There were no multiple vehicles in a traffic management plan back then, because you always knew when the grader was around. The newly graded road told you so, and we respected the nature of a newly graded road and we wished that some day it might be sealed.
Today many of these metal roads are potholed and corrugated with weed-filled drains and blocked culverts and we cynically blame the state of our roads on the extreme rain and the numerous weather events!!
It is well known that water is the enemy of asphalt in causing damage to the asphaltic surface. It makes them more prone to cracking, wear and tear with the subsequent scabbing, potholes and overall surface breakdown. Water is also a common enemy, especially when significant rainfall events occur.
Natural servitude is an inherent property right in New Zealand law, meaning that lower land is obliged to receive surface water which falls naturally from higher land. But you can’t legally disturb the natural flow without consent. Roads do that, and road drainage captures this flow, redirecting it towards a natural river or waterway or a constructed discharge point.
A recent international review of the effects of poor drainage on road performance identified that; “Drainage is the most important aspect of road design and proper design of drainage is necessary for the prolonged performance of the pavement. In designing drainage, the primary objective is to properly accommodate water flow along and across the road and to conveniently transport and deposit the water to the downstream without any obstruction to the flow.”
Once constructed, though, the drainage system needs maintaining and there are potentially legal consequences if a blocked drain causes stormwater to trespass or cause a nuisance to someone else’s property, and it can be proven that negligence is the cause.
This is where Northland councils could be culpable for damage caused by flooding due to unmaintained roadside drainage. A recent report to Northland’s Regional Transport Committee indicates that over the past five years Northland councils had only completed and spent a third of the allocated funding for roadside drainage. A further calculation indicated that, at that rate, it would take 65 years to get the appropriate works done on Northland’s rural roading network.
Councils are currently funded lump sum for the following works: Weed control in channels, culvert end clearing, securing culvert markers, cesspit grate clearing, pre and post-storm drainage patrols, and annual drain inspections.
Councils have also expected rated funded ordered works which are regular monthly activities including: water table maintenance and restoration, new water tabling, clearing of side drains, culvert flushing, sump clearing and channel sweeping
The report indicated that cost escalation in the last year had meant a 15 per cent reduction in achievable works, but that was not the case in the previous four years. The only conclusion that can be drawn is that Northland’s councils are just not doing the funded and required roadside drainage maintenance work.
Enhanced road maintenance, especially roadside drainage, is essential to maintaining our roading assets and that will require a significant readjustment of our councils’ priorities.
