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.
An entry from Ruth Gardner's Blog for 22 January 2014 entitled, "Poor Poplar".
The Anzac Drive bridge. The path underneath has slumped quite dramatically and the abutment is severely warped.
Photograph captioned by BeckerFraserPhotos, "An aerial photograph of the Anzac Drive Bridge showing extensive liquefaction".
An aerial photographof New Brighton and Bexley.
Flowers float down the Avon River during the River of Flowers memorial event. The photographer comments, "One year on, Riverside residents gather for a 2 minute silence and to cast flowers in the river. Riverside residents met at the Medway St bridge to commemorate the anniversary of the 22/2/11 quake".
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.
- The Avon-Ōtākaro Redzone is an 11 kilometer stretch of land along the Avon-Ōtākaro River in Christchurch. - This project focused on the creation of a publicly available biodiversity map of the AvonŌtākaro River Corridor, a project undertaken as part of the ecological restoration of the Christchurch redzone. - This project originated from the Christchurch 2010-2011 earthquake sequence which saw liquefaction damage along 11km of the Avon River. Under guidance from The Nature Lab & Ōtākaro Living Laboratory, and various other experts, the primary research objective was to map historical biodiversity, identify hotspots, and assess areas for potential revegetation. - The data collected came from historical black maps, current iNaturalist data, and soil classification information. - The findings show that, pre-colonialism, the area was composed of herbaceous areas, wetlands, native shrubland, and tussock land, with key plants such as river, fern, tutu, and cabbage trees. - The post-earthquake analysis shows a transition from a residential area to patchy grasslands and swampy areas. - The findings also showed a strong relationship between historic sites and soil classifications, providing knowledge for past and future vegetation patterns and spread. - This map will be a valuable resource for conservation efforts and public engagement as the area transitions into a blue-green corridor.
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.
A photograph captioned by BeckerFraserPhotos, "A view looking into the central city from the banks of the River Avon just below the Colombo Street bridge".
Photograph captioned by BeckerFraserPhotos, "Avonside Drive".
A sewage pump and flooding on Avonside Drive.
Photograph captioned by BeckerFraserPhotos, "New Brighton Road".
An aerial photograph of Avonside and its surrounding suburbs.
A gravel walkway in the process of being paved next to the Avon River. On the side are piles of dirt that has been dug up to make way for the walkway.
A gravel walkway in the process of being paved next to the Avon River. On the side are piles of dirt that has been dug up to make way for the walkway.
People cast flowers into the Avon River during the River of Flowers event held in Riccarton Bush, commemorating the second anniversary of the 22 February earthquake. In the background is the string quartet from Christchurch Girls High School which played before the event.
People cast flowers into the Avon River during the River of Flowers event held in Riccarton Bush, commemorating the second anniversary of the 22 February earthquake. In the background is the string quartet from Christchurch Girls High School which played before the event.
People cast flowers into the Avon River during the River of Flowers event held in Riccarton Bush, commemorating the second anniversary of the 22 February earthquake. In the background is the string quartet from Christchurch Girls High School which played before the event.
Photograph captioned by BeckerFraserPhotos, "Kate Sheppard memorial, near the former Municipal Chambers on the Avon Riverbank".
An army truck travelling down a gravel road in Avonside. To the right is a digger which has been used to fix the road.
A woman casts flowers into the Avon River during the River of Flowers event held in Riccarton Bush, commemorating the second anniversary of the 22 February earthquake. In the background is the string quartet from Christchurch Girls High School which played before the event.
Photograph captioned by BeckerFraserPhotos, "The Avon River is at this point on Avonside Drive 10 km from the estuary. At high tide the river now overflows its banks showing that the ground has sunk by about 40 cm".
Photograph captioned by BeckerFraserPhotos, "The Avon River is at this point on Avonside Drive 10 km from the estuary. At high tide the river now overflows its banks showing that the ground has sunk by about 40 cm".
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 dock by the riverbank walkway alongside New Brighton Road which has been closed off to the public. The area has flooded at high tide due to ground subsidence".
Photograph captioned by BeckerFraserPhotos, "A sculpture on the Cambridge Terrace side of the River Avon which marks 15 years of the Seattle-Christchurch Sister City Association".
Photograph captioned by BeckerFraserPhotos, "Avonside".
Photograph captioned by BeckerFraserPhotos, "Extensive cracking to the Wainoni Road bridge. There has been a vehicle weight limit of 3500kg placed on the bridge. A person was placed on duty at all times to police this".
Photograph captioned by BeckerFraserPhotos, "This loop of the Avon encircles Horseshoe Lake and gives the area its name and its attraction as a place to live. The land close to the Avon River has severe issues with slumping, lateral movement and liquefaction, so that much of it is red zoned and the houses will be demolished".