Preprints
https://doi.org/10.5194/egusphere-2024-326
https://doi.org/10.5194/egusphere-2024-326
22 Feb 2024
 | 22 Feb 2024
Status: this preprint is open for discussion.

Developing water supply reservoir operating rules for large-scale hydrological modelling

Saskia Salwey, Gemma Coxon, Francesca Pianosi, Rosanna Lane, Chris Hutton, Michael Bliss Singer, Hilary McMillan, and Jim Freer

Abstract. Reservoirs are key components of many water supply systems, providing functional capability to manage, and often mitigate, hydrological variability across space and time. The presence and operation of a reservoir controls the downstream flow regime, such that in many locations understanding reservoir operations is crucial to understanding the hydrological functioning of a catchment. Although substantial progress has been made in modelling reservoir operations, several key challenges remain, particularly for large-scale applications including hundreds of reservoirs. In these cases, generic and uncalibrated reservoir operating rules are often applied. However, these rules were developed from global reservoir databases that consist mostly of large irrigation reservoirs and thus are not transferable to smaller reservoirs or those fulfilling other purposes, such as water supply. An alternative option is to use a calibrated, data-driven approach but such techniques require reservoir inflows, outflows and storage data which are rarely available across hundreds of reservoirs. To overcome these problems, here we design a set of simple reservoir operating rules (with only two calibrated parameters) focused on simulating small water supply reservoirs across large scales with various types of open access data (general catchment attributes such as surface area or reservoir capacity, and flows at downstream gauges). Using Great Britain as a case study, we integrate our rules into a national-scale hydrological model and compare hydrological simulations from two modelling scenarios, with and without the new reservoir component. Our simple reservoir operating rules significantly increase model performance in reservoir-impacted catchments, particularly when the rules are calibrated individually at each downstream gauge. We also test the feasibility of using transfer functions (which transform reservoir and catchment attributes into operating rule parameters) to identify a nationally-consistent parameterisation. This works well in ~50 % of the catchments, while nuances in individual reservoir operations limit performance in others. We suggest that our approach should provide a lower benchmark for simulations in catchments containing water supply reservoirs, and that more complex methods should only be considered where they outperform our simple approach.

Saskia Salwey, Gemma Coxon, Francesca Pianosi, Rosanna Lane, Chris Hutton, Michael Bliss Singer, Hilary McMillan, and Jim Freer

Status: open (until 18 Apr 2024)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2024-326', Anonymous Referee #1, 20 Mar 2024 reply
  • RC2: 'Comment on egusphere-2024-326', Anonymous Referee #2, 11 Apr 2024 reply
Saskia Salwey, Gemma Coxon, Francesca Pianosi, Rosanna Lane, Chris Hutton, Michael Bliss Singer, Hilary McMillan, and Jim Freer

Data sets

Flow outputs, parameter sets and performance metrics from the best performing model simulations (associated with both a catchment-by-catchment and nationally-consistent calibration) Saskia Salwey https://doi.org/10.5523/bris.3elcv1fhj0cxl2u45mmkb8y8op

Model code and software

DECIHeR model code Gemma Coxon and Saskia Salwey https://github.com/uob-hydrology/DECIPHeR

Saskia Salwey, Gemma Coxon, Francesca Pianosi, Rosanna Lane, Chris Hutton, Michael Bliss Singer, Hilary McMillan, and Jim Freer

Viewed

Total article views: 400 (including HTML, PDF, and XML)
HTML PDF XML Total Supplement BibTeX EndNote
314 73 13 400 38 8 8
  • HTML: 314
  • PDF: 73
  • XML: 13
  • Total: 400
  • Supplement: 38
  • BibTeX: 8
  • EndNote: 8
Views and downloads (calculated since 22 Feb 2024)
Cumulative views and downloads (calculated since 22 Feb 2024)

Viewed (geographical distribution)

Total article views: 414 (including HTML, PDF, and XML) Thereof 414 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
1
 
 
 
 
Latest update: 18 Apr 2024
Download
Short summary
Reservoirs are essential for water resource management and can significantly impact downstream flow. However, representing reservoirs in hydrological models can be challenging, particularly across large-scales. We design a new, simple method for simulating river flow downstream of water supply reservoirs using only open-access data. We demonstrate the approach in 264 reservoir catchments across Great Britain where we can significantly improve the simulation of reservoir-impacted flow.