In previous posts, I have mentioned a little of what I started to do when I got the clay samples back to the studio. In this post I will expand on that and also how I began to think about making glazes from these samples and pre-existing water data.
At the beginning of the project Ian Danby, the then director of the gallery, obtained some water sampling data from the North Devon Biosphere. This was a large database spreadsheet of water data from a range of rivers across Devon. It took a while to begin to decipher it and I was doing this as I began to research places to sample water from in June and July. Isolating the information specific to the Torridge, I realised also that the sampling was varied in what was being sampled according to who was doing the sampling. Certain sets of data seemed to be much more comprehensive in the quantity of tests being undertaken whilst others seemed to test for only a few things. So many of the initial choices I made about places to explore centered around places where more comprehensive water data was available.
I made these intial choices about places to for 3 reasons:
- The first being that I had a relatively short period of time in which to complete the project, as the initial deadline was in September. I realised that to organise the resources, conduct the testing and then make some work from it would be very difficult to do in the time I had.
- Secondly, in July and August 2022 there had been very little precipitation for quite some time and parts of the Torridge catchment area were under hosepipe bans. The flow in the river, especially further up, would be very low and it would be hard to make accurate testing possible.
- Thirdly, that the “Hydrological Year” starts in the Autumn when traditionally there is more rain and so more flow. Speaking to a well known hydrologist friend of mine was what made decision for me and I realised then that the project would need to go beyond the 1 year initial timescale in order to be effective.
Looking at the pre-existing data, I isolated several places in the lower stretches of the Torridge where there were water testing had taken place & I thought I might be able to access the river to take samples of minerals & clay. These were:
From my notebook:
River Torridge Sampling points
- By Napp House Northam
- Bideford – Cornborough sewage treatment works
- Bideford – Lttle America Surface
- Beam Bridge
- Great Torrington Sewage Treatment Works
- Beaford Sewage Treatment Works
Looking closely at these samples, there are some important issues regarding testing and sampling water:
- A need to make comparisons across the various sampling sites chosen, so that these can be compared & some sort of relationship / ratio can be calculated in ornslate thisder to know how to translate this into glaze additions in the tests. I.e. what pecentage of copper or zinc to add for instance.
- Different sampling locations offer different data. These are (generally) either Sewage Treatment Works or Environmental Monitoring Stations.
- Sewage works data varies enourmously. Larger STW’s measure a wider range of data points, whilst small ones measure very little except suspended solids, BOD (ATU) (Biochemical Oxygen Demand or Dissolved Oxygen) & Ammoniacal Nitrogen.
Where water is tested for EU environmental standards there are more data points. At Beam Bridge there are 47 tests per date and at Little America there are 25.
The timescale for these tests are roughly monthly, but the available data from this set is for the first quarter of 2022. Some sites have only 2 months data in this set.
Sampling quantities
Either in milligrams per litre – 1000’ths of a gram/l or micrograms per litre – 1000000’ths of a gram per litre.
How to make an equivalence
