Infrastructure Strategy Options Implications Option Implications Accept a Benefits stabilisation have been trialled with varying success over recent reduction in the This approach delays expenditure. It could be expected that years. With NZTA now agreeing to subsidise justified dust current level of levels of service for bridge assets would be decline significantly treatment Council is taking advantage. service to reduce as a result of deferred renewals, although this result has not In November 2004 the Transfund New Zealand Technical Review expenditure. occurred so far. of Local Roading in the Marlborough District recommended that Costs the Council would get significantly better unsealed road conditions if investment was made into a programme of unsealed The quantity of bridges waiting for end-of-life intervention would road pavement rehabilitation based around appygpp continue to increase, and a decrease in levels of service would be bound pavement dressed with an unsealed running course. This inevitable in the near future if renewal budgets were not should reduce maintenance costs and public complaints. A increased. reduction in dust was also noted to be an outcome from better unsealed pavements. The outcome would be likely to include accelerated deterioration of older structures and more bridges having loading restrictions and/or being closed, especially in remote areas. The risk of a catastrophic failure of a bridge would increase with a 3. Most likely scenario diminished maintenance and monitoring regime. 3.1 Renewals 2.2 Levels of service – Unsealed Roads It is essential that Marlborough has a network of bridges that is capable of supporting the Primary Industries, tourists and residents so that they are able to access the Option Implications district.There are a large number of bridges on the Marlborough network that will Status quo Benefits need to be replaced over the next 50 years. No additional expenditure. This current investment of approximately $1m per annum (1% of asset value) is Costs delivering a Level of Service that the Community accepts. However from around 2045 investment will need to be increased to approximately $2m per annum (2% of asset Ongoing complaints from motorists and rural residents about the value) to cope with bridge renewals which are expected to fall due. condition of unsealed roads and the impacts of dust. PREFERRED Benefits [of a dust mitigation strategy] We will use weight and speed restrictions on bridges where immediate upgrade is not OPTION essential or affordable. Reduced level of complaints from motorists and rural residents Invest in better about the condition of unsealed roads and the impacts of dust. 3.2 Levels of service management of Costs [of a dust mitigation strategy] The unsealed network reduces in length by approximately 0.7% per year due to the dust and effect of seal extension works. No new unsealed roads are added to the network, so increased Level of Council has approved a $200K (33%) increased in annual the total length of unsealed roads reduces by around 4 km per year. Service on budgets as part of the LTP process. $40k of this amount will be unsealed road allocated to applying dust suppressant to areas that meet the requirements of the Low Volume Roads Dust Mitigation Chart. The likely high cost of moving freight from remote areas in Marlborough will ensure that heavier vehicles are the preferred transport method, and the unsealed road Notes network will continue to come under significant pressure well into the future. Trial dust reduction systems, eg; Otta Seal, Dust Palliatives and Maintaining the condition of the pavement will be a critical element in the asset life. 2018-2028 Long Term Plan Page 184