• Introduction

In this assignment, you are tasked with analysing the flow records from Mooloolah River at Mooloolah (Station Number 141006A). The Mooloolah River is in the Maroochy Basin.

The boundary of the Maroochy basin is shown in blue in Figure 1, with the location of the gauging station shown by the red dot.

The background image for the catchment is from Google maps, which has been plotted in Figure 1 using the “ggmap” and “maptools” packages. Don’t forget you have to use the install.packages( ) command before you can load them using the library command. This map is imported using the default projection in Google map, and the type is “terrain”.

Figure 1: Maroochy Basin boundary (red line) showing Mooloolah River at Mooloolah Gauging station (red dot).

The outline for the Maroochy River catchment boundary, shown in blue in Figure 1, was obtained from the Queensland Government wetlands information server

(This file is available in a kml format by clicking on the “Download Boundary KML” button on the right of the Wetland information server page). Open the file in Google earth, and you can download the kml file through the File, Save, Save Place as menu option, and save as a KML file.

The details of the Mooloolah River at Mooloolah gauging station can be obtained from the Queensland Goverment water monitoring portal.

The Task

For the Mooloolah River at Mooloolah gauging station, you have been tasked with implementing flow duration curves and a flood frequency analysis in R.

a report is required as part of the Html (or pdf) document. The length of the document should be such that it sufficiently conveys how and why you did the analysis you did and meets the requirements outlined in the criteria.

The flood frequency analysis you are required to undertake is to fit a flood probability model to the Annual Maximum Series.

The following steps are required to be implemented in knitr and uploaded to Bb. You should include both the .Rmd and html or pdf files that are produced (the marks assigned to each part are in []):

  1. Construct three flow duration curves using (i) all the data, (ii) the low flow months, and (iii) the high flow months. You will need to first construct a monthly Box and Whisker plot to determine the months to include in each category. [10%]
  2. Extract the Annual Maximum Series from the daily data, and compare with the Annual Maximum Series extracted from the annual data (from the Qld Water Monitoring Portal). [10%]
  3. Construct three empirical distribution functions (or probability plots) using the Annual Maximum Series and the three plotting position formula from the revised Book 3 of ARR [20%]
  4. Fit a distribution to the plot and comment on it’s fit and why you chose it.[10%]
  5. Apply confidence limits to the distribution. [10%]
  6. Comment on the largest flood in the record, and estimate it’s AEP.[10%]

Assessment Criteria

Additional criteria under which you will be assessed are:

Criteria / Weighting
The R code is set up to be dynamic
(ie. other stations can be analysed
by simply changing the station number) / 10%
The description of the methods implemented
and choices made are clear / 10%
Error and uncertainty are incorporated
(ie. a sensitivity analysis is implemented) / 5%
Standard of report with appropriate referencing / 5%