Conservation and Management Plan for Dal- Nagin Lake

2 DATA COLLECTION AND ANALYSIS

In order to prepare a plan, a data is the first and foremost requirment. All the available data was , therefore , examined and an attempt ,made to fill the gaps to the extent possible within the limited time available for preparing the plan . The first volume of the report , which comprises nine chapters primarly deals with studies connected with data collection . These studies are summarised below: -.
The problems facing the lake can be summarised below. Top

2.1 Hydrology and water Balance Studies
The Hydrologic studies were aimed at obtaining lake water balance on weekly, monthly and yearly bsi , as well as predicting future scenarios and operation of outlets .This has been done using the available meteorological and discharge data . No information is available on the discharge contributed by the springs in the lake bed. In the present study this has been estimated to be of the other of 0.28 m3 / s with large year to year variation .The normal lake level for the water balance has been taken to be 1583.16 m above msl with the max. probale flood in Telbal Nala is an important parameter to be used hydraulic design this has been estimated at 141.5 m3 /s (5000 cusecs) for a hundred return period , using appropriate models it would not be about out of place to mentiion herethat the 1973 flood in Telbal nala is estimated to be about 113m3 /s (4000 cusecs). Top
2.2 remote sensing and GIS application

Remote sensing (RS) and geographic information system (GIS) are generic technologies used for a variety of application .In the present study, these have been used for prepartion of land use maps of the dal lake change detection studies, derivation of Digital Elevation models(DEM) and prepartion of socio-economic Database. The Satllite and Digital data from IRS –1A-LISS,II IRS –IC-LISS-III and PAN procured from National Remote sensing Agency (NRSA) was used for these studies. The latest land use map shows that of a total 337.17 sq.km of catchment, 160.97 sq.km is bare ground , 52.02 sq.km is dense forest, while 34.15 sq.km is open forest and 1.85 sq.km is declined forest . snow cover is 9.25 sq.km bulit up and unclassified area is 45.44 sq.km and 33.49 sq.km is lakes and shadow areas . The Data obtained during the Bathymetric survey was also transferred to a GIS plateform for further analysis and use. TOP

Creation of stagnant zones . These zones are general at the periphery and close to the effuent discharge locations In those areas where there is some movement of water the stagnation zones are not appreciable . In time scale the worst conditions are visible in spring. Around 50 percent of the observed max. values of specific conductivity, dissolved oxygen. Number No₃-N,NH₃– N P0₄ and total phosphates have been noticed in the spring season. Summer season has 25 % of such observation and the remaining 25% are distebuted in autumn and winter seasons. This may possible be due to start of activities in the catchment , mixing or resuspension. TOP
A comparison of values our a period of time shows that the dal lake has passed through several stages of trophic evolution. Extensive data establishes for reaching chabnges in its physico- chemical environment.
Dal lake receives large quantities of nitrogen and phosphorus from point sources ( incoming nallahs-Telbal, Botkal and sewage drains) as well as from non point sources like seepage and diffused runoff. The lake is peculiar in having human habitations settled along its periphery as well as of large population living inside the lake in hamlets, house boats and dooga boats . Amoung point sources 15 drains release significant quantities of sewage , of the total –phosphorus in flow of 156.62 tons from all sources, the quantity contributed by the drains work out to be 56.36 tons. In the case of inorganic Notrogen (No₃– N) and NH₃–N) these figures are 241.18 tons and 77.609 tons with a flow of 11.701 million m3 / year. Similarly 4.5 tons of total phosphates and 18.14 tons of nitrogen (N0₃– N and NH₄–N ) are added to the lake from non point sourecs TOP

2.6 Limnological and Hydrobiological Aspects.

Hydrobiology and limnology are the studies related to the presence of planktonic, nektonic and benthic communities in a lake body and their interaction with environment. In an eutrophic lake, benthic community is represented largely by macrophytic vegetation . They play a key role in determining the structural and functional aspects of lakes. Management of macrophytes in Dal lake, therefore assumes great importance . Three vegetation zones viz. Emergent, rooted and submerged have been reported in dal lake in addition to communities of wet lands and moist banks . Thirty three species of emergent, twelve species of submerged eighteen floating and forty three species of moist bank and wet lands have been indentified. The vegetation patterns in the different abasins are different . Hazratbal basin is dominated by submerged vegetation zone. TOP
The macrophytes derive nutrients from bottom sediments and lock them in the biomass. It is estimated that every year eighty six tons nitrogen and four tons of phosphorus is locked in macrophytes with forty tons of potassium and eight tons of sodium.

Diatoms followed by desmids and bluegreens dominate the planktonic population . Euglenoids also show their presence sproradically in blooms. TOP

All major invertebrates and vertebrate groups represent the animal communicities. Annelids Arthropods and Molluse are common nektonic and benthic forms. Rotifers, Copepods and cladoeerans lagely represent the Zooplankton .

2.3 Bathymetric Survey

A bathymeric survey was commissioned for the purpose of this project and has resulted in production of maps givigg the lake boundary and depth contours of the Dal- Nagin lake TOP

2.4 sedimentation studies

A study of the rate of sedimentation in the lake was carried out using radioisotopes. 210 Pb and 137 Cs isotopes were used for dating the sediments. The 210 Pb content was determined based on α measurement of 210 po, while gamma counting was used for determination of 137 Cs. Fourteen sediments cores wre collected from different locations in the lake . The length mof the cores ranged from 30 to 64 cm. TOP
All the sediments cores collected were found to contain organic matter in considerable quantity While the organic matter in sediment from location near the Nelbal Nala was 4-19%, it increased to about 25% as one moved away from the Nala. One sample from the eastern part of Bod-dal Sub-basin had about 63% organic matter. Considering all the, sub basins, the organic matter was found to contribute about 25-30% in the sedimentation process. Since incoming water is seen to be contributed less than 10% of the organic matter, it is obvious that underwater weeds are contributing the rest of it.
The rate of sedimentation varies in the various basins . However , the mean rate in the Dal lake is 0.52 ± 0.04 cm since 1964, which has been reduced to 0.22 ± 0.03 cm/y since 1987 . For the nagin basin the corresponding values are 0.41 ± 0.05 cm/y and 0.34 ± 0.03 cm/y respectively
The estimated life of Dal alke considering the average rate 1964 is about 154 ± 12 years while that of Nagin lake is 315 ± 38 years . However, based on the sedimentation rate after 1987. These values stand modified to 364 ± 50 years and 379 ± 33 years for the Dal & nagin lake s repectively .
2.5 Water quantity and Sources of Pollution TOP

Water quality of the Dal lake has been seriously altered over a period of time because of human interventions which include agriculture development in the catchment, urbanisation and waste discharge . All this along with natural forces have made the lake cutrophic and it is under great stress.

The deterioration of the lake ecosystem has been progressing at an alarming rate . The Research & Development Laboratory National Insitute of Ecology of JKLWDA has been monitoring the lake in a systematically drawn out programme at 20 smapling locations in all the lake basins and the data in the form of reports is available from Sept.1997 1999. There are four sampling locations in the gargribal ( Nehru park ) basin five in BOD –dal (Nishat), four in Hazartbal basin ,four in Nageen basin and three in Brari Numbal.

2.6 Geological Aspects TOP

Dal lake is situated at the foolhills of the Zabawan mountain –off shoot of the Himilayan Chain . The Dachihgam-Telbal Nala forms the major drainage of the local catchment area . The drainage pattern is , in general , dendsitic signifiying poorly porous and poorly premable nature of rocks .
Geologically the terrain in and around dal catchment has a Wide variety of lithounits. Lithologically all types of rocks igneaous , metaphorphic and sedimentary are found in the area. .structurally , the Dachigam Telbal Nala system appears to follow two major lineaments. The angular and parallel drainage pattern suggests discontinuity surfaces in the terrain. The water table cuts the hill slopes as is evidenced by the occurrence of numerous springs. The kashmir valley shows intense seismic activity and is in Zone V of the seismic zoning map of INDIA , as givien by the Bureau of Indian Standards 1984. This is the most severe zone where frequent damaging earth quakes of intensity IX and above can be expected repeatedly
2.7 Socio- economic Aspects Top

The Dal lake is unique in the sense that a large member of people live in hamlets inside the lake . There are all kinds of structures in theses hamlets . There are also a number of houseboats and Doonga boats in the lake. Activities like cultivation, fishing and many others are carried out within this area . In order to collect information about the lake dwellers, a socio – economic survey was carried out. The survey covered 105 mohalls, which were divided into 22 areas on the basis of topography. Data was collected covering a wide range of activity and the salient features that emerged are summarised below.
There are 775 houseboats, 328 doonga boats 4210 pucca houses and 3493 huts in the lake. The houseboats and doonga boats occupy 1,39,716 sq.m(15,03,900 sq.ft) of water area while the pucca houses and huts occupy 2,48,120 sq.m (26.70,745 sq.ft) and 60,096 sq.m(6,46,878 sq.ft) of floor area respectively TOP
The average income of 59.64% households is between Rs 1,000/- to 3,000/- pm. While that of 21.9% is between Rs 3,000/- to 7000/- pm 13.7% households have an income below Rs 1,000/- pm. While only 1.46% earn above Rs 10,000/- p.m .The number of persons earning from within the lake is 7,870 while 7728 people have livelihood from other sources . The remaining 23,199 are unemployed, though they help their families in cultivation, carpets weaving etc. All the above data has been put on GIS database for easy retrieval and manipulation.TOP