CIV3285 Engineering Hydrology | My Assignment Tutor

CIV3285 – 2021 – Assignment 2Page | 1MONASH UNIVERSITYDEPARTMENT OF CIVIL ENGINEERINGCIV3285 Engineering Hydrology (2021)Group Size: Students are to work in groups of 4Max. mark 10% (of total unit mark)Water Balance ModellingAssignment 2 – Due Tuesday, 25 May 2021, 3pm[1] As part of a consultancy project that deals with potential contaminant sources within acatchment, your team has been previously tasked with the development of a simple dailywater balance model for obtaining the daily change in water storage 𝑑𝑆𝑑𝑡, where𝑑𝑆𝑑𝑡= 𝑃 – 𝐸 – 𝑅 (Eq. 1)where S is the storage of water within the soil [mm]; P is precipitation [mm/day]; E isevapotranspiration [mm/day]; and R is the total runoff (i.e., the sum of surface runoff Rs andbaseflow Rb) [mm/day]. Rb [L/T] can be expressed as a function of the free water storage:Rb = k * S. You will need to calibrate k and the soil’s infiltration capacity using a simplecalibration approach (running a combination of all k and infiltration combinations anddeciding on the best run using an objective function).[2] Unlike in Assignment 1 the observed daily evapotranspiration was provided as the inputforcing data. However, in Assignment 2, it will be calculated by your water balance model(WBM). This is achieved by obtaining ETp based on the BoM climatology maps (as in thepractice classes), utilizing the relation between ETp and S for the calculation of ETa, (seethe lecture contents covered in Week 3).[3] For the initialisation of your storage (S), you will need to make an assumption of S thatis reasonable for the location and starting time of your simulation.[4] As a simplifying assumption, the soil depth can be set to 785 mm, with a wilting point at0.12, field capacity at 0.33, and saturation at 0.45 (all in volumetric soil moisture, i.e. m3 m-3).[5] Test your WBM parameters (e.g., total size, field capacity, and wilting point) carefully byinvestigating their sensitivities to the model response individually. Remember that once yourmodel has reached the wilting point, no more water can be removed, and once the store isfull, no more water can be entered the already saturated soil.[6] Another important task in Assignment 2 is the “calibration and validation”. In this task,the standard “split-sample test” is used (i.e., using 1/2-1/3 of the total data length forcalibration with the remaining data for validation). Only using the observed streamflow asthe calibration target will be sufficient. The Monte-Carlo simulation approach (i.e. run yourmodel with each parameter combination) should be used for this purpose whereby at least100 runs for each parameter should be sufficient to find a good minimum function. Eachtime, calculate your objective function (e.g. the Nash-Sutcliffe coefficient) and store it in amatrix that 100×100 large. You can then find the run with the best value amongst all runs.CIV3285 – 2021 – Assignment 2Page | 2You have a total of 12 years (2005-2016) at your disposal to calibrate and validate yourmodel.[7] In the next few days, you will also receive the BoM’s soil moisture data for the sameperiod. Compare both BoM’s runoff and soil moisture against your runoff and storage terms.Discuss briefly the potential differences. Remember that this comparison needs to beundertaken on the part of the data that you have not used for the calibration.[8] In your report, briefly explain your model set up (focus on the new parts, the waterbalance has already been presented in Assignment 1) and how you created the differentruns. Show your results for the matrix of the objective function and discuss its variation orlack thereof. Also show and discuss how similar or different the runoff and soilmoisture/storage of your model and the BoM data are.CIV3285 – 2021 – Assignment 2Page | 3This assignment is worth 10% towards the final grade for the subject. Lateassignments will receive a penalty of 10% of the total assignment value per day (includingweekend days), unless an extension has been previously applied for and approved inwriting.Submission RequirementsSubmission is to be in the form of a typed report in A4 by the deadline to the Moodlesubmission tab for Assignment 1. The report should:• not exceed 10 A4 pages (excl. table of contents, executive summary, but incl. figures,not counting the appendices such as the Matlab script), with exact margins of 2cm on allsides, either with Times New Roman (12pt) or Arial (11pt). The formatting of the reportis to be as a professional report, with minimal grammatical mistakes, correct punctuation,and good formatting. 10% of the overall mark will be given to the layout of the reportitself;• you may present a summary of your results (in tabular form) in the body of the reportalong with figures that may be appropriate;• an appendix may be used (and not counted towards the page limit), but can only be usedas an essential support mechanism, e.g. for submitting your MATLAB script (do not insertscreenshots, only the actual text) or showing large tables.CIV3285 – 2021 – Assignment 2Page | 4Data SectionThe data files for the different groups have been uploaded to Moodle and can be found in afolder within the Assignment 1 section. The different teams are to use the following datasets:Groups 1-12 : Adelaide (ADL)Groups 13-24 : Brisbane (BRS)Groups 25-36 : Darwin (DRW)Groups 37-48 : Hobart (HOB)Groups 49-60 : Melbourne (MEL)Groups 61-72 : Perth (PER)Groups 73 & above : Sydney (SYD)The content of the files is as follows:– Files named qtot_*.mat contain daily runoff data.– Files named rain_A2_*.mat contain daily precipitation.– All data sets are provided in mm day-1.


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