Water quality monitoring
means examining the physical, chemical and biological characteristics
of water - observing how these factors change over time, and over
different positions along a water body.
include, colour, smell, water velocity, temperature, acidity and
turbidity (ie the quantity of suspended solids in the water giving
it a murky or cloudy appearance). Important chemical characteristics
are the levels of nitrates, phosphates and salt in the water.
The physical characteristics
of rivers can change rapidly and over a wide range. Seasonal changes in rainfall make rivers run fast or slow, pollution can be a shockwave
of chemicals let loose in the night, gone the next day. The kinds
of plants and animals living in the water are a better long term
index of the health of the water. Some creatures are easier to
measure than others and are useful biological indicators. One
useful index of river water condition is derived from the presence
or absence of macroinvertebrates (animals, not including fish
and frogs, larger than 5-mm in length). In New Zealand rivers,
water bugs such as dragonflies, beetles, and other insects, have
different tolerances to pollution. By identifying which ones are
present, and which ones are absent, it is possible to determine
how much pollution has been in the water during the length of
time it took the creatures to become established and grow up there.
By making records of
these, and other factors, at a number of points along local waterways
community groups build up a picture of local water quality and
pinpoint problem areas. Collected data may then be exchanged through
electronic networks with neighbouring groups to create a picture
of water quality through an entire catchment - and beyond.
Water quality monitoring programs are set up as a means of identifying problems and working out ways to improve conditions in the waterways. Depending on the problem, enhancement of waterways might be accomplished by tree planting and fencing of some areas of river banks to exclude stock, reducing the community's use of fertilisers and pesticides, or constructing artificial wetlands downstream of agricultural settlement ponds.
After you have organised
your Water Watch group and discovered what is already known about
your river, the next step is to devise a monitoring plan.
The monitoring plan
determines where, what, how, and how often you will take measurements
or observations of the waterway. It depends on the concerns of
people in your community, what monitoring is already being done,
and observations made during your baseline survey.
Like all plans, the monitoring plan must be reviewed and revised as new discoveries are made. In the beginning, it is best to start with easily obtained observations and measurements.
1. The preliminary survey is
a critical first step. Working out where you will take your measurementsmakes all the difference in the world to the ease and validity
of your efforts. It's a question of checking out the river for
the best and most meaningful sites, ones that are easy to get
to, can be found again with little effort, and safe. The preliminary
survey is done in two parts, first using maps and asking questions
of people and councils in the catchment area to find out what
is already known, and second, visiting likely places to survey
and recording general information about them.
2. A baseline survey
establishes what the health of the river is now so later surveys
can tell if water quality is improving, or getting worse. It's
important to take measurements that can be replicated in later
surveys. Since the data is the foundation (baseline) for future
comparisons, sampling sites should be selected to represent the
complete range of conditions in the catchment.
3. A water quality
standards survey determines whether the water meets water
quality standards for designated uses (such as swimming) and values
(such as aquatic habitat or aesthetics). Obtain copies of the
Ministry for the Environment's Water Quality Standards for information on the standards that apply to the waters you are monitoring.
4. A pollution sources
survey measures the affects of people on the waterway. Generally,
three sites should be chosen. Immediately upstream of the impact.
Immediately downstream of the impact where the water has mixed,
and even further downstream, where the water has at least partially
recovered from the impact.
5. An event survey measures the amount of sediment, nutrients, salt or litter that is washed into a waterway during heavy rain. Measurements are taken before, during and after a storm.
Check your results against
those obtained by council or NIWAR professionals for a similar
waterway or at other locations in your waterway. If the results
are similar to the professionals, you are probably doing OK.
If your data shows a
water quality problem, or is well outside the limits of other
data, check over your work carefully. Go back to the site and
take replicate samples. Do you get the same results again?
Check to be sure the results are not a result of incorrect recording (such as an impossible reading like pH 15 or 125 degrees C.)
Could the samples have been contaminated in some way?
Could you be measuring some unusual natural weather or water flow conditions?
Show your work to at least two experts and clarify any seeming contradictions or confusing facts. If you have made a mistake, be the first to admit it, then correct it. If the result is valid, find out what is causing the problem. You may need help here from your city, district, or regional councils.
There may be occasions
when a problem can be traced to a particular source such as high
nutrients from a piggery, a sewage overflow, or an unauthorised
industrial emission. In these situations it is important that
a non-confrontational approach is adopted. Select a capable person
to coordinate contact between your group and those responsible
for pollution. The following procedure should be followed:
Remember, if people have willingly worked together to arrive at a solution, they are more likely to make that solution work.
A credible program
incorporates regular reviews and analyses of training, satisfaction
and morale as well as technical matters like monitoring techniques,
equipment performance, data recording and reporting.
Use newsletters, phone calls and easily understood and useable reports to keep your group informed of results, program progress and events. Most important, be sure to publicise any action or improvement in water quality that results from your monitoring.
References: Waterwatch Australia