Friday, March 12, 2010

A giant effluent pond

Over on Frogblog, Green co-leader Russel Norman blogs about his trip to Lake Ellesmere, which he described as having the consistency of "toxic pea soup". This is what he found:

There were signs by the boatramp that said not to touch the water, as it’s a health hazard due to toxic algae. That made us extra careful not to fall in. Monique and I did manage to splash ourselves while Jolyon avoided all contact, showing what a pro he is.

Currently the Canterbury Regional Council says that groundwater levels in the Central Plains are at an all time low, and flows in the Selwyn and other rivers such as the Irwell and the Boggy that feed the lake are at minimum or lower. Irrigation is sucking the rivers and groundwater dry. This, combined with big inflows of nutrients and warm weather, has led to the toxic algal blooms.

And the reason for that irrigation and nutrient loading? Dairy farming. The quest for "white gold" has turned Lake Ellesmere into a giant dairy effluent pond. It has also polluted the drinking water supply of local communities, who are having to invest in expensive water treatment facilities. Another example of how dairy farming externalises its costs onto the rest of us.

The solutions to this are known and simple: reduce irrigation, so the lake can fill again and there is less runoff. And restrict nutrient loading by farmers so it doesn't overload the ecosystem. The farmers will scream, but its basically them or us - because what is happening to Lake Ellesmere today will happen to Christchurch's drinking water tomorrow. But these necessary measures seem to be the exact opposite of what National is planning...