Though there was little conscious town planning in Sagar till recent times, the town of Sagar itself was constructed around the large lake, which according to tradition, is believed to have been constructed by one Lakha Banjara in the 11th century. It was however, Govind Rao Pandit, the Peshwa's representative in charge of Sagar Kingdom who first planned Sagar town as the capital of the territory. The British who took the town on 1818 made it a Commissioner head quarters and a Cantonment for the army.

The lake which forms the centre of the town, extends over an area about 400 acres. Formally it was perhaps much larger and covered the ground on which the Town Hall, the Tehsil Office and Gopal ganj quarters now stand. The present Collectorate a large building situated on a hill overlooking the City, was constructed in 1820 as the residence of the Governors General Agent. The lake improved and deepened during the famine of 1900 at a cost of about Rs. 7000. Due to topography of the region and the existence of the Sagar Lake very little improvement was effected in the old parts of the town.

Location and general features: Sagar Lake is situated in the heart of Sagar city ( 23 degree 50 Minutes N: 78 degree 45 Minutes E and 517 MSL) with an area of 82 hectares . It is a shallow, rained lake with a small catchment (588 hectares), and its north westward drainage agrees well with the general north westward drainage pattern of the district (Mishra, 1969). The entire lake can be divided into two parts; the main lake occupying an area 68 hectares and a small wetland of 14 hectares . The main lake is well protected by a large number of ghats, houses, roads and a stone fencing wall all around, except on the southern open side which ultimately terminates in the satellitic wetland which is connected to the main lake by a narrow passage through the earthen bound. The rain water from the south-western side enters in the satellite lake through the feeder canal in the west, whereas the outflow is through Mongha weir in the main lake situated at the back of the Ganga Mandir. This weir regulates the outflow and helps to maintain the water level. The main lake is shallower on the north-eastern, eastern and south-western sides, with its deepest point (5.5m) near the fort side and the average depth is around 2 meters. The lake is used for bathing, washing clothes, recreation, navigation, Trapa cultivation etc. A large number of cattle may be seen wallowing specially at the southern side, disturbing and churning the sediments.

History and Geology: According to Mishra (1969), the lake has been formed by the damming of the north-westward drainage of the basin by an elongated lunate-shaped Vindhyan outcrop, lying west-north-east of the lake; the depression in front of the outcrop may have resulted from the rapid removal of the intertrappean limestone horizon at 533 m level by solution weathering. The capacity of the lake was increased by the construction of a weir on the western side as a part of relief operation during disastrous famines at the end of the 19th century. According to West (1959), the probable depth of the lake and its sediments is more than 18m and the present-day drainage pattern could be regarded as the reflection of the earlier pretrappean Vindhyan drainage. The Vindhyan orthoquartzite, being comparatively more resistant to weathering, became exposed due to denudation of the overlying 5th flow of Decca basalt which forms rich agricultural land around Sagar (West and Choubey, 1964). The earthen dam on the southern side, Pithoria Bound, separating the main lake from the satellitic wetland was built in 1927 to check the incoming silt. Only a few years ago the water level of the lake was raised by increasing the height of the weir by two feet, and a pucca road is being built over the bound which will connect Tilli region with Purviau Tori, and thus will be helpful in reducing congestion of the Parkota road during peak traffic hours. The lake had been a principal source of Municipal water supply since 1911-12 upto 1962,when the new water work was constructed at the University hills, which derives water from the river Bebus and supplies it to the township. Not many aquifer formations are possible underground in the compact Vindhyan Sandstone;and only low-yielding wells could be bored at certain places with underlying aquifer intrusions and pearch pockets (Krishna, 1967). Deccan traps behave as multiaquifer systems, and ground water occurs either in the permeable zone near flow contacts or in vesicular or fracturedparts of an individual flow; the recharge is very poor, being only 10 to 15% of the total rainfall and, due to extreme inhomogeneity, lateral hydraulic continuity is limited (Subramanian, 1973). Hence, Sagar remains a drought-prone area when the rains are scanty or below normal. The basalt weathers with a characteristic spheroidal exfoliation and thus two visibly distinct soil types are found over partially, weathered trappean basaltic flows; the soils on the hill tops are invariably red or reddish brown (lateritic) whereas those at the foothills are usually black in colour. Climate : The climate of Sagar can be categorised as monsoon type. The monsoon or rainy season commences from mid June and continues till September. This period is characterised by heavy rains, high temperatures, relatively high humidity and high wind velocity. About 90% of the annual rainfall is received during this period. Thus the maximum water level in the lake could be observed by the end of this season. The monsoon is followed by a brief post-monsoon period (October-November) when temperature remains high and the humidity decreases considerably; only a nominal precipitation occurs and wind velocity is also lower. Winter starters from late November and continues upto February. It is characterised by low temperature, low irradiant and moderate relative humidity. The average annual rainfall varies from 565 mm to 1680 mm. The maximum temperature recorded at Sagar is about 44.8 degree C.in the month of May-June and minimum temperature is 5 degree C. in the month of January. The relative humidity shows changing trends throughout the year.

Morphometric features: The main morphometric features of the lake are given as under :- Water spread area - 1.1 Sq.Km. Catchment area - 5.88 Sq.Km. Maximum Water level - 109.50 M. Full Reservoir level - 108.21 M. Quantity of inflow - 62 M.ft. Maximum depth - 5.5 M. .JY

Water quality characteristics: The lake is grossly contaminated by the inflow of waste water and shows high levels of organic matter associated with coliform bacteria etc. The gradual accumulation of nutrients involving increased productivity and decrease biological diversity is responsible for deterioration of water quality. Higher values of suspended solids, chlorides, nutrients and organic matter have been observed near the chakraghat as compared to bus stand area indicating that the drains joining the Chakra Ghat carrying the municipal wastes from residential colonies and, the government hospital contain high pollution loads. The water near the Sanjay bridge, which is covered with Hyacinth has also high amounts of nutrients.

MACROPHYTES: The macrophytic species found in the lake are :- Parsicum orolofexum, Oryza Sativa, Paspalidum, Serminatum and Hydrorhiz, aristata and some sedges like Elcocharis plantaginea, Scripps littorals, Faimbristvlis diphylia, kyllinga brevilla, jungellus alopecuroides, Cypress exaltatus, C.indicus, Cerymbosus, Crisum sp; cryptogorying retrospiralis, Marsilea guadrifolia etc. The Eichhornia Grassipes grows very rapidly from the lake margins and spread over the whole water surface. Hydrilla verticillata Ceratophyllum sp., Vallaisneria Spiralis are the common rooted plants. These remain submerged throughout life span and reach the surface only during flowering season. In Sagar lake Najas Dp. Hydrilla verticillats and Potamogeton crispus (locally known as "Choi") grow in such a large amount that these create a nuisance in fishing and navigation. Nelumbo nucifera, Nymphaea stellata, N-Lotus, Traps bispiposa, Nymphoides sp., and N-indicum are the most common macrophytes with floating leaves and are frequently observed in this lake. In free floating plants, Lemna trisula, Spirodela.sp., Wolffia arrhiza and Pistia sp. are commonly found in this lake.

ENVIRONMENTAL ISSUES : POLLUTION: Being located in the close vaccinate of the town, the Sagar lake has a great importance for the human activities, like boating, recreational, washing of cloths, bathing etc. As a result of these anthopogenic activities dumping of liquid and solid wastes including garbage into the lake through open drain as well as flushing of solid waste lying along its back slopes has caused considerable deterioration in water quality. About 1/3rd of the town drains into Sagar Lake. Such accumulation of dead organic matter has threatened lake to eutrophic conditions. The major inflows of pollutants are as follows : The lake is heavily loaded with pollutants joining through drains carrying waste water mixed with organic waste of the residential areas. The seasonal rainy season drain of the Southern side bring a lot of silt agricultural residues with organic chemicals, pesticides, fertilizer etc. Following main drains are joining the lake. The Krishnaganj, Gopalganj and part of Shanichari area drains, join the lake through the nallah coming from the Bus stand side. The drainage of Madhukarshah ward and three cross drains joining the lake from the Tilli hospital road side. Cross drains near Duffrin hospital, drainage from Shanicheri (partly), Shukravari, Lajpatpura discharge waste into the lake. Discharge of parkota ward waste water in the lake. Drainage water of Purbiyau, Bariya Ghat, Chakra Ghat ward is also discharged in the Lake. Inflow of Kanera village (Nahar) canal rain water. Inwading of cattles in the lake. Washing of clothes. Washing of vehicles.

SEDIMENTATION: The deforestation in the catchment area is mainly responsible for the erosion of the top soil. The eroded soil get deposited into the lake and results in heavy siltation. The canera feeder canal is mainly responsible for bringing the silt from western and southern side of the lake. These areas are sparsely covered with vegetation. During last two decades the regular deposition of the silt in the buffer zone has reduced the water storage capacity of the lake. Apart from siltation the night soil from the seven sewage drains, garbage and other solid wastes deposit in the lake and decreasing the water holding capacity. The deposition of organic matter from decaying of macrophytic vegetation add to the dimension of problem of sedimentation of the lake. Water Quality Deterioration : The water quality of the lake is grossly polluted as is revealed through high values of suspended solids, Chlorides nitrates, Phosphate etc. and high NPM count of E.Coli. The pollution of the lake gets aggravated when the water depth is reduced during summer. The stagnant water gives an erratic smell. Weed Infestation : The prolific growth of Eichhonia crassipes along with Azolla Pinatta are posing the great threat to the natural vegetation of the lake. The high amount of organic matter present in the lake is mainly responsible for the luxuriant growth of the species. The death and decay of macrophytic species along with Microcystis aerugnosa emits foul smell during summer. These conditions of the lake leads to mosquito menace and reduce its aesthetic value. Decrease in Fish Yield : During last two decades the fish yield has decreased due to the eutrophic conditions of the lake. The investigation carried out indicate that about 60% fish yield has decreased and mostly major carps are badly affected. The decreased water quality and quantity restricts the stocking capacity of the fish seed. In summer season the fish survival is difficult as the dissolved oxygen level goes down due to floating macro phytic vegetation and due to high amount of pollutants in the lake. Action Plan for conservation and Management of the Lake : On the basis of the problems identified and in continuation to the already mentioned activities, an action plan has been formulated and being implemented with local available resources on the following lines :- (i) Diversion of domestic sewage entering the lake by construction of sewage treatment plants and laying down diversion pipelines. (ii) Waste minimisation plan to reduce the load of pollutants in the lake. (iii) Desolation of the lake through dredging. (iv) Soil erosion control through tree planting in the catchment area. (v) Control of weeds. (vi) Water quality monitoring. The main components of the Action Plan are briefly mentioned as under : In order to arrest the amount of sewage/sludge flowing into the take, it is essential to divert it away by construction of sewage treatment plant and laying down diversion pipe lines. Sagar city is not provided with proper sewerage system thus the sludge/sewage flows through open drains which ultimately meets the nallah passing through city. There are nine major nallas flowing into the lake. Most of the houses around the lake have conservative type of latrines and therefore part of the sullage contaminates the water.

(With Thanks from "sagar.nic.in")