Options development and appraisal for the Isle of Wight

Our approach to options development and appraisal (ODA) is explained in a technical summary.

We commenced the ODA process at the river basin catchment (RBC) scale (level 2 planning) in order to look across all the wastewater systems in the river basin. This enabled us to consider generic options that could work at the catchment scale, as well as those specific to a wastewater system. 

The generic options are grouped into those that help tackle the risks at ‘source’, those that help to improve the wastewater system ‘the pathway’, and those that protect or mitigate the impacts on the receiving waterbodies, ‘the receptors’.

This process helped to identify the types of options that could be used individually or in combination with other options. The generic options which have been screened as the type of options to progress further in the planning process for each wastewater system can be downloaded using the links in the table below.

We held meetings with partner organisations to build upon the list of generic options relevant to the wastewater system. As a group we identified and proposed options to take forward into the evaluation stage to consider the benefits (positive and negative) and costs of each option. The meetings generated a long list of ‘unconstrained’ options. The options proposed were to tackle the drivers and causes of risks identified during the Problem Characterisation stage of the DWMP.

The appraisal stage involved evaluating each of the options in two stages, firstly to screen out unviable options to leave a set of ‘constrained’ options, and then a second stage to reduce the list further to leave only potentially ‘feasible’ options. The process for evaluating the benefits and how we have taken the environment into account is set out in our Strategic Environmental Assessment (SEA) Scoping Report and the SEA Progress Report. At this stage of the ODA process, the options were then costed so a preferred option could be selected.

Our preferred options are set out in Investment Needs table for the Sandown system, which was the only system in the Isle of Wight that we took through the option development and appraisal stage of the DWMP. The accompanying map shows the location of the proposed options within the wastewater system. Because the size of the Sandown system is so extensive, we have also broken down the map into a number of constituent sub-catchments.

The options and investment needs are not committed funding but an identification of the needs for funding. We will include these options in our future business plans as part of the Ofwat periodic review of Water Company funding to secure the investment needed to implement these options.

System ref. Wastewater system Generic options screening Investment needs Investment needs map
SAND Sandown Sandown Options Screening Investment needs Sandown Map
Newport Map
Ryde Map
Shanklin Map
Wooton Map
Yarmouth Map
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