Papanui Dashboard

KEY:

>= 100

< 100

Checked Data

Unchecked Data

Rolling average: 57.374

Aquatic macroinvertebrate communities are at the centre of aquatic food webs, and link the energy of the sun to fish and birds. They respond to a combination of water quality, habitat (including river flow), and climate.

We report upon macroinvertebrates by calculating the Macroinvertebrate Community Index (MCI). The MCI assigns a score to each species or taxon (1 to 10), based on its tolerance or sensitivity to organic pollution, and then calculates the average score of all taxa present at a site. Increases in MCI are generally considered to be good.

What's going on here!

Macroinvertebrate communities of the Papanui reflect poor water quality (e.g. low dissolved oxygen) and degraded habitat, characterised by excessive weed and sediment.

KEY:

< 260

>= 260

Checked Data

Unchecked Data

Rolling median: 150 E. coli/100ml

We use E. coli as an indicator of faecal contamination from warm blooded animals. Not all strains of E. coli are hazardous; however, high concentrations suggest that other pathogens maybe present.

River flow has a strong influence on water quality and ecology. High flows are associated with increased sediment loading and associated contaminants.

What's going on here!

Heavy rain events wash animal faecal matter into the stream. Spikes in E. coli (and turbidity) suggest that for the majority of the catchment, the margins of the Papanui stream are not an effective filter for run-off.

KEY:

< 0.8mg/L

>= 0.8mg/L

Checked Data

Unchecked Data

Rolling average: 0.717mg/L

An essential element for plant growth but elevated levels can lead to excessive plant and algal growth with associated problems. It is readily transformed between soluble and insoluble forms. The graph represents changes in Dissolved Inorganic Nitrogen (DIN) which is the form of nitrogen available for aquatic plant and algae growth.

What's going on here!

During the summer months, excessive DIN is absorbed by weeds and changed into other forms of Nitrogen by warm temperatures.

KEY:

< 0.015mg/L

>= 0.015mg/L

Checked Data

Unchecked Data

Rolling average: 0.164mg/L

We measure a particular form of phosphorous - Dissolved Reactive Phosphorous (DRP) because this is the only form available for aquatic plant and algae growth. Phosphorous is an essential element for plant growth but elevated levels can led to excessive plant or algal growth with associated problems. Over time, phosphate bound to sediment (soil particles in the water) dissolves and becomes DRP.

What's going on here!

The green line at the bottom of the graph represents the plan target for the Papanui catchment (0.015mg/L). Various land use activities are likely to be contributing to these high levels.

KEY:

<= 5.6NTU

> 5.6NTU

Checked Data

Unchecked Data

Rolling median: 2.8mg/L - NB the calculated median is calculated from both FNU and NTU data, so should be treated with caution.

Increases in turbidity are associated with elevated sediment loading which is often caused by erosion. River flow has a strong influence on turbidity and other aspects of water quality. High flows are associated with increased sediment loading and associated contaminants. The relationship between turbidity and rainfall/river flow is a complex one. During heavy rain solids are washed into the stream but there is also more dilution. Compared to large powerful rivers like the Tukituki, the fine sediment and organic matter is more likely to settle on the bed of the Papanui. Sedimentation reduces habitat quality, and limits the type of animals that can live in the waterways.

What's going on here!

Turbidity is often moderately high in the Papanui, and not only during high flows. Reducing hill country erosion, and protecting and stabilising stream banks, should be a priority for landowners in these catchments.

There are many direct and indirect ways in which temperature can influence aquatic life. For example, warmer temperatures increase the metabolic rates of stream life, in turn increasing the amount of oxygen they require. Oxygen is produced by plants during photosynthesis. However, poor reaeration of oxygen at low flows, combined with high consumption of oxygen by plants and bacteria can result in oxygen dropping to low levels overnight, when there is no photosynthesis. The percentage saturation of dissolved oxygen is water is a useful measure of ecological health, especially in the low-gradient streams like the Papanui where oxygen is a critical issue.

What's going on here!

Saturated oxygen levels in the Papanuiare generally too low, and temperatures too high. This is due to a combination of issues located within the stream (e.g. low flow), the river margins (e.g. lack of shading), and land use. Large fluctuations in oxygen and temperature over a period of 24 hours are particularly stressful. Extensive stands of exotic weeds contribute to this by generating oxygen during daylight hours, and depleting it during the night.

Turbidity

Increases in turbidity are associated with elevated sediment loading which is often caused by erosion. River flow has a strong influence on turbidity and other aspects of water quality. High flows are associated with increased sediment loading and associated contaminants. Turbidity in shallow rivers such as the Papanui has a relatively weak influence upon plant growth. The relationship between turbidity and rainfall/river flow is a complex one. During heavy rain solids are washed into the stream but there is also more dilution. Compared to large powerful rivers like the Tukituki, the fine sediment and organic matter is more likely to settle on the bed of the Papanui. This fine material has poor stability, and limits the type of animals that can live here.

Flow

The long, dry Hawke's Bay summers allow flow to drop to very low levels in many streams. For low-gradient streams, like the Papanui, flow can drop to the point where mixing and reaeration is inadequate to maintain oxygen levels. Low flows, combined with the low-gradient, limit the life-supporting capacity of streams like the Papanui. The low gradient also limits the power of floods to flush weeds from the stream, which can then reach nuisance levels where shade is lacking.

What's going on here!

Turbidity in shallow rivers such as the Papanuihas a relatively weak influence upon plant growth. The relationship between turbidity and rainfall/river flow is a complex one. During heavy rain solids are washed into the stream but there is also more dilution.