Upper & Lower Lakes of Bhopal

The Upper and Lower Lakes of Bhopal, both man made reservoirs, along with their catchment areas, as a comprehensive system constitute the extent of the Bhoj Wetland.

The Upper Lake was created by Raja Bhoj, the King of Dhar in Central India, in the 11th century by constructing an earthen dam across the Kolans River. The Kolans was originally a tributary of the Halali River, which in turn joins Betwa River near Vidisha. With the construction of this earthen dam and a spill channel a major change in the hydrological basins was effected almost about 900 years back, in the sense that the Kolans basin was linked to the Betwa River directly through Kaliasote River. Outflow from the Upper lake which receives water mainly through the Kolans river drains into Kaliasot river and finds its way to Yamuna river through the Betwa river. A waste weir at Bhadbhada, constructed in 1965 to increase the storage capacity of the Upper Lake, now controls the outflow.

The Upper Lake, in a linear east-west alignment, has a catchment area of 361 sq. km & at present a water spread area of 31 sq. km. The Upper Lake has a partial Urban component in its catchment on the eastern end while the remainder is Rural. 

The Lower lake, locally known as Chhota Talab (Small Lake), is situated towards the east end of Upper lake and is fully surrounded by built-up areas. This lake was created in 1794 AD by Nawab Chhote Khan, Minister of Nawab Hayath Mohammad Khan to add to the beauty of the city. Compared to the Upper lake, it has a small catchment area of 9.60 sq.km. and a water spread of 1.29 sq.km. 

Lower lake which receives seepage water from the Upper lake and drainage from several drains outflows into the Patra drain which subsequently joins Halali river, a tributary of Betwa River.

Both the Lakes are separated in a terraced manner by the earthen dam built by King Bhoj in the 11th century and the lowest level of the Upper Lake is just below the highest level of the Lower Lake.

 The Characteristics of the two lakes are

The Land , Geology and Climate:

The city of Bhopal is situated on a series of rolling hills and valleys interspersed in between. The north- eastern, eastern and south- eastern edges of the Upper Lake and the entire Catchment of the Lower Lake is characterized by rolling hills. The western, southern and the north-western parts of the Upper Lake are relatively flat.

The Deccan trap Basalts and Vindhyan Sandstones (Bhander series-Upper Precambrian) are the principal rock formation of the area. The weathering of the volcanic rocks results in a characteristic heavy soil known as Black Cotton soil., which abounds in the lower areas where as the higher grounds are characterised by the rocky strata. 

The area has a dry climate except during the south west monsoon season. The period from March to mid June is the summer season with a mean daily max. temperature of 40.7° C, and mean daily min. temperature 26° C. The monsoon season is effective from June to September. After the withdrawal of the monsoon, by the end of September, there is slight increase in the day temperature but nights become progressively colder. Post monsoon period extends upto mid December, and winter season is upto February with January as generally the coldest month with a mean daily max. temperature of 25.7° C and the mean daily minimum temperature of 10.4°C.

The average annual rainfall for past 21 years is 1179.16 mm. About 92% of the annual rainfall is received during the monsoon months. On an average there are 53 rainy days during the year.

During the monsoon, relative humidity is usually about 70%. Rest of the year the air is generally dry and the relative humidity is less than 20%. However, in the areas adjacent to the lakes, the relative humidity is about 40%. 

Ecological Features 

The wetland supports a wide variety of flora and fauna. Diverse flora provide ideal habitat in the form of food and shelter for a large number of avifauna. Due to biotic interaction and natural selection process a characteristic relationship between vegetation and the avifauna has developed.

The Wetland could be divided into three zones- perennial water covered area, marshy area and submerged cum dry area (transition zones). The transition zone is shallow in nature and thus is exposed gradually from post monsoon period to summer season. The wetland supports mainly 3 types of vegetation consisting of more than 100 terrestrial/marshy plant species and 34 aquatic species. The aquatic species could be categorized as floating forms (10 ), submerged forms (14 ) and emergent forms (10). 

The wetland is rich in bio-diversity, principal components being phytoplankton, zooplankton, macrophytes, aquatic insects and avifauna (both resident and migratory). The Biodiversity range is as follows:

All the macrophytes growing within the lake or in its catchment, have medicinal values. However, following are rare or less abundment/endangered in the eco-system :-

Noteworthy Fauna 

Fish Fauna :

Culturable And Other Fishes Commonly Found

Catla catla, Cairrhinus mrigala, Cyperinus carpio, Labeo rohita, Cirrihnus reba, Labeo bata Labeo dussuniere, Labeo calabasu, Labeo gonius, Lepulocephalichthyx, Trichogaster faciatus

AVIFAUNA

Upper lake of Bhopal hosts a large number of birds in its water as well as around it. The total number of species observed in the surroundings of the upper lake of Bhopal exceeds 160. These include the local, local migratory and migratory species. A total of more than 20000 birds were observed in Bhopal this year. Some species, which have never shown up or are rare to be seen here, gave evidential sightings. White Stork, Black necked Stork, Barheaded Goose, Spoonbill etc. are some of the species which were rarely or never seen before. The White Stork has no records in the near history of being sighted here. 

A very surprising phenomenon is of congregation of more than 121 Sarus Cranes in Bhopal. The largest bird of India, Grus antigone is known for its size, majestic flight and ever lasting partnership. According to Mr. BC Chaudhary of Wildlife Institute of India who is monitoring this endangered bird for last 2 years, there are no previous records of such a big congregation of the Sarus Crane in Bhopal. 

Similarly, the Bank Mynah, though a common specie North of Bhopal, has recently shown up in the western regions of the upper lake. The Mynah, which can be seen easily in neighboring places has no previous record in Bhopal. 

Even when the maximum temperature is approaching 400 oC one can still observe a total of more than 4000 birds of various species. This is a remarkable occurrence as the birds are normally observed and believed to have returned by late March. The flocks can be seen at the western region of the upper lake where the water is receding with high speed. The receding water and shallow waterlogged area hence provides an ideal feeding ground to birds feeding on fish, molluscs, shoots and weeds.

Recently a heavy congregation of white Scavenger Vultures in the south Eastern buffer of the Upper lake which is a national Park has been observed. These vultures, also known as Pharaohs chicken or Egyptian vulture seem to have survived.