Introducing Oracle 1
Oracle 1 is a prototype, real-time data sensor which was developed for us, exclusively, by our friends at Kotahi Net.
Oracle 1 was grounded at Avonhead in July of 2019 to take half-hourly measurements of pH, nitrates, temperature, dissolved oxygen (DO), conductivity, and reduction-oxidation (redox) potential.
There are additional contaminants (such as E. coli) which must be tested manually, so we've been examining those readings as well. We are currently exploring options to expand our data set to include other documented contaminants in our waterways, and fine-tuning our hardware and software requirements before we launch the next Oracle.
Our goal is to make this data readily available, open-source, and transparent, and to eventually ground Oracles throughout our waterways. We aim to use this data and other available data sources to provide you with the most complete and up-to-date picture that the current technology allows and, in doing so, start to give our rivers a voice.
The information below is displayed using basic data analysis tools while we work quickly to upgrade our data dashboard to v2.0.
HUGE thanks to our friends at ECan for helping us to describe the information you’re seeing here.
Oracle 1 Location - Head of the Avon River/Ōtakaro, Corfe Street, Christchurch.
The Real-Time Data
Data not loading in your browser? You can view it directly HERE!
For best results, we recommend viewing the data from a computer, not a mobile device.
NOTE - We’re having Oracle 1 serviced at the moment, so you may see some unusual or missing readings. Everything should be back up and running as normal ASAP! In the meantime, feel free to download the historical data in full below.
Temperature
The temperature of water is an important factor to consider when measuring water quality. It directly influences what freshwater species (e.g. fish and macroinvertebrates) will thrive in the water, as well as influencing the growth rate of plants and algae. Temperature can also play an important role in influencing the other physical and chemical properties of water described on this page.
Temperatures naturally fluctuate throughout the day, and it is not uncommon to see variation from day to night. The Avon River/Ōtākaro temperature in winter can drop below 10°C. In summer, temperatures may climb above 20°C.
Nitrates (Nitrate-Nitrogen)
Nitrate is a highly soluble molecule that is made up of nitrogen and oxygen. It is the primary form of nitrogen used by plants to stimulate growth, and is a very important fertiliser. However, because it is highly soluble, it leaches through soils very easily, particularly after heavy rainfall.
Dissolved nitrogen is one of the most common contaminants in waterways in rural and urban areas. Sources include excessive application of fertiliser, septic tanks, and leaking sewage systems. Nitrate is just one form of dissolved nitrogen. It may change into different ‘species’ under changing water conditions. The pH, temperature, and oxidation reduction potential play an important role in this process.
High nitrate concentrations may cause aquatic weeds and algae to grow too fast. This increased plant growth can smother the natural environment and reduce the available oxygen in the water. These effects pose a threat to aquatic life. High concentrations of dissolved nitrogen can cause direct harm to fish and macroinvertebrates. It can also be dangerous to drink when concentrations are high, particularly for bottle-fed babies. The current NZ drinking water standard is 11.3 mg/L of nitrate-nitrogen (NO3-N).
Learn more about nitrate at Land, Air, Water, Aotearoa (LAWA).
pH
The pH of water is a measure of its acidity or alkalinity. This is measured on a scale of 0 to 14 where 7 is neutral, less than 7 is more acidic, and greater than 7 is more alkaline. The pH of most natural waters ranges between pH 6.5 to 8.0. It is often dependent on the geology of the catchment, the river flow, and on discharges into the river. It can also be influenced by biological processes. For example, plant photosynthesis can lead to variations of both dissolved oxygen and pH in water.
Aquatic life requires suitable pH conditions to thrive. pH values below 4.5 and above 9.5 are typically lethal to many fish and macroinvertebrate species.
Dissolved Oxygen
Dissolved oxygen is the oxygen content of water. It is essential to the survival of fish and other aquatic life. It can also be an important indicator of pollution in rivers.
Changes in dissolved oxygen can be caused by temperature variations and use by aquatic organisms. For example, waters that are rich in nutrients and plant/algae growth can become ‘eutrophic’. This can have a great influence on dissolved oxygen concentrations throughout the day. As plants and algae photosynthesise during the day, they can increase oxygen concentrations to very high levels. However, in the night levels can seriously decline, which can harm or kill aquatic life in the system.
Learn more about dissolved oxygen at Land, Air, Water, Aotearoa.
Conductivity
Conductivity is the measurement of the ability of water to conduct an electric current. Its value is mostly influenced by the concentration of dissolved ‘ions’ (charged molecules) in the water. For example, seawater has a lot of dissolved salts in the water, which means it has a high conductivity.
Rivers have varying conductivity depending on the source of the water. The Avon River/Ōtakaro water is spring-fed, which means that the water is sourced from groundwater. This water has dissolved some salts from sediment in the ground, which means it has a higher natural conductivity. This is normal.
Conductivity changes to water can provide an indication of changes to the river system. For example, the conductivity can change during a rainfall or pollution event. However, it is important to examine these results with other water quality parameters to better understand the story.
Learn more about dissolved oxygen at Land, Air, Water, Aotearoa.
Oxygen Reduction Potential
Reduction-oxidation (Redox) potential of water is the measure of the oxidising or reducing potential of the water body. Rivers that have normal levels of dissolved oxygen, such as healthy rivers, lakes, oceans and rainwater have oxidizing conditions (positive values). Many important chemical transformations are oxidation or reduction reactions. An important example is the reduction of nitrate (NO3) to nitrite (NO2) and ammonium (NH4).
Raw Data
In the graphs above, we have displayed a week’s worth of hourly data, so that you can view as many measurements as possible in real-time,. We also have the full, raw data from Oracle 1 dating back to its grounding in 2019 and are happy to make it available to you in an open-source format.
The graph to the left shows a snapshot of our raw data, covering the 3-month period from when Oracle 1 was first calibrated in August of 2019 through September of 2019. You can download the full raw data by period through the archive links below. Data downloads are taken mid-month and cover a 30-day period.