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Sustainable drainage systems technical guide

Sustainable drainage systems technical guide
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Sustainable drainage systems technical guide

Product catalog summary
The Environment
Sustainable drainage systems (SUDS) are crucial for managing stormwater in the face of climate change and urban development. They replicate natural drainage processes to prevent flooding and support groundwater replenishment, aligning with environmental policies.
Environmental Policy
Marley Plumbing & Drainage, part of the Aliaxis group, is dedicated to sustainable practices, adhering to environmental legislation, enhancing performance, and increasing the use of recycled materials. The company complies with BS EN ISO 9001:2008 and BS EN ISO 14001:2004 standards.
Key Components
The Waterloc250 modular geocellular unit is designed for efficient water storage with a 96% void ratio, minimizing excavation needs. It offers easy assembly, high loading capacity, and design flexibility. The Flowloc vortex controller manages water discharge rates, ensuring consistent flow.
Regulations and Guidance
Documents like PPS25 and the Pitt Review highlight the importance of SUDS in flood risk management. In Scotland, legislation requires Scottish Water to maintain public SUDS. CIRIA publications provide best practices for SUDS implementation.
Applications
Waterloc250 cells are used in infiltration systems to temporarily store surface water, allowing natural dispersion into the soil. These systems require less volume than traditional soakaways and depend on soil permeability. Geotextile wrapping is necessary for installation, and multiple inlet chambers can be used for larger schemes.
Flow Control and Attenuation Systems
Overview: The document discusses stormwater management systems focusing on attenuation and infiltration techniques. These systems temporarily store stormwater and release it at a controlled rate to prevent overloading downstream pipelines and watercourses.
Attenuation Systems: Attenuation involves storing water in a chamber and releasing it slowly using a vortex flow control unit or orifice plate. Proper sizing of the attenuation tank is crucial to prevent upstream flooding. Tanks must be encapsulated within an impermeable membrane and geotextile.
Hydraulic Design: Hydraulic design considers rainfall intensity, storm duration, and return periods. Rainfall intensity is inversely related to storm duration, and the critical duration must be determined for storage or infiltration designs. Return periods help assess storm frequency and intensity, with guidance from statutory bodies.
Infiltration Systems: Infiltration systems allow water to disperse into the ground. Two design methods are discussed: BRE 365, using only the sides of the soakaway, and CIRIA 156, including the base and sides. Important considerations include ensuring soakaways empty within 24 hours and are located at least 5 meters from buildings.
Design and Sizing Calculations: Computer software is recommended for calculating stormwater management system sizes. For smaller areas, BS EN 752-4:2008 provides guidance. The document includes a table showing effective height increments for Waterloc250 cells.
Structural Design: Structural design uses limit state design philosophy to ensure tanks support imposed loads. Considerations include ultimate limit state and serviceability limit state of deflection. Guidance is provided on installation depths and cover for different applications.
Installation Guidelines: Installation involves positioning Waterloc250 cells on a prepared sand bed with a geotextile or impermeable membrane. The base plate must be fixed to the first layer of cells, and subsequent layers interlock vertically.
Conclusion: The document provides comprehensive guidelines for designing and implementing stormwater management systems, emphasizing the importance of accurate calculations and site-specific data.
Installation Procedures: The document outlines the installation process for sustainable drainage systems using Marley Waterloc250 cells. The cells should be aligned and secured with base cell clips, and further layers are rotated 180° for interlocking without additional clips. The top cell connector secures the entire construction.
Pipe Connections: Marley offers various options for inlet and outlet pipe connections ranging from 110mm to 300mm. The WLRE250 is suitable for 110mm and 160mm pipes, while WLRE250L and WLRE250M are for 225mm and 300mm pipes. Installation involves aligning and securing the connector to the mounting plate and ensuring a tight fit with the impermeable membrane.
Flow Control and Silt Traps: The document describes the use of Flowloc vortex flow control units and silt traps for managing water flow. The USW30 chamber base can be installed in a concrete manhole or with a riser piece, requiring a level base and proper bedding. The UG60 silt trap should be installed with a pea shingle bed and solvent cement for bonding.
Typical Installation Details: Several configurations are provided for soakaways and attenuation tanks, including the use of geotextile protection fleece, impermeable membranes, and granular surrounds. Detailed instructions are included for fitting risers, sealing membranes, and ensuring proper drainage flow.
Key Specifications:
  • Use of silicone sealant for sealing membranes.
  • Installation of 600mm riser kits with clamps and seals.
  • Requirement for 150mm concrete bed and surround for stability.
  • Use of 100mm sharp sand base for foundational support.
Recommendations: Ensure all connections are leak-tested before backfilling, and use appropriate materials for sealing and securing components. Follow the specified configurations for optimal performance and compliance with drainage standards.
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Catalog excerpts

Sustainable drainage systems technical guide-1

Plumbing & Drainage Solutions

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Sustainable drainage systems technical guide-3

sustainable drainage systems geocellular unit is the result of extensive research and testing This improved product forms part of the range of Marley sustainable drainage systems, which also includes the Flowloc vortex controller. Plumbing & Drainage Solutions

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Sustainable drainage systems technical guide-4

have necessitated dealt with. Sustainable drainage systems (SUDS) provide an effective way of mimicking natural drainage before development takes place; whether to counteract the effect of overloading gravity pipelines and watercourses, which can contribute to flooding downstream; or conversely, dealing with rainwater run off on site to replenish ground water levels, particularly in times of water forefront of environmental policy marley.co.uk Technical hotline: 01622 852695

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Sustainable drainage systems technical guide-5

sustainable drainage systems ground SUDS solutions: ■ No health and safety risk ■ Adaptability to suit site conditions Compared with the more traditional metl storage, such as concrete rings or large d some distinct advantages. ■ Geocellular units are exceptionally easy to handle on site, allowing rapid construction of the tank ■ The modular format allows flexibility in the design of the tank plan area or depth to suit available space and ground water levels. nods of creating underground stormwater iameter pipe sections, modular cells offer ■ A square or rectangular tank amount of excavated spoil...

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Sustainable drainage systems technical guide-6

Key components The Marley Waterloc250 cell is ideal for use in either an underground infiltration or attenuation system. 96% of the cell volume is available to store water, minimising the extent of excavation required for the installation. In addition, the innovative design of Waterloc250 enables the cells to be quickly built into layers and configured to suit the area available. Waterloc250 benefits ‧‧ ‧‧ ‧‧ Unique nesting ability of cells reduces storage on site and WLRE250 110mm/160mm inlet/outlet connector (inlet configuration) WLRC250 top layer cell connector Cell lifting bars WLRB250 Waterloc250...

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Sustainable drainage systems technical guide-7

sustainable drainage systems Unit dimensions Length: 1200mm. Width: 800mm. Height 290mm* Void ratio Storage volume Storage capacity * Effective depth when installed in multiple layers: 260mm Vertical loading Lateral loading Short term characteristic compressive strength Short term load to transportation - saving Waterloc250 has lifting bars and an arrow moulded into the top face. The cells are assembled by rotating them by 180° from the nested stack. The cell connector actually consists of two clips; the 'pop-out' clip in the centre is the base cell clip, for securing the base layer, the remainder...

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Sustainable drainage systems technical guide-8

Key components flowloc Flowloc is a Vortex flow control unit, which is used as part of an attenuation scheme. Flowloc controls the rate at which water is discharged to a surface water drain or Heavy duty aluminium flow tank. Available to accommodate flow rates ranging from 2 l/s to 15 l/s, Flowloc is controller and coupling system, installed in a chamber base with a withdrawal handle to allow easy access from the electro coated for long service life. surface for maintenance. In the unlikely event of blockage, an overflow pipe allows Available to suit a wide range of water to bypass the controller...

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Sustainable drainage systems technical guide-9

sustainable drainage systems Inlet/inspection chamber The Marley inlet chamber provides access to the soakaway or attenuation scheme for inspection and cleaning. A column of cells is omitted beneath the chamber to provide an inspection well. The chamber is seated into an adaptor tray (ordered separately). It can also be used as an inlet connection or connection for an air vent. For larger installations, multiple inlet chambers can be used, but must be bounded on Silt traps with or without additional filters. It is recommended that all stormwater drainage systems that discharge into infiltration...

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Sustainable drainage systems technical guide-10

Over recent years a guidance documents have been published, Added to this, regulatory guidance is also evolving. Planning Policy Communities and Local Government Development and flood risk sets out the Government's policy on different aspects of land use planning in England. With respect to SUDS, the policy document states that "Regional planning bodies and local authorities should promote the use of SUDS for the management of run-off Local planning authorities should ensure that their policies and decisions on applications support and complement Building Regulations." Communities and Local Government...

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Sustainable drainage systems technical guide-11

sustainable drainage systems CIRIA publications This guidance provides best practice advice on the planning, design, construction, operation and maintenance of Sustainable Drainage Systems (SUDS) to facilitate their effective implementation within Sustainable drainage systems - Hydraulic, structural and water quality advice 2004. CIRIA C609 A report which details the successful design and construction of Sustainable Drainage Systems. Structural design of modular geocellular drainage tanks 2008. Co-sponsored by Marley, this report focuses specifically on the different types of underground geocelluar...

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Sustainable drainage systems technical guide-12

Infiltration systems are designed to provide temporary storage of surface water run off while natural dispersion into the surrounding soil takes place. Conventional soakaways are the most common example of below ground infiltration. The high void area of Waterloc250 (96%) means that a third of the volume is required compared with a conventional gravel/shingle filled soakaway. The success of any infiltration installation is wholly dependent on the permeability of the surrounding soil. Waterloc250 cells require a geotextile wrapping in accordance with the specification in appendix one, (page 28)...

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Sustainable drainage systems technical guide-13

sustainable drainage systems Designed to store stormwater temporarily in a suitable chamber below ground and release it at a pre-determined rate via a vortex flow control unit, such as the Marley Flowloc or an orifice plate. This limits the peak flow of water, thereby reducing the likelihood of overloading pipelines or watercourses downstream. The sizing of the attenuation tank is critical, to allow sufficient capacity to prevent upstream flooding. The Marley Technical Services team offer a design service to assist with this calculation. Attenuation tanks must be encapsulated within an impermeable...

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*Prices are pre-tax. They exclude delivery charges and customs duties and do not include additional charges for installation or activation options. Prices are indicative only and may vary by country, with changes to the cost of raw materials and exchange rates.