Horizons State of Environment Report 2019

Horizons Regional Council have recently released their State of Environment Report 2019 and it’s an interesting read. It’s clearly written and well-designed which makes it easy to find the information you’re interested in. Waikawa Beach is specifically mentioned a couple of times.

Horizons region map.
Horizons region map.

If you can’t get the report at the link above, it’s also available here: Horizons Regional Council State of Environment Report 2019 (21MB zipped file of PDF).

One thing to know is how huge the Horizons area is: 2.2 million hectares, or 8% of New Zealand’s total land area, with a population of about 240,000.

Below are some extracts that caught my attention. I’ve highlighted the 5 Waikawa Beach mentions.

Page 8: A case study of the impacts of climate change on sedimentation of rivers shows the current projected 27 per cent improvement in sediment loads in the region’s rivers by 2043 due to hill country erosion control, are projected to reduce to 19, 12 or 5 per cent improvement under minor, moderate or major climate change scenarios, respectively. Further modelling suggests a greater pace of works will be required to offset the impact of climate change on sedimentation of rivers in the long term. A further case study predicts summer river flows in the Manawatū are projected to decrease by 14 per cent by 2090 and there is likely to be an increase in the number of high flow events per year.

Page 9: Wetland extent has reduced from approximately 22,000 hectares historically to less than 700 hectares presently (3 per cent of the former extent).

Page 11: There are 40 estuaries in the region – 25 on the west coast and 15 on the east coast. Of these, five estuaries (12.5 per cent) have been identified as moderate to high vulnerability to eutrophication (nutrient and sediment). These are the east coast estuaries Wainui and Tuatane and the west coast estuaries Kai Iwi, Hōkio and Waikawa.

Page 15: Climate change has been identified as a significant issue in Horizons’ 30-Year Infrastructure Strategy, and in 2018, we introduced a dedicated research programme to investigate the impacts of climate change in our region.

Page 19: Climate change experts predict larger and more frequent storm events in our region during this century.

Page 75: Since our last State of Environment report in 2013 we have:
Completed hydrogeological studies throughout the region, including Whanganui, Turakina- Rangitīkei, Manawatū (Tararua and Whakarongo) and Horowhenua (Lake Horowhenua and Ōhau- Waikawa)

Page 77: Guidance For Private Bore Owners. In most cases groundwater is suitable for stock water and irrigation but, throughout much of the region, water drawn from a bore will require some form of treatment before human consumption. If you have a private groundwater well or bore, there are some important steps you can take to look after it and minimise the risk of you or your family getting sick.

Page 92: Inanga. Inanga (Galaxias maculatus), the smallest of our whitebait species, are found throughout our region’s streams, rivers and estuaries. More than 90 per cent of whitebait caught in our region are Inanga, and Horizons has an active programme dedicated to identifying the location and extent of their spawning habitat in the region. This is so that we can better manage consented activities in these areas and, where necessary, work with landowners to restore spawning habitat.

In autumn, Inanga migrate down to our estuaries, where they await the king tide. They gather and lay their eggs at the base of grasses near the water’s edge, so that when the tide subsides the eggs remain clear of the water. Here they are kept damp by the thick mass of grass roots and stalks on which the eggs adhere. Around two weeks later, the next king high tide arrives, covering the eggs with water. The eggs hatch and the newly hatched fry are washed out to sea where they stay for around six months before returning for their freshwater run in early spring.

Page 105: In our region estuaries, freshwater from streams and rivers mixes with seawater, influenced by tides as water flows upstream and downstream twice each day. There are 40 estuaries in the region, 25 on the west coast and 15 on the east coast. This represents almost ten per cent of the nation’s estuaries. Estuaries receive and transport nutrient and sediment daily from land, and via streams, rivers and from the sea. They are highly productive, providing habitat for a range of birds, fish and other aquatic life.

Page 107: Five of these estuaries have been identified as moderately to highly vulnerable to excess nutrient and sediment loads. These are the east coast estuaries Wainui and Tuatane, and the west coast estuaries Kai Iwi, Hōkio and Waikawa.

Page 109: Comparison Of Estuary Water Quality To One Plan Targets. For our estuaries, a comparison of water quality to One Plan targets also highlights issues at some estuary sites (Table 7). As with our beaches, all sites meet the criteria for ammoniacal nitrogen and temperature, with the exception of the Rangitīkei Estuary … The Ōhau and Waikawa Estuaries fail to meet One Plan targets for dissolved oxygen and chlorophyll a.

Page 112: Estuary Trophic Index Case Study. In the Horizons Region, trophic scores have now been calculated for the Ōhau and Waikawa estuaries. Ōhau Estuary has a score of 0.68 and is classed as Band C (moderate), while Waikawa Estuary has a trophic score of 0.85, placing it in the Band D (high) category.

Page 113: Get Involved. Protect sensitive coastal environments by walking instead of driving. Driving on beaches, sand dunes and/or salt marsh can kill plants and animals living there and destroy the habitat so they cannot resettle

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