EW considers stakeholder questions on hydrology report

Environment Waikato says it will consider carefully points and questions raised by stakeholders about its new draft report looking at the potential impacts of pine-to-pasture conversions in the Upper Waikato River catchment.

At a meeting recently, some stakeholders raised questions about the report’s projections of more than 500 square kilometers of pine forest being converted to pasture over 15 years from 2007. The actual level of conversions so far is only around 200 sq km.

Environment Waikato will provide more detailed information on the exact basis for the 500 sq km-plus projection but acknowledges that the new Emissions Trading Scheme has slowed the pace of conversions as it provides a disincentive to cutting down trees.

“We welcome stakeholders taking a strong interest in the complex issues raised in the draft report which is aimed at ensuring we have good information on the potential changes and impacts on the flood hydrology of the Waikato River,” said EW chairman Peter Buckley.

“The stakeholders provided some very helpful comment on the study, and the technical expert panel and EW staff will now carefully consider all stakeholders’ points before the report is finalised so that we have a sound basis for developing a collective response to the issues.”

The draft report said the projected level of conversions over 15 years could generally increase the risk of localised flooding of streams feeding the upper Waikato River. While generally the effect on the lower Waikato river was small, there was the possibility of higher water levels at downstream sites in very extreme weather events than would otherwise occur.

On releasing the draft report in early February, EW said the findings didn’t ring any major alarm bells at present but that the report raised questions over what to do if conversions occurred at the projected level.

Some stakeholders wanted the report to highlight the uncertainty involved, while one also wanted to see further modeling done on how much extra water would actually run-off from land already converted.

In response to a question on the relevance of the very extreme weather event projections, EW explained that building good understanding and use of flood hydrology information is important for a number of purposes. This included an understanding of the risks associated with such weather events for civil defence and emergency management purposes.

Feedback on the draft report is due by 12 March. The panel will then formally consider feedback before looking to finalise the report later in March. It is then due to go to EW’s council in April. Council would be asked to confirm the report as the basis for future consideration of the issues raised.