Background: Ujni dam is constructed on the river Bhima, one of the chief rivers in Pune district. The river collects untreated sewage from the urban areas upstream,
treated and untreated industrial effluents and non-point run-offs from the agricultural fields growing irrigated cash crops. The water shows high values of biological oxygen demand and high Maximum Permissible Number counts. The dam is located in the rain-shadow region of the Sahyadris with rainfall less than 50 cm per annum. The reservoir is a shallow water reservoir and treated as a wetland.
The water level shows high fluctuations as its supply is dependent on the releasing of water upstream and demand for water in command area. The farmers utilize the exposed area of the submergence region for cultivation and grazing of livestock. Cultivation and Grazing on Bank This has rendered the area barren and infested with weeds like Alternanthera. Weeds like Eichhornia and Ipomoea spread in the submergence area. The vegetation and habitats along the rivers and streams joining the reservoir are degraded.
To prepare a management plan for the Ujni reservoir that included reconciliation of the interests of wildlife and people.
The site located in the submergence area of the Ujni reservoir experienced a seasonal flooding and draw down regime.
- An initial socio-economic survey of the people inhabiting the area surrounding the reservoir was carried out. It showed a lack of biomass availability for local people to fulfill their needs of fuel, fodder and timber.
- The selected project area was divided into 7 sectors. A contour survey was undertaken to mark the elevations and measure the extent of water spread on the site during different water levels of the reservoir. The correlation between water level and distribution of flora and fauna on the project site was examined by keeping a daily record of the distribution of bird species in different sectors. A habitat suitability index was worked out for the project area.
- A plan of action to improve the habitat suitability for avifauna and to provide resources for local people was worked out and implemented on the site. The plan was -
- To create a mosaic of habitats on the project site.
- To lessen the severity of conditions created by the annual flooding and rapid draw down
- To attempt to increase the usable biomass by encouraging production of fodder, timber and other useful produce like fish.
- To provide conditions in which riverine fish and waterfowl will be able to breed
- To provide conditions in which birds that use marshes, mudflats and shallow water will be able to sustain themselves
A variety of habitats were created on the project site - trees and shrubs, grassland, wet meadows, bank vegetation, marsh vegetation, pools of calm water, islands and open water.
Three large mounds were built, high enough not to be submerged during high water level, to serve as islands.
Built Island Island
A series of dykes connecting these islands and the edges of the reservoir was constructed. These created pools which held water for longer periods and provided fish breeding habitat. They also served as refuge for birds, invertebrates and vegetation. Species like Nymphaea were introduced in the pools.
Construction of Dykes
Tree species like Salix were planted for multiple purposes - providing shade over water, their roots spreading in water acted as anchorage for fish and invertebrates, shelter for birds and source of fuel and timber for local people.
Plantation of Salix Plantation for Bank Protection
Earthen mounds were built along the edges of the reservoirs and planted with Acacia nilotica, sedges and grasses. They were mainly to perform two functions - bank protection such as defense against flood and erosion and shelter for fauna.
Some parts of the site were planted with useful grasses like Pennisetum, Cynodon dactylon and Senchrus ciliaris, shrubs like Aloe, Agave. Trees like neem, tamarind, Ficus, Pongamia were planted to provide fuel, fodder and wood to local inhabitants. First the land was ploughed to loosen the compacted soil.
Land ploughed to loosen Soil
The area covered with Paspalum was ploughed and the roots were removed to avoid germination. Spread of Ipomoeawas controlled by physical removal and burning.
A part of the existing island was raised by piling earth to provide resting sites to diving ducks and other waterfowl.
Raising of Existing Island
- The pools recorded an increase in fish numbers.
- The grass growth and the rainwater puddles attracted grassland and wet meadow birds.
- The shallow water areas showed good growth of sedges like Cyperus and attracted marsh birds.
Growth of Sedges like Cyperus Marsh Birds
- The pools attracted surface feeding waterbirds like spot-billed ducks.
- It was observed, that during high water level the surface feeders dominated while during the low water level wet meadow birds dominated.
- During the project implementation of the project, the area experienced drought conditions. This led to the spread of Paspalum and the saplings introduced had to be watered by irrigation.
Unfortunately, the Government passed a resolution demarcating the area for bird sanctuary. The villagers feared they would lose their lands as they had done due to the dam construction. They posed an opposition against the sanctuary and also the project. They damaged the trees and saplings on the area and prevented the project staff from further implementation. The project actually implied that people and birds could live in harmony if proper management and conservation measures were taken. It also eliminated the necessity of creating a sanctuary for protection of birds and instead relied on the co-operation of local people. But the villagers could not be convinced of the idea. Only monitoring was now possible on the project site.
However, the attempts to improve habitat conditions for waterfowl on a man-made reservoir proved successful. There was an increase in diversity due to the manipulation of the previous uniformity in the area.
This shows that rejuvenation of aquatic ecosystems is possible through cost effective measures and proper management. This can be done by taking the local inhabitants into confidence and explaining to them the benefits of restoration to wildlife and humans.