Ecological Studies of Barwala Link Canal in Narwana Region , Haryana

The present paper deals with the monthly variations in physico-chemical characteristics and planktonic diversity of Barwala Link Canal which link the Bhakra Main Canal with Sirsa Branch of Western Yamuna Canal in Narwana Region, Haryana. Surface water samples were collected on monthly basis and analyzed for physico-chemical parameters (water temperature, total dissolved solids, electrical conductivity, turbidity, pH, dissolved oxygen, free CO2, alkalinity, hardness, chlorides, biochemical oxygen demand, o-phosphate, nitrate and ammonia). An attempt was also made to assess the biological parameters including population density, their abundance and species diversity index of plankton life which were used as a measure of water quality. Phytoplankton was abundant as compared to Zooplankton. A total of 14 taxa of phytoplankton were recorded of which 9 taxa of Chlorophyceae and 5 taxa of Bacillariophyceae. 8 taxa of zooplankton were recorded of which 4 taxa of protozoa, 3 taxa of rotifera and one taxa of insecta. Shannon diversity index of phytoplankton ranges from 2.47 to 3.29 and Zooplankton ranges from 2.60 to 2.99. It is revealed that the quality of canal water is good throughout study period as estimated by the weighted arithmetic index method.

Haryana is the northwest state of India and located between 27º39' to 30º35'N latitude and between 74º28' to 77º36'E longitude.It's climate is arid to semiarid with average rainfall of 354.4 mm.Around 29% rainfall is received during the monsoon season (July to September) and remaining is received during winter season (December to February).To cultivate the land, irrigation depends upon the canals.The two main canals which are operating in the state include Bhakra canal and Western Yamuna canal.The supplies in Western Yamuna canal fluctuate with variations in flow of river Yamuna.All the distributaries could not be fed all together; hence, all the distributaries are fed on rotational basis.In 1972, feeder canal, Barwala link canal was constructed to supply water from Bhakra Main Line into Sirsa branch of Western Yamuna Canal.
Ecology of lotic waters is characterised by a range of hydrological parameters, source of water, substrate, and availability of nutrients and by their associated organisms 1 .Physical habitat structure (depth, current velocity and substrate) influence species composition and species diversity in correlation with habitat diversity 2 .There are two methods for the measurement of water quality deterioration in lotic systems 3 .The first method involves the measurement of physico-chemical parameters of lotic systems in to gain some insight into their water quality.In many of the cases, this method allows only immediate measure ments which restrict the knowledge of water con ditions during the measurements period.The second method involves use of biological meth ods (biological monitoring), which provide a direct measurement of ecological integrity by us ing the response of biota to environmental changes.Keeping in view of above, present investigations have been undertaken to assess the water quality of Barwala Link Canal.It originates from Khanauri head (Sangrur district, Punjab) on Bhakra Main Line and joined with Sirsa branch of Western Yamuna Canal in Narwana region.

mATERiALS AND mETHoDS
Study site is located in Narwana region on Barwala link canal (Longitude 29º61'N and latitude 76 º15'E).The dimensions of canal at site are top  Bottom width of this canal is zero because of their bowl shape.Surface water samples for the present investigation were collected in polythene bottles.Physicochemical parameters like temperature, depth, width, water current, pH, fixation of dissolved oxygen were determined on the spot, whereas, other parameters were analysed in the laboratory according to standard procedures 4,5 within 3 to 4 days, during which samples were kept in cold storage.The weighted arithmetic index method 6 has been used for the calculation of Water Quality Index.
For plankton study, the water samples were collected with the help of conical plankton net fitted with a wide mouthed bottle.100 litres of canal water was filtered through the net.Plankton was preserved in 4% formaldehyde solution.The organisms were sorted out manually for qualitative and quantitative study and standard references 7,9 were consulted for the identification of plankton.Population density was calculated from the concentrated sample following drop method and biodiversity indices were calculated Shannon and weaver diversity index 10 , Simpson Diversity Index 11 and Pielou's evenness index 12 .Correlation between various recorded parameters was calculated by Karl Pearson correlation coefficient.

Physico-chemical characteristics of water
Monthly fluctuations in the physicochemical characteristics of canal water have been given Table 1.The value of temperature during the present investigation ranged from 14.0ºC-24.0ºCwith maximum values in July and minimum in January.Depth and width values recorded high during March and lower during the month of April.Maximum water current (58.59 cm sec -1 ) was recorded in January and minimum (48.60 cm sec -1 ) in April.The pH values   2).The concentration of o-phosphate, nitrate and ammonia in canal was recorded high during April-May and low during July-August.The values of Water Quality Index ranged from 36.89 to 50.42 and water quality status was good and safe for human consumption throughout the study period (Table 1).

Biological characteristics Phytoplankton
During present study, a total of 14 taxa of phytoplankton were recorded of which 9 taxa (64.28%) belonged to Chlorophyceae, followed Fig. 4: Population density (No. /L) of zooplankton species at study sites by 5 taxa (35.71%) of Bacillariophyceae (Fig. 2).Mean values of Shannon-Weaver diversity index in different months fluctuated from 2.47 to 3.29 (Table 3) and high diversity was recorded during September and October.Simpson's diversity index ranged from 0.11 to 0.23 revealed maximum species dominance in the month of June and minimum in October.Equitability index ranged from 0.71 to 0.93 which shows variation in species distribution (Table 3).Maximum density of phytoplankton (495±5.31L-1 ) was recorded during April and minimum (203±8.49L -1 ) during August (Fig. 1).Spirogyra sp. was found to be dominant followed by Ulothrix sp., Zygnema sp. and Cladophora sp.. Species like Diatoma sp., Fragillaria sp., Gomphonema sp., Melosera sp., Pinnularia sp. and Staurastrum sp. were found relatively in less number (Fig. 2).

Zooplankton
They are heterotrophic planktonic animals floating in water.The findings of zooplankton community residing in fresh water have significant potential for assessing aquatic ecosystem health.Zooplankton comprised a minor portion of total plankton.A total of 8 taxa of zooplankton were recorded of which 4 taxa (50%) belonged to protozoa, followed by 3 taxa (37.5%) of rotifera and one taxa (12.5%) of insecta.Maximum density of zooplankton (94±2.38L -1 ) was observed in the month of April and minimum (38±2.09L -1 ) in the month of July (Fig. 3).Dominant taxa were Diffusia sp. and Peridinum sp. of family Protozoa and water mite of family Insecta (Fig. 4).Zooplankton density show significant negative correlation with water current, TDS, turbidity and electrical conductivity (Table 3).
Shannon-Weaver diversity index ranged from 2.60 in July to 2.99 in March which indicated that this site had great diversity throughout the study period (Table 3).Simpson's diversity index ranged from 0.16 in September to 0.23 in June.Equitability index in different months varied from 0.75 to 0.85 which show small variations in species distribution (Table 3).

DiSCuSSioN
All physico-chemical parameters were within the limits as prescribed by WHO 13 .Water quality status was good and safe for human consumption at study site.Jindal and Sharma 14 have found water quality in the range of good at Ropar Head Works on Sutlej River, Punjab.Thus Bhakra canal receive clean and relatively unpolluted water from its source.
During the whole study period, Phytoplankton was abundant as compared to Zooplankton which goes in concurrence with the findings of many workers 15,17 .Their abundance in summer was because of higher values of temperature, hardness and nutrients; moderate values of water current, turbidity and alkaline pH [18].Minimum number of plankton during July-August could be attributed to cloudy weather, high values of turbidity, fast current of water and dilution in the concentration of some salts.Dominance of green algal flora indicated unpolluted nature of the site which was also supported by other workers 19,21 .
Statically, significant negative correlation between phytoplankton density and water current (r= -0.935, p<0.05),TDS (r= -0.824, p<0.05) and turbidity (r= -0.923, p<0.05) was observed.However correlation between phytoplankton density and DO (r=0.707,p<0.01), hardness (r=0.881,p<0.05) and alkanity (r=0.608,p<0.01) was significantly positive 22,23 .also reported negative correlation between volume of plankton and water current.The current of fast water not only results in high turbidity and high TDS but also causes the mechanical damage to the plankton which resulting the destruction of plankton by churning 24 .Shannon-Weaver diversity index values showed a decline in diversity from April-May to July-August and then progressively increased in the month of October-November.The maximum density and diversity of plankton in winter was due to relatively less values of temperature and turbidity; moderate values of nutrients; and higher values of dissolved oxygen.
Total phytoplankton density was positively correlated with total zooplankton density.Zooplankton peaks either coincided or followed the peaks of phytoplankton 17 but highly significant (p<0.001)inverse correlation between relative abundance of phytoplankton and Zooplankton was observed 25 .

CoNCLuSioN
It could be concluded from present findings that the water in Barwala link canal is of good quality and safe for human consumption throughout the study period.Biological analysis revealed that plankton density as well as diversity recorded high during summer and postmonsoon season and lower during monsoon season and values of species diversity indices also indicate unpolluted nature of water.