Anglian Water is the largest water and water recycling company in England and Wales by geographic area. They work to bring environmental and social prosperity through their commitment to Love Every Drop.

System Description

Anglian Water supplies water and water recycling services to almost seven million people in the East of England and Hartlepool. Optimatics and Anglian Water focused on the Louth sewer collection system for this pilot application. An InfoWorks ICM™ hydraulic model of the system, which included projected future growth, was used for the analysis. The projected population was 19,000, the area was 755 ha, and the network length was 94 km. The system consists of a main wastewater collection system covering the city of Louth and additional small systems covering small villages in the northeast.

Purpose

As part of their Drainage and Wastewater Management Plan (DWMP), Anglian Water used Optimizer to target DG5 flooding locations, where existing confirmed flooding occurring within the network needed to be reduced or eliminated under future growth conditions.

The main objective was to find the most cost-effective strategy to accommodate the anticipated growth while preventing any detriment in terms of flooding or CSOs. All water is conveyed to a single treatment plant located in Northeast Louth. Capacity limitations within the existing conveyance system prevent additional flow from being conveyed to the treatment plant during wet weather events and present significant challenges for reducing or eliminating flooding and CSOs.

Outcomes

With Optimizer for ICM, the following three strategies were first considered independently and then combined in the same formulation: impervious area reduction, conveyance upsizing, and offline storage.

Optimizer demonstrated how holistically considering all decisions simultaneously within an optimisation could provide a better strategy than a traditional manual approach that considered the different options independently first and then combined and adjusted through manual iterations.

There was no room in the current system to reroute flow in order to remove flooding and CSOs where they occurred. Water had to be removed or detained within the collection system either by reducing the inflow or by providing storage. There were no “easy wins” in terms of large-scale conveyance upgrades; significant conveyance upgrades on their own only pushed hydraulic deficiencies downstream. Only targeted conveyance in combination with storage and inflow reduction strategies could provide the necessary hydraulic improvements.

Inflow reduction optimisation results were combined with SuDS Studio data to provide more realistic results of what levels of inflow reduction could be achieved in reality. This dataset was also used to inform constraints on how the inflow reduction had to be implemented on the subcatchments identified by Optimizer.

I think this would flow better: The Optimizer™ analysis showed that a holistic approach that optimizes all strategies simultaneously can help identify a better, more cost-effective solution than a traditional approach, which constructs a solution piece by piece by testing different strategy types individually. Optimizer found the most optimal combinations of specific inflow reduction, conveyance, and storage strategies for a given cost. Of particular interest in the results findings was that the best locations for storage in a storag-eonly solution are dramatically different than the best locations for storage in a holistic storage/conveyance/inflow reduction solution, stressing the importance of a truly holistic approach.