The Issues Of Lake Torrens
Lake Torrens is an endorheic Salt Lake, it locates in between the Arcoona Plateau to the Flinders Ranges to east, around 65km north of Port Augusta and about 345 km north of the Adelaide city centre. The Lake Torrens catchment is an endorheic basin, there are no outflow of water to the ocean. The purpose of this article is how to manage the Torrens and minimise the occurrence of algal blooms or pollutions of water
First of all, there are few issues the Lake Torrens is facing. The water quality in the urban area of the Torrens is usually poor because of the stormwater from the built-up urban environment and the lack of flows from upstream. During the summer weather is usually hot and dry, it means because of the temperature of water increase, it provides a perfect condition for blue green algal growth. Blue green algae are actually a type of bacteria, two of the most common species are Dolichospermum and Microcytis, most common type found in river. In normal situation, it is harmless, but under high water temperatures and in sedentary bodies of water, it may cause huge number of algae blooms or outbreaks. They are potentially toxic containing neurotoxins, liver toxins and skin allergens, with a high concentration could be led to the death of domestic animals and fish. Phosphorus and nitrogen area essential element for plant life and the nutrients of lake plants, but when high concentration of these nutrients in water, it can increase the growth of algae and green plants, specially the algal blooms. The blue green algae also are be able to fix nitrogen directly from the air, so in times of low nitrogen some blue green algae are still able to grow. The major sources to cause the excess phosphorus are come from agriculture reason, such as animal manure and chemical fertilizers. During the hot summer weather, when the sun directly heats the Torrens, it will cause thermal stratification, it also will increase huge number of algae blooms. The Torrens could become deoxygenated after a summer rainfall, because of the huge number of algae blooms, they can provide the oxygens but also will absorb the oxygens, it also will cause a huge number of death of water animals, because the water are lack of oxygen, it could be a big trouble to the life cycle of lake.
Secondly, I am going to discuss the current solutions of the Lake Torrens and the effectiveness. During the summer time release the fresh water flows from upstream reservoirs into the River Torrens to dilute blue green algae concentration, reduce the likelihood of bloom. Regularly to monitor the water quality in Torrens lake and in the river, upstream and downstream, check water sources every day for blooms stock. Also, chemical control, such as the herbicide or algaecide, for example, use the hydrogen peroxide as a potential algaecide, using hydrogen peroxide in a stabilised granular form to control blue green algae. But algicides and herbicides are not really effective to control the growth of algal, because they can make the water more toxic, decaying algal cells could release even more high levels of toxic which have to persist for many months. Ferric alum also can be used to treat algal blooms, it used for the prevention of increase, it limits algal growth by removing phosphorus from the water. In addition, algae can be killed by some chemicals, such as calcium hypochlorite, Cupricide and Simazine. Another way to prevent is spreading barley straw over the water to breaks up algal rafts. However, some chemicals may be toxic to plants or livestock and the animals from the water, such as fish and crustaceans.
Finally, I am going to talk about other alternative solutions, first, the main reason of cyanobacterial blooms is the accumulation off excess nutrients in the body of water. Therefore, we could look at some human activities, such as do not overfeed fish or birds near the river or lake, do not let the pets or livestock to defecate in the river or lake, do not over use lawn and garden fertilizers, specially near the body of water. Also, the government can plant and maintain native flora around ponds and streams, it can help filter water and do not require fertilizer.