Surface Water
Horizons plays a key role in ensuring the sustainable use of surface water - enabling it to sustain the aquatic life that call the region’s waterways home and provide the services upon which people depend. The region's rivers supply drinking water, power homes through hydroelectric schemes, support farming and industry, and provide recreation for swimmers, anglers, kayakers, and families.
Water quality
Research associates, environmental data technicians, and water quality scientists have monitored the region’s rivers since 1978. Horizons now boasts one of the longest-running and most extensive river monitoring networks in Aotearoa.
Under our State of Environment (SoE) and point-source discharge monitoring programmes, we measure up to 16 different water quality indicators (measurable characteristics) in the region’s rivers, streams, lakes, estuaries, and beaches.
We measure these indicators against the region’s water quality targets, outlined in the One Plan, Horizons’ “one-stop shop” resource management planning document. Targets represent the state (condition) a water quality indicator should be to protect what our communities’ value about the region’s waterbodies. The One Plan’s rule framework outlines tools to manage people’s activities and resource use to maintain or improve water quality to meet the targets.
What we monitor
quality indicators, including the “Critical Four” contaminants.
Nitrogen and phosphorous
Horizons measures the concentrations (amount) of nitrogen and phosphorous in the region’s waterways because, while these naturally occurring nutrients are essential for plant growth, too much can negatively impact the health of freshwater and marine ecosystems and the communities who rely on them.
Nutrients are often applied to pasture and crops as fertiliser, excreted by cows through urine, or bound to soil particles. Some ways nutrients enter waterbodies are:
via run-off (water not absorbed by soil) after rain,
when groundwater feeds into surface waterbodies,
directly via wastewater and stormwater discharges, and
erosion (worn away soil).
The nutrients can accumulate in the water, causing an overgrowth of weeds and algae. This plant matter can smother the habitat of fish and aquatic insects. When weeds and algae photosynthesise during the day, they produce lots of oxygen in the water. However, when weeds and algae respire at night, or die and decompose, they deplete the surrounding water of oxygen, choking aquatic life.
E. coli
Horizons sample the water for the faecal indicator bacteria E. coli (in rivers, streams, lakes, and estuaries) or enterococci (at beaches).
These bacteria are commonly found in the gut of warmblooded animals and people. However, elevated levels of this bacteria indicate faecal (poo) contamination of the water, suggesting other disease-causing bacteria, viruses, and protozoa might also be present, increasing the risk that people playing in and on the water could become sick.
These bacteria enter waterways through animal and bird droppings, overland flow, and wastewater and stormwater discharges.
Sediment
Horizons monitors the water for sediment because the fine particles can fill up small spaces between rocks on riverbeds, making the habitat unsuitable for fish and macroinvertebrates to live in. These small particles of soil, plant and animal matter can also make the water cloudy, obscuring people’s view of hazards in waterways, and making the water unpalatable for stock.
Erosion (the process of wearing away the land by water or wind) – a natural process that can be accelerated by human activities, such as clearing vegetation – causes sediment to wash into rivers and streams. The water then transports these particles in suspension (supported in the water current) or deposits them on the riverbed.
Water quantity
Water quantity scientists and environmental data technicians have spent decades investigating the state of water quantity in the Horizons Region. Horizons keeps a close eye on surface and groundwater levels across the region because water is essential for supporting aquatic ecosystems, providing for communities, and enabling economic activities.
Horizons Regional Council’s surface and groundwater allocation frameworks, implemented through the consenting process, aim to provide for our region’s precious freshwater species and habitats while supplying our communities with access to the water they need to survive and thrive.
The water cylce
WaterMatters
Check out daily water-use data by catchment or Surface Water Management Area using our WaterMatters tool.
Individual consent holders with telemetered systems can also log in to monitor their water use.