Catch small crustaceans, algae and cyanobacteria on the water surface and in the water column with the plankton net. Wash out the plankton net by turning it inside out and washing the contents into a deep white bowl. The bowl will be teeming with plankton if you repeat this several times. Strain the contents of the bowl through a fine tea strainer and tap it into a Petri dish leaving only a bit of water. You can watch the microscopic critters directly in the Petri dish or transfer them to a specimen slide using a dropper or pipette. Add a cover slip if the slide allows and observe the drop of water with plankton with a microscope. The recommended magnification of the microscope is 10 x 20 to 10 x 40. Be careful not to let the drop of water dry out during the observation. Return the plankton back to the bowl with water after observing.

 

How do you identify algae, cyanobacteria and zooplankton?

There are many guides which can be taken outside to help identify plankton in the field but it is advisable to search for atlases which are specific for your location. General, all-encompassing guides tend to be in the “tome” size which makes field research difficult.

 

There are a number of online resources which are quite encompassing but allow for quick referencing:

 

http://www.phytovre.lifewatchitaly.eu/vre/phyto-list/

 

https://wcwc.ca/wp-content/uploads/2020/12/Algae-identification-lab-guide.pdf

 

has great descriptions but might be location specific to Canadian Algae. A good search term is “freshwater Plankton Identification WORKSHEET“ and add your location.

 

 

The first step is to determine how much water will rain at your school in one month (we recommend May, June and September) and how much, in turn, evaporates. To begin with you need a rain gauge. This can either be bought or made:

 

You can build your own rain gauge quite easily with commonly found materials.

 

Totaliser

There is no need to empty and record measurements of the rain gauge every day. A thin layer of oil on the surface of the water prevents water from evaporating and visibly separates the water level (incident precipitation) from the oil. The oil can then be separated or deducted from the total liquid volume.

 

We call such a rain gauge a totaliser. You will find this device on mountain tops and inaccessible places which aren’t read every day. These totalisers are being replaced by automatic stations.

 

 

Measurement of vapour from the free water surface – an evaporimeter

The second step is to measure the local evaporation. A washing up basin or perhaps a deep plate located outside is used to monitor evaporation (because it also rains into it, both precipitation and evaporation are monitored). Such a professional device Is called an evaporimeter. Professional evaporimeters are pools with dimensions exceeding a square metre, so you can also use your pond or a children's pool.

 

At the end of each week, find the total volume of water:

- how much water fell into the rain gauge (O1)

- how much in total disappeared in the evaporimeter (O2) ... or increased if it rained a lot

- total water evaporated (O3)

 

We know that: O2 (difference of levels in the evaporimeter) + O3 (evaporation) = O1 (amount of precipitation)

So the final balance is: O3 = O1 – O2

 

- If O3 > O1, evaporation prevails over precipitation, there is a precipitation deficit.

- If O3 < O1, precipitation prevails over evaporation and the ground is saturated with water.

 

Place precipitation and evaporation stations both under trees and away from them to monitor the difference between the water balance in the forest and outside the forest.

 

Keep in mind these results measure the difference between precipitation and evaporation from the free water surface. A device called a lysimeter is required to calculate the transpiration of vegetation (transpiration occurs in a whole forest or even a single blade of grass).

 

According to the map, mark out the territory you will map. It should be an accessible place, not surrounded by fences. School grounds, a public space such as a park or square are best. Add the place into your plan, buildings included.

 

And now distinguish areas where:

1) you collect water for further use (for example, in barrels and underground reservoirs);

2) water seeps into the ground (areas that end up in drains and seepage points, green areas, areas with trees, semi-permeable parking lots or paved sidewalks, sand and gravel surfaces...);

3) the rainwater drains into the sewers (surfaces of roads, asphalt parking lots...).

 

Find the total area of the individual plots of type 1–3. Try to suggest how to turn the places marked with the number 3 into permeable or semi-permeable surfaces, or how to collect water. You can find ideas for solutions on the internet.

 

More ideas:

What volume of water will fall on one square metre of area if it rains 1 mm? Find out experimentally, or do the maths.

 

Find out when it rains how much water falls under the trees and how much in open spaces. How much precipitation does a tree retain?

 

In the case of heavy rain, try to measure its intensity: amount of precipitation (mm) per hour. In a big storm, measure how long it rains, and after the rain, measure the amount of precipitation. Divide by the number of hours of rain to get the hourly rainfall.

 

The brave researchers can go out into the rain and watch the change in rainfall every ten minutes and multiply by six to get the current hourly intensity.

 

Forecasts of such rains should be found at your national weather office. Precipitation at specific meteorological stations can be found in some applications which you can download.

 

Compare the actual amount of precipitation with the Aladin forecast models used by such sites as wunderground.com and YR.no.

 

 

Soil water capacity (experiment lasts two days)

Water the soil in any given location thoroughly with water from a sprinkler until the soil is saturated. Cover the test site and take a soil sample from the site the next day. Measure the sample's mass. Next, dry the sample in the sun (or use a dehydrator) and weigh it once more. Calculate the difference in measurements and convert that to a percentage to find the water capacity. Here is a table which will help to determine the approximate soil type based on water capacity.

 

Table of full water capacity according to Mitscherlich (how much dry soil will increase in weight when fully saturated with water)

 

Type of soil               Full water capacity

Sandy                         18.8%

Sandy loam                20.2%

Sandy with humus     52.8%

Clayey                        80.9%

Peat                            126.0%

 

Water absorption of soil (experiment lasts 45 minutes)

Measure water absorption in exactly the same way. Collect fresh soil samples from selected locations and weigh them. Place the soil samples into the perforated PET bottles and immerse them in an aquarium with water so that the level is at the level of the sample (you can weigh down the bottles with stones so they don't float). When the soil in the bottles is completely saturated with water, take them out and let them drain any excess water from the bowl. Now weigh the sample again (including the PET bottle, whose weight will later be subtracted) and calculate the difference to determine current soil permeability.

 

 

Soil buoyancy (experiment lasts 60 minutes)

Find out how fast water rises through different types of soil. Again, small PET bottles with perforated bottoms are used which are filled to the brim with selected soil samples. Shake off stray particles with a few hits on the table top and to eliminate any air pockets. Place all the sample bottles in a bowl with water at the same time and top up the water when the soil drinks it up. Find out how high the water in the bottles rises in 5 / 10 / 15 / 20 / 30 and 45 minutes. Either write the results in a table or make a graph or both.

 

Water rises from the lower layers to the higher ones due to buoyancy. In coarse-grained samples, it first rises faster than in fine-grained samples, but in a short time water overtakes it in fine-grained samples.

 

Permeability of the soil for water (experiment lasts approx. 30 minutes)

Another important quantity is permeability. You find it by hanging perforated bottles with freshly taken samples over measuring cups and pour 200 ml of water into each bottle. Monitor how long it takes for the first drop to drip, the amount of water dripped at 5 / 10 / 15 and 20 minute intervals as well as the time when the seepage stops.