St Nicholas College Middle and Senior Schools
Number of team members:
How are changes in climate mainly rainfall and temperature impacting water flow and farming in Qlejgħa Valley - Malta.
Summary of the project:
Wied il-Qlejgħa has high water flow during winter. We examined rainfall data from 1952 to 2020, temperature data from 1952 to 2020, satellite imagery from Landsat 5 and a fieldwork at Wied il-Qlejgħa. There is no quantitative data to show water flow in the valley. Malta has an average annual rainfall of 550mm of rain. Investigation of rainfall data shows there was little change in rainfall averages but rain is decreasing in spring and increasing in autumn. Rainfall from 1st September 2019 to 22nd May 2020 was only 347mm. February 2020 has been the driest since 1923. Research shows that the overall trend in air temperature over the period 1923-2005 indicates an increase at the rate of 0.71°C every 100 years and of 1.5°C since the 1970s. We compared surface water in Wied il-Qlejgħa during winter for different years using Landsat 5, which goes back to 1984, and Sentinel 2 for recent satellite imagery. We found imagery dated November 1984. Due to the small size of Malta and the valley, it was difficult to observe any changes since 1984. During the fieldwork, we noticed that most of the valley was dry. Water was flowing only in the upper part of the valley. We observed meanders and a minor channel eroded in the main channel indicating that water flow in the past was higher. There was no water behind the dams of the reservoir. We interviewed two farmers who work fields along the valley. According to one farmer interviewed , the climate is changing - there is either too much rain or too little. Another farmer said that water in the valley has decreased since a heavy storm on 25th October 1979. The heavy rainfall carried about 3 metres of soil which were deposited in the valley, decreasing space for water.
As can be observed in the data analysis, the water flow of Wied il-Qlejgħa has decreased throughout the years. Many features found in Wied il-Qlejgħa such as the building of dams in 1890 and the reservoir walls indicate that the level of the water was higher. The formation of meanders and the smaller channel that has formed in the main channel are all indications that rainfall in Malta has decreased throughout the years and so, it effected the water flow in this valley. Moreover, the rainfall graphs continued to highlight that precipitation has indeed decreased these last few years. However, given that the data collected is for a few decades and that no quantitative data is available on water flow in Qlejgħa valley, we cannot conclude that it is a result of long term climate change. Variability in the annual rainfall in Malta as well as human activity in the valley may be the reason for the almost dry valley this winter. The presence of alien plants, such as reeds, eucalyptus and castor oil tree may also be influencing the amount of water flowing through this valley as these plants tend to take up more water than indigenous plants. Increased pumping of water from the reservoirs behind the dam for irrigation by farmers due to a decrease in rainfall may also be depleting the water flow in the valley. Following our observations we concluded that we cannot be certain that a decreased water flow in Wied il-Qlejgħa is a result of climate change. However satellite photos show that human activities, such as urbanisation, may be diverting rainwater away from the valley. These results is suggesting the need for a follow up research investigating the impact of urbanisation on waterflow in valleys.
Actions to help lessen the problem:
We observed that people find it very difficult to link their behaviour with a change in climate. Therefore, our aim was to raise awareness and promote minor everyday lifestyle changes that would leave a big impact if all should follow suit. A group of students created different promotional material to act as reminders for the students at our school to switch off the lights, use natural lights instead of artificial ones and save water. They created stickers to be stuck on every classroom door, posters and desktop images which were uploaded on all the school computers. Another group of students from the Eco-schools team raised awareness of the need to Reduce waste rather than just recycle it. They collected items from the students such as used crayons, colouring pencils and small toys (the ones you get with kids fast food meals) and created projects with those items to show that you can give a second life to items thus decreasing the carbon footprint. The idea was to look at waste as a resource and not as junk. Many of these projects are still work in progress and will be finalised during the next scholastic year. Now that the students understood how delicate the natural balance is, and how vital trees are to reduce the excess Carbon dioxide in the air which is the major factor that is effecting Climate change, they wanted to embark in an even larger project. We planted various indigenous trees on the school grounds and we also started collecting clean milk cartons. The idea is to have every single student in our school plant a tree and foster it till it is strong enough to be given to the various NGOs that plant these trees all around the island.
Projects are created by the teams and they take the full responsibility of the shared data.