Surface Water Quality Evaluation and Modeling of Ghataprabha River, Karnataka, India

Environ Monit Assess (2012) 184:1371–1378DOI 10.1007/s10661-011-2047-1

Surface water quality evaluation and modelingof Ghataprabha River, Karnataka, India

B. K. Purandara · N. Varadarajan ·B. Venkatesh · V. K. Choubey

Received: 24 July 2010 / Accepted: 18 March 2011 / Published online: 15 April 2011© Springer Science+Business Media B.V. 2011

Abstract Belgaum city is a developmental hubof Karnataka State in India. In the recent time,the Government of Karnataka has planned toset up many processing industries in the vicinityof Belgaum to meet the growing needs of theregion and to ease out the pressure on the al-ready existing industrial hubs in Karnataka State.Ghataprabha, a tributary of river Krishna, is oneof the major sources of water supply to Belgaumcity and adjoining areas. During the last decade, alot of anthropogenic activities such as unplannedagricultural activities are ongoing in many partsof the catchment. Therefore, people of Belgaumare more concerned about the quality of water inGhataprabha river. Considering the significanceof water quality of the river, surface water sam-ples were collected during Pre- and Post-monsoonseason from selected locations and analyzed forboth physical and chemical constituents in the

B. K. Purandara (B) · N. Varadarajan ·B. Venkatesh · V. K. ChoubeyRegional Center, National Institute of Hydrology,Hanuman nagar, Belgaum, Karnataka, Indiae-mail: [email protected]

N. Varadarajane-mail: [email protected]

B. Venkateshe-mail: [email protected]

V. K. Choubeye-mail: [email protected]

laboratory. The results indicate that the chemicalparameters such as bicarbonates, sulphates, chlo-rides, sodium, potassium, calcium and magnesiumare within the permissible limits. QUAL2E modelwas applied to assess the impact of point and non-point sources of pollution on the river water qual-ity. Results show that the water quality conditionsare highly acceptable all along the river stretch.Further, the variation of DO–BOD5 with riverdischarge was also estimated. Also, a significantvariations in DO (decrease in DO) with the in-crease in river flow was observed. However, atthe downstream end, considerable improvementin DO was noticed which is attributed to thedamming effect of the reservoir.

Keywords Water quality modeling ·Dissolved oxygen · Biochemical-oxygen demand ·Reareation

Introduction

The environmental consequences of industrializa-tion and intensification of agriculture have, fora long time, been neglected and unfortunatelystill are in many parts of the world. Exploitationof mineral resources and energy production havemade deep cuts into the natural landscape andaltered the flow of water in large river basins.Concentrated effluents from manufacturing and

1372 Environ Monit Assess (2012) 184:1371–1378

industrial production plants have added haz-ardous substances to natural water courses andreduced their ability to sustain aquatic life. Therapid increase in population density has gener-ated human wastes, which have reached surfacewaters or percolated into the ground with bothimmediate contamination and long term deteri-oration of the aquatic environment. To feed theever-increasing populations a highly intensifiedagro-industry, depending more on massive use ofchemicals as fertilizers or pesticides, has emergedin the industrialized as well as many develop-ing countries like our country. In addition, themost devastating effect on water quality are byanthropogenic activities combined with deforesta-tion and related activities. In order to formulate

water pollution control policies and programs, it isnecessary to know the existing nature, magnitudeand sources of the various pollution loads whichdegrade the quality of river water. The studyof behaviour of these pollution loads especiallythe concentration profile of different pollutantsin the river water is equally important to assessthe degree of pollution that are prevailing and toidentify the stretches which violate the standardsand harmful for use. The Ghataprabha River isone of the major sources of water for the people ofMaharashtra and Northern districts of Karnataka.However, industrial development accompaniedby population and consumption growth may im-pose heavy pollution loads to the river. Further,discharging of organic and inorganic pollutants as

Fig. 1 Ghataprabharepresentative basin withwater sampling locations

Environ Monit Assess (2012) 184:1371–1378 1373

well as nutrients may damage the river qualityconditions. Keeping the significance of river waterquality maintenance of Ghataprabha River, thepresent study has been carried out to understandand assess the possible sources of point and non-point source pollution.

Study area

The study area of Ghataprabha is the watershedup to Daddi, which is the first gauge-dischargesite on the stream (Fig. 1). The catchment areaof the sub-basin lies between latitudes 15◦50′ and16◦40′ N and longitude 74◦08′ and 74◦30′ E. TheGhataprabha River originates from the WesternGhats at an altitude of 884 m, flows eastwards for alength of 283 km before joining the Krishna. Tam-raparni River is a tributary of river Ghataprabhajoins the main stream at Daddi. A dam has beenconstructed at Hidkal (which is about 20–25 kmfrom Daddi) in Hukkeri taluk (Belgaum district,Karnataka, India) to impound 2,200 Mm3 of waterfor supplying to adjoining taluks for irrigationpurpose.

Geomorphology, soil and geology

Geomorphologically, the catchment is relativelyflat and gently undulating with isolated hillocksintervened by valleys. The catchment is somewhatoval in shape. The relief of the basin varies be-tween 682 and 1,039 m. Very steep contours areobserved towards western side of the basin. Thehigh basin relief observed in the catchment is anindication of higher potential energy available tomove water and sediment downstream. Lateriticsoils (Coarse shallow soil, 22.3% and mediumdeep soil, 21.4%), coarse shallow black soil (10%)and Medium black soil (45.8%). According toMunsell’s system of colour notation, soils in theupper catchment areas having dense forest coverare characterized by brown (7.5 YR-4/4) to darkreddish brown (5 Y-3/3) color and light loam toheavy loam in texture. In areas covered by shrubs,soils are brown (5 YR-4/4) in color. However, inthe northern boundary of the catchment the soilsare reddish brown (5 YR-3/4) in nature with a

medium loam texture. In the downstream of thecatchment (near Daddi), color of the soil variesbetween yellowish brown (10 YR-5/8) and reddishbrown (5 YR-4/3) with medium to heavy loam tex-ture. The geological formations found within thebasins are (1) Deccan traps of Tertiary age and (2)sedimentary formations known as ‘Kaladgi group’comprising limestone, shale and quartzites. Thespatial distribution of land use shows that 13.8%is covered by forest, 35.05% is covered by shrubs,8.35% covered by fallow lands and 42.8% coveredby Agriculture (Purandara and Choubey 1996).

Materials and methods

Field investigation and laboratory analysis

Field investigations were carried out along thestretch of the Ghataprabha River (about 40 kmlength). Water quality parameters such as Dis-solved Oxygen (DO), Biochemical Demand (BOD),pH, Turbidity and also major cations and anionswere considered for the analysis. DO and pH wasdetermined in the field and BOD five days BOD)was determined in the laboratory. Six cross-sections were taken, samples were taken and theanalyses were carried out as per the StandardMethods for examination of water and wastewater(APHA 1992). The flow rate at each point wasmeasured using a float method.

Water quality modelling

QUAL2E model is a comprehensive and versatilestream water quality model, which permits simula-tion up to 15 water quality constituent in any com-bination desired by the user in a branching streamsystem using a finite difference solution to theone-dimensional advective–dispersive mass trans-port and reaction equation (Brown and Barnwell1987). The model allows multiple waste dis-charges, withdrawals, tributary flows, and inflowand outflow. It also has the capability to computerequired dilution flows for flow augmentation tomeet the pre-specified dissolved oxygen level. Thefirst step in using QUAL2E is to discretizationof river stretch, which is to be modeled. This in-volves dividing the system into reaches of constant


hydro-geometric characteristics. For each compu-tational element, a hydrologic balance in terms offlow (Q), a heat balance in terms of temperature(T), and materials balance in terms of concentra-tion is considered. The 1-D advective–dispersiveequation is solved for the steady flow and steadystate condition. Flow and loads must be steady,but temperature, wind speed and light may varywith time.

Discretization of river reach

The total length of the river considered for thestudy is about 40 km which extend from Kanurto Daddi. The entire stretch of river was dis-cretized into 10 reaches with computational ele-ment lengths of 4 km each.

Hydraulic data

Flow measurements and river geometry weremeasured on various dates from November 2005to May 2006. For an assumed value of roughnesscoefficient (0.025), the energy gradient slope wascomputed using the Manning’s equation from thefield measured hydraulic data. River hydraulicparameters for velocity and depth were measuredat seven different locations. The variation of depthof water varied from 0.5 to 1.2 m across theriver. The discharges from the point sources werecalculated using the velocity and cross-sectionalarea. Similar method was adopted by Ghosh andMcBean (1998).

Deoxygenation coefficient

The deoxygenation rate coefficient has been ob-tained by the standard procedure of incubation ofthe over a period of time and the samples havebeen analyzed for different days at 20◦C. Plots be-tween the DO consumption and incubation timegive the laboratory rate constant at incubatedtemperature.

Re-aeration rate coefficient

The oxygen transfer coefficient in natural waterdepends upon the various factors such as internal

mixing and turbulence, temperature, wind mixing,sewage out falls and surface films. A fast mov-ing, shallow stream will have a much higher re-aeration coefficient than a sluggish stream. Thereare number of methods available for the esti-mation, and most commonly used are those ofChurchill et al. (1962), O’ Connor and Dobbins(1958), Owens et al. (1964) and Langbein andDarum (1967), which are all in terms of depthand velocity. In the present study, the re-aerationcoefficient was estimated by the method suggested(O’ Connor and Dobbins 1958). Sediment oxy-gen demands were obtained by collecting samplesfrom the vicinity of selected outfalls and upstreamof the local drains. Samples were analyzed in thelaboratory using standard methods to quantifythe oxygen demand. QUAL2E, being a steady-state one-dimensional model, has got its limitationof data acceptability. Keeping all these aspectsin view, data collected from field observationsand obtained from laboratory analysis have beenmade on representative form as acceptable to themodel and calibrated the model to match theobserved values. Once the input file is prepared,the foremost task in model application is that ofcalibration and validation of the model. In thiscase, for DO–BOD modelling, the first task wouldbe to match the observed and computed BODrather than DO. This is because the concentra-tion of DO is mainly governed by many factorse.g., conversion of NH3–N to NO3–N, re-aerationcoefficient, river hydraulic parameters, algal con-centration conservation and respiration, etc. OnceBOD is got matched, the second task would beto match the DO concentration in each reach.Since the re-aeration coefficient varies with riverhydraulic data and climatological data, efforts areto be made to calibrate those data rather than ad-justing the measured values. Option of sensitivityanalysis of each/multiple parameters given in themodel provides the appropriate tool to determinethe response of the parameters on any desire lo-cation. The trail run, which represents the bestmatching between observed and computed values,is considered as the calibrated values of the model.During the calibration, utmost care was taken tomatch the calibrated and observed values of riverdata.


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Fig. 2 Percentage distribution of a cations and b anions in Ghataprabha River during Post-monsoon

Results and discussion

Surface water quality evaluation

The pH of water in Ghataprabha sub-basin variesfrom slightly acidic 6.3 to slightly alkaline 7.6 dur-ing pre-monsoon and 5.9 to 7.7 in post-monsoonseason. The results indicate the lowering of pHduring the post-monsoon is the result of wastewater discharge from neighbouring villages. A pH

value of 7.5 to 8 usually indicates the presenceof carbonates of calcium and magnesium. How-ever, in the present study, it is observed that thepH in majority of the samples were less than 7.5indicating the absence of carbonates. One of theinteresting feature that is observed in the presentstudy is the pH value in post-monsoon samplesare much lower than that in pre-monsoon. This isbecause in the catchment area, the mining activ-ities are going on and it brings lot of sediments

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Fig. 3 Percentage distribution of a cations and b anions in Ghataprabha River during Pre-monsoon


Table 1 Inputparameters consideredfor the study

Cases Incremental BOD decay BOD settling SOD Outfallsflow m3/s rate rate m3/s

Case I 0.1 0.3/day 0.125 m/day 1.5 g/m2/day NilCase II 0.25 0.5/day 0.75 m/day 5 g/m2/day 1Case III 0.40 0.6/day 1 m/day 10 g/m2/day 2

and reduces the pH considerably. The electricalconductivity showed a general trend of decreasetowards downstream. However, there are someexceptions due to the mixing of Ghataprabhawater with tributaries and also few local drainscarrying sewage water. The observed mean elec-trical conductivity was 101.30 micromhos/cm andmedian 75.45 micromhos/cm. The maximum elec-trical conductivity was observed at Daddi 203 mi-cromhos/cm. Total dissolved solids observed inthe surface water varied from 20 mg/l to 139 mg/lindicating the suitability of water for all purposes.Laboratory analysis of major anions and cationswere also conducted. The concentration of majorcations and anions are shown in Fig. 2a and b(pre-monsoon) and Fig. 3a and b (post-monsoon).The results clearly indicate that the concentrationsof major anions and cations are well within thepermissible limits.

From the above laboratory analysis, it is foundthat the Ghataprabha water completely satisfiesthe water quality standard prescribed for drinkingand irrigation purposes. However, a detailed fieldinvestigation carried out by the authors all alongthe Ghataprabha catchment showed that there arenumber of waste water streams carrying domesticsewage from local areas drain to GhataprabhaRiver. This could damage the water quality ofriver water. Therefore, to understand the impactof sewage effluents, QUAL2E model was appliedto predict the future trend of water quality deteri-oration in Ghataprabha River.

Application of QUAL2E model to GhataprabhaRiver

Ghataprabha River is a fresh Water River, whichsupplies drinking water to Belgaum City from thereservoir located at Hidkal in Hukkeri taluk ofBelgaum district. Water quality parameters (ma-jor cations and anions) showed that the waterquality of the river is very good for drinking pur-pose. However, the MPN count showed a veryhigh increase (exceeds 1200 MPN/ 100 ml) at vari-ous locations, indicating bacteriological infection.DO–BOD monitoring was carried out through outthe stretch of Ghataprabha (May 2005 and No-vember 2006). From the available monitored data,attempts were made to understand the impact ofsewage water disposal to drinking water stream,QUAL2E model was applied for the simulationof DO–BOD concentrations. The input parame-ters used for the application is shown in Table 1.Case-I represents the observed conditions in theGhataprabha River and Case II and Case III areprojected conditions.

In the case-I, the model was calibrated for DOand BOD by varying parameters like BOD decayrate, BOD settling rate, sediment oxygen demand,and incremental inflow.

Table 2 shows the observed and simulated DO–BOD variation with temperature. Observed DOshowed a decline at Hindgaon 6.8 mg/l and Sat-wane 6.7 mg/l. Further, downstream of Satwane,DO showed an improvement from 6.7 mg/l to

Table 2 Observed andSimulated DO and BODvalues in Ghataprabhasub-basin

1 Kanur; 2 Hindgaon; 3Satwane; 4 Adkur; 5Tarewadi; 6 Daddi

Stations Temp ◦C DO DO BOD BODobserved simulated observed simulated

1 18.13 7.4 7.96 1.1 0.902 18.27 6.8 7.90 1.4 1.103 18.40 6.7 7.83 1.5 1.104 18.53 6.8 7.74 1.3 0.925 18.56 7.0 7.64 1.3 0.986 18.80 7.0 7.53 0.9 0.65


Table 3 Simulated DO–BOD concentration usingQUAL2E

Stations Case II Case III

DO BOD DO BOD(mg/l) (mg/l) (mg/l) (mg/l)

1 7.0 4.1 6.0 13.82 6.7 5.6 5.5 14.23 6.7 6.5 5.2 13.74 5.8 5.9 5.1 13.55 5.6 5.5 4.9 13.96.2 4.4 5.8 5.2

7.0 mg/l. However, the simulated values showeda steady decline in DO from upstream to down-stream and BOD concentration showed an in-crease at Hindgaon 1.4 mg/l and Satwane 1.5 mg/l.The observed BOD reduced to 1.3 mg/l at Ad-kur and Tarewadi. Minimum BOD was noted atDaddi. During the field observations, it is evidentthat the variation of BOD is the result of domesticsewage outfalls. Similar observation was madeby Pawar (2000).The magnitude of anthropogenicactivities influencing environment has increasedsignificantly in the catchments and riparian areasof the river Ghataprabha. In this connection, anattempt was made to project the entire sewageoutfalls resulting from urbanization draining intothe river.

To represent the impact of urbanization, twocases, cases II and III, were considered as shownin Table 1 as input parameters. The results showedthat there is a considerable change in DO–BODlevel along the course of the river. Though thereis no immediate impact as evident from the results

obtained by projecting the existing conditions asshown in Table 3 however, setting up of any kindof industry may cause problems in maintaining theDO level.

It is noted that in both the cases the BODlevel at the downstream end (Daddi) is far lessthan other locations which could be attributed tothe damming effect (Daddi) forms the part of thereservoir back water) of Ghataprabha reservoir.

In order to understand the variation of DO–BOD, flow measurements were taken from eachlocation. It is found that there is a gradual de-crease in DO in spite of having a considerableincrease in flow conditions (Fig. 4). This clearly in-dicates that various kinds of pollutants are addedall along the course of the river. During the fieldinvestigation it was evident that the major causeof water quality deterioration is due to the non-point sources of pollution particularly from agri-culture fields and village sewage outlets. A sharpincrease in DO was observed at the downstreamend (Daddi) of the river which is attributed tothe steep increase in flow condition from 32.3 to43.98 ft3/s.

Conclusion

The chemical quality of Ghataprabha Rivershowed that all major cations and anions are wellwithin the permissible limits and is a safe drinkingwater source for Belgaum and adjoining areas.QUAL2E model results also indicated that thewater is fully acceptable for both domestic and

Fig. 4 DO–BODvariation with river flow

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irrigation purposes. Further, the relationship be-tween river discharge and DO–BOD concentra-tion indicated that, there is a reduction in DOwith increase in flow which could be attributedto the addition of point and non-point sourcesalong the course of the river. It is also foundthat there is an improvement in water quality atthe downstream end (Daddi) which could be dueto high flow conditions existing at Daddi. Fromthe study, it is imperative that it is necessary tomaintain minimum flow requirement to keep thewater in good condition.

Acknowledgements Authors are highly grateful to Sh.R. D. Singh, Director, NIH for his encouragement andsupport. Mr. Satish Babu, JRF, NIH is acknowledged forhis assistance in preparing the script.

References

APHA (1992). Standard method for examination of wa-ter and wastewater. Washington DC: American PublicHealth Association.

Brown, L. C., & Barnwell Jr., T. O. (1987). The enhancedstream water quality models QUAL2E-UNCAS. Doc-umentation and users manual. U.S. EPA/600/3-87/007.

Churchill, M. A., Elmore, H. L., & Buckingham, R. A.(1962). The prediction of re-aeration rates. Interna-tional Journal of Air and Water Pollution, 6, 467–504.

Ghosh, N. C., & McBean, E. A. (1998). Water quality mod-eling of the Kali River, India. International Journal ofWater, Air and Soil Pollution, 102, 91–103.

Langbein, W. B., & Darum, W. H. (1967). The aerationcapacity of streams. U.S. Geological Survey (p. 542).Washington, D.C.: Circular.

O’ Connor, D. J., & Dobbins, W. E. (1958). Mechanismof reaeration in natural streams. Transactions ASCE,123, 641–684.

Owens, M., Edwards, R. W., & Gibbs, J. W. (1964). Somereaeration studies in streams. International Journal ofAir and Water Pollution, 8, 469–486.

Pawar, M. G. (2000). Evaluation of surface waterquality parameters and water quality modeling us-ing QUAL2E model. Belgaum, Karnataka, India:Visvesvaraya Technological University, M. TechDissertation.

Purandara, B. K., & Choubey, V. K. (1996). Hydrologicalland use study of Ghataprabha catchment using IRS-1A data. Asian-Pacif ic Remote Sensing and GIS Jour-nal, 8(2), 5–10.

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Surface Water Quality Evaluation and Modeling of Ghataprabha River, Karnataka, India