Discriminant analysis for estimation of groundwater age from hydrochemistry and well construction: application to New Zealand aquifers

Daughney, Christopher J.; Morgenstern, Uwe; Raaij, Rob van der; Reeves, Robert

doi:10.1007/s10040-009-0479-2

Cited by 29 publications

(36 citation statements)

References 36 publications

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“…Major ion concentrations, which are easier to measure than tritium concentrations, have the potential to complement tritium dating, and help us understand the groundwater dynamics Daughney et al, 2010). Major ion concentrations increase with groundwater age due to mineral dissolution during water-rock interactions.…”

Section: Water Datingmentioning

confidence: 99%

Dating of streamwater using tritium in a post nuclear bomb pulse world: continuous variation of mean transit time with streamflow

Morgenstern

Stewart

Stenger³

2010

Hydrol. Earth Syst. Sci.

176

184

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Abstract. Tritium measurements of streamwater draining the Toenepi catchment, a small dairy farming area in Waikato, New Zealand, have shown that the mean transit time of the water varies with the flow rate of the stream. Mean transit times through the catchment are 2-5 years during high baseflow conditions in winter, increasing to 30-40 years as baseflow decreases in summer, and then dramatically older water during drought conditions with mean transit time of more than 100 years. Older water is gained in the lower reaches of the stream, compared to younger water in the headwater catchment. The groundwater store supplying baseflow was estimated from the mean transit time and average baseflow to be 15.4 × 10 6 m 3 of water, about 1 m water equivalent over the catchment and 2.3 times total annual streamflow. Nitrate is relatively high at higher flow rates in winter, but is low at times of low flow with old water. This reflects both lower nitrate loading in the catchment several decades ago as compared to current intensive dairy farming, and denitrification processes occurring in the older groundwater. Silica, leached from the aquifer material and accumulating in the water in proportion to contact time, is high at times of low streamflow with old water. There was a good correlation between silica concentration and streamwater age, which potentially allows silica concentrations to be used as a proxy for age when calibrated by tritium measurements. This study shows that tritium dating of stream water is possible with single tritium measurements now that bomb-test tritium has effectively disappeared from hydrological systems in New Zealand, without the need for time-series data.

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Section: Water Datingmentioning

confidence: 99%

Dating of streamwater using tritium in a post nuclear bomb pulse world: continuous variation of mean transit time with streamflow

Morgenstern

Stewart

Stenger³

2010

Hydrol. Earth Syst. Sci.

176

184

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“…Water age provides important information on vulnerability to contamination and can therefore be used to assess the security of drinking water supplies, particularly from groundwater bores Morris et al, 2005;New Zealand Ministry of Health, 2008). Water age measurements can also be used to quantify rates of hydrochemical evolution resulting from water-rock interaction (Katz et al, 1995;Burns et al, 2003;Glynn and Plummer, 2005;Daughney et al, 2010;Beyer et al, 2014). These applications of water dating cover the spectrum from applied water resource management to fundamental scientific research.…”

Section: Introductionmentioning

confidence: 99%

Using groundwater age and hydrochemistry to understand sources and dynamics of nutrient contamination through the catchment into Lake Rotorua, New Zealand

Morgenstern

Daughney

Leonard

et al. 2015

Hydrol. Earth Syst. Sci.

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Abstract. The water quality of Lake Rotorua has steadily declined over the past 50 years despite mitigation efforts over recent decades. Delayed response of the groundwater discharges to historic land-use intensification 50 years ago was the reason suggested by early tritium measurements, which indicated large transit times through the groundwater system. We use the isotopic and chemistry signature of the groundwater for detailed understanding of the origin, fate, flow pathways, lag times and future loads of contaminants. A unique set of high-quality tritium data over more than four decades, encompassing the time when the tritium spike from nuclear weapons testing moved through the groundwater system, allows us to determine detailed age distribution parameters of the water discharging into Lake Rotorua.The Rotorua volcanic groundwater system is complicated due to the highly complex geology that has evolved through volcanic activity. Vertical and steeply inclined geological contacts preclude a simple flow model. The extent of the Lake Rotorua groundwater catchment is difficult to establish due to the deep water table in large areas, combined with inhomogeneous groundwater flow patterns.Hierarchical cluster analysis of the water chemistry parameters provided evidence of the recharge source of the large springs near the lake shore, with discharge from the Mamaku ignimbrite through lake sediment layers. Groundwater chemistry and age data show clearly the source of nutrients that cause lake eutrophication, nitrate from agricultural activities and phosphate from geologic sources. With a naturally high phosphate load reaching the lake continuously via all streams, the only effective way to limit algae blooms and improve lake water quality in such environments is by limiting the nitrate load.

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“…Due to the oxic environment and lack of carbon sources, denitrification is usually limited in vadose zones, with particular in semiarid regions (Zhou et al, 2016). Although groundwater DO concentrations usually decrease with groundwater age (Daughney et al, 2010), denitrification is likely limited by the lack of a microbially labile organic carbon source in many regions (Pabich et al, 2001). In shallow, well-oxygenated groundwater, denitrification is limited by the presence of oxygen although dissolved organic carbon or pyrite is usually available (Sanford and Pope, 2013).…”

Section: Legacy Nutrient Dynamics In Vadose Zone/groundwatermentioning

confidence: 99%

“…The relationship between dissolved reactive P and groundwater age is purported to exists because older groundwater is more likely to be reduced (anoxic) (Daughney et al, 2010) resulting in favorable conditions for iron oxide dissolution and release of associated P (Carlyle and Hill, 2001). Groundwater contribution of dissolved P is also dependent on the redox condition of the stream hyporheic zone, where oxic conditions at the streambed interface may allow SRP sorption or mineralization coupled with iron reduction reactions (Carlyle and Hill, 2001;Ptacek, 1998;Van der Grift et al, 2014).…”

mentioning

confidence: 99%

Legacy Nutrient Dynamics at the Watershed Scale: Principles, Modeling, and Implications

Chen

Shen

et al. 2018

Advances in Agronomy

106

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Discriminant analysis for estimation of groundwater age from hydrochemistry and well construction: application to New Zealand aquifers

Cited by 29 publications

References 36 publications

Dating of streamwater using tritium in a post nuclear bomb pulse world: continuous variation of mean transit time with streamflow

Dating of streamwater using tritium in a post nuclear bomb pulse world: continuous variation of mean transit time with streamflow

Using groundwater age and hydrochemistry to understand sources and dynamics of nutrient contamination through the catchment into Lake Rotorua, New Zealand

Legacy Nutrient Dynamics at the Watershed Scale: Principles, Modeling, and Implications

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