Introduction

The greatest degradation effects/impacts to lakes and reservoirs are generally caused by human activities in their surrounding drainage basins (Rast 2009; Mishra and Garg 2011). World’s urban population has increased 15 times from 200 million in 1900 to about 2.9 billion in 2000, and is further projected to increase to about 5 billion by 2030 (United Nations 2002). In developing countries, urbanization is associated with natural population growth, rural–urban migration, convergence in rural and urban lifestyles, and the economic and political processes associated with globalization (Cohen 2004a). The demand for water and land resources expand with the increase of human activities in many regions, resulting in ecological and environmental concerns (Singh et al. 2010). Land is the basic natural resource that provides habitat and sustenance for living organisms, and a major source of economic activities (Amin and Fazal 2012). Simultaneously, the growing human requirements and activities determine fate of land use (Mohamed et al. 2000; Bacon et al. 2002). Land use shows its close correlation with human activities and ecological environment (Styers et al. 2009). The demand for the products of the land is likely to continue growing in the fore-seeable future (Fazal and Amin 2011). Along with the land use/land cover change (LULCC), interchange or transformation is presently being experienced in and around growing towns (Ifatimehin et al. 2009). It affects the values defined by aesthetic and other environmental qualities of a region (Wear and Bolstad 1998). The rapid population growth, per capita consumption of resources and per capita generation of waste as output, and the consequent unprecedented changes in historical land use pattern come at a cost to the natural environment (Cohen 2004b). It may also lead to the detrimental effects in the form of reduction in water quality and scenic values (Gottfried et al. 1996). Surface runoff and sewage discharge brings sediments and chemicals to aquatic systems and which promote excessive growth of plants in the lake. Such undesirable change affects water quality (Khan and Ansari 2005). The rapid undergrowth of weeds, especially Azolla Pinnata as studied by Kundangar et al. (2003), has threatened the existence of Dal lake. Water contamination and its sustainable management need our attention because of far reaching impact on human health (Singh et al. 2009). The present study focuses on the land transformation brought down by the Hanji community in and around the Dal lake.

Material and Methods

Description of Study Area

Dal lake is a Himalayan lake which is located in Srinagar city, India (longitude 74°48′ to 75°08′ and latitude 34°3′ to 34°13′) (Fig. 1) at an average elevation of 1,583 m. The total area of the Dal lake catchment is about 314 km2. Dal Lake is the largest water body of Srinagar city and because of the land bridge and the marshy land, has been divided into two parts Lokut-Dal and Bud-Dal. Practically it is divisible into four major sub-basins, i.e., Hazratbal, Lokut-dal, Gagribal and Nigeen basin (Fig. 1). Nigeen basin is the deepest of all with the depth more than 6 m (Fig. 2).

Fig. 1
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Location and bathymetric map of Dal lake, Srinagar, India

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Fig. 2
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Location of Hanjis mohallas/localities of Dal lake, Srinagar, India

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The position and the morphology of the study area revealed that the lake has been derived from an enlarged oxbow lake in flood plain of river Jhelum than from progressive shrinkage of a glacial lake (De and Paterson 1939). According to Wadia 1947, that the lakes of Kashmir to be formed from the inundated parts of the river Jhelum having alluvial dams and marshy borders. Presently the lake is spread over 1,620 hectares (ha), consisting 1,305 ha of water body and 315 ha of marshy area. This shallow lake is encompassed by gentle slopes on its east and southeast. Srinagar city has a sub-Mediterranean type of climate with warm summers from June to August and cold winters from December to February. The average temperature of the warmest month is 30 °C in July whereas it is 3.5 °C in the coldest month i.e., in January (State Meteorological Department 1999). Over the last 30 years, the climate change indicator for the region reveals a warming trend. The maximum temperature recorded during the period from 1901 to 1950 was 30.80 °C (July) and the minimum of −2.30 °C (January). Whereas from the year 1979–1996, 32.40 °C (July) and −5.4 °C (January) were recorded as maximum and minimum temperatures respectively.

Hanjis Origin and Socio-Economic Profile

The boatmen of Kashmir are known as Ha’enz, Kishtiban (Boatman) or Jalbashi (Water-dweller) in local language and descendents of Nishada tribe. Hanjis are considered as strong, hard working and have many sub-castes who have mastery in art of living on water and know the real depths and mysteries of lakes and rivers (Sufi 1949; Ray 1970). They are categorized into 8 groups; Demb Ha’enz (Vegetable growers), Gari Ha’enz (Water-nuts gatherers), Dunga Ha’enz (Owners of passenger boats, dunga), Ma’er Ha’enz (Boat men of Ma’er Nallah), Gaad Ha’enz (Fishermen), Haka Ha’enz (Collectors of wood from water bodies), Shikara Ha’enz (Shikara owners), and Houseboat Ha’enz (Houseboat owners). The main mohallas of Hanjis has shown in Fig. 2. The Dal Gate and Gagribal area of the lake has high population density of Hanjis. As per 2001 census of India, the Hanjis population living in the lake and its periphery was about 135 thousand (which is currently estimated to be nearly 175 thousand and was only 70 thousand in 1980). The sex ratio among Hanjis was 919 males per thousand females, and about 61 % of the population is in the productive age group of (15–59 years) and literacy is being only about 24 %. The estimates showed that there were 4210 permanent houses and 3493 temporary houses and rest of the people lived on the lake water itself in their house boats. A section of Hanjis community has property rights over 300 ha of agricultural land and 670 ha of water area. There are more than 775 houseboat owners, and about 400 Dunga boat owners (Rather 2004).

Data and Methodology

The data used for the preparation of land use land cover (LULC) map of the study area was collected from town planning department of Srinagar city on 1:15,000 scale of 1981. Similarly, the LULC map of 2011 was prepared using IRS-1D LISS III + PAN merged satellite imagery. Both the images were first geo-corrected and geo-referenced in Earth Resource Data Analysis System (ERDAS) Imagine 9.0 software, by assigning UTM WGS 84 projection system. The satellite data was classified into 5 classes. The trend and pattern of Dal lake transformation were calculated and every polygon representing the particular class was quantified and displayed in respective maps. The detailed monitoring strategy is defined in Table 1. Water samples were collected from all these sites during 2010–2011 on 15 days time intervals in 1.5 L plastic bottles. Water quality analysis was carried out as described in (A.P.H.A. 1998) by the collection of water samples from 12 sites in the lake. It includes 4 sites in Hazratbal basin, 3 in Lokut Dal basin, 3 in Gagribal basin and 2 in Nigeen basin (Fig. 2). The major aquatic ecosystems problem is eutrophication, which arises due to high amounts of phosphates and nitrates, is a main cause in the destruction of lake ecosystems around the world (Ansar and Khad 2005). Several scientists have studied mineral levels in different water bodies, and have found that the level of phosphates and nitrates has heavily impact on the overall health of the water and its inhabitants (Yanamadala 2005). For the collection of socio-economic data 58 Hanjis respondents were interviewed with the help of structures questionnaires using stratified random sampling technique.

Table 1 Monitoring strategy
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Results and Discussions

Land Use/Land Cover Change in Dal Lake and its Environs

The area under built-up has increased from 5.5 ha to 53 ha during last 30 years (1981–2011) (Table 2, Fig. 3). Non built-up area has decreased from 2444.5 ha to 2,397 ha i.e., decreased by more than 47 ha. There has been increase of 863 % in built-up area whereas a decrease of 1.9 % was witnessed in non built-up area. Water body includes the water area of the lake excluding the marshy area and floating gardens. This water area is used for various purposes such as navigation, site seeing, houseboats, fishing etc. The total area under water body in the year 1981 was 1,538 ha and which was decreased to 1,305 ha (decreased by 233 ha) in 2011, witnessed of 15 % decrease in its areal extent. Marshy area includes the area which is under the cover of weeds inside the lake where water related activities like the extraction of aquatic foods is carried out. However this area is not used for other water activities like Shikara riding. The area under this land use category in the year 1981 was 862.5 ha and which was decreased to 315 ha in 2011, witnessed of decrease of 547.5 ha (i.e., decrease of 63 %). In the lake area agricultural activities are performed on the floating gardens where vegetables are grown. The total area under agricultural land use in the year 1981 was 36 ha and which was increased to 749 ha in 2011, witnessed an increase of 713 ha (i.e., increase of 1,980 %). Plantation includes the area where the trees like willows and poplar have been planted. Orchards have also been clubbed in this class. The total area under this class in the year 1981 was 8 ha and which was increased to 28 ha in 2011, witnessed of total increase of 20 ha (i.e., 250 % increase). Built-up class refers to the dwelling places of Hanjis on land and bank of Dal lake. This includes the residential houses and hamlets of Hanjis. The total area under built up land use in the year 1981 was 5.5 ha which increased to 53 ha in 2011; increased by 47.5 ha (this is an 863 % increase). The present study is confined to an area of 2,450 ha, which is spread over the municipal ward number 58 and 59 of the Srinagar city. The statistics revealed that the lake area has shrunk to 1,305 ha i.e., a decrease of 233 ha during 1981–2011.

Table 2 Land use/land cover of Dal lake and its environs
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Fig. 3
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LULC and it’s change map of Dal lake in Srinagar, India

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Land Transformation in Dal Lake and its Environs

In this study we also found that besides transformation among land use/cover classes there was also substantial interchange of land among different land use/cover classes during the study period. Table 3 and Fig. 3 showed the interchange of various LULC. The growing Hanjis population and their increased demand for their economic sustenance and settlement have led to these changes. Moreover the increase in tourist flow to the lake has also resulted in city residents acquiring space to establish and run their business in the form of hotels and restaurants in and around the lake. All these factors have significantly contributed to the land transformations in the environs of Dal lake.

Table 3 Land Transformation in Dal lake and its environs (1981–2011)
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Significant land transformation was witnessed among marshy, water body and built-up classes. Marshy areas has decreased in and around the lake by 547.5 ha, losing its area to built-up (16 ha) and floating/vegetable gardens (locally known as Radh) (591 ha). The area under built up land has increased by 47.5 ha, gaining area from lake area (31.5 ha) and marshy area (16 ha). Similarly, plantation/orchards has also recorded increase of 20 ha, gaining land from marshy area (13 ha), lake area (12 ha) and agricultural land (3 ha), it also lost area to agriculture (8 ha) (Fig. 3). The decrease in the area under marshy, lake water and plantation/orchard was gain for the area under agricultural land use which increased by 713 ha during the study period. Similarly, the area under lake water decreased by 233 ha, losing area to agriculture (122 ha), marshy (94.5 ha), built up (31.5 ha) and plantation/orchard (12 ha). This clearly showed that there is a pattern of land transformation, where lake water is converted to marshy lands which subsequently converted for agriculture, orchards and built up uses. These interchange of land use classes has led to diverse effects on the areal extent of the lake and its water quality. Table 4 showed the causes and consequences of land transformation in Dal lake and its environs.

Table 4 Transformation of land use classes in Dal lake and its environs (1981–2011)
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Impact of Land Transformation on Quality of Water in Dal Lake

The land transformation analysis showed that the increase in agriculture, plantation/orchards and built-up classes led to the decrease in the area under lake water and marshy area. Therefore the physical and chemical state of the lake water showed deterioration. The major component composition of surface is largely considered to be controlled by primary mineral dissolution although precipitation of weathering minerals (Singh et al. 2012). The driving forces for such changes are the Hanjis people who draw their livelihood from the lake. The present study has found that over the years the concentration of chemicals in the lake has increased. It has recorded increasing levels of nitrates and total phosphorus concentration in the lake water (Table 5). However, pH value and alkalinity were also found in the higher range. From the perusal of Table 5, it is evident that during the process of land transformation the quality of water has significantly changed. The changes were deduced by comparing the water quality in the past with the analysis carried out in the present study. The analysis suggested that the significant changes have been taken place in the nitrate and total phosphorus content in all the basins of the lake. The water is alkaline in all the four basins. Increase in the area under agriculture activities by Hanjis led to the addition of various minerals and organic matter resulting into high pH content in the lake water. pH has fairly decreased in the Nigeen basin from 9.5 to 9.1 during the study period. In other basins it has remained more or less the same. The reason behind the decreasing pH value in Nigeen lake is deweeding and dredging which was carried out by the Lakes and Water Ways Development Authority in the past few decades. Also an NGO named as Nigeen Lake Conservation Organization (NLCO) has carried out various lake conservation programmes in this basin and is comparatively deeper than the other three basins containing larger volume of water, which somewhat neutralize the effect. Waste water released from various activities is rich in nitrate content. Nitrate concentration has increased 6 folds in all basins of the lake. Highest nitrate concentration was observed in the Gagribal basin followed by Hazratbal basin. The fertilizers and manures used by the Hanjis and dumping of their agricultural wastes further adds nitrate content into the lake. If the current rate of addition of nitrate continues, it is likely going to exceed the permissible limits of 4,500 μg 1−1 in the near future. Phosphates comes from fertilizers, animal manures, pesticides, construction materials, nurseries, lawns, orchards and sewage added due to agricultural, plantation/orchard activities by Hanjis. There has been significant increase in total phosphorus content (all forms of phosphorus dissolved or suspended found in any water sample) from 1977 to 2011 in all the basins. Total Phosphorus was found highest in the Gagribal basin and Hazratbal basin because of high concentration of Hanjis. Phosphorus is important nutrient but its increased concentration has led to the rapid growth of algae and weeds in the lake. Thereby has transformed once fresh water lake into the hub of marsh. Rapid rate of deforestation brings lots of silts rich in nutrients by surface runoff into the lake through the Tailbal channel which feeds the lake. However, after 1989 the rate of addition of silts has decreased due to the construction of silting basin at Tailbal. As per the estimates, 15 tonnes of phosphate and 322 tonnes of nitrogen are added to the lake every year from this drain (J&K LAWDA 1998, 1999, 2000). The study conducted by National Institute of Hydrology in 2000 revealed that organic matter contributes about 25 % in lake sedimentation process in the form of aquatic weeds. It also states that the incoming water to the lake is contributing less than 10 % of organic matters and the rest are being contributed by the underwater weeds.

Table 5 Chemical effluents in Dal lake
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Conclusion

The study revealed that significant transformations in the LULC have been taken place during the study period (1981–2011) in and around the Dal lake, because of the activities carried out by the Hanjis community. The increase in the area under agriculture, plantation/orchards and built-up land use has resulted into increase in the concentration of total phosphorus and nitrates into lake. The lake area has reduced considerably and is rapidly shrinking due to illegal expansion of Hanjis localities, siltation, weed invasion, discharge of domestic sewage, surface runoff carrying pesticides and other chemicals used in agricultural activities by this community. The overall impact of these activities has resulted in the reduction of lake capacity, deterioration of lake water quality, and loss of aesthetic value of Dal lake.