenario Setup and Execution (5 Points) All scenarios for the chosen problem are set up correctly (e.g., pumping well location, industrial area recharge changes, particle tracking setup). Model runs are executed correctly and all required figures and tables included. Scenarios are set up with minor errors (e.g., incorrect recharge value, wrong drawdown constraint) and most of required figures and tables included. Major errors in scenario setup that prevent a meaningful analysis. Scenarios are not set up or are fundamentally flawed.
Analysis and Calculation (2.5 Points) Maximum pumping rates are accurately determined while respecting drawdown limits. Head distribution changes are correctly shown and analyzed. All required calculations (e.g., conversion to MGD, population served) are correct. Pumping rates and required calculations are mostly correct with minor errors. Analysis of head changes is adequate. Significant errors in determining pumping rates or performing required calculations. Analysis is minimal. Pumping rates are not determined, or calculations are missing/incorrect.
Recommendations and Justification (2.5 Points) Actionable recommendations (e.g., infiltration area location, landfill site) are provided and are strongly supported with clear evidence from model simulations (e.g., head maps, particle pathlines). Recommendations are provided but the justification from model results is weak or not clearly articulated. Recommendations are given but are not supported by model results. No recommendations are provided.

4.4 Modeling Report (20 points)

This section assesses the quality, clarity, and completeness of the final written report.

Criteria Excellent (100-90%) Proficient (89-75%) Developing (74-60%) Unsatisfactory (<60%)
Structure & Completeness (10 Points) The report follows the suggested outline precisely and includes all required sections. The narrative is logical, coherent, and provides comprehensive information. The report includes most required sections, but the structure may be disorganized, or some information is missing. The report is missing multiple key sections or is poorly structured. The report is incomplete and does not follow the required structure.
Quality of Figures and Tables (5 Points) All required figures are included, are of publication quality, and are clearly labeled, referenced, and explained in the text. All required figures are present but may lack professional quality, clear labels, or sufficient explanation. Several required figures are missing, or the included figures are low quality and not explained. Figures are largely absent or irrelevant.
Discussion and Professionalism (5 Points) The report presents a clear and insightful discussion of the results, assumptions, and model limitations. The writing is professional, concise, and free of grammatical errors. The discussion of results is adequate but may lack depth or critical analysis of limitations. Some grammatical errors are present. The discussion is superficial, and the report is difficult to read due to poor writing and grammatical errors. The report lacks any meaningful discussion, and the writing is unprofessional.

Tutorials

FAQs

Q.1: I can not run the model because the path to save it will not work.

A: If the path name has a dot . or special characters, you will have this issue. Keep your path name simple.

References

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