Restoration of Urban Lakes
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CONSERVATION OF URBAN LAKES IN HYDERABAD METROPOLITAN AREA Jayesh Ranjan, IAS Vice-Chairman, HUDA Hyderabad - Profile z Located between 17°21' - 17°71' N Latitude and between 78° 21' - 78°76'E Longitude with an average altitude of 560 m above MSL. z Hyderabad Metropolitan Area comprises 8500 sq. km. z Topography – Rocky, undulating with gentle slopes, red gravely soils z Tropical climate with annual rainfall of 800 mm (under semi-arid) z Decadal growth rate - 37 % z Ranked 6th in population among the metropolitan cities in India. HYDERABAD URBAN DEVELOPMENT AUTHORITY y The Authority is constituted in1975 under Urban areas (development) act 1975. y HUDA is a statutory Planning Authority to develop Master Plan for planned development and controlled growth of urban areas. y To plan for a sustainable development of Hyderabad urban agglomeration. y To develop policy framework, zoning regulations and land use plan. y To plan and implement infrastructure facilities like road network and overall transportation plan. y To plan for sustainable environmental management. LAKES OF HYDERABAD z About 400 big & small lakes in HUDA area. z 169 lakes notified by HUDA for protection and conservation of water spread area with no activity in 30 m buffer around the water bodies. INDIAURBAN LAKES – DRAINAGE MAP Hyderabad Urban Development Authority India Andhra Pradesh Hydrological regime & role of urban lakes z Urbanization has led to loss of water bodies resulting in increased runoff z Lakes contribute significant additional recharge to the ground water regime due to infiltration z Over-exploitation of ground water due to urbanization leads to rapid depletion of ground water level Hydrological regime & role of lakes z Polluted water body causing unhygienic and health hazards for lake neighborhood. z During the past few years there is a fall in water level of 1-2 m per year all over the City z The worst ground water scenario is experienced by apartment complexes Problems faced by urban lakes z Urbanization. z Change of land use. z Tampering inflow & outflow channels. z Cattle Wash z Washing clothes z Indiscriminate dumping of debris and garbage. z Industrial effluents. z Continuous flow of untreated waste waters. zInvasive weed - throttling the lake ecosystem zPollution due to Idol Immersion zInappropriate shoreline development (Encroachments) Need for restoration of urban lakes z To harvest the precious rainwater and augment shortfall in water supply needs of Hyderabad z To moderate the flood risk by interconnecting the lakes z To utilize the wastewater by treatment process during the dry weather and maintain lake water balance z To improve the scope for recharge of ground water within the influence zone of the lakes Need for restoration of urban lakes z To improve the health conditions of people living in the lake surroundings. z To enhance the biodiversity in and around the lakes. z To induce recycling and reuse of wastewater after treatment for non-potable uses for gardening and industrial purpose. z Develop local economy through eco-tourism activities at lakes. HUDA has taken up the task of restoration of lakes in the Hyderabad Metropolitan area to conserve the water bodies and to increase the ground water table with clean water. In the first phase, out of 169 large water bodies notified, 87 lakes are being taken up under Green Hyderabad Environment Programme (GHEP) from 2004 onwards Categorization of lakes for development These lakes are categorized based on certain criteria like degree of pollution, size of the lake, proximity to habitation, etc. • Category – I (more polluted) - 18 nos • Category – II (moderately polluted) - 69 nos Baseline Work z Detailed survey of the lake and its surroundings and preparation of the lake plan. z Bathymetry of the lake for area - volume of the lake. z Database on watershed and the ground water quality and water table in all seasons. z Preparation of the Catchment area plans. z The flow measurements of all incoming dry weather flows and outflows of the lake z The flow measurements of all incoming wet weather flows and outflows of the lake. z Daily lake water level recordings. z Pan evaporation data from the Meteorological dept. z Rainfall data from the Meteorological dept. for calculating the storm water runoff from the catchment area into the lake. Cont.. Baseline Work z Dry weather flows for the projected population for the year 2031 is calculated by using census data. z The capacity of Sewerage Treatment Plant is fixed based on the quantity of minimum flow required into the lake to maintain its water balance which is equal to the maximum water loss due to evaporation and percolation under no outflow condition during the dry season when the evaporation is highest. z Water quality analysis of inflow, lake water and outflow of the lake for all parameters such as BOD, COD, DO, Total Nitrogen, Total Phosphorus and trace metals etc. z The sediment analysis of the lakebed in different layers depending up on the nutrient values in the sediment. z Socio economic study of the lake surroundings for identification of direct and indirect dependents within the vicinity of the lakes. z Biodiversity study of the lake for compiling on the current biodiversity. Restoration works at lakes Category - I z Formation of peripheral bund along the shore line of the lake z Desilting the lakebed by dredging z Strengthening and widening of main bund z Restoration of surplus weirs and sluices z Construction of STP for treating the raw sewage and letting the treated water into the lake to maintain the lake water to the desired level Restoration works at lakes z Restoration of inflow and outflow channels z Diversion of excess sewage by laying pipelines. z Beautification of lake bunds and periphery with landscaping and plantation. Restoration works at lakes Category - II z Formation of peripheral bund along the shore line of the lake z Desilting the lakebed by dredging z Strengthening and widening of main bund z Restoration of surplus weirs and sluices z Restoration of inflow and outflow channels z Plantation on Lake bunds Process Details of The STP z Interception, diversion and collection of sewage z Screening of floating matter & grit z De-Nitrification (Biological process) z Extended Aeration with fine pore diffused membrane z Flocculation with Alum dosing for phosphorus removal z Settling by Plate Settlers z Chlorination & Filtration z Clear treated effluent to wetland where special type of plants viz. cattails and bullrush are planted for removal of further phosphates and nitrates Tertiary Treatment Process Raw sewage Wetland Lake A View of the STP Lab DN Tank Aeration Plate settlers Flocculation tank Power room Sludge drying beds Pressure filter Restoration of Safilguda Lake Before Intervention After Intervention Restoration of Langerhouse Lake Before intervention After intervention A View of Saroornagar Lake Description BOD COD DO TKN Total P Lake Water Before Intervention 65.00 212.00 3.40 14.00 5.87 Lake Water After Intervention 25 92 6.2 9 1 Standards <10 <50 >5 <5 <1 A View of Langerhouse Lake Description BOD COD DO TKN Total P Lake Water Before Intervention 120.00 270.00 0.40 29.00 5.22 Lake Water After Intervention 14.00 32.00 5.40 4.15 0.80 Standards <10 <50 >5 <5 <1 A view of Pedda Cheruvu, Nacharam Description BOD COD DO TKN Total P Lake Water Before Intervention 82.00 370.00 0.40 29.00 5.60 Lake Water After Intervention 16.00 42.00 5.60 6.15 1.20 Standards <10 <50 >5 <5 <1 A view of Resident friendly STPs Mir Alam Tank Saroornagar Lake Biological Treatment Facility Trees, Bamboo and ground cover helps in increasing the Bio-diversity as well as self purification by absorption of phosphates and Nitrates Floating macrophytes like pistia and duckweed help in removal of inorganic Nitrogen and Phosphorus in the wetland Lake Landscapes Provides enhanced aesthetics to the lakes. Increases opportunity for gainful employment through eco-tourism Bio-diversity of Restored Lake Exclusive Bird Island created at Safilguda Lake Rich faunal and floral Bio-diversity in the midst of the city A Paradise for Birds in the midst of urban built-up area Lake eco-system and wetland contribute a lot to the bio-diversity OUTCOME : SOCIO-ECONOMIC BENEFITS z Improvement in the Lake water quality from Hyper-eutrophic condition to Mesotrophic condition z Increase the Biodiversity of the Lake z Increase in pisciculture activities z Employment generation by Eco-tourism activity z Increase in recreational facilities and water sports. z Improvement in the groundwater quality z Improvement in human health of lake surround z Improved aesthetics z Enhancement of property values in the lake surroundings .