HYDRO-CHEMICAL ANALYSIS AND EVALUATION OF LAKE WATER QUALITY IN AND AROUND MALURPATTANA USING GIS TECHNIQUES,

Dr. Jagadeesha M Kattimani, Praveen N, Santosh N and Deepashree R. Assistant Professor and Under Graduate Students, Department of Civil Engineering, JSS Academy of Technical Education, Bengaluru, Karnataka. ...................................................................................................................... Manuscript Info Abstract ......................... ........................................................................ Manuscript History


Methodology:-
The water samples were collected from different lakes of Channapatna Taluk namely (Chakkere, Malurpatna, Chakluru, Sulleri, Sadarahalli, Akkuru, Averahalli, Hosahalli, Santemogenahalli, Honganuru, Borewells in the area, and Kanva river sample) in 1 liter polythene bottles at inlet and outlet. Various physical parameters like Ph, EC, and TDS were determined in the laboratory. Calcium (Ca2+), Magnesium (Mg2+), Chloride(Cl+), Carbonate(CO3-2-), and Bicarbonate(HCO3) volumetric titration methods. Nitrate(NO3) and sulphate (SO4 2-) were estimated by turbidity method. While Sodium(Na+) and Potassium (K+) determined by Flamephotometry. Lake samples were collected from 19 lakes located in different parts of the study area during pre-monsoon (/April May/June 2018). analysis of chemical characters. Chemical analyses were carried out using the standard procedures (APHA-2002). The suitability of the surface water from these two lakes for drinking, domestic, and irrigation purposes was evaluated by comparing the values of different water quality parameters with those of the Bureau of Indian standards (BIS 1998) guideline values for drinking water.
Evaluation of surface water quality for irrigation:-Chemical analysis of major ions in groundwater, standard analytical chemistry procedures, comprising titrimetry and spectrophotometry, were employed following American Public Health Association guidelines (APHA 1995)

Sodium Adsorption Ratio (SAR):-
If the SAR ratio of the water samples in the study area is less than 10, it is excellent for irrigation purposes. The SAR values for each water sample were calculated using the following equation (Richards 1954). The sodium or alkali hazard in the use of water for irrigation is determined by the absolute and relative concentration of cations and is expressed in terms of sodium adsorption ratio. If the proportion of sodium is high, the alkali hazard is high and conversely if calcium and magnesium is predominant, the hazard is less. In the study area, 20 samples come under the excellent category that is SAR content is less than 10 (fig 1.1

Percentage Sodium (%Na):-
The percentage of sodium in water is a parameter computed to evaluate the suitability for irrigation. As per the Indian standards a maximum of 60% sodium is permissible for irrigation water. The relative proportion of sodium to other cations in water is usually expressed as percentage of sodium among the principle cations.

Residual Sodium Carbonate (RSC):-
The total concentration of soluble salts (salinity hazard) in irrigation water can be expressed in terms of specific conductance. Thematic maps of Electrical Conductivity (EC) and Residual Sodium Carbonate (RSC) were created for both Pre-monsoon and Post-monsoon seasons using Arc GIS 10.3 software. Bicarbonate concentration in water affects the suitability of water for irrigation purpose. If the water has high concentration of bicarbonate ion, there is a tendency for Ca and Mg ions to precipitate as carbonates. As a result, relative proportion of sodium increases and gets fixed in the soil. As the increase in proportion of sodium gets fixed in the soil, decreasing the permeability. In the study area out of 20 samples 17 of them came under safe category with RSC values less than 1.25 epm , 1 sample was marginally safe, and 2 samples were not suitable for domestic purposes with RSC values greater than 2.5 epm (fig 1.3).

Hill Piper Trilinear diagram:-
The Piper-Hill diagram (1953) is used to infer hydro-geochemical facies. These plots include two triangles, one for plotting cations and the other for plotting anions ( figure 1.4). The cations and anion fields are combined to show a single point in a diamond-shaped field, from which inference is drawn on the basis of hydro-geochemical facies concept. These tri-linear diagrams are useful in bringing out chemical relationships among groundwater samples in more definite terms rather than with other possible plotting methods.
The Hill Piper diagram is used to infer hydro geochemical facies. A trilinear diagram was created to classify the water from different parts the study area and to reveal any groupings, similarities or trends of the samples. The HCO 3, Cl, SO 4 , anion triangle shows groundwater samples have plotted bicarbonates and chloride type end members, and sulphate is not present in any significant proportion. The Ca and Mg-Na cations triangle shows that the major cations present in the sample are Na and Mg.
With the above procedure, the location of each corresponding sample of the study area was made on the central diamond shaped field. Samples falling in different sub-divisions of diamond shaped field indicate the type of water. Class-A: Ca + Mg + CO 3 + HCO 3 , Class-B: Na + K + CO 3 + HCO 3 , Class-C: Ca + Mg + Cl + SO 4 , Class-D: Na + K + Cl + SO 4. 23