Guidance

3. Design and build your nature-based solutions for water resources project

Published 17 August 2026

Applies to England

Use this guide to approach the design and building of your nature-based solutions (NbS) for water resources solution. It sets out how to assign roles and responsibilities, assess impacts, manage construction and get permissions.

The planning, design and construction phase of NbS projects are highly iterative. You will need to engage with a wide range of different stakeholders throughout to:

• understand the catchment
• assess the opportunities and constraints
• find the best locations in a catchment for NbS implementation
• find willing landowners keen to support NbS implementation on their land
• appraise and select the right NbS for a specific location
• design NbS measures which will work within the constraints of a specific site

1. Before developing your NbS design

Before you can begin to design your NbS, you’ll need to use the information collated during the desk-based assessment and site walkover to develop and appraise all the potential NbS options.

The outcomes of the NbS options appraisal process will be the development of your preferred option. This will include either a single NbS measure or a suite of measures.

For guidance on planning your NbS project, including selecting the best location for NbS implementation and working with landowners and stakeholders, see NbS for water resources: plan your project.

2. Assign roles and responsibilities

You must follow the Construction (Design and Management) (CDM) Regulations where applicable.

The CDM regulations:

• help to identify the roles and responsibilities of people involved in project design and construction
• aim to uphold health and safety in the construction industry
• apply to the design and construction of NbS measures

Each role in a project has responsibilities for producing different documentation to ensure that their project complies with regulations. You must make sure that the following roles, as set out in the CDM regulations, are defined:

• clients
• designers
• principal designers
• principal contractors
• contractors
• workers

You must ensure that the client is also trained and certified as a CDM client. The client is responsible for providing the principal designer and principal contractor with a letter of appointment.

You should refer to the Institution of Civil Engineers’ (ICE) manual of health and safety in construction throughout the project’s development. This provides a useful summary of the roles and responsibilities involved.

3. Designing the NbS

Designing an NbS scheme will usually follow a series of steps. You’ll need to develop a high-level concept design and refine this as more information becomes available to develop an outline and eventually a final detailed design.

The NbS designer will need to develop a design buildability statement. This is a statement to show that buildability has been evaluated and may include:

• methodology 
• feasibility
• managing health and safety
• environmental risks

In the pre-construction phase, principal designers must plan, manage, monitor and coordinate health and safety. They must consider relevant information (for example health and safety files) that may affect design work done both before and after the construction phase begins.

For more information on the role of principal designers see the CDM regulations.

Design considerations for water resource benefits

Most existing guidance is aimed at designing natural flood management (NFM) measures with features which slow or store water for flood benefits. Instead, we suggest that you consider water resources during the design of NbS schemes. This can increase the overall benefits and ensure that water resource improvement opportunities are not overlooked.

For funding opportunities, see NbS for water resources: plan your project.

When designing NbS for water resources, you should:

• aim to improve groundwater resources, low flows in rivers and resilience to drought and flood in land and water
• work with natural processes to reduce long-term maintenance
• highlight positive outcomes of existing, good management practices
• sustain what already works well

Table 1 summarises the considerations you should make when designing these measures for water resources benefits.

Table 1: Considerations for designing NbS for water resource benefits

Name	Change to the water cycle	Design considerations
Water usage	Reduce evaporation and transpiration, reduce interception of rainfall and reduce irrigation demands.	NbS include planting crops and trees (deciduous woodland pasture) that reduce irrigation needs and have lower evapotranspiration rates. The layout of tree planting regimes can also be planned in such a way that it helps capture and augment water resources.
Runoff infiltration split	Improve soil health to allow more infiltration and increase surface roughness to slow runoff at source.	NbS that fall under this category include crops that help improve soil health and increase surface roughness to slow runoff. Planting crops across slopes can help to capture and store water. Sustainable forms of agriculture can also help improve surface roughness. Intelligent management of livestock can reduce soil compaction and retain good soil structure. These measures need to be planned to encourage infiltration specifically.
Runoff capture and infiltration	Capture runoff on the surface and allow it to infiltrate into the ground	NbS that fall under this category include measures which capture and store water (for example, runoff attenuation features, infiltration basins and cross-slope planting). The location of these measures needs to be planned to not only intercept flow but also to encourage groundwater recharge. They need to be designed to function during ‘typical’ rainfall events to enable rapid infiltration. This may mean that these features are smaller in size but greater in number than those designed for flood risk purposes. Engineering input will be required for implementation.
Floodplain and river restoration	Raise the bed of an over-deepened river, so it has less impact on the local water table. Improve floodplain connectivity – allowing floodwaters to be stored on the floodplain. Create wetlands on the floodplain, increasing the storage of water on the floodplain.	NbS in this category aim to restore the connection between rivers and their floodplain, restoring wetland and floodplain habitat. Designing these NbS for water resources rather than flood purposes is different. While it is important to reconnect the river to the floodplain, the project will need to be designed to not affect the local water table. This means the design will need to focus potentially on bed raising and storing water on the floodplain. This can involve infilling and narrowing a channel to raise the bed of the river, which will in turn encourage water to be stored on the floodplain. Engineering, ecological and geomorphological input will be required for implementation.

Impacts of NbS for water resources for other objectives

NbS for water resources can be integrated into other NbS projects such as habitat creation, water quality, and NFM, with wider benefits beyond water resources.

NbS interventions should assess the overall benefits to the water environment against evidence of any adverse effects on water availability in low-flow conditions, factoring in the local context. During implementation, you should consider the net impacts and manage the relative importance and aims of any conflicting objectives.

When designing and constructing your suites of NbS, you should exploit the wider environmental co-benefits of NbS implementation to maximise natural capital gains. You need to also consider the parts of your design that are optimal for water resources but may not be optimal for delivering other benefits.

Habitat creation NbS

Habitat creation NbS offer several ecological benefits to water resources, such as:

• improve the resilience of wetland and aquatic habitats to droughts and low flow conditions
• reduce sensitivity of habitats to the impacts of abstractions
• change the abstraction sensitivity band for the Environmental Flow Indicator (EFI)
• support an alternative flow constraint
• mitigation against drought

Broad Habitat Creation Type	Water resources outcome	Explanation
Scrapes and ephemeral waterbodies	Net benefit (positive)	These can be designed to act like infiltration basins and runoff attenuation features, capturing water when it is in excess.
Arable to pasture	Net benefit (positive)	Converting arable agriculture to pasture can have water resource benefits, if replacing water hungry crops, although this depends on crop type.
Soil structure	Net benefit (positive)	Healthy soils can support invertebrate populations while improving water retention, drainage and increasing infiltration.
Improved pasture to extensive grassland	Mixed response (neutral)	Moving from improved pasture to extensive grassland may increase the roughness of the ground surface, improving infiltration. However, the deep root systems of established grasslands may increase the removal of water during dry conditions. Limited research was found for the variation within grassland types.
Wetland creation	Mixed response (neutral)	Our literature review suggests that the effect of wetland creation is variable. Increased storage of water in wetlands can aid water resources, but there will be increased evaporation, which can lead to greater water losses, particularly in wetlands fed directly by rivers in the summer.
Woodland	Conflict of outcomes (neutral)	The water resource benefits of replacing arable land with woodland is complex and is affected by climate and geology. In many cases dense coniferous woodland will have a higher water demand, but less dense woodland pastures may result in limited changes to the water budget.

Water quality NbS

Water that is stored in the soil, ground, or held on floodplains or wetlands by NbS measures, can deposit silt and undergo physical and biological filtration, removing sediments, heavy metals and nutrients.

Water quality NbS can benefit from NbS for water resources interventions because of:

• improved soil health
• runoff attenuation features
• infiltration basins
• protection of groundwater from contamination
• reduced turbidity in downstream water
• reduced siltation of storage systems or water treatment (reducing the need for additional treatment)

NbS for water resources intervention	Water Resources outcome	Explanation
Cover crops to bare soils	Conflict of outcomes (negative)	Changing from cover crops to bare soils can reduce evapotranspiration losses, improving infiltration and recharge. However, the loss of cover crops can negatively affect water quality, as they can limit nitrate leaching into aquifers and reduce soil erosion.
Improved soil health	Net benefit (positive)	Improving soil structure can reduce erosion and increase infiltration capacity and improve water quality by removing pollutants from surface water.
Woodland Planting	Mixed response (neutral)	Woodlands can significantly improve water quality, as they stabilise soils and reduce sediment and nutrient pollution. They can also reduce landslides and mudflows. However, their impact on groundwater recharge can be mixed and is frequently negative.
Runoff attenuation features	Net benefit (positive)	Can slow flows, increasing recharge to depth, while reducing erosion and limiting the movement of diffuse pollutants.
Infiltration basins	Net benefit (positive)	Can significantly increase recharge to the saturated zone, while improving water quality and reducing nutrient and sediment load.
Floodplain connectivity	Mixed response (neutral)	Increased storage in the floodplain can reduce the movement of pollutants, improving water quality and sediment deposition. Floodplain inundation can store water offline during flood events, slowly releasing water to increase groundwater resources. However, the raising of riverbeds can raise groundwater levels, increasing evaporative losses. The response appears to be highly specific to each location.
Wetland Restoration	Mixed response (neutral)	Wetlands store water in the landscape, which can significantly improve water quality, particularly from diffuse pollutants. They allow increased settling of particulates and filtration of pathogens, nitrates and phosphates. Reuse of filtered nutrients can help to support plant and animal diversity. Our literature review suggests that the effect of wetland creation for NbS for water resources is variable. Increased storage of water in wetlands can aid water resources by slowly releasing retained waters during drought. However, there will be increased evaporation, which can lead to greater water losses, particularly in wetlands fed directly by rivers in the summer. The response appears to be highly specific to each location.

NFM NbS

NFM NbS can benefit from NbS for water resources measures which:

• slow runoff
• increase infiltration
• reduce the impact of flooding
• increase storage capacity
• reduce flood peaks and flow velocities
• increase the replenishment of groundwater resources

NbS for water resources intervention	Water resources outcome	Explanation
Woodland creation	Mixed response (neutral)	Woodland planting can stabilise slopes and reduce flood risk by intercepting rainfall and slowing runoff velocity, reducing peak flows. However, in many cases woodland will have a higher water demand than other land use covers, reducing water resources. Less dense woodland pastures may result in limited changes to the water budget, and at the large and long-term scale there may be water resource benefits from increased woodland planting.
Soil health	Net benefit (positive)	Improved soil structure can reduce runoff, both reducing flood peaks and potentially increasing infiltration and recharge.
Runoff attenuation features	Mixed response (neutral)	Runoff attenuation features can slow the flow of water to rivers, reducing flood peaks, and increasing recharge. However, to maximise infiltration, runoff attenuation features would be designed to fill during average rainfall events. These would not have the capacity for attenuating greater than average flows during flood events.
Infiltration basins	Net benefit (positive)	Infiltration basins can significantly increase recharge, reducing overland runoff during heavy rainfall.
Floodplain connectivity	Mixed response (neutral)	Floodplain inundation can store water offline during flood events reducing flood peaks while slowly releasing water to increase water resources. However, the raising of riverbeds can raise groundwater levels increasing evaporative losses. The response appears to be highly specific to each location.
Wetland restoration	Mixed response (neutral)	Wetlands can slow runoff and store water offline during flood events, decreasing flood volumes. Wetlands can increase groundwater recharge; However, they can also increase evaporation, leading to water loss. In some cases, this can result in overall negative water resource impacts. The response appears to be highly specific to each location. Additionally, some kinds of floodplain wetlands can increase peak floods. The impact is therefore highly variable depending on wetland type and location in the catchment.

Future opportunities

Further overlapping opportunities beyond these three objectives include:

• improving runoff-infiltration splits through the installation of infiltration basins in urban areas can have social benefits
• wetland restoration can improve air quality and help temperature regulation
• improved soil health can benefit food security and carbon sequestration
• the introduction of beavers can improve floodplain connectivity alongside biodiversity gains

For a list of UK and EU policy drivers supporting the use of NbS, see Overview of nature-based solutions for water resources. For a list of the potential NbS funding sources, see NbS for water resources: plan your project.

Potential conflicts

Your suite of NbS for water resources measures may sometimes conflict with other environmental objectives.

If improving the quantity of infiltration and the recharge of groundwater was the sole objective, you may use the following measures:

• land use cover would be chosen based on the lowest evapotranspiration losses – potentially limiting woodland cover, choosing crops that minimise field cover during the late summer months, negatively affecting water quality
• runoff attenuation features would be designed to maximise infiltration – they would be filled by typical rainfall events, limiting their effectiveness in attenuating flood flows
• some wetland and river restoration schemes would not be encouraged where they resulted in reduced low flows downstream

However, a singular focus on water resources may fail to realise a healthier, more resilient river system.

For example, a river system where riparian woodlands increase water losses by evapotranspiration, beavers contribute to floodplain connectivity and raise groundwater levels. This reduces infiltration due to cover cropping. Such a system may receive reduced volumes of water during low flows but may be healthier overall and more resilient to the reduction in low flows.

Re-naturalised landscapes may not always be associated with increased low flows. Due to current land management practices, modern rivers may have higher flows than they did historically. Modern systems may have adapted to the increased flows and may not be revertible to historic conditions.

Other NbS design requirements

During the design phase, you must complete the design risk assessment (DRA) and pre-construction information (PCI). These are legally required under the CDM regulations. You must also develop a hazards and constraints plan.

Design risk assessment (DRA)

You must create a DRA to identify the hazards and evaluate the potential design risks. The designer should implement appropriate controls to either remove or mitigate the risk, depending on the hazard.

By identifying the risks, the DRA can help you to discuss who is responsible for owning and accepting liability for any outstanding risks with your client.

Pre-construction information (PCI)

PCI involves collecting, collating and communicating relevant health and safety information before construction work begins. The aim of PCI, as defined by the Veriforce and The Contractors’ Health and Safety Assessment Scheme, is:

to ensure that all parties involved in any project understand the risks and hazards associated with the work, enabling them to take steps to protect themselves and others.

PCI includes, but is not limited to:

• plans and specifications
• environmental assessments
• health and safety assessments

You should provide the PCI to the client along with a construction phase plan (CPP) for their approval.

The client is responsible for completing an F10 form which notifies the Health and Safety Executive of a notifiable construction project.

Hazards and constraints plan

You must develop a hazards and constraints plan for the site. Considerations include, but are not limited to:

• location of services, infrastructure (for example roads, rail and flood defences) and public rights of way
• unexploded ordnance (UXO) risk
• accessibility for machinery
• waste management
• consenting requirements
• presence of protected species or habitats and invasive non-native species presence
• future maintenance needs

4. Impact assessments 

You may need to undertake specific assessments of your NbS project, such as through biodiversity net gain (BNG) assessments, flood risk assessments (FRA) and habitat regulation assessments (HRA).

BNG assessments

BNG is an approach to development that ensures habitats for wildlife are left in a better state than they were before the development. BNG could be relevant to implementing your NbS project because:

• landowners or managers may be able to sell biodiversity units to developers to enable habitat creation on their land – BNG could help to fund your NbS
• if the NbS project needs to apply for planning permission, then a BNG assessment may need to be submitted if the site is over 1 hectare in size

For more information on biodiversity net gain, see Understanding biodiversity net gain.

Flood risk assessment (FRA)

You may need to conduct flood modelling when developing your NbS design to ensure the proposal does not increase the risk of flooding.

This will also form part of the Flood Risk Activity Permit (FRAP). This will likely need to be accompanied by a FRA to ensure the NbS does not have an adverse impact. To check if you need to do a FRA, see Flood risk activity risk assessment for your environmental permits.

Habitat regulation assessment (HRA)

The Conservation of Habitats and Species Regulations 2017 as amended (known as the Habitats Regulations) protects the species and habitats present on sites designated as Special Protection Areas (SPAs) and Special Areas of Conservation (SACs).

If you are an appropriate authority and if your NbS proposal is on or close to an SPA or SAC, you will need to carry out an assessment under the Habitats Regulations. This will establish if your project could significantly harm the designated features of a European site.

You will need input from an ecologist to work out the impact of your proposal on European-designated sites. You can use Natural England’s MAGIC mapping system to work out whether your site is designated or not. Some ecological surveys must be undertaken in the spring and this needs to be factored into any time plans to avoid delaying construction.

For more guidance on carrying out an HRA, see Habitats regulations assessments: protecting a European site.

Water Framework Directive (WFD) assessments

The WFD assessment looks at the impact of a proposal on the water environment to determine its potential effect on the ecological status of a waterbody. If your proposal leads to a deterioration in ecological status, it is unlikely to be acceptable.

To be acceptable from a WFD perspective, your proposal must lead to either no deterioration in ecological status or an improvement in ecological status.

WFD assessments are usually required as part of a FRAP and planning consent.

For guidance on doing a WFD assessment for fluvial or terrestrial environments see WFD risk assessment, and for intertidal or coastal environments see WFD assessment: estuarine and coastal waters.

5. Get permissions

As part of any proposal to design and construct NbS measures you need to be aware of which permits, consents, licences and assessments are needed to deliver the works. This section summarises some of the main permits, licences and assessments which may be needed.

At the project’s outset, you will need to discuss and agree on a full list of all necessary permits and licences with relevant regulators. This is to ensure the proposed NbS scheme fully complies with the law.

Flood risk activity permits (FRAPs)

FRAPs are needed for proposed works:

• on or near a main river
• on or near a flood defence structure
• in a floodplain
• on or near a sea defence

The purpose of the FRAP is to ensure that the proposed works do not increase the risk of flooding or negatively impact existing flood risk management infrastructure.

If your project is being delivered on a main river, you will likely need to apply for permission to undertake the works. See the following guidance to help you determine if your works:

• are exempt and do not need a FRAP
• are covered by a standard rules permit
• need a bespoke permit

Depending upon the scale of the project, flood modelling may need to accompany the FRAP to demonstrate that the proposal does not increase the risk of flooding.

Your FRAP may also need to be accompanied by other assessments such as WFD assessments and HRAs, as set out in Section 3.

For more information on flood risk activity risk assessments, see Flood risk activity risk assessment for your environmental permits.

Ordinary watercourse consents

Ordinary watercourse consents, also known as Land Drainage Consents (LDCs) are needed for works affecting the flow of ordinary watercourses. These consents need to be submitted either to the Lead Local Flood Authority (LLFA) or the Internal Drainage Board (IDBs), depending upon which organisation is responsible for the ordinary watercourse you are working on.

If you are working on an ordinary watercourse, you need to work out which flood risk management authority you will need to apply for consent to. To find your flood risk management authority, see Internal Drainage Boards - Association of Drainage Authorities and Find your local council.

Ordinary watercourse consents have a two-month determination period and will need to be supported by information such as site location plan, designs and associated survey results.

Natural England assent

Natural England Assent may be needed for proposed works on a Site of Special Scientific Interest (SSSI). Each SSSI has a list of activities, known as ‘operations’, which need Natural England’s Assent.

If your proposed project is on a SSSI, you should contact Natural England to discuss the proposal and agree whether assent is needed. Even with Natural England’s consent, you may need to get other permits and licences discussed in this section.

Protected species licences

Depending upon the species present on your site, you may need to apply for protected species licences if you plan to disturb or remove wildlife or damage habitats. To check if you need to apply for a wildlife licence, see Wildlife licences: when you need to apply.

You can employ an ecologist to undertake a site walkover to help establish which protected species may be present. This will help you establish which licences may be needed. They will also be able to help develop an ecological calendar to work out the best time of the year to undertake the works to reduce the likelihood of impacting species.

Planning permission

NbS schemes, particularly those that involve earthworks, may require planning permission. You should get pre-application advice from your relevant local authority to determine if planning permission is needed. For guidance on pre-application discussions, see Before submitting an application.

Sometimes NbS may be classified as agricultural developments and may be exempt. As a precaution, you should still contact your local authority and seek their advice at the project’s outset.

If you do need planning permission, many of the assessments in Section 3 will form part of your planning application processes. These will be needed to show that the potential impacts of the NbS have been fully assessed and mitigated where necessary. Other assessments or surveys may also be needed, and you should allocate a sufficient budget to ensure that these can be delivered to support the planning application.

Utilities permission

You may also need permission to build near different types of utilities.

You will need to identify any utilities present on the site and ensure that any necessary permissions are obtained.

6. Building the NbS project 

You should conduct baseline monitoring before construction begins to understand the environmental conditions of the site or catchment. This allows comparisons to be made before and after construction to understand the effectiveness of your NbS measures.

For guidance on the lifecycle and stages of a construction project, see the guidance from the Royal Institute of British Architects (RIBA).

Role and responsibilities of the principal contractor

If you are a principal contractor, you must plan, manage, monitor and co-ordinate health and safety during the project construction involving, or likely to involve, more than one contractor. You must plan, manage and monitor all work done by yourself and your workers. This is required by the CDM regulations.

For guidance on how to comply with CDM regulations during the construction phase, see the Health and Safety Executive’s (HSE) guidance on planning for construction work.

You should also meet with the NbS designer to allow the handover of all relevant design information and the PCI. This allows the designer to take the contractor through the designs, the DRA, PCI and relevant drawings.

Before construction, you will need to develop:

• working method statements
• risk assessments
• biosecurity procedures
• environmental or site management plans

You are responsible for health and safety during the construction phase and must ensure that all staff:

• are fit for work
• are appropriately trained
• hold the correct permits
• have access to appropriate personal protective equipment (PPE)

The construction phase can officially start as early as the ground investigation and ecological surveys.

As the contractor, you will need to ensure that you understand the ecological calendar for your site so that construction does not disturb or negatively impact protected species. You may wish to always have an ecological clerk of works on site to help mitigate the potential negative impacts of construction on plants and animals.

You will need to decide whether to develop the scheme under either:

• traditional contracts in which a designer and a contractor are appointed separately
• a design and build contract where one organisation delivers the entire scheme – this may suit many smaller NbS for water resources features, especially if lots of small schemes will be delivered at scale

Getting landowners involved

The landowner and farmers must be involved in the construction phase to ensure that construction is done at suitable times and without being overly disruptive. Before construction, the principal contractor should meet with the landowner to agree on:

• programme and timing of works
• site access or egress
• storage areas for any materials or plant
• contact details (day to day and emergency)
• monitoring during construction
• updates or progress meetings

Landowners may wish to enter a legal agreement before construction.

7. Next steps when your NbS is built

Monitoring and maintaining NbS features

Once NbS design and construction has been completed, you will move into the monitoring and maintenance phase.

Once construction has completed, the CDM regulations require you to:

• consider post-construction activities
• develop an approach to the inspection and maintenance of the NbS which can be undertaken safely
• ensure that the inspection and maintenance activities are done by appropriately trained individuals

You need to plan and budget for monitoring and evaluation at the start of a project. Maintenance and adaptive management should also form part of the organisation’s long-term funding plans.

Monitoring of your NbS project is important to:

• demonstrate project success or failure
• learn from mistakes
• know when adaptive management is needed
• fill known research gaps
• inform funders, partners and local stakeholders about project outcomes
• determine to what extent project objectives have been met

For guidance on monitoring and maintaining your NbS project, see NbS for water resources: monitoring and maintenance.

Decommissioning

The final stage in your construction project may involve a decommissioning phase, where you take steps to handover responsibility for assets to a landowner.

This stage can involve retrieving your monitoring equipment that is no longer needed or filling in boreholes that were constructed during an earlier phase of work.

You will likely need to engage with the landowner to design and agree a long-term plan for any necessary maintenance works.

8. Contact the Environment Agency

If you have questions about any aspects of this guidance, contact the Environment Agency.

General enquiries

National Customer Contact Centre
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Rotherham
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Email enquiries@environment-agency.gov.uk

Telephone 03708 506 506

Telephone from outside the UK (Monday to Friday, 8am to 6pm GMT) +44 (0) 114 282 5312

Monday to Friday, 8am to 6pm.