Field Trip with Andy Bruere

I went out on a field trip with Andy Bruere, an engineer with the Bay of Plenty Regional Council. Andy's children went to St Mary's and I had his son in my class for 2 years. Andy explained to me about a lot of the infrastructure around the Rotorua Lakes that he responsible for as an engineer, particularly to do with improving water quality. We went to the alum dosing plant which puts aluminium into the water at the Utuhina Stream and Puarenga Stream to remove excess phosphorus from the water of Lake Rotorua, phosphorus being partly responsible for poor water quality, including algal blooms in the lake. This intervention has been very successful. We also saw the Lake Rotoiti wall, which diverts Lake Rotorua water down the Kaituna River and has vastly improved the water quality in Lake Rotoiti. The photo is of Lake Tarawera, which is currently being monitored carefully and needs to be watched because so many other lakes flow into it either by way of streams or ground water and some of these lakes have poorer water quality themselves.

Water Quality Monitoring

 I went out on the Bay of Plenty Regional Council regular water monitoring run around many streams and rivers that flow into or out of the Rotorua Lakes. The people you see are Dr Troy Baisden for Waikato University with his graduate student Clare and Kasjan from BOPRC. This work is important in order to see how well our waterways are doing and whether they are improving in quality or deteriorating. The tests look for water flow speed, water clarity, suspended solids and nitrogen and phosphorus levels in the water

Smaller Te Arawa Lakes

 These are some of the smaller beautiful lakes within the Rotorua Lakes district which are under the guardianship of  the Te Arawa Lakes Trust. They are Ngahewa (at the Murupara turnoff next to Rainbow Mountain), Ngapouri (along Waikiti Valley Road), Tutaeinanga (a very small lake near to Ngapouri) and Okaro (just along the Murupara Road a little). Being small these lakes are susceptible to pollution, particularly farm runoff. Okaro has had major issues and one summer recently suffered from aquatic hypoxia and so most organisms died in the lake.  This also happened to Ngapouri number of years ago, but this lake has now improved significantly.

Our Beautiful Lakes

 These photos show what the Rotorua lakes on a good day with no wind. Most of the lakes except Lake Rotorua are in at least a reasonably good state as far as water quality and pest invasions go. Unfortunately all of the people involved with looking after the lakes, Te Arawa Lakes Trust, Bay of Plenty Regional Council and all of the scientist need to be constantly vigilant against threats to this balance. Pest catfish are currently infesting Lake Rotoiti and threatening Lake Rotorua by entering the Ohau Channel and water quality in some of the lakes has been slowly declining over the past few decades. Fortunately everyone is mostly on the right page and programmes are in place to deal with the problems, and progress is being made on some issues. But this costs money, sometimes lots of money. In the case of the catfish invasion one careless or nasty person will cost ratepayers and taxpayers 100s of thousands of dollars to deal with the problem.

Science work out on the lake

Finally got out to the lake for the first time on a beautiful calm Rotorua afternoon. I am beginning to make contacts with many scientists working with Te Arawa Lakes Trust so I should be out of the office and into the mud, sand and freezing water more often very soon. I should have the chance to run my own mini science projects as well. Shane, one scientist running the pest catfish project, is getting some box traps made and is willing to give me some to do some catch rate studies in Lake Rotoiti, the infested lake and on other control lakes whre the catfish are not yet present. I am getting involved with some koura (waikoura - freshwater crtayfish) projects with local scientists and iwi who are looking to increase koura numbers in some lakes and looking at the commercial viability of breeding them as well. The initial research is looking at current koura numbers and also how to protect koura from catfish predation.