“Above Dam” irrigators (Nth Opuha, Sth Opuha, upper Opihi and Te Ngawai irrigators)
In today’s Restrictions Page issued by ECan the Opihi at Rockwood and North and South Opuhas are all off restriction with regards your tributary flows. The Water Shortage Direction however has a requirement that the lake is at or above 370.5m before you are able to irrigate. We are close to that but under all the same so until we can get a little more into the lake, we aren’t able to irrigate.
The lake has actually held up quite well this week (see below) however we are still releasing more than inflows on a daily basis. The good flow in the Opihi today has enabled us to back off the releases now to 1.6 cumecs to maintain our 2 cumec minimum at Saleyards Bridge so we are trying to capture the benefit of the trib flows albeit on a slightly deferred basis by increasing the lake storage. There are very long lags in the river system under these low flow conditions but we are monitoring all the flows and attempting to anticipate any increased inflows by backing off releases from the dam up to 12 hours ahead of Saleyards Bridge responding.
We are trying to squeeze things as much as possible to try and build that lake reserve both short term (above 370.5m at least to give us enough reserve for a week of river running at our new minimum of 2 cumecs and also enable opportunity irrigation for you) but also long term to firstly try and enable one round of irrigation downstream (current target for that is 374m) and then, obviously, to fill the lake for next season.
I had indicated I would have a general newsletter out earlier this week but I haven’t managed that and this email is intended as an update for your group specifically. I will continue with the newsletter which I plan to complete for tomorrow.
Regards, Tony McCormick
