Inspired by permaculture’s commitment to observation, over the last couple of years, we’ve become enthusiastic/compulsive gatherers of data about our farm. Everything we can think of to measure, we’ve tried to measure. Now, as we scale up our interventions, we can begin to track our impact and refine our management accordingly. As part of this, we’ve started a seasonal water quality testing program to monitor changes in the quality of our catchment as we revegetate the catchment and manage grazing more intensively.
We’ve assembled our own water testing kit, all stored conveniently in a secondhand mayo bucket from the local chip shop. Using this, there are a few characteristics we’ll test seasonally:
- salinity and temperature (both tested using an EC (Electrical Conductivity) Meter from your friendly local hydroponics vendor),
- pH (tested using pool pH strips from the hardware shop),
- turbidity is a measure of the amount of solids suspended in the water (measured with a DIY Secchi disk or turbidity tube),
- macroinvertebrate populations, the presence and composition of which is also an indicator of pollution levels (gathered with buckets and nets, and sorted with teaspoons into ice-cube trays).
To start with, we threw the large bucket out into the dam (while still holding onto the attached rope), in order to take a water sample while avoiding scooping up sediment. We tested this sample for salinity, temperature, pH and turbidity, using the equipment described above. Turbidity is measured by lowering the Secchi disk slowly into the water, and measuring the distance at which the disk is no longer visible. We constructed our Secchi disk broadly along the lines of this tutorial, substituting the acrylic disk for a circle cut out of the lid of a white bucket, then spray painting the black quadrants. Turbidity tubes are an alternative measurement tool which could be constructed from rigid clear plastic tubing.
Finally, we conducted a macroinvertebrate survey, taking samples from around the dam using small buckets and a pool net, then sorting the critters gathered according to identifiable species into ice-cube trays for further inspection. There are a range of good resources to support identification and recording of aquatic macroinvertebrates, among the best is the Adelaide and Mount Lofty Ranges NRM Macroinvertebrate ID Chart, and accompanying teacher resource. The teacher resource contains some great information on process and recording formats. The Murray-Darling Freshwater Research Centre has an alternative ID resource, together with explanation of the SIGNAL rating system to generate a score for your macroinvertebrate biodiversity and habitat quality. If you’re feeling especially enthusiastic, the South Australian Environmental Protection Agency has a detailed Critter Catalogue that provides macroinvertebrate species information and diagrams.
Conducting our first proper water quality testing in the middle of summer after a dry year is perhaps strategic: it gives a low baseline from which our water quality can improve! We’ll continue tracking changes through the year, and from year to year, hopefully seeing more critters moving in as our aquatic zones slowly become healthier.
This video from Victoria’s Strathbogie Ranges is a great summary of water quality testing process, and is part of an excellent series on using farm dams to enhance habitat:
If the phrase ‘baseline data’ stirs something deep within you, or if you think you might enjoy a day out on the Fleurieu, stay tuned for our inaugural permaculture farm planning walk-and-talk in May, in collaboration with the Southern Fleurieu Permaculture Group.