End-to-end stormwater providers spanning design, equipment, and construction for runoff quantity and quality control.

    Find a Stormwater Management Provider

    Matched providers: 39

    Top countries: United Kingdom, Netherlands

    Popular technologies: Flat Sheet UF Membranes, Hollow Fiber RO

    Stormwater Management: SuDS Design, Drainage Modelling, and Flood Risk Reduction

    Stormwater management in the UK is shaped by the requirement to implement Sustainable Drainage Systems (SuDS) under Schedule 3 of the Flood and Water Management Act 2010 (mandatory SuDS approval in Wales since 2018; England SuDS standards under NPPF/CIRIA C753). SuDS design hierarchy: source control first (permeable paving, green roofs, rainwater harvesting, soakaway); linear drainage second (swales, filter strips, vegetated channels); attenuation third (detention basins, ponds, underground storage); combined strategies to limit runoff to greenfield rate (typically 1.4 to 5 L/s/ha for 1-in-30-year event). Design standards: CIRIA C753 SuDS Manual (2015) is the primary UK design guide; Welsh Government SuDS Standards under Schedule 3; DEFRA Non-Statutory Technical Standards for SuDS (2015) covering runoff rate, volume, and water quality; LASOO (Lead Local Flood Authority Organisations) implementation guidance. Hydraulic design: peak flow attenuation to greenfield equivalent rate for all events up to 1-in-100-year (QBAR or T100 Q design); climate change uplift applied to rainfall intensity (PFEAs: +20 to +40 percent increase in peak rainfall for 2050 and 2080 climate scenarios per UKCP18); urban creep allowance (10 to 30 percent increase in impermeable area over design life); CIRIA Table 4.3 for runoff coefficient by surface type.

    Drainage modelling and hydraulic analysis: urban drainage modelling uses 1D software (Innovyze InfoWorks ICM, Autodesk Storm and Sanitary Analysis, Microdrainage WinDes) to simulate existing sewer network performance and proposed SuDS attenuation; network model calibration from flow monitoring data (electromagnetic or Doppler flow meter, data logger) in existing sewers; design rainfall inputs from the FEH (Flood Estimation Handbook, CEH Wallingford) rainfall statistics; duration-frequency-intensity (DFI) profiles for critical storm durations (15 min to 48 hours); QMED (median annual flood) and FSR rainfall for all return periods. Flood risk assessment: Sequential and Exception Test for development in flood zones (NPPF Table 2); EA Flood Zone Maps and Environmental Flood Risk Assessment data; surface water flood risk mapped using uFMfSW (updated Flood Map for Surface Water); culvert capacity assessment (CIRIA C689); catchment-wide catchment flood management plan (CFMP) context. Integration with Combined Sewer Overflow (CSO) reduction: SuDS upstream of combined sewers reduces inflow to combined network during storm events, reducing CSO spill frequency; EA requires CSO reduction plans under WINEP (Water Industry National Environment Programme).

    Water quality treatment in SuDS: stormwater runoff carries pollutants from roads (hydrocarbons, heavy metals: Zn from tyres, Cu from brake pads, Pb from historical fuel, Ni, PAHs), roofs (Cu and Zn from flashing and guttering; biocides from roofing membranes), and agricultural land (nitrates, phosphates, sediment). SuDS treatment train: filter strips (first-flush treatment; 20 to 50 m wide; remove 40 to 70 percent of SS) to swales (vegetated channel; remove 50 to 70 percent TSS, 20 to 40 percent heavy metals) to constructed wetland (detention time 24 to 72 hours; remove 60 to 90 percent TSS, 50 to 80 percent BOD, 30 to 70 percent total nitrogen, 40 to 70 percent total phosphorus) to infiltration basin or pond for final polishing. Specific pollutants: zinc from roads (EU EQS for Zn in freshwater 7.8 ug/L dissolved); PAHs (WFD priority substances; EQS for benzo(a)pyrene 17 ng/L annual average; PAH removal by activated carbon-enhanced SuDS); copper (EQS 1 to 3.4 ug/L dissolved dependent on hardness; bioavailability correction factor applies). EA SuDS adoption: public SuDS (serving more than one property) can be adopted by the LLFA or sewerage undertaker under FA 2010 Schedule 3; SuDS adoption standard requires 25-year design life with 100-year maintenance plan.

    Frequently Asked Questions

    What are SuDS and when are they required in the UK?

    Sustainable Drainage Systems (SuDS) are drainage approaches that mimic natural water movement, controlling runoff at source, slowing flow, reducing flood risk, and improving water quality, rather than channelling rainwater as fast as possible to piped drains. SuDS types: source control (permeable paving: BS EN 1338 block paving; green and brown roofs: BS 8495 specification; rainwater harvesting to BS EN 16941-1; soakaways to BS EN 752 and BRE 365 soakage test); collection and conveyance (swales: vegetated channels with side slopes 1:3 to 1:4; filter strips: 5 to 50 m vegetated buffer strips; filter drains: linear drains filled with clean stone, 600 mm to 1,200 mm wide); storage (detention basins: dry basins with permeable base; retention ponds: permanent water body; underground storage: geocellular crates at 90 to 95 percent void ratio). UK mandatory requirements: Wales: Schedule 3 Flood and Water Management Act 2010 commenced January 2019; all new drainage for development above 100 m2 must be SuDS approved by Schedule 3 Approving Body (SAB) at LPA; SuDS must meet National Standards for Sustainable Drainage. England: SuDS required by NPPF (National Planning Policy Framework) policy direction; LPA planning conditions require SuDS unless demonstrated that SuDS are not reasonably practicable; Scottish Environment Protection Agency (SEPA) SuDS mandatory for all development in Scotland under SEPA Technical Guidance.

    How is the runoff rate from a development calculated for SuDS design?

    Greenfield runoff rate calculation for SuDS attenuation design: the greenfield equivalent runoff rate is the pre-development rate of runoff from the site that the SuDS must not exceed after development. Methods: (1) Institute of Hydrology Method 124 (IH124, 1994): QBAR (median annual flood) estimated from catchment area (AREA, km2), base flow index (BFI), standard annual average rainfall (SAAR, mm), and soil permeability index (SPRHOST); urban adjustment applied for post-development impermeable fraction. (2) FEH Statistical Method: catchment descriptors (AREA, SAAR, URBEXT, BFI, FARL) from FEH Web Service; QMED estimated by pooling with gauged catchment data; growth curve scaling for T-year return period flows. (3) Simplified greenfield rate (DEFRA 2015 non-statutory standards): 1.4 L/s/ha for undeveloped sites with sandy soils; 5 L/s/ha for clay soils and steeper slopes; local LLFA may specify pre-set greenfield rates for simplicity in small developments (less than 2 ha, less than 50 dwellings). Climate change: EA and Defra 'Flood risk assessments: climate change allowances' (2019 update) require adding Higher Central or Upper End allowance to peak rainfall or peak flow depending on flood risk vulnerability; for residential development in Flood Zone 1: Higher Central +20 percent peak rainfall depth to 2089 epoch. Storage volume: SuDS storage volume calculated by critical storm method (trial storm durations from 5 to 1,440 minutes; largest storage volume requirement identifies critical duration; typically 30 to 120 minutes for urban catchments).

    What is the SuDS approval process in England and Wales?

    SuDS approval process: Wales (Schedule 3 mandatory since 2019): Developer submits SuDS drainage scheme to Schedule 3 Approving Body (SAB) at the Local Planning Authority (LPA); SAB is separate from planning department; SAB must determine application within 7 weeks of valid submission; SAB checks conformity with National Standards for Sustainable Drainage (Welsh Government 2018); SAB issues approval with conditions or rejection; adoption: SAB adopts public SuDS elements on behalf of LLFA after satisfactory completion inspection and 12-month maintenance bond; adoption gives LLFA responsibility for long-term maintenance of adopted SuDS. England (planning-led, not Schedule 3): SuDS Drainage Strategy submitted with planning application to LPA; Lead Local Flood Authority (LLFA) consulted as statutory consultee (NPPF Paragraph 167); LLFA issues objection or no-objection response; planning condition typically requires SuDS drainage scheme approval before works commence; discharge of planning condition involves surface water drainage design and management plan (SWMP) submission; adoption: sewerage undertakers may adopt compliant SuDS under Section 7 of the Flood and Water Management Act 2010 (voluntary, not mandatory in England); many LLFA refuse adoption leaving long-term maintenance with management company or residents. Scotland: SEPA SuDS mandatory for all development; building standards system; SEPA SuDS design guidance 2015 plus LDP policies.

    How do you design a SuDS pond or detention basin?

    SuDS pond and detention basin design process: (1) Site assessment: soil permeability (BRE 365 soakage test or full infiltration test per BS EN ISO 22282-2); groundwater level (winter groundwater table must be at least 1 m below SuDS base; CIRIA C753 Section 8); proximity to buildings (minimum 5 m from building foundations; EA groundwater flood risk guidance); contamination risk (EA controlled waters classification; historical site use). (2) Hydraulic design: attenuation volume calculated for critical storm (1-in-100-year plus 40 percent climate change allowance; 15-minute to 24-hour storm duration analysis); pond depth: permanent water depth 0.5 to 1.5 m; flood storage depth above permanent pool 0.3 to 1.0 m; freeboard 0.3 m; side slopes 1:3 minimum (1:5 preferred for mowing and safety; CIWEM safer by design guidance). (3) Outlet structure: control outflow to greenfield rate for all events up to 1-in-100-year; orifice plate size calculated (Q = Cd x A x sqrt(2gh); Cd = 0.6 for sharp-edged orifice); sump and debris screen upstream of orifice; emergency spillway at 1-in-100-year design water level (broad-crested weir, 0.9 m/s max velocity). (4) Water quality treatment: permanent pool provides 24-hour detention for particle settling; planting (native marginals: Phragmites australis, Typha latifolia, Iris pseudacorus; zone 1 to 4 planting per CIRIA C753); sediment forebay at inlet (sized for 10 to 15 percent of total pond volume; stone check dam to slow inlet velocity less than 0.3 m/s). (5) Maintenance plan: sediment removal every 5 to 10 years (when sediment forebay reaches 50 percent capacity); vegetation management (annual cutting; removal of non-native invasive species); outlet structure inspection annually.

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    Stormwater Management Companies

    End-to-end stormwater providers spanning design, equipment, and construction for runoff quantity and quality control.

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    Find a Stormwater Management Provider

    Showing 1-20 of 39

    39 results from 39 matched providers

    Hainan Litree Water Purification Technology Industry Co., Ltd. logo

    Hainan Litree Water Purification Technology Industry Co., Ltd.

    Verified
    China200+ employees
    Tubular Ultrafiltration Units · Hollow Fiber UF Modules · Flat Sheet UF Membranes +17 more
    apac · china · europe +3 more

    Litree: Pioneering Ultrafiltration for a Water-Secure World Founded in 1992, Litree has dedicated 30+ years to redefining water purification through ultrafiltration (UF) membrane technology—our core expertise and passion立升(Litree). As a global high-tech enterprise rooted in independent innovation, we’ve evolved from a membrane R&D startup to one of the world’s leading water problem solvers, with over 146 core patents and state-of-the-art manufacturing hubs in Haikou and Suzhou, China立升(Litree). Our signature hollow fiber UF membranes are engineered to deliver unmatched performance: 0.01μm precision removes 99.99% of bacteria, viruses, and contaminants while preserving essential minerals—striking the perfect balance between purity and health立升(Litree). This technology powers our diverse solutions, from residential whole-house systems to large-scale municipal projects and industrial wastewater treatment, all designed for sustainability and cost-efficiency. What truly sets us apart is our commitment to making safe water accessible. We’ve completed projects serving 50,000+ residents with centralized purification systems that cut construction costs and footprint by 50% compared to traditional setups—proof that advanced technology can also be affordable. Today, our solutions reach 60+ countries, supporting 3,000+ industrial clients and millions of households worldwide. At Litree, water isn’t just our business—it’s our mission. We believe every drop matters, and we’ll keep pushing boundaries to create a future where clean, safe water is a universal right, not a privilege

    Ultrafiltration (UF) Systems
    Membrane Filtration Technologies
    pH Adjustment and Neutralization
    +64 more
    agriculture
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    Ecosystems International logo

    Ecosystems International

    Verified
    Indonesia51-200 employees
    Flat Sheet Microfiltration Units · Hollow Fiber MF Systems · Ceramic Microfiltration Modules +80 more
    apac · china · europe +3 more

    PT Ecosystems International (PT ESI) was established at Jakarta on 21st November 2006. We are an industrial effluent treatment systems integrator specializing in electrocoagulation (EC), a unique waste water treatment profile. PT ESI has capabilities in designing complete waste water treatment solutions by combining various effluent treatment systems such as the electro-coagulation, biological, chemical processes and membrane filtration, offering its customers a wide and comprehensive range of solutions, tailored to suit their various needs – ranging from basic effluent treatment for discharge to effluent recycling for water reuse. The Company is experienced in handling the design, engineering, procurement, construction and operation of new Effluent Treatment Plants (“ETP”) and possesses expertise in retrofitting existing ETP to increase the flow rate and treatment capability without any major infrastructure increase PT ESI is also a premier waste water treatment service company specializing in handling waste water generated from Exploration (Drilling) and Produced Water. Customers in Indonesia include major Oil & Gas companies such as Pertamina, Exxon, Chevron, Petro-China and Medco. Operations in Indonesia are provided by both mobile and fixed units. At drill sites where waste-water recycling is required, PT ESI supplement these treatment units with skid mounted mobile Reverse Osmosis systems. The technologies and solutions employed by PT ESI are developed in-house and examples of these are its proprietary Trident™ Electro Contaminant Removal (“ECR”) system, the Stage Contaminant Removal (“SCR”) process and Mobile On-Site Waste-Water Treatment (“OWT”) units

    Reverse Osmosis (RO) Systems
    Ultrafiltration (UF) Systems
    Multi-media Filtration (MMF) Systems
    +63 more
    agriculture
    manufacturing
    Brine Consulting logo

    Brine Consulting

    Verified
    Netherlands1-50 employees
    Mechanical Vapor Recompression (MVR) · Atmospheric Evaporator · Spray Evaporator +130 more
    apac · china · europe +3 more

    BRINE CONSULTING delivers senior-level strategy, technical design, and actionable insight across the full lifecycle of water-related challenges. We support clients with advisory and due diligence, advanced brine management and resource recovery, industrial and municipal water reuse, and MLD/ZLD systems. Our team also leads ESG and climate-resilience strategy, innovation scouting, and international development and PPP advisory. With deep specialization in desalination, brine valorization, circular economy models, and high-impact infrastructure, we help organizations turn water and waste streams into opportunities, providing clear thinking, rapid delivery, and solutions built for real-world results.

    Activated Carbon Filtration
    Reverse Osmosis (RO) Systems
    Ultrafiltration (UF) Systems
    +85 more
    manufacturing
    energy-production
    BM

    Butler MS

    Ireland
    Nitrification systems for ammonia removal · Hydrodynamic vortex separators · Hydrobrake stormwater flow control
    Europe

    Butler Manufacturing Services is a family-owned company established in 1986 that manufactures packaged products for wastewater and stormwater treatment, exporting to over 50 countries. The company provides sewage treatment systems, pump stations, and surface water management solutions, supported by a free design service, operation and maintenance with repair and testing, and on-site CPD presentations. Headquartered in Longford, Ireland, it applies nitrification, vortex separation, and hydrobrake flow control across its product range.

    Free design service for sewage treatment and surface water management
    Operation and maintenance including repair and testing
    On-site CPD presentations
    +1 more
    Devram International logo

    Devram International

    Verified
    India1-50 employees
    Granular Activated Carbon (GAC) Filters · Fixed Bed Activated Carbon Adsorbers · Powdered MOF Adsorbent Systems +19 more
    apac · mea

    DEVRAM INTERNATIONAL, headquartered in Surat, India, is a pioneering enterprise specializing in Snow and Rainwater Management with advanced contamination reduction abilities for storage and artificial groundwater recharge. Established as the commercial wing of Shree Someshwar Education Trust (SSET), DEVRAM INTERNATIONAL is driven by a mission to provide tech-enabled, nature-based solutions that address the world’s most pressing water and climate challenges. The company’s work integrates Integrated Water Resources Management (IWRM) principles and contributes across the source-to-sea water management cycle, ensuring holistic restoration of the global water cycle. Its innovative portfolio includes rainwater harvesting systems, stormwater management, aquifer recharge, artificial glaciers, desert trenches, rooftop water filtration, and green infrastructure models. These interventions directly reduce salinity in soils and aquifers, restore ecological balance, and enhance resilience to droughts, floods, and climate change. As the commercial promoter of the Global Rainwater Management Program (GRMP), DEVRAM INTERNATIONAL advances the vision of GRMP as a Global Common Minimum Program (GCMP) for nations and international bodies. GRMP demonstrates how rainwater and snowwater retention can restore entire natural cycles, while delivering unmatched benefits across the Sustainable Development Goals (SDGs). Alignment with the SDGs • SDG 2 (Zero Hunger): By reducing soil salinity, supporting organic farming, and ensuring water availability for agriculture, GRMP safeguards food security. • SDG 6 (Clean Water & Sanitation): DEVRAM’s recharge structures and contamination reduction technologies guarantee safe, sustainable drinking water for communities. • SDG 7 (Affordable & Clean Energy): By reducing dependency on energy-intensive desalination, GRMP lowers national energy bills and improves hydropower capacity. • SDG 9 (Industry, Innovation & Infrastructure): DEVRAM integrates nature-based water infrastructure with industrial operations, reducing OPEX and water footprints. • SDG 11 (Sustainable Cities & Communities): Through stormwater management and aquifer recharge, GRMP mitigates urban flooding and secures municipal supplies. • SDG 12 (Responsible Consumption & Production): Promotes a circular water economy, reusing wastewater, biogas from organic waste, and aligning with industrial CSR. • SDG 13 (Climate Action): By lowering GHG emissions and cooling local climates through water cycle restoration, GRMP strengthens resilience to global warming. • SDG 14 (Life Below Water): Free-flowing rivers, improved aquaculture, and reduced dam-related aquatic pollution support marine and freshwater ecosystems. • SDG 15 (Life on Land): DEVRAM’s interventions restore wetlands, mangroves, peatlands, and biodiversity-rich ecosystems, addressing land degradation. • SDG 17 (Partnerships for the Goals): The company actively collaborates with UN agencies, governments, World Bank programs, and private investors to scale GRMP globally. Founders and Leadership Dhaval Pandya, Co-Founder of DEVRAM INTERNATIONAL and CEO of SSET, is a globally recognized sustainability leader. He co-developed the Global Rainwater Management Program (GRMP), recognized by the United Nations Global Water Partnership (GWP) and the Government of India. As a Technical Committee Member (WRD03) of the Bureau of Indian Standards (BIS), he contributes to national water policy frameworks. His work is featured in UNCCD IWRM Action Hub and global forums like COP, Stockholm World Water Week, and World Bank SDG reviews. Manalika Pandya, Co-Founder, plays a critical role in embedding social, gender, and educational dimensions into GRMP. Her focus on women empowerment, local capacity building, and community-driven adoption ensures the program’s sustainability at the grassroots. Impact and Recognition DEVRAM INTERNATIONAL has piloted groundbreaking projects such as: Kawas Village (Gujarat, India): A GRMP model village achieving self-reliance in water, organic farming, and biogas, while resolving conflicts with industries. Delhi’s Water Paradox (Figshare Study): Shows how GRMP can solve megacity water crises without costly desalination or dams. GSECL Surat Project: Demonstrates reduced industrial water costs through GRMP recharge planning, aligning profitability with SDG and ESG goals. These projects show GRMP’s potential to reduce industrial and municipal water supply costs by up 60%, avoid massive investments in desalination and dams, and enable nations to achieve water sovereignty. Core Competencies • Rainwater & Snowwater Harvesting • Artificial Groundwater Recharge & Salinity Reduction • Stormwater Management & Urban Flood Control • Transboundary Water Cooperation • IWRM & Source-to-Sea Water Governance • AI-Enabled Hydrological Modelling & Policy Analytics • Environmental Services Restoration (Wetlands, Mangroves, Peatlands) • Circular Economy.

    Activated Carbon Filtration
    Granular Activated Carbon (GAC) Filters
    Multi-media Filtration (MMF) Systems
    +25 more
    manufacturing
    utilities
    Bioclear earth logo

    Bioclear earth

    Netherlands1-50 employees
    Zero-valent Iron (ZVI) · Anaerobic Systems · Natural Zeolite Packed Columns +1 more
    europe

    Bioclear earth specializes in resolving complex environmental and soil issues. We provide sustainable solutions through research and the application of innovative environmental technology. Additionally, we support companies in the areas of knowledge development, process optimization, and sustainable business practices.

    agriculture
    manufacturing
    DALI - Pipeline Monitoring logo

    DALI - Pipeline Monitoring

    Belgium1-50 employees
    europe

    DALI - Pipeline Monitoring specializes in advanced real-time leak and intrusion detection for pipelines using Distributed Acoustic Sensing (DAS) and fiber optic technology. Their solutions help utility companies and industrial facilities minimize Non-Revenue Water (NRW) losses, reduce waste, and prevent costly incidents, ensuring efficient pipeline management.

    Online/Real-Time Monitoring
    Remote Sensing and Telemetry
    IoT and Smart Monitoring
    Utilities
    Public Administration
    PNR ITALIA Srl logo

    PNR ITALIA Srl

    Verified
    Italy51-200 employees
    Spray Evaporator · Self-cleaning Screen Filters
    apac · europe · latam +2 more
    19 case studies

    We produce a comprehensive range of spraying solutions, encompassing everything from small-scale nozzles to large industrial spraying systems. Our diverse product line includes various types of nozzles tailored to meet the specific requirements of every application and customer need. The company was established in Milan in November 1968, focusing on distributing parts and components for fire protection systems. Over time, we expanded our offerings to include a diverse range of industrial sprayers tailored to various applications. In addition to our distribution and manufacturing of fire protection system components and industrial sprayers, we specialize in designing and producing pneumatic spray nozzles for industrial use and tank washing nozzles. Our product line also encompasses a variety of complementary accessories essential for industrial washing, including filters, spray guns, and hoses. Furthermore, we offer ejectors, blower nozzles, swivel joints, and hose clamps to provide comprehensive solutions for our customers' needs. PNR Italia is part of the Tecomec Group and oversees four other affiliated companies to form PNR Company, a consolidated reality with a significant presence on the market.

    Microfiltration (MF) Systems
    Disinfection Technologies
    Disinfection Chemicals
    +7 more
    agriculture
    manufacturing
    Holland Innovation Park logo

    Holland Innovation Park

    Netherlands51-200 employees
    europe

    Holland Innovation Park by Water Alliance is a leading network and industry organization in the Netherlands, dedicated to fostering innovation and collaboration in the water and environmental technology sectors. It supports companies through expert groups, networking, and business development activities.

    Waste Management and Remediation
    Utilities
    Ixom Watercare logo

    Ixom Watercare

    United States51-200 employees
    Ion Exchange
    north-america

    Ixom Watercare specializes in innovative water treatment and distribution solutions, offering advanced equipment and technologies for wastewater, stormwater, and water reuse applications. With a focus on improving water quality and efficiency, they serve utilities and industrial sectors across North America.

    Storage Tanks and Reservoirs
    Municipal WWTPs
    Industrial Water Reuse
    Utilities
    Waste Management and Remediation
    Pollet Water Group logo

    Pollet Water Group

    Belgium200+ employees
    Filtration
    europe

    Over three decades, Pollet Water Group has been thinking water. It’s our mission to improve the quality of life, the comfort of doing business and the efficiency of industrial processes through a network of specialized water treatment companies.

    Reverse Osmosis (RO)
    Ultrafiltration (UF)
    Industrial WWTPs
    +1 more
    Utilities
    Manufacturing
    Swissenviro GmbH logo

    Swissenviro GmbH

    Switzerland1-50 employees
    Europe · Middle East & Africa (MEA)

    Swissenviro GmbH specializes in organizing Swiss Pavilions at international trade fairs, promoting Swiss environmental technologies across the globe. They provide a platform for Swiss companies to showcase their innovations in waste management, water treatment, and green energy solutions.

    Waste Management and Remediation
    Utilities
    PLR Building Services Ltd logo

    PLR Building Services Ltd

    United Kingdom

    Here at PLR Building Services, our team brings extensive experience in the water industry, specialising in top-tier electrical installation work for framework companies across the utility companies. Our primary focus is on ensuring compliance with regulatory requirements for water systems. We offer a comprehensive electrical design package and project management services. Our team is equipped with the latest health, safety, and electrical qualifications to meet all your project requirements efficiently. As a NICEIC approved contractor, we excel in both new systems installation and the refurbishment of existing installations. Water treatment Wastewater treatment Sludge treatment Pumping stations Reservoirs Inspection Testing Electrical Design Project managing

    Contractors
    Water Pumping Stations
    Technocover Ltd logo

    Technocover Ltd

    United Kingdom

    Technocover is an approved ISO 14001:2004 Environmental and ISO 9001:2008 Quality Accredited Company, dedicated to the Design, Manufacture, Installation and Maintenance of Physical Security Access Solutions for protection to all industrial sectors. Our extensive in-house design and manufacturing facilities are home to well established research and development unit and comprehensive testing facility. Our commercial offices incorporate our design team who utilise the latest computer aided design technology and work alongside our dedicated planning section who oversee everything from surveying, scheduling and contract reviews, to the management of framework agreements. We have been designing and manufacturing innovative steel products since 1993. In that time, through organic growth, planned expansion and acquisition, we have gained a reputation as the UK’s leading supplier of Physical Steel Security Access Products. We have a range of aperture security solutions for virtually every application, establishments in the UK and overseas have sought our expertise in providing security products for asset protection. We operate a Total Service Philosophy and can handle complete projects from site survey to final installation, whether for new or refurbishing projects, the adaptability of our galvanised steel access products means the most complex design criteria can be met. Our range of high quality access products offer custom built operational and security solutions to prevent unauthorised persons gaining access, securing key assets against all levels of trespass, malicious vandalism, theft, extortion, contamination or terrorism. Many of our access system products have been tested and approved by the Loss Prevention Certification Board (LPCB)  to LPS 1175 issue 5 or above, Security Rating Levels 2, 3, 4 or 5. Frameworks We hold both exclusive and shared framework agreements with most of the major UK water companies. Framework Security items include: LPCB Level 2 Universal Gas Cylinder Clamps LPCB Level 3 Mesh Cage Systems LPCB Level 3 Flush Access Covers LPCB Level 4 Upstand Access Covers LPCB Level 4 Padlockable Access Doors LPCB Level 4 Key Entry Doors LPCB Level 4 Enclosures/Kiosks/Cabinets LPCB Level 4 Walk-In Modular Buildings LPCB Level 4 Window Bar Sets LPCB Level 5 Louvres

    Security Solutions
    Asset Maintenance & Rehabilitation
    SDS Limited logo

    SDS Limited

    United Kingdom

    Protecting Water. Protecting Life.  SDS designs, manufactures and installs water management systems for sustainable infrastructure. Innovation is at the heart of what we do. Every SDS solution is intelligently engineered to protect our precious water environment effectively and efficiently. Twenty-five years ago we started with a great idea: our GEOlight® geo-cellular stormwater attenuation and infiltration system. Now SDS is the UK’s leader in Sustainable Drainage Systems with a broad product portfolio that includes solutions for flood prevention, environment protection and drought mitigation. We help our customers, both in the UK and around the world, to control, treat, store and reuse water. Our systems are used in all kinds of infrastructure projects from residential, industrial and commercial developments to leisure, highways and transportation.Our systems are engineered to be practical and cost-effective. We help to ensure they meet regulations and continue to perform as designed throughout a long life. Our customers depend on us, because we take responsibility for each element of a project from specification, design and manufacture to delivery, installation and maintenance.

    River & Coastal Flood Protection
    Contractors
    JN Bentley Ltd logo

    JN Bentley Ltd

    United Kingdom

    JN Bentley Ltd (JNB) is a leading, privately owned construction services provider in the UK. We now have an annual turnover in the region of £100 million, generated from projects in both the building and civil engineering markets. JN Bentley JN Bentley delivers civil engineering contracting services, together with mechanical and electrical expertise. Founded in 1972, the company has grown largely from repeat work, maintaining a focus on providing construction services with an open and honest approach. The JN Bentley team numbers over 2,000 colleagues. We pride ourselves on our large, directly employed construction workforce, a team that gives us and our clients added assurances for safety and quality. We look to find innovative solutions to traditional construction challenges, applying the latest technologies to drive efficiency and reach sustainable outcomes. Across JN Bentley and our design and build companies MMB and JBA Bentley, annual revenue now exceeds £500 million. Mott MacDonald Bentley (MMB) MMB provides fully integrated civil engineering feasibility, design, construction and commissioning services to the UK water sector. Established in 1999, it harnesses the contracting strength of JN Bentley and the design specialisms of Mott MacDonald to form a 3,000-strong team – with further expertise brought in from across the Mott MacDonald Group when required. MMB was formed specifically to deliver long-term, high-volume capital programmes collaboratively with water companies. With a focus on innovation, affordability, and flexibility, since securing its first contracts with Yorkshire Water in AMP3, MMB has grown to deliver work for eight of the largest water companies in the UK.

    Renewables & Energy Management
    Contractors
    Enisca Ltd logo

    Enisca Ltd

    United Kingdom

    Enisca is a multi-disciplinary design, engineering and construction business operating in the power and environmental sectors delivering innovative, sustainable and quality solutions for public and private sector clients in these markets. Enisca has developed and maintained strong partnerships and collaborative relationships in our industry. Our focus on safety, our customers’ needs, programme, cost and the efficiency of project delivery support our key objective of ensuring high levels of customer satisfaction. Design and construct Our experienced and skilled engineering teams work in partnership with our clients and related stakeholders from an optioneering stage through the cycle of design, construction, commissioning, training and handover to the aftercare of asset operation and maintenance. Process & MEICA design services. Feasibility ctudies and cite surveys. Carbon/energy and whole life cost assessment. Water treatment and pumping. Wastewater treatment and pumping. Industrial effluent treatment. Process plant and controls. Turnkey mechanical and electrical installation. Commissioning and training Our experienced skilled commissioning engineers (process, mechanical and electrical/control systems) endeavour to provide clients with a seamless, trouble free handover of completed projects from pre-commissioning through to process proving and training of operators. Power, control and automation Enisca Automation is the motor control centre and control systems integration division of Enisca. Enisca Automation provides a range of power distribution, control and automation solutions to a range of public, commercial and industrial clients. The Automation Division is TickIT accredited and our engineers work in partnership with our clients through the cycle of design, manufacture, commissioning, training and handover. Enisca Automation aftercare provision includes planned maintenance and service with emergency callout. MCC manufactured solutions to Form 2 and Form 4. ICA, SCADA, HMI and systems integration. G5/4 harmonic studies and reports. Power factor correction and surge protection. Thermographic surveys. Certified Profibus design and installation. Enisca Automation customers include a range of engineering & building services contractors, commercial and industrial business clients. Utilizing fully automated design, materials management, assembly and testing processes Enisca can supply product in compliance with the rigorous standards set out in BS EN 60439-1:1999 for low voltage switchgear and control gear assemblies, all products are fully CE certified. Process plant The in-house capabilities of our business set us apart. With the process, civil, mechanical, electrical and chemical engineering skills of our people we design and construct turnkey water and wastewater treatment and pumping solutions. In-house we design and manufacture water and wastewater process plant that can be incorporated into overall solutions. Our Power, Control and Automation Division designs, builds and commissions the motor control centres, automation software and SCADA systems that control our plants. Package treatment plants – Wastewater treatment for municipal and industrial applications. Package treatment plants – Potable water applications. Process plant manufacture. Screens. Scraper bridges. Picket fence thickeners. Package DAF plants. Package pumping stations and booster sets. Chemical dosing plants. Stormwater attenuation and pumping. Sampling and recording. Operation and maintenance Our operations and service engineers provide operation, maintenance, service and callout support. We have a strong, resourceful team to manage utility and industrial process plant installations. The Enisca Automation aftercare provision, includes planned maintenance and service with emergency callout.

    Networks - Water Supply
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    AVK UK Ltd logo

    AVK UK Ltd

    United Kingdom

    AVK UK is part of the globally renowned AVK Group who are based in over 100+ countries and has over 4,500+ employees worldwide. The AVK Group is privately owned by the founder Niels Aage Kjaer, and is named after his father Aage Valdemar Kjaer. As part of the AVK Group, we pride ourselves in being one of the leading valve manufacturers for the water, sewage, firefighting, and gas industries. Our product program comprises a large range of valves, hydrants, pipe fittings and accessories, each complying with the highest standards of safety and durability. Our focus is on the products designed and manufactured to the British Standards, however, the AVK Group today offers products in accordance with the most national and international standards. Our product portfolio also includes AVK Smart Water Management valves and sensors for real-time network information and status. We also offer Pressure Management solutions such as air valves, PRVs, and control valves, AVK Assist which enables GPS product location and, the market leading Donkin PUR range of gas valves. Our UK sales offices and manufacturing sites respond quickly to the needs of our customers and for fittings required on an express or emergency service we have a dedicated same day 24/7 helpline – 0800 202 8228. In addition, we cooperate with local and national distributor partners to offer our customers AVK products as part of multi-product packages. AVK UK is the sales division and has offices in Staveley, near Chesterfield, also known as the home of Bryan Donkin gas valves, and Northampton. AVK in the UK comprises of 7 companies and has over 500 employees. Find out more here: https://www.avkuk.co.uk/en-gb/solutions-and-information/about/avk-in-the-uk/avk-uk

    Treatment Works Products/Services
    Asset Maintenance & Rehabilitation
    Coleman James logo

    Coleman James

    United Kingdom

    At Coleman James, our purpose is to connect top talent with ambitious businesses in the built environment and rail sectors, helping companies and candidates grow and prosper. Dynamic, driven, capable, knowledgeable and culturally aligned; we employ a razor-sharp focus to searching for and selecting the very best people. We do this through our niche, dedicated team of award-winning recruitment consultants, who have over 200 collective years of experience and knowledge of your industry. We’re known for our long-standing relationships, enviable contacts book, broad network and our bespoke methodology, making us the specialist recruitment agency of choice for building services, civil engineering, construction, facilities management and rail. Ours is a consultative, tailored approach. Our clients don’t simply transact with us; instead, we build long-term, collaborative partnerships. We pay attention to the details, from pre-screening to psychometric testing, we match the right people to the right roles. We add value at every turn; we’re problem solvers who operate with absolute integrity, delivering customer excellence at every step and tangible results you can rely on.

    Recruitment
    Spray Nozzle People logo

    Spray Nozzle People

    United Kingdom

    Suppliers of spray systems and solutions, including the StormBlaster™ stormwater attenuation tank cleaning system, the ScreenBlaster CSO screen cleaning head and specialised spray solutions for odour control, foam suppression and other water and wastewater applications. There are many applications for spray nozzles and systems within the water and wastewater treatment sector. SNP have worked on projects for most of the main water suppliers in the UK & Ireland as well as with many in Europe and beyond. We have listed some key applications for spray nozzles below. For a full list of applications and for further details on key applications, follow the menu to the right. Cleaning systems The United Kingdom’s water industry is poised for its most ambitious transformation yet under the AMP8 (Asset Management Period 8) investment cycle, which runs from 2025 to 2030. Backed by an unprecedented £108 billion investment, the largest in the sector’s history, AMP8 is focused not only on maintaining and upgrading ageing infrastructure but also on addressing growing environmental and regulatory challenges. A significant £11 billion of this total has been earmarked specifically for stormwater and sewage spill mitigation, reflecting mounting pressure from regulators, the public, and environmental groups to curb pollution in rivers, lakes, and coastal waters. At the heart of this environmental push lies the urgent need for more stormwater retention tanks and combined sewage overflow (CSO) systems. It is estimated that some 2,000 such systems will need to be updated, refurbished or built in the AMP round of funding. This stormwater management infrastructure is vital if the target of reducing spills and sewage discharges into waterways by 44% is to be met. Much of this new infrastructure will require specialised cleaning systems. Storm water attenuation tanks can cause serious smell pollution if left improperly cleaned after usage. The StormBlaster tank cleaning system is a more effective alternative to tipping buckets, swirl eductors and manual entry cleaning. Screen cleaning Combined Sewer Overflows (CSOs) are a key feature of combined sewer systems, where rainwater and wastewater share the same pipework. During heavy rainfall, these systems can become overwhelmed without proper control measures. CSO chambers manage excess flows by allowing water levels to rise and diverting surplus into overflow pipes. A crucial component of CSOs is the screening system, which traps solids and keeps them within the sewer network. This prevents solid waste from entering local waterways and protects the environment. Foam control The formation of a stable foam in the water treatment process is a common problem. Foam can occur in aeration tanks, anaerobic digesters or secondary clarifiers. Foam is undesirable because it can overflow vessels, create slippery and unsafe working conditions, interfere with processing, damage materials, and cause tanks to drain and dry slowly. Controlling foam can be accomplished by spraying liquid onto the pool, vessel, or reservoir’s surface and allowing the spray’s droplets to impact the foam bubbles, causing them to break. Spray nozzle arrays positioned above fluid level can be used to knock back the foam and keep it under control. Odour control The use of sprays to knock down and neutralise odour is a common application for our spray nozzles. Nozzles are either used to directly treat odour particles in the air or as part of scrubber systems.

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    Stormwater Management: SuDS Design, Drainage Modelling, and Flood Risk Reduction

    Stormwater management in the UK is shaped by the requirement to implement Sustainable Drainage Systems (SuDS) under Schedule 3 of the Flood and Water Management Act 2010 (mandatory SuDS approval in Wales since 2018; England SuDS standards under NPPF/CIRIA C753). SuDS design hierarchy: source control first (permeable paving, green roofs, rainwater harvesting, soakaway); linear drainage second (swales, filter strips, vegetated channels); attenuation third (detention basins, ponds, underground storage); combined strategies to limit runoff to greenfield rate (typically 1.4 to 5 L/s/ha for 1-in-30-year event). Design standards: CIRIA C753 SuDS Manual (2015) is the primary UK design guide; Welsh Government SuDS Standards under Schedule 3; DEFRA Non-Statutory Technical Standards for SuDS (2015) covering runoff rate, volume, and water quality; LASOO (Lead Local Flood Authority Organisations) implementation guidance. Hydraulic design: peak flow attenuation to greenfield equivalent rate for all events up to 1-in-100-year (QBAR or T100 Q design); climate change uplift applied to rainfall intensity (PFEAs: +20 to +40 percent increase in peak rainfall for 2050 and 2080 climate scenarios per UKCP18); urban creep allowance (10 to 30 percent increase in impermeable area over design life); CIRIA Table 4.3 for runoff coefficient by surface type.

    Drainage modelling and hydraulic analysis: urban drainage modelling uses 1D software (Innovyze InfoWorks ICM, Autodesk Storm and Sanitary Analysis, Microdrainage WinDes) to simulate existing sewer network performance and proposed SuDS attenuation; network model calibration from flow monitoring data (electromagnetic or Doppler flow meter, data logger) in existing sewers; design rainfall inputs from the FEH (Flood Estimation Handbook, CEH Wallingford) rainfall statistics; duration-frequency-intensity (DFI) profiles for critical storm durations (15 min to 48 hours); QMED (median annual flood) and FSR rainfall for all return periods. Flood risk assessment: Sequential and Exception Test for development in flood zones (NPPF Table 2); EA Flood Zone Maps and Environmental Flood Risk Assessment data; surface water flood risk mapped using uFMfSW (updated Flood Map for Surface Water); culvert capacity assessment (CIRIA C689); catchment-wide catchment flood management plan (CFMP) context. Integration with Combined Sewer Overflow (CSO) reduction: SuDS upstream of combined sewers reduces inflow to combined network during storm events, reducing CSO spill frequency; EA requires CSO reduction plans under WINEP (Water Industry National Environment Programme).

    Water quality treatment in SuDS: stormwater runoff carries pollutants from roads (hydrocarbons, heavy metals: Zn from tyres, Cu from brake pads, Pb from historical fuel, Ni, PAHs), roofs (Cu and Zn from flashing and guttering; biocides from roofing membranes), and agricultural land (nitrates, phosphates, sediment). SuDS treatment train: filter strips (first-flush treatment; 20 to 50 m wide; remove 40 to 70 percent of SS) to swales (vegetated channel; remove 50 to 70 percent TSS, 20 to 40 percent heavy metals) to constructed wetland (detention time 24 to 72 hours; remove 60 to 90 percent TSS, 50 to 80 percent BOD, 30 to 70 percent total nitrogen, 40 to 70 percent total phosphorus) to infiltration basin or pond for final polishing. Specific pollutants: zinc from roads (EU EQS for Zn in freshwater 7.8 ug/L dissolved); PAHs (WFD priority substances; EQS for benzo(a)pyrene 17 ng/L annual average; PAH removal by activated carbon-enhanced SuDS); copper (EQS 1 to 3.4 ug/L dissolved dependent on hardness; bioavailability correction factor applies). EA SuDS adoption: public SuDS (serving more than one property) can be adopted by the LLFA or sewerage undertaker under FA 2010 Schedule 3; SuDS adoption standard requires 25-year design life with 100-year maintenance plan.

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    Frequently Asked Questions

    What are SuDS and when are they required in the UK?

    Sustainable Drainage Systems (SuDS) are drainage approaches that mimic natural water movement, controlling runoff at source, slowing flow, reducing flood risk, and improving water quality, rather than channelling rainwater as fast as possible to piped drains. SuDS types: source control (permeable paving: BS EN 1338 block paving; green and brown roofs: BS 8495 specification; rainwater harvesting to BS EN 16941-1; soakaways to BS EN 752 and BRE 365 soakage test); collection and conveyance (swales: vegetated channels with side slopes 1:3 to 1:4; filter strips: 5 to 50 m vegetated buffer strips; filter drains: linear drains filled with clean stone, 600 mm to 1,200 mm wide); storage (detention basins: dry basins with permeable base; retention ponds: permanent water body; underground storage: geocellular crates at 90 to 95 percent void ratio). UK mandatory requirements: Wales: Schedule 3 Flood and Water Management Act 2010 commenced January 2019; all new drainage for development above 100 m2 must be SuDS approved by Schedule 3 Approving Body (SAB) at LPA; SuDS must meet National Standards for Sustainable Drainage. England: SuDS required by NPPF (National Planning Policy Framework) policy direction; LPA planning conditions require SuDS unless demonstrated that SuDS are not reasonably practicable; Scottish Environment Protection Agency (SEPA) SuDS mandatory for all development in Scotland under SEPA Technical Guidance.

    How is the runoff rate from a development calculated for SuDS design?

    Greenfield runoff rate calculation for SuDS attenuation design: the greenfield equivalent runoff rate is the pre-development rate of runoff from the site that the SuDS must not exceed after development. Methods: (1) Institute of Hydrology Method 124 (IH124, 1994): QBAR (median annual flood) estimated from catchment area (AREA, km2), base flow index (BFI), standard annual average rainfall (SAAR, mm), and soil permeability index (SPRHOST); urban adjustment applied for post-development impermeable fraction. (2) FEH Statistical Method: catchment descriptors (AREA, SAAR, URBEXT, BFI, FARL) from FEH Web Service; QMED estimated by pooling with gauged catchment data; growth curve scaling for T-year return period flows. (3) Simplified greenfield rate (DEFRA 2015 non-statutory standards): 1.4 L/s/ha for undeveloped sites with sandy soils; 5 L/s/ha for clay soils and steeper slopes; local LLFA may specify pre-set greenfield rates for simplicity in small developments (less than 2 ha, less than 50 dwellings). Climate change: EA and Defra 'Flood risk assessments: climate change allowances' (2019 update) require adding Higher Central or Upper End allowance to peak rainfall or peak flow depending on flood risk vulnerability; for residential development in Flood Zone 1: Higher Central +20 percent peak rainfall depth to 2089 epoch. Storage volume: SuDS storage volume calculated by critical storm method (trial storm durations from 5 to 1,440 minutes; largest storage volume requirement identifies critical duration; typically 30 to 120 minutes for urban catchments).

    What is the SuDS approval process in England and Wales?

    SuDS approval process: Wales (Schedule 3 mandatory since 2019): Developer submits SuDS drainage scheme to Schedule 3 Approving Body (SAB) at the Local Planning Authority (LPA); SAB is separate from planning department; SAB must determine application within 7 weeks of valid submission; SAB checks conformity with National Standards for Sustainable Drainage (Welsh Government 2018); SAB issues approval with conditions or rejection; adoption: SAB adopts public SuDS elements on behalf of LLFA after satisfactory completion inspection and 12-month maintenance bond; adoption gives LLFA responsibility for long-term maintenance of adopted SuDS. England (planning-led, not Schedule 3): SuDS Drainage Strategy submitted with planning application to LPA; Lead Local Flood Authority (LLFA) consulted as statutory consultee (NPPF Paragraph 167); LLFA issues objection or no-objection response; planning condition typically requires SuDS drainage scheme approval before works commence; discharge of planning condition involves surface water drainage design and management plan (SWMP) submission; adoption: sewerage undertakers may adopt compliant SuDS under Section 7 of the Flood and Water Management Act 2010 (voluntary, not mandatory in England); many LLFA refuse adoption leaving long-term maintenance with management company or residents. Scotland: SEPA SuDS mandatory for all development; building standards system; SEPA SuDS design guidance 2015 plus LDP policies.

    How do you design a SuDS pond or detention basin?

    SuDS pond and detention basin design process: (1) Site assessment: soil permeability (BRE 365 soakage test or full infiltration test per BS EN ISO 22282-2); groundwater level (winter groundwater table must be at least 1 m below SuDS base; CIRIA C753 Section 8); proximity to buildings (minimum 5 m from building foundations; EA groundwater flood risk guidance); contamination risk (EA controlled waters classification; historical site use). (2) Hydraulic design: attenuation volume calculated for critical storm (1-in-100-year plus 40 percent climate change allowance; 15-minute to 24-hour storm duration analysis); pond depth: permanent water depth 0.5 to 1.5 m; flood storage depth above permanent pool 0.3 to 1.0 m; freeboard 0.3 m; side slopes 1:3 minimum (1:5 preferred for mowing and safety; CIWEM safer by design guidance). (3) Outlet structure: control outflow to greenfield rate for all events up to 1-in-100-year; orifice plate size calculated (Q = Cd x A x sqrt(2gh); Cd = 0.6 for sharp-edged orifice); sump and debris screen upstream of orifice; emergency spillway at 1-in-100-year design water level (broad-crested weir, 0.9 m/s max velocity). (4) Water quality treatment: permanent pool provides 24-hour detention for particle settling; planting (native marginals: Phragmites australis, Typha latifolia, Iris pseudacorus; zone 1 to 4 planting per CIRIA C753); sediment forebay at inlet (sized for 10 to 15 percent of total pond volume; stone check dam to slow inlet velocity less than 0.3 m/s). (5) Maintenance plan: sediment removal every 5 to 10 years (when sediment forebay reaches 50 percent capacity); vegetation management (annual cutting; removal of non-native invasive species); outlet structure inspection annually.

    Case Study·Residential development
    Challenge

    A 320-dwelling residential development in Cheshire on a former greenfield site needed to demonstrate SuDS compliance under NPPF policy and achieve greenfield runoff equivalence for a 1-in-100-year storm with 40 percent climate change uplift, while also satisfying the Lead Local Flood Authority's requirement for SuDS adoption.

    Approach

    A treatment train was designed: permeable block paving on the estate road (CBPP to BS EN 1338, 20 percent void ratio) draining to roadside bioretention cells with iron-amended sandy loam media; bioretention overflow directed to a 1,800 m3 retention pond (permanent pool 0.8 m; 1.2 m flood storage; 1:4 side slopes; native planting zones 1 to 3). Outlet was controlled by a 125 mm orifice plate delivering 4.2 L/s (equivalent to 1.4 L/s/ha greenfield rate) to a receiving beckett. CIRIA C753 guidance and FEH rainfall statistics governed all hydraulic calculations.

    Outcome

    The SuDS drainage scheme was approved by Cheshire East LLFA's SAB-equivalent process in England; total SuDS capital cost was GBP 285,000 (GBP 890 per dwelling). The retention pond was adopted by the LLFA under the Section 7 Flood and Water Management Act 2010 framework, with a 100-year maintenance plan secured by a Section 106 agreement. Post-construction hydraulic monitoring confirmed peak runoff of 3.9 L/s in a significant storm event against a greenfield target of 4.2 L/s.

    Questions to Ask Shortlisted Providers

    1. 1

      Has the LLFA pre-application process been completed and what are their specific adoption criteria for SuDS on this site?

      Different LLFAs apply substantially different standards for SuDS adoption; early pre-application engagement prevents designing to CIRIA C753 only to find the LLFA has additional requirements that require costly redesign.

    2. 2

      How are climate change rainfall uplifts applied in your hydraulic calculations and which UKCP18 epoch and vulnerability class have you used?

      The EA's flood risk climate change allowances differ by vulnerability class and epoch; residential development in Flood Zone 1 uses different uplifts from highly vulnerable development in Flood Zone 2, and using the wrong values voids the hydraulic calculations.

    3. 3

      What BNG (Biodiversity Net Gain) contribution will the SuDS features provide and how have they been scored under the Defra BNG Metric version 4.0?

      Mandatory 10 percent BNG from April 2024 means SuDS must be designed as habitat features, not just hydraulic structures; wetland pond and native planting scores can make the difference between achieving BNG on-site or purchasing expensive statutory biodiversity credits.

    4. 4

      What sediment forebay sizing and maintenance protocol have you assumed and who is responsible for dredging under the adoption agreement?

      Sediment forebays fill at 2 to 5 percent per year in typical residential catchments; if the maintenance protocol requires dredging every 5 years and that obligation is not clearly assigned to the estate management company, it will fall back to the developer.

    5. 5

      Have you modelled the interaction between the proposed SuDS attenuation and the downstream sewer capacity in a 1-in-10-year event?

      Planning conditions often require SuDS to also protect the downstream combined sewer from surcharging at intermediate return periods; a design optimised for 1-in-100-year flood storage may not protect the 1-in-10-year sewer.

    What Drives Cost in This Category

    SuDS area requirement relative to developable land

    A well-designed SuDS scheme for a 2-hectare residential site requires 8 to 15 percent of site area for attenuation and treatment features; in a high-value urban location where each m2 of developable land is worth GBP 500 to 1,500, SuDS area has a real land opportunity cost that drives pressure to minimise pond size.

    Soil permeability and groundwater depth

    Clay soils (k less than 10-6 m/s) preclude infiltration-based SuDS entirely; all attenuation must be above-ground or in oversized geocellular storage, increasing cost by 30 to 60 percent compared to a free-draining sandy site where soakaways provide storage.

    Biodiversity Net Gain specification

    Designing a SuDS pond as a rich habitat feature (native planting to CIRIA C753 Zone 1 to 4; loafing banks for wildfowl; varied substrate) rather than a bare engineered basin adds GBP 15,000 to 40,000 in specification but generates BNG units that may avoid GBP 42,000 to 650,000 per biodiversity credit costs from the EA.

    Long-term maintenance and adoption liabilities

    A SuDS pond not adopted by the LLFA or sewerage undertaker must be maintained by a management company indefinitely; annual SuDS maintenance costs of GBP 3,000 to 10,000 per year, capitalised at 3.5 percent over 100 years, represent a GBP 85,000 to 285,000 long-term liability that should be priced into the development appraisal.

    Key Regulations & Standards

    NPPF and DEFRA Non-Statutory Technical Standards for SuDS (2015)

    All major planning applications in England must demonstrate compliance with NPPF SuDS policy and DEFRA's non-statutory technical standards covering runoff rate (greenfield equivalent), volume, and water quality; LPAs use these standards as the basis for planning conditions.

    Schedule 3 Flood and Water Management Act 2010 (Wales)

    In Wales, Schedule 3 has been mandatory since January 2019; all new drainage serving more than 100 m2 must be SuDS approved by the SAB at the Local Planning Authority before construction; SuDS must meet Welsh Government National Standards for Sustainable Drainage.

    Environment Act 2021 - Mandatory BNG (10 percent)

    From April 2024, all new major developments in England must achieve a minimum 10 percent net gain in biodiversity units calculated using the Defra Statutory Biodiversity Metric 4.0; SuDS features including wetland ponds and bioretention cells with native planting contribute habitat units toward the mandatory BNG target.

    EA Flood Risk Assessments: Climate Change Allowances (2019)

    Sequential and Exception Tests for development in flood zones require the EA's current climate change allowances to be applied to all flood risk assessments and drainage designs; for residential development in Flood Zone 1, the Higher Central allowance (+20 percent peak rainfall depth to 2089 epoch) must be applied as a minimum.

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    Comparing stormwater management companies is one slice of a larger shortlisting decision. Explore the complete directory of wastewater treatment companies, then filter by region, sector, and technology before you request scoped proposals.

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