Programme appraisal

The Programme Appraisal brings the investment needs for each wastewater system together into an investment needs programme for the Cuckmere and Pevensey Levels Catchment. We look across the river basin catchment to review the investments needed, the timing of these needs and how they combine to reduce the risks to our customers and the environment.

We also look at the wider risk reduction that each option provides across all the planning objectives. Some actions, like separating rainwater from wastewater sewers, could reduce risks under several planning objectives such as storm overflows, external flooding, bathing water quality, shellfish water quality and good ecological status. The details of the method for prioritisation can be found in our Technical Summary on Programme Appraisal.

The investment needs in the Cuckmere and Pevensey Levels River Basin Catchment include:

• Reducing the number of spills from the 66 storm overflows which together currently spill around 1200 times per annum
• Separating or attenuating excess rainwater in the sewer networks to reduce the risks of flooding and frequency of storm overflow discharges, especially in Bexhill, Hastings, Newhaven and Hailsham
• Investigating the potential impact of wastewater discharges on Good Ecological Status in designated Habitats at Cuckmere, Pevensey and Hastings
• Developing a nutrient budget by investigating the sources impacting designated habitats sites at Cuckmere and the Pevensey Levels
• Planning for potential significant development at Bexhill-on-Sea
• Addressing saline intrusion and tide locking as part of the Blue Heart Project and Pevensey Bay to Eastbourne Coastal Management Scheme
• Improving the resilience of our networks and treatment works to prevent pollution incidents, particularly in Bexhill, Eastbourne and Hailsham
• Reducing the risk of sewer blockages by increasing sewer jetting and targeting customer campaigns to reduce the amount of FOG (fats, oils and grease) and unflushables in the sewer network around Eastbourne, St. Leonards (Warrior Square) and Castle Hill, Hastings
• Reducing the risk to groundwater by reducing leakage from our sewers in the Westham area of Eastbourne.

Investment Needs for the river basin catchment

We progressed four wastewater systems through the ODA stage in the first cycle of the DWMP. These four wastewater systems serve a population of around 300 000 which is approximately 93% of customers in this river basin catchment.

We extrapolated the investment needs for these four systems to the other 14 systems in the Cuckmere and Pevensey Levels river basin catchment. This provides an estimate of the total investment needs required to reduce the risks in all our wastewater systems in the catchment to Band 0 (not significant). This concept of “Band Reduction” and full details of the process for extrapolation is explained in the Technical Summary on Programme Appraisal.

A graph to illustrate the extrapolation of investment needs across the whole river basin catchment is shown in figure 1.

Figure 1: Cuckmere and Pevensey Levels: Extrapolated Investment Needs and Risk Band Reduction

The programme appraisal for the Cuckmere and Pevensey Levels identified the following

• A total of 48 band reductions are required in 2020 to reduce the risks across the 14 Planning objectives in the 4 wastewater systems
• By 2050, this requirement will increase to 54 band reductions due to the impact of climate change, growth and creep.
• The options identified to date would cost around £443 million for the 4 systems and is expected to provide 26 Band reductions in 2050 (the options do not result in a Band 0 for all risks)
• The Cuckmere and Pevensey Levels consists of 18 wastewater systems, which require 73 band reductions in 2020 and 88 band reductions by 2050 in order to achieve band 0 across 14 planning objectives.
• Extrapolating the investment needs for all the systems in the Cuckmere and Pevensey Levels will cost around £1.01 billion for a population of 322,000. This illustrates the scale of investment needed to get to Band 0 by 2050 for all 14 planning objectives.

These investment needs provide indicative costs that allow us to understand the level of funding required to reduce the risks. The funding has not been secured at this stage. The DWMP informs the development of our 5 yearly Business Plan which is submitted to our economic regulator, Ofwat, to agree how we should invest the money received from our customer bills.