For children at Manawaru School on the Hauraki Plains, ducking in and out of the stream at the back of the grounds is a birthright.
A few years back, the gully was overgrown with trees and "pretty manky", says principal Rosemary Hendrikse. Under the Enviroschools programme, the school community has cleaned up the wilderness as a place to roam wild and cool off - a "real" adventure playground. Parents have helped, putting in native plants to stabilise the banks. Some children are growing eels, just as their forebears used Te Horo stream as a food source.
It's a fair bet there are times when swimming in the stream is unhealthy. "We know to not go down there after heavy rain," Hendrikse says.
Te Horo stream runs through some of the most intensively-farmed dairy flats in the country and into the Waihou river, which, on the plains, is unfit for swimming year-round.
"It's so important for kids to be swimming in real places, not just concrete boxes," she says. "The kids learn to take responsibility for keeping waterways clean and they take that message home with them."
Hendrikse says there's growing awareness in the farming community of the need to fence off waterways, undertake riparian planting and take better care of streams. Unless fast progress is made to limit pollutants going into waterways, the outdoor lifestyle for which New Zealand is known will be damaged. The ecological consequences could be far worse.
Last month, a Ministry for the Environment report found more than half of our monitored freshwater swimming spots were health risks - exposing the folly of Prime Minister John Key's glib invitation last year, to a BBC interviewer who challenged our clean and green credentials, to come here and "jump in any New Zealand river or stream".
The big threat to human health is the E.coli bacteria from faecal contamination by sewage treatment plants and pastoral farms. But the ecological health of waterways and estuaries is further threatened by increased nutrients - particularly nitrates and phosphorus from farms, dairy factories, meatworks and town sewerage - and sediment washed off hills and stream banks.
The Hauraki Plains' badly-polluted main rivers - the Waihou, the Piako and their tributaries - deposit tonnes of nitrates and phosphorus and sediment into the Firth of Thames, an important nursery for the Hauraki Gulf which is already degraded by urban pollution. A report last year by Waikato Regional Council chief water quality scientist Bill Vant found nitrogen levels at points on the Piako and Waitoa Rivers were up to five times the satisfactory limit and phosphorous loadings up to seven times the guideline.
Elsewhere, demand for water for irrigation, industry and drinking is close to exceeding supply. Canterbury has 10 red zones, where water has been fully allocated, and four other areas where allocation exceeds 80 per cent of the limit. But in most of the country's rural catchments, demand to convert to dairying and farm more intensively, with increasing reliance on fertiliser, is growing.
The coming water crisis is one of the most challenging issues facing the country because of the possible shackles on economic growth and development. The Government's solution - requiring regional councils to set limits on water quality and water use (with possible trading of water and contaminant rights in future) - has gained impetus with the release of the third report of the Land and Water Forum, with a raft of recommendations on how to progress a regime that everyone can live with: farmers, factories, iwi, councils, ratepayers, greenies - and eels.
Regional councils will take charge of what the forum believes should be a collaborative process involving all stakeholders. Iwi will have significant roles - though the extent of iwi rights to freshwater has still to be determined.
For water use, consents will be needed once supply is threatened.
The spectre of restrictions - on both water use and pollution - is so scary it has forced farmers, greenies, industries and recreational groups to seek a consensus. Urban growth could be curbed - for instance, if leaching from septic tanks on Waiheke Island can't be brought within national guidelines or if new subdivisions threaten the supply of water. On farms, the amount of nitrogen leaching into streams could be capped and reduced for individual farms.
A major plank is that farmers and factories can reduce contamination through better environmental management and efficiency gains.
Considerable scientific measurement and monitoring will be needed: the dynamics affecting every waterway are different. Much is already being achieved - on farms through the Clean Streams Accord and better nutrient budgeting; in cities by limiting pollutant discharges and in catchments by clean-ups led by the Landcare Trust and others.
But when push comes to shove - when ratepayers have to fork out for sewerage upgrades or farming is restricted because a pollution threshold is reached - will it all unravel? Or will environmental bottom lines be compromised?
Just how hard the task facing councils is, is illustrated by the Horizons Regional Council's battle to set limits on discharges to waterways in its unitary "One Plan" covering the southern King Country, Wanganui and Manawatu.
After eight years of consultation, drafting and wrangling, Federated Farmers is taking the council to the High Court to challenge an Environment Court ruling, which supported appeals by the Department of Conservation and Fish and Game NZ to toughen up the plan.
Federated Farmers' president Bruce Wills says the limits set by the council are too prescriptive and will force farmers to convert from dairying to sheep and beef or replace crops with pine trees. He claims the losses in farming profitability will be far greater than the council's cost-benefit analysis, and Primary Industries Minister David Carter has come out in support. But the Environment Court preferred the council's estimate that farm costs would increase by between 5 per cent and 16.6 per cent.
The search for a less litigious course began at an Environmental Defence Society conference in 2008, from which the Land and Water Forum emerged. The forum now has more than 60 member agencies and is tasked with informing Government policy development. Its early work led to a National Policy Statement for fresh water, charging councils with safeguarding the life-supporting capacity of waterways and improving waterways degraded "to the point of being over-allocated".
Its most remarkable achievement has been to keep the disparate interest groups on board. Four years, three reports and 158 recommendations later, a lot more dirty water will flow before a better management regime is in place, let alone tradeable water rights.
Glaring omissions are charges for commercial use of water and national objectives for water quality, says Green Party water spokeswoman Eugenie Sage.
The latter task was taken from the forum and handed to a Ministry for the Environment technical group.
Sage says charges for irrigation water would be an effective price signal and money raised could be used for clean-ups. Tradeable rights, on the other hand, could result in water barons - a few companies or individuals locking up water for profit.
EDS chairman Gary Taylor says getting the national framework right will be critical. Also important, he says, is that the recommendations are taken as a package rather than cherry-picked. With the key players broadly in agreement, the proposals will be hard to dismiss.
The report doesn't go into costs. But a hint of what is to come lies in the $318 million committed by the Government to cleaning up Lake Taupo, the Rotorua lakes and the Waikato river and the $800 million estimated by Watercare in Auckland for a new pipeline to reduce sewage overflows into the Waitemata harbour.
On the web:
Key freshwater management recommendations of the Land and Water Forum:
Following national guidelines, communities will set local objectives for water quality on a catchment and sub-catchment basis. From these, limits on pollutants (e.g. nitrogen, phosphate, E.coli) will be set.
Activities (farming, factories, sewage plants, etc) will need authorisation to discharge contaminants within limits.
When limits are reached, activity will be limited. (e.g. no permits for new discharges; excess discharges banned).
The "take" will be limited to ensure river levels in summer maintain aquatic health.
When scarcity thresholds are reached, users will need consent. When water is fully allocated, communities will agree on measures to bring usage back into compliance, and new users could be restricted.
Consents or permits may be tradeable.
Drinking water, contaminants and discharges, including stormwater and wastewater, will be managed within limits.
Once catchment is fully allocated, new consents will not be granted.
If efficiency is maximised and more water is needed, voluntary and compulsory transfers may be used, with compensation paid.
For a stable and durable system, iwi rights and interests need to be resolved between iwi and the Crown.