3.2.3 Improved Levels of Service The implications of meeting the current levels of service are discussed in Chapter 2: Levels of Service. There are no significant changes expected to the levels of service that will influence growth in demand for stormwater services. 3.2.4 Climate Change There continues to be debate amongst the experts on the exact nature of climate change. The Ministry for the Environment is however publishing clear advice on the possible implications. The advice on their web-site was last up-dated in July 2014 as follows: Projections of climate change depend on future greenhouse gas emissions which are uncertain. Also, global climate models used to predict future climate vary in their sensitivity to these emissions. The combination of these factors means that projections of future climate are usually expressed as a range of likely values. This information is mostly from 'middle-of-the-range' climate change projections. Temperature - Temperatures are likely to be around 0.9˚C warmerby 2040 and 2.0˚C warmer by 2090, compared to 1990. By the end of the century, Marlborough is projected to have about 10–40 extra days per year where maximum temperatures exceed 25˚C. The number of frosts could decrease by around 20–45 per year, with even greater reductions in frosts possible further inland. Rainfall - Rainfall will vary locally within the region. While annual rainfall is likely to increase in the inland high country, eastern Marlborough and the Kaikoura Coast are likely to become drier. In Blenheim, there is likely to be little change in average annual rainfall by 2090. Seasonal projections show summer and autumn rainfall both increasing by 5 per cent in Blenheim, with very little change in winter and spring rainfall by 2090. Very heavy rainfall events are likely to become more frequent. Sea-level rise - New Zealand tide records show an average rise in relative mean sea level of 1.7 mm per year over the 20th century. Sea levels are expected to continue to rise into the future. The Ministry for the Environment recommends planning for future sea-level rise of at least 0.5 m, along with consideration of the consequences of a mean sea-level rise of at least 0.8 m (relative to the 1980–1999 average) by the 2090s. Storms - The number of storms crossing the Tasman Sea is expected to increase in summer and decrease in winter, by the end of the century. The intensity of these storms is likely to decrease in both summer and winter. Wind - The frequency of extreme winds over this century is likely to increase by between 2 and 5 per cent in almost all regions of New Zealand in winter, and decrease by a similar amount in summer. There may be more north-easterly events over the top of the South Island and less frequent westerly winds. Climate change - is only one of the variables to take into account in the design and operation of the infrastructure. However it is critically important and is being incorporated into all current designs. 3.2.5 Resilience Following the Christchurch Earthquake sequence there has been substantial research and information on the resilience of utility infrastructure. The Wairau Plains has many common geographical features with the Canterbury Basin and comparisons can be usefully made. Lateral spread adjacent to water courses was particularly damaging to stop banks, utilities and other structures. New set-back standards are being incorporated into new designs. Page 31