The Ōroua sub-catchment:
- is approximately 90,000ha in area,
- land use is 63% sheep and beef, 19% dairy, 11% forest (native and exotic),
- has a number of popular swimming spots,
- Since the 1820s strong Iwi connections of Tainui Waka through Ngāti Toarangatira, Ngāti Raukawa and Ngāti Kauwhata have influenced life of the Ōroua River from the headwaters to the confluence with the Manawatū River at Puketōtara, near Rangiotū. Ngāti Kauwhata has maintained important Maori concept of “ahi kā and kaitiakitanga o te Awa Ōroua”. There are shared arrangements with other neighbouring Iwi including Ngāti Hauiti and Ngāti Apa,
- contains historic Rangitāne O Manawatū wāhi tapu and customary fishery areas throughout, along with mahinga kai, and kāinga sites,
- has three sites of rare/threatened native fish,
- has a blue duck (whio) population in its headwaters,
- is an important trout fishery and contains important spawning habitats around Feilding and above Kimbolton,
- contains 47 high priority bush and 2 high priority wetland sites, including Kitchener Park, and
- includes parts of the Pohangina-Ōroua, Lower Manawatū and Manawatū Drainage schemes, the Lower Kiwitea Scheme, and the Te Kawau drainage scheme.
The water quality of the Ōroua catchment is characterised by medium-high suspended sediment loads, low-moderate nutrient levels upstream of Feilding, and high nutrient levels downstream of Feilding. Pathogen levels are generally safe for swimming upstream of Feilding, but are consistently unsafe for swimming downstream of Feilding. The Feilding sewage discharge is a major contributor to the poor water quality downstream of Feilding, however the overall situation is due to the cumulative effects of the other point source discharges and nonpoint source run-off.
THE WATER QUALITY STATE IS EXPLAINED BY:
- this sub-catchment contains approximately 5,700ha of unprotected erosion prone land (15% of the unprotected erosion prone land in the entire Manawatū Catchment) and is contributing 10% of the total suspended sediment load to the Manawatū Catchment,
- there are 21 consented discharges to water in the sub-catchment, six of which are considered significant. These are: Cheltenham sewage, Kimbolton sewage, Feilding sewage, Rongotea sewage, Awahuri sewage, and the AFFCO Manawatu meat plant. Applications for consents for Feilding sewage and the discharge from the AFFCO Manawatū meat plant are currently being considered through the consenting process. Kimbolton sewage was granted a new consent in 2008. The compliance rate of the discharges monitored is 81%,
- some consent holders continue to operate a number of years after their consent has expired, while negotiating consent renewal. They are legally able to do this,
- there are 110 consented dairy shed effluent discharge consents, all of which are discharges to land. The compliance rate for this season is 78%, and
- the exact level of progress towards the Dairying and Clean Stream Accord targets (around stock exclusion from waterways, stock crossing, and nutrient management) by dairy farmers in this sub-catchment is unknown, but there is extensive riparian fencing and planting, and stock crossings (bridges and culverts). Farmer surveys in the Manawatū-Whanganui region indicate the majority of Dairying and Clean Stream Accord targets are achieved.
- there are no known man-made barriers to native fish migration,
- public access to the Ōroua River is limited for much of its length except in its headwaters, through Feilding, and at road crossings,
- only 4% of high priority bush remnants and none of the high priority wetlands are protected, and
- the water quantity resource of the Lower Manawatu sub-catchment is 97% allocated. All major takes are metered and automatically monitored.