Dr. Priyanka Jamwal on Lake Revive and the Future of Sustainable Lake Management in India

Lakes in India are under severe ecological stress due to multiple pressures such as untreated sewage inflows, solid waste dumping, industrial effluents and rapid urbanisation. These stressors have led to harmful algal blooms, fish mortality, eutrophication, and encroachment of lake ecosystems. As a result, lake water quality has deteriorated significantly, causing a decline in aquatic biodiversity and degradation of critical habitats.

Monitoring the water quality of lakes is essential because it forms the foundation for effective management. Regular monitoring helps in three critical ways. First, it identifies existing problems and pollution sources. Second, it guides the design and scale of restoration or management interventions. Third, it enables evaluation of the impact of these interventions on lake health. Without systematic monitoring, restoration efforts remain ad hoc and ineffective.

A well-known example is Bellandur Lake in Bengaluru, which has become a symbol of the consequences of unregulated sewage inflows and pollution. Episodes of frothing, fires, and large-scale fish kills in this lake highlight the urgent need for sustained water quality monitoring and restoration strategies across Indian lakes.

To address lake degradation, several restoration projects have been undertaken across India. These projects often include the installation of sewage treatment plants (STPs), the construction of wetlands, and the development of sedimentation ponds, all aimed at improving water quality. However, these initiatives largely follow a checklist-based approach, where standard solutions are applied uniformly rather than being guided by science-based, site-specific strategies. This limits their effectiveness in achieving long-term ecological recovery.

One of the major limitations of current restoration practices is the absence of clearly defined goals or measurable targets that can guide and evaluate the success of interventions. In addition, stakeholder engagement is often minimal, and expectations are not adequately set or communicated, which reduces community ownership and long-term sustainability. Further, practices such as the diversion of inflows, removal of shoreline vegetation, and large-scale desilting to increase water-holding capacity tend to disturb the natural ecological balance of lakes. Such interventions often create stagnant, pool-like conditions that favour the growth of blue-green algae, ultimately leading to frequent algal blooms and fish kills.

Nature-based solutions (NbS) rely on natural systems such as wetlands, floating islands, green buffers, and bio-swales to treat polluted water and restore lake ecosystems. Unlike purely engineered approaches, they complement grey infrastructure by working with natural processes to improve water quality, enhance biodiversity, and strengthen climate resilience. In addition, NbS are generally cost-effective and generate multiple co-benefits, including groundwater recharge, carbon sequestration, and the creation of recreational and aesthetic spaces for communities.

Evidence from other countries highlights their effectiveness. For instance, Singapore has successfully used constructed wetlands for stormwater management, the United States has adopted green infrastructure to reduce urban flooding, and sponge city initiatives in China have restored lakes and wetlands to enhance urban water security. These examples demonstrate that NbS delivers long-term, sustainable outcomes, offering more resilient alternatives to short-term technological fixes.

One of the biggest challenges in implementing nature-based solutions (NbS) is the lack of financial investment and long-term funding support. These systems also require adequate land and space, which is often difficult to secure in densely built urban areas. Another challenge is that NbS typically take longer to deliver visible results compared to engineered fixes, making it harder to convince policymakers and stakeholders of their value in the short term. In addition, there is no robust framework to systematically assess their overall impact, which limits evidence-based decision-making. Finally, limited awareness, fragmented governance structures, and weak coordination among institutions further constrain the scaling and sustained adoption of NbS.

Lake Revive is an innovative decision-support tool developed to assist contractors, site engineers, environmental professionals, and citizen volunteers in selecting appropriate nature-based solutions (NbS) for urban lake restoration. What makes the tool unique is that its recommendations are grounded in the self-assimilation capacity of the lake, which takes into account the morphometry and internal processes to identify optimal solutions for addressing water quality challenges of the lake.

A second important feature is the use of restoration benchmarks based on total phosphorus (TP) levels. These benchmarks are derived from the average maximum water clarity that can realistically be achieved in lake systems (tropic countries, rapidly urbanising catchments), making the tool context-specific and science-based. Together, the self-assimilation capacity and the TP benchmark provide a robust foundation for designing targeted interventions.

The tool guides users through a step-by-step process to assess whether blue-green infrastructure, such as constructed wetlands, floating islands, or a combination of both, would be most effective under given conditions. It also offers recommendations for shoreline rejuvenation, which supports both water quality improvement and biodiversity enhancement. By integrating ecological processes with practical restoration needs, Lake Revive enables informed decision-making for sustainable lake management.

Lake Revive is recommended over other methods because it integrates the self-assimilation capacity of lakes with realistic restoration benchmarks to design nature-based solutions (NbS) tailored to local conditions. Unlike generic approaches, it is grounded in scientific evidence drawn from extensive work across 32 lakes in Bengaluru, ensuring that the solutions are context specific and effective.

The tool offers several advantages. It avoids both overdesigning and underdesigning interventions, thereby providing cost-effective solutions that optimise resources. It is also user-friendly, helping practitioners save time during the design process while maintaining scientific rigor. Moreover, the tool is continually being upgraded. Future versions will incorporate action-based science and artificial intelligence to generate detailed reports and offer even more robust decision support for lake restoration.

Lake Revive is a web tool that helps pick the right nature-based solution (constructed wetlands, floating islands, or both) for an urban lake and guides design + O&M.

Step-by-step user journey

1. Collect basics (from your available sources): lake area & average depth, available area for interventions, Secchi depth, and TP levels.

2. Add inflow details: flow (m³/day or KLD) and inflow TP; for multiple inlets, use sums/weighted averages as noted in the tool.

3. Note visible issues: fish kills, algal blooms, sewage odour, floating vegetation, foaming.

4. Run analysis: the tool estimates nutrient loads and feasibility, then recommends CW, FI, or a combo (and flags if NbS isn’t feasible within space limits).

5. Get implementation guidance: sizing, expected removal, plant lists, and maintenance pointers; use the linked SOPs for CW/FI/shorelines.

6. Track outcomes: use the built-in Lake Health Index (Secchi, TP, algae, shoreline) to monitor improvements over time.