The level at which an opening can be considered at this time of year is 1.13m above mean sea level.

The graph below is a summary of lake level and openings for 2011, to mid December.

To:

M

Customer Services

Thursday, 11 August 2011 9:50 a.m.

Good morning to you all,

The lake is closed to the sea. The average level of the lake as recorded Wednesday 10 August was 1.02m.

The lake was opened to the sea on Thursday 4^th August at a level of 1.17m and closed naturally on Tuesday 9^th August.

The level at which an opening is considered at this time of year is 1.05m.

Te Waihora/Lake Ellesmere maintains important customary and commercial tuna (eel) fisheries. Two species, shortfins and longfins, are present and there is evidence to suggest that the proportion of longfins has declined over time. A NIWA report, prepared for ECan in 2010, provides details of the tuna populations in the lake and tributaries.

In light of the decreased abundance of longfins in the Te Waihora/Lake Ellesmere, they are no longer landed by commercial fishers and are voluntarily released.

This has now been updated and investigates changes to the Halswell River following the 2010 and 2011 earthquakes. The plan, which was outlined at a community meeting in March, covers progress, works required and costs to reinstate the waterway capacity and bank stability of the Halswell River and the associated drainage network.

The reports can be found on the ECan website.

Katie’s thesis, submitted as part of her Masters of Resource Studies is a look at Evaluating the effectiveness of riparian plantings on water quality: A case study of lowland streams in the Lake Ellesmere catchment.  It can be downloaded from the Lincoln University Research Archive.

Nazra submitted a dissertation as part of a her Masters of Applied Science. Her topic was Understanding the Spread of Riparian Restoration in the Te Waihora/Lake Ellesmere catchment and it is also available from the Lincoln University Research Archive.

Evaluating the effectiveness of riparian plantings on water quality: A case study of lowland streams in the Lake Ellesmere catchment

Katie’s research included surveys of water quality indicators above and below selected restoration sites to see if there was any statistically significant change in water quality that might be attributable to the plantings.

Although the sites selected (on Harts Creek, Birdlings Brook, and Boggy Creek) are often used as good examples of riparian restoration in the Lake’s catchment, they fall well short of the minimum width of planting recommended by experts. They are also relatively short lengths of planting. Consequently, we had not really expected that the plantings would result in any statistically significant improvement in water quality until they were much more mature, if at all.

Some of the results were quite mixed and did not provide any clear evidence of significant changes. However, we were surprised to find significant increases in dissolved oxygen content and decreased turbidity at the downstream ends of the restored sites. Basically, this means better conditions for fish (and clearer water to enable us to catch them!). The results of this research have been accepted for publication in early 2012 in the well-respected, international scientific journal “Restoration Ecology”.

Understanding the Spread of Riparian Restoration in the Te Waihora/Lake Ellesmere catchment

Nazra’s research was seriously disrupted by the 22^nd February earthquake. She was particularly interested in understanding how the concept of restoration was being spread in the catchment and applied theories of innovation and diffusion to her analysis.

These approaches are usually used to explain the adoption of new farm equipment or practices, and are not common in looking at restoration work. Because of the earthquake, the results are tentative, but it seems clear that the network of professionals working for community organisations (like WET) and councils play a critical role in the uptake of restoration. This is important as it supports the need to have continuity amongst people in such positions in these organisations and the need for councils to support NGO staffing and their own ‘care’ people if the community is to see real improvements on the ground.

From a Trust perspective it was good to get this independent validation of the efforts our staff have expended in building networks with council staff at several levels and, as a ratepayer, the value that councils get from supporting the Trust as well as its own staff. The message to staff is that time spent in networking is not wasted!

All students submitting work in recent years have been asked to give permission for their work to be included in the online archive and to be freely available. Where possible permission has been sought from former students to make earlier research available.

It’s on Thursday March 29th at 7.30pm at Lincoln and full details are on the Lincoln University website. Doors open at 7pm.

To find out more about what’s happening for Earth Hour 2012 in Selwyn, visit Lincoln Envirotown’s website.

Further information about the process and the scenarios that will be discussed is included in the first information sheet and background information and the the presentations from a range of experts are on the website.