Response to Reviewers

Reviewer 1
- Comment: Replace or substantially justify the use of the Rational Method with a more appropriate hydrological model for an urban setting, detailing its limitations.
  Response: Addressed in the revised manuscript.
- Comment: Expand the methodology section to explicitly address data limitations, uncertainty analysis, and assumptions in both hydrological modelling and economic appraisal.
  Response: Addressed in the revised manuscript.
- Comment: Restructure the abstract to be concise and complete, ensuring it accurately reflects the full study's scope and key findings.
  Response: Addressed in the revised manuscript.
- Comment: Strengthen the discussion by comparing findings with similar studies in other African cities and explicitly addressing practical implementation barriers in Juba's context.
  Response: Addressed in the revised manuscript.

Reviewer 2
- Comment: Conduct proper hydrological model calibration using observed flood data and multiple rainfall stations
  Response: Addressed in the revised manuscript.
- Comment: Provide detailed methodology for field survey design including sampling strategy and quality assurance procedures
  Response: Addressed in the revised manuscript.
- Comment: Strengthen literature review with specific focus on urban drainage studies in similar developing city contexts
  Response: Addressed in the revised manuscript.
- Comment: Include sensitivity analysis for cost-benefit assumptions and clearly document all economic parameters
  Response: Addressed in the revised manuscript.

Reviewer 3
- Comment: Substantially revise the methodology section to justify model selections, document data limitations, and validate hydrological outputs against independent observations.
  Response: Addressed in the revised manuscript.
- Comment: Complete and transparently report the cost-benefit analysis methodology, including all assumptions, parameter values, and sensitivity testing.
  Response: Addressed in the revised manuscript.
- Comment: Provide explicit discussion of study limitations regarding data quality, model simplifications, and generalisability of findings.
  Response: Addressed in the revised manuscript.
- Comment: Standardise language to British English conventions throughout and restructure the abstract to focus on key findings rather than methodological details.
  Response: Addressed in the revised manuscript.