93 DWMPs and SuDS – joining the dots

This week’s blog was sparked by the publication of the new Policy Position Statement on SuDS (Sustainable Drainage Systems) by environmental body CIWEM.  It is worth reading.  It gives a really good concise case for why we should be using SuDS and sets out recommendations for government action to encourage their use.  One recommendation was for improved integrated drainage planning.  I have been advocating that water company DWMPs should be integrated with local authority flood risk planning and environmental regulators’ River Basin Management Plans.  But how could this be organised?  How difficult would it be?

So, let’s try and join up the dots.

Benefits of SuDS

The CIWEM policy statement comprehensively sets out the benefits of SuDS including:

• Surface water and sewer flooding.  Reduction of peak flows and of runoff volumes through detention and infiltration.
• Water quality.  Reducing the spill of untreated sewage through overflows and the discharge of polluted highway drainage.
• Nutrient neutrality.  Reducing nutrient runoff from hard surfaces and reducing flow through treatment works.
• Climate change: net zero and adaptation.  Nature based approaches can have a smaller carbon footprint that grey infrastructure.
• Nature recovery and biodiversity net gain.  Create habitats in our urban areas.
• Enabling economic growth by allowing sustainable housing development.
• Water neutrality and integrated water management.  Reuse of rainfall at source reduces the pressure on water resources.
• Place-making and health and wellbeing.  Greening our urban areas makes us healthier and happier.

Basically SuDS are just better for everything.

Recommendations for government

The policy statement sets out ten recommendations for government action.  All are sensible and should have been implemented years ago.  I will pick out a few for additional comment.

Make the right to connect to the sewer conditional on having delivered an appropriate drainage hierarchy, in line with mandatory standards.

This goes further than just requiring detention and infiltration of runoff to reduce problems downstream but also proposes making the best use of rainfall as a resource at the location where it falls.  This helps solve problems of both excess runoff and lack of water resources.  I think that it will be a significant culture change to get housebuilders to implement this as the preferred option.  Tightening the targets on expected water consumption of new properties could be required to encourage this.

SuDS rules to apply to all new developments

The current suggestion is that SuDS will only be mandatory for developments of ten or more houses.  However most planning applications are for fewer.  I don’t have the figures for the proportion of houses that are built are on small developments, but it is significant.  Extending the rules to small developments is essential not only to reduce their impact but also to reinforce the message about how important it is.

Direct and enable extensive retrofit of SuDS as a means to manage local surface water flood risk, highway runoff pollution and storm overflow discharges

We have got to crack the retrofit problem.  SuDS retrofit has not featured enough in water companies DWMPs because it is perceived as being more expensive and taking longer to deliver than grey infrastructure.  However this ignores the extra benefits that it brings. 

This policy recommendation is aimed at Lead local flood authorities, water and sewerage companies, highway authorities and other relevant stakeholders.  However it doesn’t mention individual householders who also need to take action.

I would go further and argue for a power to force the retrofit of SuDS in areas that suffer from surface water or sewer flooding or where combined sewer overflows or highway drainage cause pollution.  We are happy to force householders to have a water meter in areas with limited water resources.  So why not the equivalent for drainage.

A review of the effectiveness of partnership working in urban areas.

“To maximise the benefits of SuDS, different parties with responsibility for these benefits need to be able to work effectively together. However, their planning and funding/budgeting approaches and timescales, and priorities, can severely curtail success.

…government should review how empowered the different responsible parties are to collaborate effectively. This should include how their respective plans (such as DWMPs, local flood risk management strategies and local nature recovery strategies) mesh and what might be needed to improve this.”

This last recommendation is the challenge that I was trying to address in defining how integrated DWMPs would be taken forward.

Existing guidance on integrated DWMPS

The guidance for Cycle 1 of DWMPs published in 2020 did recommend collaboration to plan drainage improvements.  However it had several limitations:

• It did not set out how to align the different planning processes to achieve joined up thinking.  For example DWMPs are done on a five year cycle.  River Basin Management Plans (RBMPs) that identify the risks to water quality impacts on the environment, and therefore drive water company improvements, are done on a six year cycle.  It doesn’t work.
• It stated that the main focus of DWMPs should be the assets owned by the water companies.
• It set out what the water companies should do to engage with other stakeholders with them taking the lead on all collaboration.  This struck me as almost a colonial attitude where the water companies knew what was best for the other stakeholders that they had to deal with.
• It doesn’t encourage collaborative planning that can then be reported in different ways by different stakeholder organisations.

Improved guidance on integration and collaboration

So what should be changed for improved guidance?

All drainage planning should be delivered and updated to five year cycles so that all plans are aligned.  The current cycles are defined in statute and regulations but there is some flexibility.  The RBMP regulations define a six year cycle but give the dates by which rather than on which the plans need to be prepared and updated.  There doesn’t appear to be anything to stop them being delivered early on a five year cycle.  It just needs government to ask for this.

The remit of drainage planning should be to cover all drainage assets and pathways but clearly showing the separate responsibilities for each stakeholder organisation This would require some careful consideration of who pays how much for developing the plan but setting national ground rules would simplify this.

Collaboration should be defined as being between stakeholders rather than being something that the water companies require other organisations to do.  Leadership of the collaborative bodies should be by whichever organisation is best placed to deliver it.  For strategic planning of river basins the environmental regulator should take the lead.  For strategic planning of drainage of a large conurbation the local authority should take the lead.

The building blocks of the plans should be integrated between all stakeholder organisations, but each organisation can report the content of the plan in its own context, reporting the components within its own organisational boundary and with a focus on the assets and investment that it is responsible for.  One colleague has likened this to looking through the different facets of a diamond to the plan at its heart.

I think that we could make this integrated planning work.  The real question is whether we have the ambition and the flexibility to make it work.