2011-2012 Annual Report - Full Version - PDF - Palmerston North ...

Activity - StormwaterEnvironmentalSustainability... What the Council Does StormwaterWhat the Council doesThe City has developed and operates a network ofdrainage systems throughout the City to provideflood protection for buildings within the urbanarea from a 100 year rainfall event and a collectionand discharge system for the roading network andprivate property land with flood protection fromstreet flooding from a 5 year event.These systems consist of 263 km of piped drains,8 km of culverts, 16 pump stations, 61 flood gatesand 21 km of open drains.Horizons Regional Council is responsible forprotecting the City from flooding of the ManawatūRiver and Mangaone Stream.The Council develops and implements aStormwater asset management plan to ensurethat these assets can deliver reliable services toexisting and future customers in the most costeffective and sustainable way.The Council manages this Activity to ensure that itsenvironmental impacts are minimised. Stormwatercontamination from both urban and rural run-offincreases the environmental impact of stormwaterdischarges. These impacts are managed througheducation, as well as monitoring and throughthe treatment (as appropriate) of the run-off. TheCouncil also works with Horizons Regional Councilto ensure environmental impacts are minimised.Why the Council does this and itscontribution to Council vision andmajor goalsStormwater contributes to all three of theCouncil’s goals for the City of people wanting tolive here, attracting and retaining businesses andenvironmental sustainability.People want to live in a place that has reliableand well maintained stormwater systems so thattheir homes, workplaces and other buildings areprotected from flooding. Business people do notwant their businesses to be disrupted by flooding.Poor infrastructure, such as stormwater, can give acity a negative image, making it harder to attractpeople and businesses.People also want to ensure that discharge fromthe Council’s stormwater system has minimalenvironmental impact.What happened in the year2011/12 was a quiet year for the Stormwateractivity. The absence of any major rainfall eventsmeant that there was no major flooding in the City.Works focused on minor improvements to reducelocalised flooding were carried out in Park Road,Moana and Manuka Streets, and several culverts inAshhurst were upgraded.Rapid flood hazard mapping and investigationswere carried out to determine how stormwater inthe proposed urban growth areas could be dealtwith in future.Work has continued on the renewal of the FergusonStreet stormwater pipe and this programme willcontinue into the next financial year.Stormwater contributes to all threeof the Council’s goals for the Cityof people wanting to live here,attracting and retaining businessesand environmental sustainability.A focus in the coming year will be to reviewthe engineering standards with the aim ofintroducing more sustainable drainage optionsand development of the long term capital worksand renewals programmes for stormwater assets.Major issues relating to theStormwater Activity include:Effects of Climate Change - As climate changeoccurs the frequency and intensity of storms willchange. Council will be undertaking studies toupdate its design standards to take account oflikely changes in storm frequency and rainfallintensities.106 Palmerston North City Council Annual Report 2011/12