Srinagar, Nov 21: In its endeavor to minimize the influx of silt and nutrients from the catchments areas into the Dal Lake, the concerned authorities have started a process to create artificial wetlands near the inflow channels of the water body.
 Experts believe that the artificial wetlands will act as bio-filters and release the waters into the lake after natural filtration.
 The Lakes and Waterways Development Authority (LAWDA), entrusted with Dal conservation, has completed surveys and identified the vulnerable inflow channel which bring silt into the lake. If all goes well, these wetlands will be ready by March 2011 and are anticipated to give the desired results within three months, officials said. 

SILT INFLUX
 According to an estimate 40,000-50,000 tons of dead and allochthonous material including silt and nutrients are added annually to the lake resulting in reduction of its depth and propelling growth of weeds in the lake.
 Dal receives its waters from Marsar, a glacial oligotrophic alpine lake through two main sub-watersheds Dhara Danihama and Dachigam. Before reaching the lake, the waters pass through denuded mountains carrying tons of silt with it.
 The problem is compounded as the catchment area spanning over 337 Sq. kms comprises of human habitations, denuded mountains, karewas, perennial plants, open scrub, agricultural fields and barren land. With even a light rainfall, tons of sediments and pollutants also make way into the lake drastically affecting its eco-system.
 Due to deforestation and soil erosion over the years in the catchment areas of the lake, the silt and nutrients flow into it, causing siltation and growth of exotic weeds. Though LAWDA has been over the past few years carrying out scientific measures including constructions of Gabian dams and afforestation to tap the silt inflow, it has not yielded the desired results.
 The excessive siltation and nutrient inflow into Dal has led to decrease in the lake’s water holding capacity and propelling growth of weeds. Since April this year, the LAWDA has carried out 80,000 cubic meters of de-weeding, 12000 cubic meters dredging respectively in various areas of the lake. However the due to presence of nutrients, the weeds are growing at a fast pace.

GO AHEAD
 Long term data base generated by the Research and Monitoring Division of LAWDA has established that streams carrying fresh water to Dal are loaded with nutrients which are harmful to the lake and are enhancing the enrichment levels.
 These findings have been confirmed through review of research work at an international level and subsequently the matter has been placed before the Scientific Advisory Committee, which comprised of Scientists from IITs, JNU, KU, SKUAST, NIT, and Wetland International. The Committee last year had approved the proposal of development of wetlands for treatment of excess nutrient levels in streams and tertiary treatment of wastewaters.

INTERVENTION
 The LAWDA has started a process to create wetlands in Telbal and Shalimar. A large chunk of land identified for the creation of the wetlands is already with the LAWDA. “These engineered wetlands will be based on surface-flow technology and planted with emergent reeds like Typha (Cattails) and Phragmites. These reeds are known to have high nutrient take-up potential and wetlands with such reeds have demonstrated significant reduction in organic, nutrient, silt and microbial levels. These wetlands for water quality remediation are being designed as per the international protocols and several case studies of temperate climatic conditions are being referred for achieving high degree of treatment,” the senior scientist of LAWDA Dr. Sabah- ul-Solim told Greater Kashmir. Solim said these wetlands rely upon natural microbial, biological, physical and chemical process for breakdown of organic and inorganic constituents into the simpler end products.
 “The wetlands will be made up of multiple treatment cells, while the in-stream ones will have reed beds in zig-zag pattern encompassing a free water surface and a reed zone to maintain integrity of the streams. The envisaged success of these wetlands are linked to the development of series of similar wetlands in the peripheral areas of the lake and consequent reduction in nutrient enrichment levels, weed growth and water quality improvement in the lake.,” Dr Solim said.
 He said in view of rapid urbanization of Srinagar city, artificial or constructed wetlands are seen as natural sponges and as a long term solution for sustainability of the lake.
 The vice chairperson LAWDA, Irfan Yasin said an action plan under the catchment area treatment has been evolved to decrease the sediment load and amount of nutrient discharge into the lake.
 “Artificial wetlands have been success as they impersonate the mechanisms operational in natural wetlands for achieving the eco-friendly and cost-effective treatment. The wetlands are envisaged to be ready by March 2011 and upon maturity of plant growth by July 2011 are anticipated to give the desired degree of treatment,” Yasin said.

Lastupdate on : Sun, 21 Nov 2010 21:30:00 Makkah time
Lastupdate on : Sun, 21 Nov 2010 18:30:00 GMT
Lastupdate on : Mon, 22 Nov 2010 00:00:00 IST