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2 maltatoday | SUNDAY • 1 JULY 2018 JAMES DEBONO A long due restoration of Chad- wick Lakes is being proposed with the aim of protecting eco- logically sensitive areas from be- ing trampled upon by picnickers. Chadwick Lakes is a popular recreational spot during winter months which attracts hundreds of picnickers. But these are also known to cause disturbance to the environment by discarding rubbish, trampling within the valley footprint and poaching tadpoles and frogs. The new project, proposed by the national Water and Energy Agency, will seek to limit pic- nickers to designated recreation- al areas, detached from the valley bed. Nature enthusiasts and trek- kers will still have access to the valley through trekking guided by informative signage on the area's aquatic, natural and his- torical heritage. This will guide trekking to established pathways and avoid trespassing in the val- ley bed. The project will also result in the removal of intrusive devel- opment, like a playground con- structed in the 1990s in the cen- tre of the valley bed. Studies prepared by Environ- mental consultants ADI, reveal that the valley is presently in a deplorable state. Lack of maintenance and prop- er management have led to a number of problems including a reduced surface water retention capacity due to the accumulation of sediment and debris, a pro- liferation of invasive and non- native plant species, the dilapida- tion of the rubble and retention walls and illegal dumping. A number of off-road motor cyclists are also known to fre- quent the area and use the rural pathways to 'scramble' around the valley. This causes harm to the vegetation. Moreover, most of the original infrastructure designed by Lord Chadwick in 1884, has been left in a derelict state. In an aver- age rainfall year, the dams are estimated full, two to five times. If the three dams are repaired, cleaned and maintained, 70,000 m3 of water would be stored. Samples taken from surface water from five sites along Wied il-Fiddien and Wied il-Qlejgha, in 2017, had been tested by the Water Services Corporation and showed high values of nitrates, probably related to the use of fertilisers in the adjacent fields. Such fertilisers are transported to the valley bed by surface run- off and groundwater seepage. Ground water extraction and the resulting use of saline water due to salt water intrusion explains the high chloride content in the water. While EU guidelines specify that surface water used for drinking purposes should not have a nitrate level of 50 mg/l, most tests showed more than double or triple that amount at Chadwick Lakes. Invasive Crayfish eating tadpoles Studies have also confirmed the pervasive presence of a crayfish native to North-Eastern Mexico and South-Central USA, which may pose a threat to the conser- vation of indigenous species at Chadwick Lakes. The crayfish is tolerant of pol- lution, reaches sexual maturity within a few months and has a high fecundity rate. Unlike most crayfish species, it is also able to tolerate slightly saline water and low dissolved oxygen content. It is able to survive periods of drought, burrowing in mud. The crayfish alters the pond landscape through its burrowing activity. This has been observed in a pond at Fiddien valley where the banks have been denuded of vegetation through the bur- rowing activity of the crayfish. The crayfish has also been seen preying on tadpoles at Chadwick Lakes. The omnivorous species may also pose a risk to plants and trees of conservation interest due to the potential presence of mi- crofungal flora species living in its gut which harm other vegeta- tion. This alien could also pose a risk to endemic freshwater crabs if it reaches watercourses where these species occur. The best way to eliminate this species is through intensive trap- ping. While other countries like Italy have resorted to the use of the European eel to eradicate this crayfish, the introduction of this species known for its voracious appetite is not being recom- mended as it could end up gob- bling other species. To further ensure that the spe- cies does not survive, the ponds will be dredged and cleared of sediment up to a depth of 1.5 metres. The dredged material shall be disposed of in a dry site to ensure that any crayfish bur- ied in it do not survive. Another alien of significant concern recorded in the area is a semi-aquatic turtle known as Trachemys scripta elegans which has been recorded un- der the Ta' Slampa bridge. This species is carnivorous and thus poses a direct threat to the en- demic frog population as well as larger insects. Since only two specimens of this species were recorded during surveys, these can be removed manually and transported off site. NEWS 90 52 20 78 66 49 26 64 30-06-2018 Draw No: 730 Date of Issue: 1 st July 2018 J. & A. Bonnici Ltd. are requesting a quotation for the following machinery: • Paper Bag Machine with a 4 Colour Inline Printer • Clam Shell Machine Prospective bidders can request the quotation document by sending an email to info@jabonnici.com Interested companies are to submit their quotation only via email to info@jabonnici.com by not later than the 15 th July 2018. GET 2 FREE TICKETS Subscribe to the MaltaToday Digital Edition for a year and get 2 FREE TICKETS for Joseph Calleja's concert The offer is available to the first 10 digital subscriptions. Send a cheque of €59 with your personal details to MaltaToday, Vjal ir-Rihan, San Gwann SGN 9016 JOSEPH CALLEJA SPECIAL GUEST EROS RAMAZZOTTI 21 ST JULY 2018 • FOSOS FLORIANA www.maltatoday.com.mt Chadwick Lakes picnickers to be steered away from valley bed Chadwick Lakes: Invasive crayfish to be eradicated While EU guidelines specify that surface water used for drinking purposes should not have a nitrate level of 50 mg/l, most tests showed more than double or triple that amount at Chadwick Lakes