The Hydro International consulting team developed a new Hydro-Logic® Aquator model to help South Staffordshire Water develop a new Water Resources Management Plan encompassing a range of climate change scenarios. 

Situation

South Staffordshire Water (SSW), a UK water utility, needed to undertake a multi-stage water resource modelling project in support of its water resource planning activities.

The project involved the following stages:

1. Develop a new Aquator model based on SSW’s existing WRAPSim water resource allocation model.
2. Update and refine the model to accommodate changes made to system assets and operations. Model refinement included a comprehensive review of the Blithfield inflow time series using HYSIM.
3. Use the updated model to support SSW in preparing its draft Water Resources Management Plan (WRMP), specifically to determine system deployable output under a set of climate change scenarios.

Problem

SSW wished to move from their existing WRAPSim models to the Hydro-Logic® Aquator water resources modelling platform.

Water resources models are complex, however, and critically underpin statutory water resources and drought planning in water companies. They are also subject to change (e.g. new hydrological or asset data) and may be improved to meet future modelling needs; any changes to model results had the potential to impact on company supply-demand investment planning, and to be subject to external regulatory and stakeholder scrutiny.

With this in mind, close attention was required on the performance of the new model and to understand and validate any differences in the results. This is particularly important considering that the models are used for statutory planning purposes.

In this case, the existing WRAPSim model was to be used as the benchmark for the new model, prior to further developments.

Solution

The Hydro International Data, Insight & Analysis team understood that moving to a new Hydro-Logic® Aquator model and subsequently developing this capability required a diligent approach, including detailed audit and analysis with reference to the legacy models. The new Aquator model needed to achieve an acceptable level of agreement with the legacy WRAPSim models in terms of the calculated DO over the historic simulation period, to be achieved prior to further improvements or changes in the data. A full review of the legacy models was also required, supported by close dialogue between the Hydro- Logic® Services team and SSW to ensure effective migration into Aquator.

The successful development of the Stage 1 model was consolidated by a detailed audit report, explaining the resultant build of the new model and reconciliation of the underpinning schematics, licenses, hydrological data, control rules, demand data and asset capacities. 

In Stage 2 the team adopted a workshop approach (complemented by day to day communications) to further develop the model to reflect the latest datasets and defined improvements, a number of which were identified as recommendations following the Stage 1 build. This allowed close working between the team and SSW, working incrementally through different data types for update and improvement following an initial scoping of the approach.

To fully justify and understand the impacts of model changes from the baseline, the team logged changes in the model and assessed and checked the impacts on Deployable Output (DO) at each phase. The team also completed sensitivity tests on the DO results for key aspects, or to enhance understanding.

Outcome

The Stage 1 model was completed on schedule, and compared favourably with the original model. Stage 2 was then implemented over 20 phases, each examining the effects of a specific class of change, and was completed on schedule eight months later. Stage 3 used the model to examine a series of climate change scenarios using datasets perturbed according to the UKCP09 Climate Projections developed by HR Wallingford.

As a result, the new Hydro-Logic® Aquator model successfully informed SSW’s development of its Water Resources Management Plan.