Wetland Restoration

The Problem

Karnataka is known for its lakes, popularly referred to as tanks in the local context, built mainly for irrigation by the region’s erstwhile rulers. These features remain critical to the water security and biodiversity of the region. But most of them are under threat due to various anthropogenic activities. Therefore, it is essential to monitor their health and devise appropriate conservation actions.

According to the National Wetland Atlas, 2021, Karnataka has 14,936 wetlands covering 0.79 million ha, which is 4.1 per cent of the state’s geographical area. With population rising in the state, especially in urban Bengaluru and nearby peri-urban areas like Doddaballapura, the demand for water has increased manyfold. This, together with the dried-up or polluted nature of water bodies, has put high pressure on the city’s underground water table, which is now found at depths of 1,500 feet in many parts.

Agriculture is a major occupation in the Bengaluru Rural district. This area, too, has undergone significant changes, with people shifting from traditional crops (millets) to cash crops (fruits and vegetables) that need more water. Groundwater must meet this extra demand since the surface water bodies created for irrigation stopped serving their purpose three to four decades ago.

Industrial belts in Bengaluru Rural, especially in Doddaballapura in the Arkavathy basin, are putting additional pressure on the groundwater. Many of these industries also pollute nearby water bodies and the groundwater by discharging their effluents directly into the environment.

A Potential Solution

The primary objective of the CSP programme in Karnataka is to reduce climate risks by restoring river connectivity, enhancing the health of wetlands, and rejuvenating catchment areas in the upper region of the Arkavathy river basin. It leverages Nature-based solutions (NbS) to address socio-environmental challenges caused by climate change.

Stakeholder engagement has been key to the success of this project. WWF-India engaged with multiple stakeholders, including the local government, state-level authorities, experts, other NGOs, and the local community. A multi-stakeholder or multi-departmental committee was formed under the chairmanship of the Deputy Commissioner and District Magistrate of Bengaluru Rural, where all the proposed plans, studies, and reports discussed. This provided transparency to all the activities and made people take ownership of the programme. The committee supported WWF-India in the initiation of studies, plan preparation, actual implementation, and monitoring work.

The wetland restoration work under CSP begins with surveys and assessments, after which a detailed plan developed for restoring catchment areas and river connectivity. Geo-mapping data was also integrated to identify blockages, then solutions were proposed to ensure seamless water flow by removing or mitigating these blockages.

Several activities have been carried out to restore inlets and outlets, including desilting that helped in removal of accumulated sediment and provided better water flow. Slopes of the inlet and outlet channels of the wetlands were maintained to ensure stability and prevent erosion. Regular de-weeding activities are conducted to enhance the health of the wetland. Invasive aquatic plants are removed to encourage native biodiversity. Natural or artificial structures are used to slow down and filter incoming water. Floating islands and fountains are also installed in the wetlands. A floating island promotes biodiversity by providing a habitat for aquatic plants and animals. It also enhances water quality by natural filtration and nutrient uptake. A floating fountain enhances aeration within the wetland, improving water quality by increasing the level of dissolved oxygen.

The Impact

The project restored around 425 hectares of wetland area in Karnataka. Some of the wetlands, identified in critical state were Nagarkere, Shivpurakere, kodihallikere, Jogahalli, Madiwala and Puttenahalli. It will benefit around 400 k people living in the surroundings of Doddaballapura and the rural regions surrounding the Arkavathy river basin. The programme emphasises climate resilience through Nature-based Solutions and collaboration with local communities, government agencies, and experts.