The Avon and Heathcote Rivers, located in the city of Christchurch, New Zealand, are lowland spring-fed rivers linked with the Christchurch Groundwater System. At present, the flow paths and recharge sources to the Christchurch Groundwater System are not fully understood. Study of both the Avon and Heathcote Rivers can provide greater insight into this system. In addition, during the period 2010-2012, Christchurch has experienced large amounts of seismic activity, including a devastating Mw 6.2 aftershock on February 22nd, 2011, which caused widespread damage and loss of life. Associated with these earthquakes was the release of large amounts of water through liquefaction and temporary springs throughout the city. This provided a unique opportunity to study groundwater surface water interactions following a large scale seismic event. Presented herein is the first major geochemical study on the Avon and Heathcote Rivers and the hydrological impact of the February 22, 2011 Christchurch Earthquake. The Avon, Heathcote, and Waimakariri Rivers were sampled in quarterly periods starting in July 2011 and analyzed for stable Isotopes δ¹⁸O, δD, and δ¹³C and major anion composition. In addition, post -earthquake samples were collected over the days immediately following the February 22, 2011 earthquake and analyzed for stable isotopes δ¹⁸O and δD and major anion composition. A variety of analytical methods were used identify the source of the waters in the Avon-Heathcote System and evaluate the effectiveness of stable isotopes as geochemical tracers in the Christchurch Groundwater System. The results of this thesis found that the waters from the Avon and Heathcote Rivers are geochemically the same, originating from groundwater, and exhibit a strong tidal influence within 5km of the Avon-Heathcote Estuary. The surface waters released following the February 22nd, 2011 earthquake were indistinguishable from quarterly samples taken from the Avon and Heathcote Rivers when comparing stable isotopic composition. The anion data suggests the waters released following the February 22nd, 2011 Christchurch Earthquake were sourced primarily from shallow groundwater, and also suggests a presence of urban sewage at some sites. Attempts to estimate recharge sources for the Avon-Heathcote Rivers using published models for the Christchurch Groundwater System yielded results that were not consistent between models. In evaluating the use of geochemical constituents as tracers in the Christchurch Groundwater System, no one isotope could provide a clear resolution, but when used in conjunction, δ¹⁸O, δ¹³C, and DIC, seem to be the most effective tracers. Sample sizes for δ¹³C were too small for a robust evaluation. Variability on the Waimakariri River appears to be greater than previously estimated, which could have significant impacts on geochemical models for the Christchurch Groundwater System. This research demonstrates the value of using multiple geochemical constituents to enrich our understanding of the groundwater surfaces-water interactions and the Christchurch Groundwater System as a whole.
Looking over the Avon River to the Liquidity Bar and Restaurant. On the walls are spray painted markings left by USAR after it was checked.
Looking over the Avon River to the Liquidity Bar and Restaurant. On the walls are spray painted markings left by USAR after it was checked.
The bridge on River Road just before the Banks Ave turn off. Looking down at the Avon River side of the Shirley Stream bridge showing how much the ground has slumped by - notice the unpainted concrete now exposed.
Looking over the Avon River to buildings inside the cordon on Oxford Terrace. Black awnings have collapsed over the windows of The Tap Room restaurant and bar.
The Avon River loop around Porritt Park has risen with the quake. Huge cracks are all through Porritt Park (rowing, hockey and cricket venue). The main section of the river is in a man made cut behind the buildings in the background of this pic.
A digitally manipulated photograph of the badly twisted Medway Street footbridge. The photographer comments, "This bridge over the Avon River in Christchurch, New Zealand has been left in place since the first major earthquake back in September 2010. Graffiti artists or taggers are still leaving their marks on it even though it is nearly twisted at 90 degrees at one point".
A video telling the story of a Dallington house which was built by Bill Cooper in 1957. The house was demolished last month as part of the clearance of the Christchurch residential red zone. The story of the house is used to illustrate what is happening in many Christchurch suburbs. The video also includes the story of a sea elephant that lived in the Avon River in the 1970s and 1980s.
A view of the bridge over the Avon River at Hereford Street. Buildings in the background have been cordoned off and an army truck can be seen in the background.
A two-storey house in Avonside Drive with a warped upper balcony. The photographer comments, "This house is on Avonside Drive opposite the Avon River. The land in this area spread laterally and had bad liquefaction of the soil. This caused some houses to sink into the ground, but as the balcony supports did not sink as much the balcony came to rest at a crazy angle".
A large crack between a row of trees and the riverbank. A fence lining the riverbank has collapsed. The photographer comments, "On the 22 February 2011 we had an earthquake in Christchurch, which ripped us apart literally. This is what happened to the riverbank at New Brighton. Some trees stayed in place and others dropped 2 feet. The amazing thing was that they all stayed upright".
The result of the magnitude 7.1 Christchurch earthquake at 4.35am on September 4th 2010. Taken from Dallington Terrace looking towards Avonside Drive. This pumping station used to be level. When the tide is in that flax bush on the bend appears to be growing from the middle of the river, suggesting the land has slumped about a meter.
The Avon river, with some cordon fence around Our City O-Tautahi, that was in the former Municipal Chambers visible on the left and the central Police station in the background between the trees.
A view down Beresford Street in New Brighton, looking west towards the city at sunset. The photographer comments, "On the other side of the Avon river from New Brighton is the Bexley red zone. Here numerous earthquake damaged streets of houses will be flattened due to it being to uneconomical in the current climate to repair the land to be suitable for housing. There is a campaign at the moment to try and convert all this red zone land, which is mainly adjacent to the Avon river to a giant park".
If you walk along the Avon River by Cashel Street you might catch a glimpse of the small gondolas taking their fares for a leisurely punt through the city and botanical gardens. Today this attraction is aimed largely at tourists, … Continue reading →
Photograph captioned by Fairfax, "Aftermath of Christchurch earthquake as residents start to clean up. City Council surveyors Michael Croucher, left, and James Anderson check stop bank levels along the Avon River in Dallington/Burwood".
Photograph captioned by Fairfax, "Locksley Avenue houses in Dallington. Owen Moore, aged 90, and dog Min laugh in the face of this afternoon's aftershock. His house was built on compacted earth alongside the Avon River".
Photograph captioned by Fairfax, "Locksley Avenue houses in Dallington. Owen Moore, aged 90, and dog Min laugh in the face of this afternoon's aftershock. His house was built on compacted earth alongside the Avon River".
A view over the Avon river, looking at the Boulevard Restaurant and Bar. The canopy over the outside seating area has been distorted, and on the doors are spray painted codes left by USAR after the building had been cleared.
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When I was a kid this bit of land in the foreground was level and extended at least three times further out, but after the earthquakes you can see the angle that land near the river slumped. We used to catch a lot of herrings (yellow -eyed mullet) here when I was a kid, hence the local name of Herring Bay. Across the river is the Bexley Wetlands.
All this is "red zone" after the earthquakes and has to be demolished. The roof of my "old" house (now owned by the government) can be seen between the third and fourth river-side houses.
When you think about the Avon River running through Christchurch, you might imagine punting boats and kayaks in Hagley Park. Such attractions in our garden city are far from new and, recently, a few of us here at Underground Overground … Continue reading →
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For six weeks after the February 2011 Christchurch earthquake millions of litres of raw sewage - along with lots of liquefaction - poured into the Avon and Heathcote Rivers. A team of biologists quickly got to work to measure the impact of this catastrophe on life in the Heathcote River and as they tell Alison Ballance, they were surprised by what they recorded over the next few months.
In what used to be sections with houses and yards. Between late 2011 and 2014 the houses (well 95% of them) were removed due to land dropping in the 2011 earthquakes and the proximity of the Avon River, tidal in this area.
The damaged Christ's College Rowing Club building at Kerrs Reach. The building has visibly slumped to one side. The photographer comments, "This is the sad state of the building after 3 earthquakes has caused the rowing club to sink like a leaky boat".
An earthquake-damaged bridge, the approach to which has slumped. The photographer comments, "Due to lateral spread and the land slumping the road leading to this bridge has moved down greatly. Just imagine making the street lamps upright and how much that section of road would rise up at the end. When you go over bridges in the east side of Christchurch it is quite a climb up and a big drop down on the other side. The bridges in most cases coped very well, but not so the land leading to them".
Urban forager and food writer, Liv Sisson finds all sorts of tasty treats in the Otautahi city centre.With some of the housing and buildings destroyed in the earthquakes, a rewilding has taken place providing a range of edible plants. Liv Sisson gathers produce thriving on berms and near the Avon River.
Demolition underway on the old Government Life building on a walk around the city September 7, 2014 Christchurch New Zealand.