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Coursework Brief - Surface water
Water Resource Planning and Management - MACE40402
Assignment description
To support water resource management, a water company has hired you to develop a rainfall-runoff model to assess
available water resources in one of their catchments. The company is especially interested in the ability to predict
reliably the occurrence of future low flow periods in order to understand potential risks posed by climate and land
use change to water users and freshwater ecosystems in the catchment.
Based on this brief, your task is to implement, calibrate and validate the GR4J rainfall-runoff model using observed
climatological and streamflow data for the catchment. Before starting your analysis, you will need to access and
download: (i) observation data (climate, streamflow, and information about relevant catchment characteristics) for
your assigned catchment, (ii) copy of the Matlab toolbox and associated scripts needed to perform calibration and
validation of the GR4J rainfall-runoff model. More details on how to access these are provided on page 3 of this brief
under section ‘Observation data and code’.
Once you have downloaded observation data for your catchment and model code files, your task is then to use
the information covered in lectures and supplementary reading for Module 1 of this unit to complete the following
analyses and then write a short report about your results and findings. Details about the report format and guidelines
are provided on page 2 of this brief under the section heading ‘Report structure’.
1. Conduct a preliminary analysis of the streamflow observation data for your assigned catchment. Explore
how streamflow varies over the observed historical record (both between and within years), and assess how
streamflow variability relates to climatic, topographic, land cover, soil and/or hydrogeological characteristics
of the catchment provided within the supplementary dataset files.
2. Modify and complete the Matlab script ‘MACE40402 CW1 AutoCalibration.m’. Once all missing parts of this
script are completed, run the script to perform an automated calibration of the GR4J model for your catch-
ment using the inbuilt local gradient-based search algorithm function (fminsearchbnd). Record the optimised
parameter values you obtain, along with relevant performance statistics illustrating the quality of the model
fit to observed data. Repeat this analysis for different initial parameter guesses, and explore if and how these
choices affect the resulting optimised values of model parameters and resulting fit to observed streamflow.
3. Modify and complete the Matlab script ‘MACE40402 CW1 URS.m’. Once all missing parts of this script are
completed, run the script to perform a batch run of the GR4J model for different potential parameter sets
using a uniform random sampling approach. Explore how model performance differs from results obtained
previously using the local gradient-based optimisation algorithm in part 2, and evaluate how any differences in
model performance using the uniform random sampling approach are affected by the choice of sample size.
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Assessment and submission
You should produce a short report (pdf format) summarising the findings of your analysis. The length of the report
must not exceed 2000 words, not counting any title, contents, or bibliography pages. A suggested structure for the
report is provided in the following section of this document, along with a breakdown of marks allocated to each
component of the analysis and report. You must include appropriate figures, tables, and supporting references when
discussing your analysis and the findings you obtain. Please provide a statement of your word count on the title page
- any reports exceeding the allowable word limit will be marked down.
The deadline for submitting this piece of coursework is 6pm on Friday 26 March 2021. You should submit your
report using the Turnitin link in the folder ‘.../Coursework/CW1 - Surface water/...’ on Blackboard. Please also
submit the completed versions of the two Matlab scripts used in parts 2 and 3 of your coursework using the respective
assignment submission links in the same folder. Coursework will be checked for plagiarism and collusion using the
Turnitin software, and any evidence of academic malpractice will be taken very seriously by the department and the
University.
This assignment is worth 20% of the total mark for this unit. Late submissions will be deducted 10% per day, and
any submissions received more than 4 days late (i.e. after 6pm on Tuesday 30 March) will be graded zero.
Report structure
It is suggested that you begin your report with a short introductory paragraph describing the objectives of the pro-
posed work. This should be in your own words - do not simply copy from the brief! The main body of your report
should then contain the following information relating to the three core tasks outlined above, with marks weighted
as outlined in brackets below:
Part 1 (20%): Describe the location, physical characteristics/attributes, and streamflow regime for your catchment.
You description should clearly evidence how streamflow varies over the observed historical record (both between and
within years), and explain this in terms of catchment characteristics and dominant runoff generation processes. You
should use relevant information provided in the supplementary files provided in the CAMELS-GB dataset to support
this discussion and evaluation of your catchment’s streamflow responses and regime.
Part 2 (40%): Report the optimised parameter values you obtain using gradient-based optimisation, along with
relevant performance statistics illustrating the quality of the model fit to observed data. Include a description and
justification of the objective function used to evaluate model performance, and provide suggestions for any discrep-
ancies between simulated and observed streamflow values. Discuss to what extent your results are affected by initial
parameter guesses, and explain why these choices do or do not affect the resulting optimised values of model param-
eter and fit to observed streamflow data.
Part 3 (40%): Report how optimised parameter values obtained using uniform random sampling differ from those
obtained using the gradient-based optimisation algorithm in part 2, and to what extent these changes are affected
by the choice of sample size. Based on these results discuss the relative strengths and weaknesses of uniform random
sampling as a calibration approach relative to local gradient-based optimisation. You may wish to comment on the
computational efficiency of this approach (and suggestions for how this could be enhanced) along with the usefulness
of this approach for understanding parameter sensitivity and uncertainty.
While no specific marks are allocated for the quality of the report presentation, please pay careful attention to the
way you structure, report and present your work. Unclear or incomplete wording, a lack of relevant supporting
figures and/or tables, and failure to include relevant supplementary references will lead to a loss of marks. A title
page and bibliography should also be included in your report.