By Dr. Ashraf Zainabi

Anyone who has observed the condition of Kashmir lakes over the past two or three decades will notice that their decline has not been sudden. 

It has happened slowly, and almost silently. 

Water that was once clearer is now frequently turbid. More recently, the Dal Lake water turned greenish, a coolant like in colour. Aquatic vegetation now covers large stretches that earlier remained open water. In many stretches, the lake depth has visibly reduced. 

These changes are often discussed in emotional terms, but they are also the outcome of very specific ecological processes. 

People living around these lakes often notice the change before any government and scientific report is published. 

The scientific explanation for the degradation of many freshwater lakes is well known. Lakes naturally receive nutrients such as nitrogen and phosphorus from surrounding landscapes. In moderate quantities, these nutrients are part of normal ecological functioning. Problems arise when the inflow of nutrients becomes excessive. 

When a certain threshold is crossed, biological productivity increases rapidly. Algae multiply, aquatic weeds expand and water quality gradually deteriorates. In lake science, this process is called eutrophication. 

As vegetation grows and later decomposes, oxygen levels in the water decline. Fish and other aquatic organisms begin to experience stress. The lake slowly moves away from its earlier ecological balance. 

The question, therefore arises, why do restoration efforts still concentrate mainly on in-box cosmetic interventions, such as removing weeds, instead of controlling what enters the lake, that is precisely an out of box appropriate solution?

Nutrient enrichment is closely connected with the way water enters the lake system in Kashmir. Feeder channels carry water and wastewater from surrounding settlements and agricultural lands. 

During rainfall events, sewage channels in the periphery of lakes and wetlands overwhelmingly pour wastewater in to these water bodies, moreover the main feeder channels transport a mixture of domestic sewage, nutrient-rich runoff and suspended sediments in more volumes during rainy days. 

Over time, the lake becomes the final receiver of everything that the catchment releases, without any out of lake interventions to de-sediment and treat inflows.

Here, we need to agree that Srinagar’s sewage treatment plants, those on the periphery of the Dal Lake, handle very little sewage for treatment. Rest of the untreated sewage finds its way into the lake. 

Imagine a freshwater lake receiving sewage for hundreds of years, especially over the past three decades, as Srinagar’s population has grown and sewage generation has nearly doubled. 

A century’s worth of sediments, silt, and untreated waste entering a lake or wetland beyond its natural capacity is directly responsible for the deterioration of these water bodies.

Sediment transport is a significant part of the problem. Soil particles eroded from catchment slopes eventually settle inside the lake basin. As sediments accumulate, the effective depth of the lake decreases. Shallow waters warms more quickly and allows sunlight to reach the lakebed. 

These conditions favour the rapid growth of aquatic plants. Gradually, the lake begins to behave like a marsh dominated by vegetation.

Why Has Dal Lake Turned Green? Locals Question, Experts Cite Ecological Factors

Video: Why Has Dal Lake Turned Green?

Public discussion has usually focused on the most visible symptoms, such as weed growth, water colour, or foul smell. Manual and mechanical harvesting of aquatic vegetation and lakebed dredging therefore became the most visible management response. 

But one must ask a simple question: If nutrients and sediments continued to enter the lake every year, can weed removal and dredging alone restore the ecosystem?

Experience from lake restoration projects around the world suggests otherwise. Removing weeds may temporarily improve navigation or the visual appearance of the lake surface. Contrary to it, several scientific studies have shown that mechanical removal of weeds actually give rise to more weed growth, as the roots and spores fracture and return back to water body during the weed removal process. 

More so, the ecological drivers of weed growth remain unchanged as nutrient-rich inflows continue to reach the water body. 

These observations must shift our attention upstream. The real challenge lies in managing what enters the lake rather than repeatedly cleaning what has already accumulated inside it. 

That is when I call for an out-of-the-box solution.  

From a scientific perspective, the logic is straightforward. If pollutants continue to reach the lake every day, every year, cleaning the lake repeatedly will never solve the problem.

One practical strategy that deserves consideration is the development of an ecological system henceforth named as Controlled Inflow Diversion System (CIDS). 

The idea is relatively simple and is based on preventive hydrological management. At locations where feeder streams and sewage drains discharge into the lake, CIDS can regulate the direction of flow. 

CIDS should be activated in feeder channels during rainy days and in sewage channels year-round. It must operate as an integrated system of flow diversion channels, sedimentation basins, and constructed wetlands to ensure sustainable and effective treatment of runoff and sewage.

Constructed wetlands are nature-based treatment systems that are widely used in many countries for storm water management and decentralized wastewater treatment. They require comparatively low energy input and rely primarily on ecological processes rather than complex mechanical infrastructure.

India has also witnessed innovative work in this field. Researchers at Pondicherry University developed a plant-based wastewater treatment approach known as SHEFROL system that has been patented. 

In this method, wastewater flows across shallow vegetated channels where plant roots and associated microorganisms facilitate pollutant removal. The system demonstrates how natural biological processes can effectively treat wastewater with minimal technological complexity. 

Detailed report about SHEFROL system was published in The Hindu newspaper under the title “Eco-friendly way of treating water,” which was a part of my PhD thesis at Pondicherry University between 2010 and 2016. 

CIDS network can create an important ecological buffer between polluted runoff and open lake water. 

Despite the challenges, the situation is not beyond recovery. Freshwater ecosystems possess an inherent capacity for resilience when external pressures decline. Lakes in several parts of the world have shown gradual ecological improvement once nutrient inflows were brought under control. 

In environmental science, this is often called a preventive approach. It may appear slow, but in the long run it is the only approach that shall work.

We need to move from reactive-management to preventive-management to save Kashmir lakes and wetlands, and CIDS is a way to go.

The author is a teacher and researcher based in Gowhar Pora Chadoora J&K. He can be reached at [email protected]. 

© Kashmir Observer