To: Maidstone Joint Transportation Board
By: Behdad Haratbar, Head of Programmed Works
Date: 21 January 2014
Classification: Information only
Summary: To update Members on the approach to maintaining and improving the highway drainage system whilst ensuring that the customer is provided with a quality service against a background of increasing severe weather events.
This paper was reported to the Kent County Council Environment and Transport Cabinet Committee on 5 December 2014
1. Introduction
1.1 The County Council is responsible for the maintenance of the 5,400 miles of public highway roads including 250,000 roadside drains (gullies) and associated drainage systems.
1.2 The primary objectives of the highway drainage system are:
a. Removal of surface water (from the carriageway) to maintain road safety and minimise nuisance,
b. Effective sub-surface drainage to prevent damage to the structural integrity of the highway and maximise its lifespan, and,
c. Minimise the impact of highway surface water on the adjacent environment including properties
1.3 In recent years, numbers of prolonged and heavy rainfall events have increased, notably the winter of 2013/14. As prolonged, heavy rainfall events have become more frequent, the number of customer enquiries has increased year on year. The volume of customer enquiries now stands at twice that of 2009. In the last 12 months, around 10,000 enquiries related to drainage and flooding have been received. Of these, 3,000 are related directly to highway flooding and 500 related to incidents of highway flooding that had resulted in damage to private properties.
1.4 The Highway Drainage service is split into two functions:
· Maintenance
· Repairs, renewals and improvements
1.5 The approach taken to delivering the service has been outlined in a document called “Asset Management in Drainage”. In summary, this details the steps that we take to manage our drainage asset. The series of questions and answers emphasise the need to spend the right amount of money at the right time and explain our focus on sites where the risk to road users and residents is the highest. This document can be found at Appendix A.
1.6 This year, the County Council has increased capital investment in drainage infrastructure to £4.3m. This is enabling completion of an additional 120 drainage improvement schemes in 2014/15. Investment has been prioritised on the basis of the following risks:
· Highway Safety
· Internal flooding of properties
· Network disruption
2. Financial Implications
2.1 The allocated budget for highway drainage cleansing is £2,408,300. This a saving of £300,000 made as part of the wider Highway, Transportation and Waste efficiencies for 2014/15. The maintenance regime outlined in this report has been developed on the basis of the current budget allocation and feedback from stakeholders to ensure a balance between the needs of the asset and the demands of the County Council’s customers.
2.2 The approach outlined for capital investment in highway drainage infrastructure ensures that the allocated budget is spent effectively
3. Policy Framework
3.1 The approaches to service delivery outlined in this report fulfil the principle of achieving value for money.
4. The Report
Maintenance
4.1 In December 2010, a change of approach to cleaning highway drains was approved. There was a transition from providing a purely reactive service to delivering routine maintenance on a cyclical basis.
4.2 At the point of moving from a reactive to a planned approach information about the quantum and location of drainage assets was limited. An understanding of the quantum of assets and traffic management required to carry out maintenance activities has been developed. This data is being used to inform planning and programming and enhance service delivery at an operational and strategic level.
4.3 The departure from a predominantly reactive service combined with very wet weather throughout 2012 resulted in an initial decline in customer satisfaction. However this improved significantly and by April 2013 customer satisfaction had reached 87%.
4.4 In 2013, the annual Tracker Survey asked:
“How satisfied or dissatisfied are you that road drains/ gullies are kept clean and working in your local area?”
Comments and feedback indicated that blocked drains were continuing to be a hot topic for Members and Parish Councils, particularly in rural areas.
4.5 In response to the feedback from the Tracker Survey and in light of the need to make significant revenue savings, the way in which drainage maintenance is delivered was subject to a further review. The table below details cleansing activities undertaken from September 2011 and the frequencies currently being trialled.
|
Road Type/ Risk Category |
Road Length (miles) |
Number of Gullies |
Cleansing Frequency 2011 |
Cleansing Frequency 2014 |
|
Hotspots (250 locations) |
NA |
NA |
Every 3-6 months |
Every 3-6 months |
|
High Speed Roads |
160 |
8820 |
Every 6 months |
Every 12 months |
|
Strategic and Locally Important Routes |
1370 |
41,191 |
Every 12 months |
Every 12 months |
|
Minor Urban1 Roads |
2190 |
112,776 |
Every 2 years |
Targeted Cleansing |
|
Minor Rural Roads |
1650 |
85,078 |
Every 2 years |
Targeted Cleansing |
|
Totals |
5370 |
247,865 |
- |
- |
4.6 The frequency of cyclical cleansing on high speed roads was reduced from six monthly to annually to be consistent with the frequency of maintenance on the County’s other main roads. This was part of a service wide saving that came into effect on 1st April and applied to all routine maintenance on the high speed road network.
4.7 Drains on minor urban roads are generally less prone to becoming blocked due to protection by kerb lines, the nature of the traffic using the roads, street sweeping undertaken by District Council and self-cleansing capabilities of the carrier pipes. Examining the data collected from routine walked inspections undertaken by the Highway Inspectorate between April and September has emphasised this point. Blocked drains were reported on less than 10% of the roads inspected.
4.8 A targeted approach to cleansing is now being trialled on minor urban roads. Rather than a cleansing crew attending every road once every two years, each road is inspected at least annually and resources are focused where the need is highest.
4.9 Drains on minor rural roads are often more prone to becoming blocked. Gullies can become overgrown by verges and hedge rows and are particularly vulnerable during peaks in agricultural activities or when silt is washed off fields during prolonged or heavy rainfall. It is not financially viable to increase the cleansing frequency and therefore a community lead approach is being trialled.
4.10 The principle behind this approach is to utilise the good relationships that have been fostered by Highway Stewards with Members and Parish Councils. Over the past three years, the Highway Stewards have developed a detailed knowledge of issues in their area. The intention here is to use this local knowledge of community issues to inform our programmes of gully cleansing.
4.11 Cleansing is now being undertaken in response to enquiries from Members, Parish Councils and customers. Each site is inspected by a highway steward, assessed and prioritised on the basis of highest risk first. The assessment criteria include, risk to highway safety and risk of internal property flooding.
Repairs, renewals and improvements
4.12 Highway flooding causes significant level of disruption; it affects movement of people and goods, therefore adversely affecting the local economy. It also causes significant damage to the highway network; at surface level, flood water scours the surface of the carriageway and footway, which will allow ingress of water to the layer below. In the short term it will result in cracking and development of potholes. Flood water also penetrates the lower layers of road construction washing away fine materials and in time results in large failures of the road structure which may require significant repairs or even reconstruction.
4.13 The weather last winter highlighted numerous pinch points in the drainage network. Some of these are being addressed by the implementation of an enhanced cleansing regime however in a large number of cases work is required to improve the functionality of the system.
4.14 The annual capital budget allocation in recent years has been around £2.7m. This has enabled the completion of around 800 priority minor repair and small improvements and a small number of larger improvement schemes each year. Nevertheless, there are many more sites that need attention and this has been demonstrated by the 3,500 enquiries received last winter.
4.15 Details of the schemes scheduled for completion by the 31 March 2015 can be found at Appendix B.
5. Conclusion
5.1 The regime adopted in September 2011 enabled us to develop a good knowledge of the drainage asset. Moving forward, we have taken on board feedback from stakeholders and tailored the service to respond to customer demand, asset need and the financial challenges.
Recommendations
It is recommended that Members note this report
______________________________________________________________
Background documents:
Appendices
Contact officer:
Kathryn Lewis
Drainage & Flooding Manager
03000 418 181