Creating a fairer Salford by:
19.1 Water is a key component of the natural environment, and a good supply of water resources is essential to health, quality of life, biodiversity and many business processes. Unlike some other parts of the country, water supply and wastewater treatment are not a significant constraint on the total amount of development that can be accommodated within Salford during the Local Plan period, although some further investment will be required to improve functionality and to facilitate individual new developments. However, water-related issues are very important to Salford as a result of significant parts of its urban area being at risk of river and/or surface water flooding, and the relatively poor quality of some of its watercourses.
19.2 Many prosperous cities across the world, such as London, successfully balance the management of flood risk with the need to accommodate large levels of development. The economic and social benefits of continuing to secure investment within areas of Salford that could be subject to flooding are considered to significantly outweigh the potential risks and costs. Some of these areas are fundamental to the prosperity of Greater Manchester, whilst others need investment to support their regeneration and to ensure that they can more actively contribute to and share in the city’s economic growth. They are also central to the overall development strategy and helping to reduce the need to travel.
19.3 The emphasis is therefore on ensuring that the scale of flood risk is minimised as far as possible, and that buildings are appropriately sited and designed so as to reduce the potential impacts in the event of a flood. When combined with the relocation of vulnerable uses, and the replacement of some existing buildings with more flood resilient designs, this should ensure that the Local Plan helps to support continued economic growth whilst reducing the overall economic and social impacts in the event of a flood. No amount of investment in flood defences would entirely remove flood risk and therefore it is important that both existing and new development in flood risk areas is resilient to flooding. Overall, the number of people who live or work in a flood risk area will see an increase, but the number who would be significantly affected by a flood event should decrease. This will provide a more sustainable position than at present whilst also maintaining investment in key locations.
19.4 Some of the measures aimed at reducing flood risk, such as minimising surface water runoff and increasing the use of sustainable drainage systems, should also help to address problems of water quality in the city’s watercourses. However, specific investment will be required, such as in improving the oxygen levels within the Manchester Ship Canal. This will help to ensure that European targets for water quality are met by the end of the plan period.
A comprehensive and integrated approach to the management of water resources will be taken, enabling significant levels of development to be delivered in accessible locations in an environmentally sensitive way. This will include:
19.5 The North West River Basin Management Plan (RBMP) seeks to tackle the pressures facing the water environment. The legal framework for protecting and promoting sustainable water management of surface waters and groundwater is currently based on the Water Framework Directive (Directive 2000/60/EC). This promotes an integrated approach to the water environment, including water quality, flood risk, biodiversity and the sustainable use of water as a resource, and requires all inland waters to achieve ‘good’ status.
19.6 The overall status of each water body is assessed as a combination of ecological and chemical status, having regard to:
19.7 The majority of watercourses in Salford and the North West, as well as some canals and reservoirs, are currently failing to meet RBMP objectives. Achieving those objectives will take a combination of measures. Major environmental improvements are needed to most of Salford’s river corridors to improve their overall quality, functioning, connectivity and ecological quality, addressing issues such as canalisation and culverting, a lack of greenspace buffers and invasive non-native species.
19.8 Development can have a major impact on the water environment, and so needs to be controlled accordingly, delivering enhancements wherever possible. Development that would be likely to lead to deterioration in the overall status of a water body, or would prevent future attainment of good status, can only be permitted in exceptional circumstances as set out in regulations.
19.9 Even with improvements to the wastewater treatment works in Salford and adjoining areas, controls over polluting activities, and restrictions on surface water discharge to the sewerage network, other measures will be required to ensure that the water quality within the Manchester Ship Canal is improved. This will be particularly important at Salford Quays given the prominence of the area and the proposed scale of investment, building on the success of the existing oxygenation scheme. The city council will work with key partners including Trafford Metropolitan Borough Council, United Utilities, the Environment Agency and the Manchester Ship Canal Company to identify a funding mechanism for a more cost-effective long-term solution that could be extended further down the Manchester Ship Canal.
19.10 The Environment Agency has identified Groundwater Source Protection Zones across the country which are intended to ensure that groundwater sources used for public drinking water are not adversely affected by contamination. In addition, all other groundwater abstractions intended for human consumption will assume a default source protection zone. The presence of these zones may lead to restriction on the activities that can take place within them.
The water quality of Salford’s water bodies will be protected and enhanced, including through the following measures:
Development must not have an adverse impact on the current overall status, or prevent future attainment of ‘good’ status, of any water body.
Where practicable, development shall take opportunities to support the improvement of water bodies to at least ‘good’ status, including through:
An assessment identifying the impact of a proposed development on water body status shall be submitted with a planning application where:
For the purposes of this policy, a water body is defined as the whole (or part) of a stream, river or canal, lake or reservoir, estuary or stretch of coastal water, or a defined area of an aquifer.
The status of a water body is its classification in accordance with the River Basin Management Plan.
19.11 Salford falls within United Utilities’ Integrated Resource Zone which covers much of the North West region. The latest baseline forecast, taking into account economic growth and climate change, suggests that the amount of water available to meet the projected demand shows a surplus over the 20 years from 2020 to 2040 [1]. Consequently, the total available water supply should not act as a constraint on the scale of development within Salford during the Local Plan period. Nevertheless, it is still more sustainable for new developments to be designed to use water efficiently, in terms of reducing greenhouse gas emissions associated with water treatment and taking pressure off wastewater treatment works.
19.12 Two critical pieces of water supply infrastructure run through Salford and so need to be protected from adverse impacts:
The Thirlmere Aqueduct and the West East Link Main will be protected from development that could compromise their physical integrity or effective maintenance.
Development is encouraged to minimise water use as far as practicable by incorporating appropriate water efficiency and water recycling measures.
19.13 The city council will use its powers under the Flood and Water Management Act 2010 to identify, protect and ensure the maintenance of structures and features that affect flooding. Planning controls will be coordinated with this regime, with developments not being permitted where they would adversely affect infrastructure that helps to reduce the risk and impacts of flooding.
19.14 The two flood basins at Littleton Road and Castle Irwell protect Lower Kersal, Charlestown and Lower Broughton from river flooding to a standard of no flooding in a 1% annual exceedance probability (AEP) fluvial event [2]. However, further measures for reducing flood risk will be sought, in order to better protect the residents and businesses of Salford and communities downstream. This will not only include activities within the city, such as the coordinated improvement of the Cambridge area, but will also involve encouraging actions upstream of Salford that could slow the flow of water into the city.
Structures and other features that help to reduce the risk of flooding or mitigate its impacts will be protected, including the flood basins at Littleton Road and Castle Irwell. Their loss, alteration or replacement will only be permitted where there would be no increase in flood risk.
Opportunities for further improvements in flood mitigation in Salford will be sought, potentially including through the provision of new open space within the Cambridge area and the raising of river banks.
The city council will work with other local authorities and the Environment Agency to identify the potential for additional flood water storage and reduced surface water runoff upstream of Salford.
19.15 Based on the 2011 Strategic Flood Risk Assessment, approximately 3.6% of Salford’s land area and around 1,664 homes would be adversely affected by a 1 in 100 year flood event [3], with significant additional areas being at risk in a 1 in 1,000 year event [4]. The main source of this flood risk is the River Irwell, although there is some limited flood risk associated with several of the city’s other watercourses, surface water, groundwater and sewers. It will only be appropriate to permit development where it can be clearly demonstrated that there would be no unacceptable risk or impact of flooding, either on the development itself or elsewhere.
19.16 National planning policy sets some requirements for managing flood risk, based largely around a ‘Sequential Test’ and an ‘Exception Test’. The Sequential Test seeks to steer development to areas with the lowest probability of flooding, with this being particularly important for the uses that are most vulnerable in the event of a flood. Some uses are considered so vulnerable that it would be inappropriate for them to be located in the highest risk areas. Where such uses already exist in those locations, the city council will work with occupants to find alternative sites wherever possible. If development proposed for a site at risk of flooding can meet the Sequential Test then, for more vulnerable uses, it also needs to pass the Exception Test, which essentially requires it to be demonstrated that the sustainability benefits for the community outweigh the flood risk, the development will be safe, and that it will not increase the risk of flooding elsewhere.
19.17 Given the scale and extent of flood risk in Salford, it is essential that a rigorous approach to assessing the flood-related implications of developments is taken. Site-specific flood risk assessments are an important part of this, and these should have regard to the strategic flood risk assessment for Salford and any other relevant information on flood risk. Critical drainage areas, where drainage is a particular problem and stricter requirements for flood risk assessments apply, were initially defined within the strategic flood risk assessment and may be refined by subsequent information.
Development will not be permitted where it would:
1A) Be subject to an unacceptable risk of flooding, with the acceptability of any risk being determined having regard to:
1B) Materially increase the risk of flooding elsewhere;
1C) Result in an unacceptable maintenance liability in terms of dealing with flood-related issues; or
1D) Require unduly complicated or burdensome emergency planning procedures.
Within areas that would be subject to a 1 in 100 year risk of flooding (1% annual exceedance probability (AEP)) (not taking into account flood defences), the following uses will not be permitted:
2A) Police stations, ambulance stations, fire stations, command centres and telecommunications required to be operational during flooding;
2B) Basement dwellings;
2C) Caravans, mobile homes and park homes intended for permanent use, including sites for gypsies, travellers and travelling showpeople; and
2D) Installations requiring hazardous substances consent, except where there is an essential need.
Development that would be subject to a 1 in 1,000 year risk of flooding shall:
3A) Be designed to minimise the impact of any flooding, in a way that is proportionate to the level of flood risk;
Development that would be subject to a 1 in 100 year risk of flooding (taking into account an appropriate allowance for climate change) shall:
3B) Broadly maintain, and wherever possible increase, the flood water storage capacity of the flood cell within which it is located;
3C) Enable the appropriate flow of flood waters;
3D) Have safe and clearly identified access and egress routes, or a safe refuge, to be used in the event of a flood; and
3E) Have clear evacuation procedures in the event of a flood, and be fully integrated into the city’s emergency planning systems throughout its lifetime.
A site-specific flood risk assessment shall be submitted with any planning application for development that would:
4A) Potentially increase the risk or impacts of flooding; and
4B) Be located on:
The flood risk assessment shall consider all types of flooding and the relationship between them, including that associated with rivers, canals, reservoirs, surface water, sewers and groundwater.
The level of detail in the flood risk assessment should be proportionate to the potential risk and impact of flooding that the development would result in or to which it would be subject.
For the purposes of this policy, all assessments of flood risk (excluding those relating to 1 in 1,000 year scenarios) shall take full account of the latest predicted impacts of climate change.
19.18 The Flood and Water Management Act 2010 introduced new responsibilities for the city council relating to the approval of proposed drainage systems in new developments and redevelopments, subject to certain thresholds and exemptions, having regard to minimum national standards. The following policy should be read in conjunction with these statutory requirements.
19.19 Given the significant risk of surface water and river flooding affecting many parts of Salford, it will be important to minimise the amount of surface water runoff and discharge from development sites across the city. In addition to reducing flood risk, using sustainable drainage systems can provide construction and maintenance cost savings and bring a wide range of benefits, adding value to schemes by enhancing water quality, providing habitats for wildlife and creating more attractive and desirable developments. The wider benefits of investment in drainage systems should be maximised as far as possible, especially by designing them to form part of the city’s green infrastructure network and supporting the objective of significantly increasing Salford’s overall biodiversity value. Such benefits will be most effectively achieved by designing sustainable drainage systems into the site layout at an early stage.
19.20 The discharge of surface water to the combined sewerage network can lead to the hydraulic capacity of that network and some of Salford’s wastewater treatment works and assets being exceeded. This results in intermittent discharges of storm sewage from those assets into the city’s watercourses, which have an adverse impact on water quality. Surface water discharge to the sewerage network can also result in local sewer flooding, due to the limited network capacity in some areas. It is therefore necessary to ensure that new developments across the whole city, including those on previously developed land, do not discharge any surface water to the combined sewerage network (either directly or indirectly).
Development shall ensure that surface water across the whole site is managed in a sustainable way, helping to minimise flood risk and water pollution, promote biodiversity, and secure compliance with the North West River Basin Management Plan (see Policy WA2).
Surface water shall be managed in line with the following hierarchy (highest priority first) recognising that a combination of measures from different levels in the hierarchy may be required to satisfactorily deal with all surface water:
On-site measures to deal with surface water shall, wherever possible, be designed as multi-functional green infrastructure connecting to the wider green infrastructure network.
Foul water shall be managed through a separate system to the management of surface water, and it shall drain to the public sewer.
Development shall result in:
Exceptions to points A and B may be made where it can be demonstrated that it is:
Where on-site attenuation measures are required to reduce the rate of surface water discharge, underground solutions such as detention tanks and oversized pipes shall only be utilised where it is not technically feasible to incorporate above ground sustainable drainage features that contribute to the green infrastructure network.
Appropriate provision shall be made for the long-term management and maintenance of any sustainable drainage features.
19.21 The main indicators that will be used to monitor this chapter are:
|
Indicator |
Target |
|---|---|
|
Percentage of surface water bodies of at least good ecological status or potential |
100% by 2037 |
|
Planning applications approved contrary to Environment Agency advice on flood risk |
Zero (2018-2037) |
|
Number of developments approved which include sustainable drainage schemes |
Increase by 2037 |
[1] United Utilities (2018) Revised Draft Water Resources Management Plan 2019, p.3
[2] That is in any year there is a 1% (1 in 100) chance of there being a river flooding event that would exceed the level of protection.
[3] A 1 in 100 year flood event is an event that has a 1% chance of occurring in any one year
[4] A 1 in 1,000 year flood event is an event that has a 0.1% chance of occurring in any one year