1. Urban Lakes:
Urban lakes are the lakes present in areas of high population density and built infrastructure. In these urban areas, the demand for housing is rising rapidly and builders are more keen to construct more. Often, a byproduct of this demand is construction without the necessary municipal approvals and sanctions which can often encroach the lakes reducing the water capacity of the lakes.
Because of a heavy population load, these lakes have inlets of highly polluted untreated wastewater that can cause bad odor and infection. Freshwater fishes and other living organisms can also be harmed.
Urban lakes are the lakes which get the most attention in the media these days due to the challenges these water bodies face. Of the challenges described above, encroachment is the most prominent one. According to a research conducted by the Indian Institute of Science, Bengaluru, 80 lakes were monitored to analyze their physio-chemical conditions. According to the survey, 98% of the lakes were found to be encroached and 90% were heavily sewage fed.
Now just imagine when such a lake encounters a heavy rainfall. What would happen to the surrounding areas?
The solution;
On the rejuvenation front, we create wetlands and lagoons surrounding the lakes which can allow natural water treatment of wastewater entering through sewage and many other sources. This water is directed to a separate outlet. The silt on these lake beds is removed and the lake is then dug by about 1 - 1.5 meters to increase the water holding capacity.
On your side, you can get the purchase agreement with a builder checked with a lawyer to ensure that the appropriate approvals are done and there is a green signal on the construction from the relevant municipal authorities.
2. Semi-Urban Lakes:
These lakes are the lakes found in emerging locations within a town or a city. These lakes are encroached, however the level of encroachment is low. The water in these lakes may have low levels of contamination. periphery
Typically, they are characterized by the presence of water plants and freshwater fishes which are often consumed by people. However, these lakes are unprepared for the upcoming influx of population. Additional burden on these lakes will increase the organic matter content and rapid infestation of water plants. Increased organic content leads to a higher demand for biological oxygen which leads to a decrease in dissolved oxygen (DO). This often leads to the reduction of the diversity of organisms and causes them to perish in the long run (3-8 years)
Solution:
On the rejuvenation front, the work is a little more analytical. First we evaluate the sources and inflow of water and how that will change in the future. Then create a pathway for its seamless outflow not affecting the main waterbody. Lagoons are created if needed for natural water treatment. The entire waterbody undergoes a process of removal of silt. The soil dug up is used to create walking tracks on the outskirts and island structures in the middle.
3. Rural Lakes:
Rural lakes are lakes in areas that do not have a dense population(villages). These can be found on the city outskirts near spots of human settlement. It is common to observe people very engaged with these lakes by means of washing clothes, livestock entry, and dumping of wastes from cultural practices and other debris in the waterbody which causes them to become contaminated.
They often do show small levels of encroachment as well.
Solution:
Reclamation of encroached lands and increasing the water holding capacity of the lakes. Removal of silt and debris on the lake beds. Here talking to the local villagers may also help bring more awareness and commitment on their end. We usually involve the villagers for the maintenance of these water bodies so that they can earn some money from the activity. They have helped in the maintenance of trees planted in the plantation drive and nurtured the development of these trees.
Conclusion:
These categories are just a generalized view of the description of the water bodies and each lake is unique in its own way. One most important takeaway from the 24 lakes developed since 2017 is that such rejuvenation is possible and effective. It requires arduous work and commitment on the end of all the parties involved - the contractors, the crane operators, the villagers/people living near the lakes, my team and I. The redevelopment has also been possible due to the flow of funds from corporates through their CSR activities and getting their teams more aware of the issues on ground.