CSW26: Enhanced floodplain storage supplement
Source: gov.uk (2025-09-10)

What you must do to get paid for this CSHT action and advice on how to do it.

This action is part of Countryside Stewardship Higher Tier (CSHT). You must read the CSHT guidance (https://www.gov.uk/government/publications/countryside-stewardship-higher-tier-csht) before you apply.

Duration

5 years

How much you’ll be paid

£366 per hectare (ha) per year

Action’s aim

The aim of this supplemental action is to increase floodwater storage in floodplains so that they hold more water for longer. You can do this by managing features such as:
- swales (channels)
- temporary ponds or depressions
The purpose is to slow the flow of water off floodplains to deliver benefits for flood and drought management.

Where you can do this action

You can do this supplementary action on land with any of the following Countryside Stewardship base actions:
- CGS26: Manage grassland with very low nutrient inputs
- CSW7: Arable reversion to grassland with low fertiliser input
- CSW15: Flood mitigation on arable reversion to grassland
- CSW16: Flood mitigation on permanent grassland
- CGS4: Herbal leys
- CGS25: Legumes on improved grassland
You can only do this action on land that:
- is in a floodplain and actively floods
- has water-retaining features by the end of year 1 on at least 20% of the land area covered by the action
Your Natural England adviser will agree with you what other supplemental actions may be needed to meet the intended environmental outcomes. These could include:
- CGS16: Rush control supplement
- CGS23: Haymaking supplement
- CGS24: Haymaking supplement (late cut)
- CSP1: Difficult site supplement
- CSP16: Keep native breeds on grazed habitats supplement (50-80%)
- CSP17: Keep native breeds on grazed habitats supplement (more than 80%)
- CSP5: Shepherding supplement (non-moorland)
- CSP6: Cattle grazing supplement (non-moorland)
- CSP7: Introduction of cattle grazing on the Isles of Scilly supplement
- CSP9: Support for threatened species
You cannot do this action on a priority habitat.

Eligible land

Same as base action.

Available area you can enter into this action

Same or less than the base action.

Rotational or static action

Same as base action.

What to do

Your Natural England adviser will assess your land. They’ll work with you to adapt and agree the activities you must do to achieve this action’s aim. All mandatory activities will be set out in your agreement document.

To get paid for this action, you must:
- maintain temporary water storage features
- remove build-up of sediment, woody debris and non-biological debris after flooding
You must not:
- apply fertilisers or manures
- apply pesticides – you may be able to use herbicides to spot-treat or weed-wipe for the control of injurious weeds, invasive non-native plant species, nettles or other plants if this has been agreed with your Natural England adviser
- allow vehicle access except on agreed routes
- create new access routes for vehicles
When to do it

You must do this action each year of its duration.

Evidence to keep

You must keep evidence to show what you have done to complete this action. If it’s not clear that you have done this action in a way that could reasonably be expected to achieve its aim, the Rural Payments Agency (RPA) may ask for this evidence.

You must supply the evidence if they ask for it, including:
- field operations at a parcel level
- associated invoices
- photographs relevant to the action
Consents, permissions and licensing requirements

To apply for this action, you’ll need:
- to agree an implementation plan or feasibility study with your Natural England adviser
- Scheduled Monument Consent (https://historicengland.org.uk/advice/planning/consents/smc/) from Historic England for any work on scheduled monuments
- consent from Natural England for any activity on land designated as a site of special scientific interest (SSSI) (https://www.gov.uk/guidance/protected-areas-sites-of-special-scientific-interest#get-consent-to-carry-out-operations-on-your-land)
- to obtain any necessary consents from the Environment Agency, Lead Local Flood Authority (LLFA) or Internal Drainage Board (IDB) before starting any work
You may also need to get:
- advice from your Natural England adviser if you have other archaeological or historic features on your agreement land
- a wildlife licence (https://www.gov.uk/guidance/wildlife-licences) from Natural England if your activities affect a protected species or their habitat
All archaeological and historic features (including scheduled monuments) are identified in your Historic Environment Farm Environment Record (HEFER).

If you’re a tenant, it’s your responsibility to check whether your tenancy agreement allows you to complete what’s required in the actions you choose. You may need your landlord’s consent.

Capital grants to support this action

If you need to complete an implementation plan or a feasibility study before you apply, you can apply for capital grants plans funding (https://www.gov.uk/government/collections/capital-items-guidance-for-applicants-and-agreement-holders#capital-grants-plans).

You can also apply for capital items (https://www.gov.uk/government/collections/capital-items-guidance-for-applicants-and-agreement-holders) to help you achieve the action’s aims. Your Natural England adviser will discuss eligible capital items with you.

Advice to help you do this action

The following optional advice may help you to do this action. Your agreement document will set out all the activities you must do.

Choosing a site

You can use this supplement in areas of permanent grassland or arable reversion to grassland within the floodplain. It is designed to store additional water in a flood and will be of greatest benefit immediately upstream of communities and areas prone to flooding.

Planning

You can create a water management plan to help decide the best position to locate the features. You can apply for a capital grants plan (PA1: Implementation plan (https://www.gov.uk/countryside-stewardship-grants/implementation-plan-pa1) or PA2: Feasibility study (https://www.gov.uk/countryside-stewardship-grants/feasibility-study-pa2)) to fund this.

The plan will identify any environmental or historic features that you need to consider when completing this action.

Establishing the storage area

You can use capital items to create temporary water storage features and swales. It may be beneficial to create multiple smaller storage features rather than a single large feature.

Design the features so stored water is slowly released through a defined flow path over 1 to 2 days after flood water has receded. This will also allow fish and aquatic invertebrates to return to the main channel.

Design capacity needs to be less than 10,000m3.

You will need to sow the storage areas with a native seed mix that complements your base action.

Managing the storage area

Storage areas are likely to collect flood debris and sediment as flood waters subside. You may need to remove this, as needed, in a way that is sensitive to wildlife. Avoid activities that could result in soil compaction.

Manage grazing to prevent poaching

Veterinary medicines such as ivermectin wormers, and livestock insecticides (especially pyrethroids) can have a negative impact on both land and freshwater ecosystems. If you’re a livestock farmer, work with your vet to see if you can agree a way to reduce the impact without affecting the animal’s welfare.

Responding to climate change

Read Natural England’s publication: ‘Adaptation for habitats in Environmental Land Management Schemes’ (https://publications.naturalengland.org.uk/file/5673659512127488) to help you consider your general response to climate change. You must continue to follow the mandatory activities for this CSHT action.