Rainwater Management

United Utilities (UU) wishes to engage the market to support the delivery of Rainwater Management schemes across the North West of England. The Environment Act and subsequent Storm Overflow Discharge Reduction Plan (SODRP) have introduced a statutory requirement to significantly reduce the operation of storm overflows, with all storm overflows expected to spill no more than ten times per year by 2050.

Approximately 54% of United Utilities' wastewater network is a combined sewer system, conveying both surface water and wastewater to Wastewater Treatment Works (WwTWs) or Combined Sewer Overflows (CSOs) prior to discharge to the environment. This framework will enable United Utilities to appoint Contractors to deliver Rainwater Management solutions that reduce the volume of surface water entering the combined sewer network.

Through the implementation of nature-based and sustainable drainage interventions, the framework aims to mitigate the impacts of storm overflows, improve network resilience, and contribute to the achievement of regulatory and environmental objectives. United Utilities’ (UU) Rainwater Management strategy is founded on Sustainable Drainage principles, which prioritise the capture, reuse and management of rainwater as close as possible to where it falls.

The strategy promotes the use of surface conveyance, infiltration, disconnection and attenuation to slow the movement of water through the catchment and reduce pressure on the wastewater network. This approach, combined with measures to improve water efficiency, creates additional capacity within wastewater catchments, reduces demand for potable water, and maximises value by delivering wider environmental, social and economic benefits through the creation of blue-green infrastructure.

By increasing the use of Rainwater Management interventions, UU can reduce its reliance on traditional, carbon-intensive engineering solutions, such as underground storage tanks, while delivering best value outcomes for customers and the environment. Whilst many of the individual interventions are well-established and proven, the scale and pace of delivery proposed by UU is unprecedented within the sector.

The opportunity lies in developing and deploying these solutions at scale, working collaboratively with customers, businesses, Local Authorities, and other key stakeholders to drive widescale delivery and maximise catchment-wide benefits. The current Rainwater Management Programme identifies approximately 6,500 interventions across the United Utilities network area.

However, Bidders should note that the programme remains subject to ongoing development and refinement may include up to 10,000 interventions over the framework term. Interventions will be delivered across the five county areas served by United Utilities: Cumbria, Lancashire, Cheshire, Greater Manchester and Merseyside.

Particular focus is anticipated within Greater Manchester and Merseyside over AMP8, reflecting the strategic importance of these areas, the presence of Combined Authorities, and the objectives set out within their respective Integrated Water Management Plans (IWMPs). Rainwater Management Intervention Types Attenuation Pond: holding water body, suitable in large natural spaces only Bio-retention: pollution control incorporated into intervention design Blue Roof: smart water storage to catch rainwater and slow the return period Disconnection: surface water systems or extraneous rainwater from the combined network to a more suitable receiver e.g. water course.

Downpipe Disconnection: from residential and business buildings, e.g. butt rainwater planter. Filter Drain: trench filled with gravel, water infiltrates to ground Green roofs: water retaining layer beneath a growing medium and planting for additional benefits e.g. air quality, biodiversity.

Natural Flood Management (NFM): landscape solutions to manage uplands to retain rainwater where it falls e.g. leaky dams, catchment planting Permeable Paving: water infiltrates to ground or stored/ attenuated underground Rain Garden: surface planting, water infiltrates to ground or stored/ attenuated underground Soakaway: excavation filled with gravel and landscaped. Water infiltrates to ground Swale: shallow wide channel to catch, slow the flow or infiltrate water to ground.

Can be wet and/ or dry Tree Pit: underground system combining urban tree planting with drainage that captures stormwater Landscape Maintenance & Management: services to undertake appropriate landscape maintenance such as mowing, watering, visual inspections, re-planting, silt removal. Disconnections Contractors will be responsible for the Design and Build of low complexity surface water disconnection works, where existing surface water pipes connected to the combined sewer network will be diverted to a more suitable receiving system.

This may include connection to existing surface water sewers, or discharge via Rainwater Interventions such as rain gardens, attenuation ponds etc. Minor Works Streets Contractors will be responsible for the Design and Build of Rainwater Management interventions located within highways. These will comprise of non-complex standardised design solutions; however, Contractors will be expected to apply appropriate design judgement, innovation and technical capability to adapt solutions to site-specific constraints, stakeholder requirements and opportunities for wider environmental or placemaking benefits.

The Contractor will be responsible for managing Traffic Management and gaining the necessary consents/ permits/ license, therefore holding the necessary Street Works Qualifications. In addition, demonstrate the appropriate balance of technical capability and relevant experience to successfully deliver nature-based solutions, encompassing both civil engineering and green infrastructure/landscape expertise.

Minor Works – Five S’s Contractors will be responsible for the design and build of Rainwater Management interventions on private sites with a specific focus on schools, supermarkets, stations, state buildings (e.g. hospitals), and social housing sites. Solutions are expected to be low complexity to support delivery at pace and may range from product-based interventions through to bespoke site-specific designs.

Contractors will need to consider practical delivery constraints within live environments, such as school playgrounds, supermarket car parks, hospital estates and residential settings. In addition to improving rainwater management, successful solutions should seek to deliver wider social, environmental and community benefits by creating attractive, functional and usable spaces for the people who use them.

Examples may include: Interactive and educational outdoor environments for schools Calming and attractive spaces that support wellbeing within healthcare settings Planted areas that improve local amenity and help promote a sense of community within social housing sites Major Works Contractors will be responsible soley for the delivery of the Works (construction) on complex packages comprising of multiple Rainwater Management Interventions across a range of typologies within a single scheme. Interventions may include, but are not limited to, permeable paving, rain gardens, swales, and detention basins.

And could be located within highways, public open space, catchment land, public realm. Design services will be provided by others, either by United Utilities' in-house team or by Design Partners appointed through a separate United Utilities framework.

The Contractor shall provide suitably qualified and experienced resources with the appropriate balance of civil engineering, green infrastructure, and landscape expertise also managing construction, to support the successful delivery of nature-based solutions in both rural and urban locations. Natural Flood Management (NFM) NFM requires specialist environmental contractors to design and build nature based solutions such as leaky dams, wetlands, earth bunds and catchment planting such as woodland buffer strips or sphagnum moss.

Habitat restoration, hydraulic assessment and traditional land management construction capabilities are essential for success. Along with working within designated and highly protected landscapes and with sensitive land owners.

This may include products designed or specified by United Utilities, including those where United Utilities owns or controls the intellectual property, alongside supplier-proposed products or product developments. Products may include, but are not limited to, water butts, rainwater planters, SuDS planters, modular attenuation or storage products, and associated components.

Suppliers shall demonstrate the ability of repeatability and delivery at scale in terms of manufacturing, storage, distribution arrangement and installation capability. Also, the ability to deliver in the UU technical, operational and customer environment.

Surveys & Investigations Contractor will provide Survey Works to support the delivery of the Rainwater Management Programme. This will include, Topographical, Ground Penetrating Radar (GPR) Drainage (Connectivity, CCTV, MH cards), Impermeable Area Survey (IAS), Contaminated Surface Water (CSW) for cross connections and infiltration tests (BRE 365)