Land‐use impacts and water quality targets in the intensive dairying catchment of the Toenepi Stream, New Zealand
- 1 March 2006
- journal article
- research article
- Published by Taylor & Francis Ltd in New Zealand Journal of Marine and Freshwater Research
- Vol. 40 (1), 123-140
- https://doi.org/10.1080/00288330.2006.9517407
Abstract
Water quality monitoring in Toenepi Stream, New Zealand, started in 1995 in a study of dairy farming influences on lowland stream quality and has continued since then with brief interruptions. Surveys have provided information about changes in farm and soil management practices as they relate to environmental sustainability. Although average water quality in Toenepi Stream has changed little during 1995–2004, there have been some notable improvements. Water clarity measured by black disc has improved from 0.6m to 1.5m, and median ammonia‐N and nitrate‐N concentrations have declined by 70% and 57%, respectively. The frequency and magnitude of extreme concentrations have declined—most notably for nitrogen (N) forms, which also had decreased mean values. Specific yields for suspended solids (SS) and phosphorus (P) forms in 2002–04 were 47–67% of 1995–97 values, mainly because of lower water yields. Reduced specific yields for N forms in 2002–04 (34–37% of 1995–97 yields) were also attributable to lower mean concentrations in stream water. Faecal bacteria concentrations have not abated and are on average 2–3 times recommended guideline values for contact recreation. Fewer dairy farms and an increased proportion irrigating dairyshed effluent to land, rather than discharging it to the stream via two‐pond systems, were likely causes of improvement in water quality. Water quality targets were developed for Toenepi Stream to achieve contact recreation criteria for the Piako River (downstream) and for intrinsic habitat values for Toenepi Stream. A range of mitigation measures has been formulated to meet these targets, but substantial uptake of sustainable farming practices is needed to improve water quality in Toenepi Stream.Keywords
This publication has 36 references indexed in Scilit:
- The use of a nitrification inhibitor, dicyandiamide (DCD), to decrease nitrate leaching and nitrous oxide emissions in a simulated grazed and irrigated grasslandSoil Use and Management, 2002
- Suspended sediment sources in two small lowland agricultural catchments in the UKJournal of Hydrology, 2001
- Water quality of a lowland stream in a New Zealand dairy farming catchmentNew Zealand Journal of Marine and Freshwater Research, 1999
- Land use in the Taupo catchment, New ZealandNew Zealand Journal of Marine and Freshwater Research, 1999
- Responses of seven species of native freshwater fish and a shrimp to low levels of dissolved oxygenNew Zealand Journal of Marine and Freshwater Research, 1999
- A lysimeter study of the impact of cow urine, dairy shed euent, and nitrogen fertiliser on nitrate leachingSoil Research, 1999
- Characterisation of lowland streams using a single‐station diurnal curve analysis model with continuous monitoring data for dissolved oxygen and temperatureNew Zealand Journal of Marine and Freshwater Research, 1998
- OPTICAL CHARACTERISTICS OF NEW ZEALAND RIVERS IN RELATION TO FLOWJawra Journal of the American Water Resources Association, 1997
- Upper thermal tolerances of twelve New Zealand stream invertebrate speciesNew Zealand Journal of Marine and Freshwater Research, 1994
- Sources and sinks of nutrients in a New Zealand hill pasture catchment II. PhosphorusHydrological Processes, 1988