Investment Planning and Prioritisation Group (IPPG) report: quarter 1 2022 to 2023

Section 3 – Progress of the development of interventions with Level 1 and 2 appraisals

The purpose of this section is to provide:

• An overview of the progress of interventions that are subject to Level 1 and 2 appraisals^[1] and their impact on the Progress to Committed List (PCL)
• Highlights from significant Level 1 or 2 project investment appraisals completed in the last quarter
• Delivery: A review of lessons learnt from the delivery of PIA forecast in the last quarter and a look ahead to the next quarter.

At the end of Quarter 1 2022-23, PCL was 111%, indicating that we are developing sufficient volumes of investment across the programme to achieve planned investment in future years. Level 1 and 2 project investment appraisals contribute around 25% to the PCL target for the year and we are to be within 2% of our forecasts at the end of the year.

Highlights from project investment appraisals completed within the quarter are included in Table 2.

Project Investment Appraisal Highlights

Black Esk WTW

Stage 3b (G70), April 2022

The areas supplied by Black Esk WTW have a history of regulatory standards being exceeded for microbiology and disinfection by-products, with the latter exceeding averages for Scottish Water and England & Wales. The shared Black Esk & Winterhope WOA has the highest number of customer contacts for discolouration in Scotland^[2]. Other high priority needs agreed with DWQR include providing automatic shutdown and run-to-waste; lead compliance; and Operational Technology.

Black Esk is subject to a DWQR letter of commitment which sets out Gate 70 completion by April 2022, Gate 80 completion by October 2023 and Acceptance by July 2027.

The option selected uses ion exchange and ceramic membranes technologies and will deliver significant water quality benefits through the production of very high-quality water. The membranes provide an absolute barrier to Cryptosporidium and produce bacteriological cell counts 100 times lower than a traditional DAF/RGF process. The option taken forward to Gate 80/90 is the lowest net present cost (NPC) and provides wider benefits.

The Stage 3a PIA has previously been shared. As the project progresses to Stage 4 (Gate 80/90) this will be shared. DWQR have been engaged on the progress.

Daer WTW

Stage 3a (G50) June 2022

During summer 2021, the Daer supply zone experienced a serious water quality incident when high levels of manganese in the water leaving Daer WTW caused numerous discolouration exceedances and thousands of customer complaints. As a result, Daer is now subject to a Letter of Commitment to the DWQR, bringing forward the wider appraisal to consider the strategic approach for the previously confirmed needs, updated for the recent manganese driven incident.

The preferred option for Daer WTW at Stage 3a is to (i) maximise the performance of the existing works and (ii) to make permanent the interim manganese reduction measures implemented in 2021, in a way that minimised disinfection byproduct formation. The option for a dedicated manganese removal stage will continue to be developed, a decision on whether to progress this to delivery will be taken at a later stage.

The PIA has been shared with stakeholders to present the preferred option - with an engagement session completed in August 2022.

Dunside Reservoir

Stage 2 May 2022

Dunside Upper and Lower raw water reservoirs were originally built in 1880 and provided drinking water to the local network. For approximately the past 15 years, the reservoirs have been non-operational following rationalisation of the local network.

As both reservoirs hold a volume of water greater than 25,000m3 they are required to comply with the Reservoir (Scotland) Act 2011 (The Act). The last 10-yearly reservoir inspection was completed of Dunside Upper in May 2021 and identified Measures in the Interest of Safety (MIOS) items that will need to be addressed for the reservoir to comply with The Act.

The Stage 2 PIA considered options including relinquishing ownership of the reservoir and surrounding land, management of water levels, and engineered and natural infrastructure solutions. Options taken forward to appraisal at Stage 3a include breaching the reservoir, or reducing the volume, and utilising the land for carbon capture (tree planting). Costing is not completed at Stage 2.

The PIA will be shared at Stage 3a with stakeholders.

Delivery: A review of lessons learnt from the delivery of PIA forecast in the last quarter

Overall, 15 project investment appraisals stages were completed within the quarter (36% of the initial number forecast). There are three main themes driving the missed forecasts:

• The main theme has been confirmation of scope & costing which has impacted on 20 appraisals. We have learnt that appraisals have required more time to consider wider range of options and to develop a more robust evidence base. This has affected the availability of scope and costing information for completion of PIA within Stage 2, 3a and 3b. The costing of options is available once technical scope is completed.

• The second theme is the ongoing reprioritisation of the programme – In the quarter there were 9 additions to the original forecast (an additional 20% of demand); 3 projects were closed down/removed from L1/2 PIA requirements (7% of the initial forecast) and 5 projects were reforecast based on the need to review against the interconnectivity with other projects.

• The third theme - has been the timescale to undertake the investigation work required which has impacted on 3 appraisals. The duration of investigation work such as water mains testing and equipment condition assessments has been challenging to forecast for a number of project.

The forecast for 2022-23 is shown below (Table 4) and the details are provided in Appendix 3.