Unplanned urbanisation has drastically altered the drainage characteristics of natural catchments, or drainage areas, by increasing the volume and rate of surface runoff. Drainage systems are unable to cope with the increased volume of water, and are often blocked due to indiscriminate disposal of solid wastes. Encroachment of wetlands, floodplains, etc. obstructs flood-ways causing loss of natural flood storage.
Water bodies – Lentic (Lakes, wetlands) or lotic (rivers and streams) have been the cradles of biodiversity and key constituent of our human wellbeing and environment. The region surrounding the water body that acts as container to drain water to the water body is a wetland which houses all requirement that offer several substantive benefits such as life support systems, winter resorts for a variety of birds, suitable habitats for fish and other flora, fauna, effective in flood control, waste water treatment, reducing sediment loads and recharging of aquifers. Thus these water bodies, though relatively small in size whether natural, or manmade play a significant vital role in environmental, social economic functions, maintaining environmental sustainability particularly in urban environments in today’s context of rapid and unplanned urbanisation. Today, these water bodies are being encroached, fed with sewage, garbage and much of the landscape around them has been covered by impervious surfaces. Table 1 lists the threat faced by Kaikondanahalli-Kasbanahalli lake series in Bangalore.

                        Table 1: Impact of mismanagement of water bodies and its implications

Status of water bodies and wetlands in India: Aquatic ecosystem in India is classified under marshes, swamps, open water bodies, mangroves, tidal flats and salt marshes etc. apart from coast. Wetlands in India (excluding rivers), account for 18.4% of the country’s geographic area, of which 70% is under paddy cultivation. The India has 5306314 ha inland wetland cover (excluding rivers) and the total wetland area of Karnataka is 542515 ha only. Table 2 explains the total area of inland wetlands of India under different categories (Anon, 2011). Inland aquatic biodiversity of rivers, lakes, reservoirs and wetlands is very rich, harbors 15% of India’s floral and 20% faunal diversities. India has lost more than 38% of its wetlands in just the last decade, in some regions rate has been as high as 88% (Vijayan, 2004). Contaminated runoff from expanding urban and agricultural areas, floating pollutants and hydrologic modifications such as drainage of wetlands are just few of the many factors that continue to degrade surface waters in recent times. Wetlands in India supports around 2400 species and subspecies of birds. But losses in habitat have threatened the diversity of these ecosystems. Introduced exotic species like water hyacinth (Eichhornia crassipes) and salvinia (Salvinia molesta) have threatened the wetlands and clogged the waterways, competing with the native vegetation (Prasad et al., 2002).
The  urban population  in  India  is growing at about 2.3% per annum with  the global urban population increasing from 13% (220 million in 1900) to 49% (3.2 billion, in 2005) and  is  projected  to  escalate to 60%  (4.9 billion)  by  2030 (Ramachandra et al., 2012). The quantum jump and instantaneous growth of urban population by expanding existing urban areas in the last century without corresponding expansion of civic facilities resulting in depletion of lakes, wetlands and becoming sinks for contaminants. The water bodies are facing degradation due to encroachments eutrophication (from domestic and industrial effluents) and silt without exception in varying degrees of environmental degradation. A survey conducted by WWF-IUCN covering some of the important wetlands in India identified wildlife poaching (38%), pollution (37%), grazing pressure, alteration to other land uses, over-fishing and siltation as some of the major threats. The lakes and wetlands jurisdiction are diffused and falls under various departments like municipal corporations, forest, agriculture, fisheries, irrigation, revenue, tourism, water resources and local bodies. The lack of a comprehensive policy frame work and coordination with each department resulting depriving these precious water resources. The developmental policies and priorities of the local governing bodies further aggravating the situation of losing water bodies by encouraging large scale aquaculture, filling with waste water and solid waste dump sites etc.

Table 2: Wetland types in India and their extent