The DWMP blog – Episode 10. Is up-to-date the same as recently updated?

If you haven’t already seen the earlier episodes in this series, they are all here (https://tinyurl.com/MartinOsborneArticles) I suggest that you start from Episode 1 (https://tinyurl.com/DWMP-blog).

This episode discusses when and how Drainage and Wastewater Management Plans need to be reviewed and updated.

DWMPs are long term plans looking more than 25 years into the future.?From them the regulatory business plans for investment over the next 5 years are derived.?Those business plans are updated every 5 years; but how often should we update the underlying long-term plans?

The DWMP guidance recommends an annual review of system performance, investment delivery and future trends.?It also expects that the DWMP process will be tied in with the 5-year business planning process.

The Environment Act 2021 is more specific requiring a review each year and a revision of the plan every 5 years, although this frequency can be altered by the Secretary of State.

So, the questions to consider are:

• What is the required frequency of review and revision?
• Do all catchment plans need to be updated at the same time?

I propose a new strategy of three levels of review and revision of the plans with a rolling programme of revision.

Annual review.

An annual review is a good idea to give early warning of differences and changes.

The delivery of the planned investment will already be being monitored as part of the Business Plan delivery and this review should be putting in place corrective action where the programme is slipping.?It is difficult to see what extra action is required to update the long-term plan unless the reason for the slippage is because a proposed investment has become impossible for physical or political reasons.?In this case an update of the plan should be triggered to derive an alternative option.?

A review of performance over the last year and as an average over the last three years is required.?This should look for any outliers in performance and try to understand them.?Most are likely to be due to maintenance issues or unusual weather conditions.?This may trigger short term maintenance actions and may also feed into the identification of changes in long-term trends.?Most companies will already be doing this review every month.

A review of long-term trends is a sensible additional task.?This would consider company wide trends such as climate change, political and regulatory changes and customer attitudes.?This should identify trends to be considered in the next longer-term review and update.?

A catchment-by-catchment review would also be required of changes in development plans and population projections.?If significant short-term changes are identified for a catchment, then a revision of the plan as set out below should be carried out.

Five-year revision

The Environment act sets out that a plan must be revised if the annual review indicates a material change of circumstances, but also not later than 5 years from when the plan was last published.

This additional requirement is not sensible.?The DWMP will have been prepared with planning horizons of typically 10 years, 20 years and more than 25 years (say 30 years) as I set out in Episode 6.?If we revise the plan after 5 years, it is not a revision of work that has already been done, but preparation of new plans for different planning horizons as shown in the diagram below with new work shown in orange.

This is a significant amount of extra work when there may have not been many significant changes.

It would be more sensible to have an interim revision after 5 years with a full revision after 10 years.?The interim revision would look only at the short-term plan, unless major unexpected changes have occurred that change the entire future planning for the catchment.?This would be as shown in the diagram below with an update of existing work shown in yellow.

Ten-year revision

At 10-year intervals there should be a full revision of the plan.?The planning scenarios for this revision would align with those already used and the revision would simply be an adjustment to the plans already prepared.?This is as shown in the diagram below.

This approach involves less work and also gives a much clearer comparison between the original plan and the revision that can be traced back to the changes in future trends.?I hope that the Secretary of State will take notice of this proposal.

Fixed or sliding deadlines

For the first cycle of DWMPs the guidance set out a fixed timeline so that plans for all catchments were completed by the same deadline.?The Environment Act does not explicitly require this in the future.?So, once we have long term plans in place is it required that they are all updated at the same time??The disadvantage of this approach would be that there is a big workload for catchment planners for a year or two to do the updates, then we can send them off to breed rabbits or do something else for a few years before we need them again.

Just because a plan has not been updated does not mean that it is out of date.?The plans take a long-term view with uncertainty of future trends included.?It is unlikely that changes in future trends over just a few years will make the plan out of date.?Collating the results of all plans as they stand at a point in time will give a sufficiently accurate picture of the overall company plan, even if some of the individual catchment plans are a few years old.

I therefore propose a rolling programme of plan updates with catchments spread out through the 5-year and 10-year update periods so that the work becomes business as usual.?At each formal submission deadline, a snapshot of the current plans is taken and collated to the company level plan.

Some catchments will set their own revision dates if there has been a major change in future trends that requires a complete revision.?Others should be actively adjusted to spread out the workload throughout the review period.