Faculty Publications
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Item Evaluation of water quality index for drinking purposes for river Netravathi, Mangalore, South India(2008) Avvannavar, S.M.; Shrihari, S.An attempt has been made to develop water quality index (WQI), using six water quality parameters Dissolved oxygen (DO), Biochemical oxygen Demand (BOD), Most Probable Number (MPN), Turbidity, Total Dissolved Solids (TDS) and pH measured at eight different stations along the river basin. Rating curves were drawn based on the tolerance limits of inland waters and health point of view. Bhargava WQI method and Harmonic Mean WQI method were used to find overall WQI along the stretch of the river basin. Five point rating scale was used to classify water quality in each of the study areas. It was found that the water quality of Netravathi varied from Excellent to Marginal range by Bhargava WQI method and Excellent to Poor range by Harmonic Mean WQI method. It was observed that the impact of human activity was severe on most of the parameters. The MPN values exceeded the tolerable limits at almost all the stations. It was observed that the main cause of deterioration in water quality was due to the lack of proper sanitation, unprotected river sites and high anthropogenic activities. © Springer Science+Business Media B.V. 2007.Item Conjunctive use in India's Varada River Basin(American Water Works Association cs-journals@wiley.com, 2009) Ramesh, H.; Mahesha, A.The use of groundwater in conjunction with surface water resources has gained prominence in regions experiencing scarce or uneven distribution of water. In the Varada River Basin in Karnataka, India, for example, an optimization model was developed for the conjunctive use of surface water and groundwater resources because of the increasing demand on agricultural and domestic sectors of this area's water supply. Monsoon rains, which occur only six months a year, predominantly control the basin's agricultural activities. However, the area has an immense need for efficient use of available water resources during the rest of the year. The model, based on linear programming, optimizes the allocation of groundwater and surface water subject to hydraulic and stream flow constraints. The model incorporates policy scenarios that add to the sustainability of the system. The developed conjunctive-use model is simple but effective in computing the optimal use of the Varada basin's water resources.Item Impact assessment of watershed development programme - A case study of Itagi watershed(2010) Palakshappa, K.; Nagaraj, M.K.; Shivapur, A.V.Soil, water and vegetation are the important gifts of nature to mankind. Welfare and development of mankind and its civilization revolves around conservation and development of these vital natural resources, which are so interdependent that one can not be managed efficiently without the other two. Watershed Development Programs (WDP) going on in India basically as soil and water conservative programs (as a policy response to the increasing environmental crisis and non-sustainability of agriculture especially in the dry land/semi-arid regions) has modified substantially with the introduction of watershed guidelines in 1994 by the Government of India. In the present study the area considered for assessment is Itagi sub watershed in Ranebennur taluk, Haveri district, Karnataka. During the watershed development programme soil and water conservation structures were constructed in the study area in the year 2004. The analysis of data reveals that there is an improvement in the groundwater recharge, increase in yield of the wells, increase in agricultural production, reduction in soil erosion and many other tangible and intangible benefits as a result of this watershed development programme. © 2010 CAFET-INNOVA TECHNICAL SOCIETY. All rights reserved.Item Analysis of observed soil moisture patterns under different land covers in Western Ghats, India(2011) Venkatesh, B.; Lakshman, N.; Purandara, B.K.; Reddy, V.B.An understanding of the soil moisture variability is necessary to characterize the linkages between a region's hydrology, ecology and physiography. In the changing land use scenario of Western Ghats, India, where deforestation along with extensive afforestation with exotic species is being undertaken, there is an urgent need to evaluate the impacts of these changes on regional hydrology. The objectives of the present study were: (a) to understand spatio-temporal variability of soil water potential and soil moisture content under different land covers in the humid tropical Western Ghats region and (b) to evaluate differences if any in spatial and temporal patterns of soil moisture content as influenced by nature of land cover. To this end, experimental watersheds located in the Western Ghats of Uttara Kannada District, Karnataka State, India, were established for monitoring of soil moisture. These watersheds possessed homogenous land covers of acacia plantation, natural forest and degraded forest. In addition to the measurements of hydro-meteorological parameters, soil matric potential measurements were made at four locations in each watershed at 50 cm, 100 cm and 150 cm depths at weekly time intervals during the period October 2004-December 2008.Soil moisture contents derived from potential measurements collected were analyzed to characterize the spatial and temporal variations across the three land covers. The results of ANOVA (p<0.01, LSD) test indicated that there was no significant change in the mean soil moisture across land covers. However, significant differences in soil moisture with depth were observed under forested watershed, whereas no such changes with depth were noticed under acacia and degraded land covers. Also, relationships between soil moisture at different depths were evaluated using correlation analysis and multiple linear regression models for prediction of soil moisture from climatic variables and antecedent moisture condition were developed and tested. A regression model relating near-surface soil moisture (50 cm) with profile soil moisture content was developed which may prove useful when surface soil moisture contents derived from satellite remote sensing are available. Overall results of this study indicate that while the nature of land cover has an influence on the spatio-temporal variability of soil moisture, other variables related to topography may have a more dominant effect. © 2010 Elsevier B.V.Item Tropical, Seasonal River Basin Development: Hydrogeological Analysis(2011) Shetkar, R.V.; Mahesha, A.This study presents a hydrogeological analysis of a humid tropical, seasonal river in the context of climate change, increasing demand for water, and uneven distribution of rainfall. We investigate the Netravathi basin, a tropical river basin of south India. The climate change effect on the basin was evident in terms of increasing trend in temperature by about 0.7°C/100 years and decreasing trend in the river flow during the monsoon by about 0.8% of average annual flow per year using the Mann-Kendall trend test. Even though rainfall was found to be decreasing, no significant trend could be established. From the trend analysis of the river flow, it was found that there is an overall declining trend with longer scarcity periods. In addition, the trends of magnitude and frequency of high flows are declining. Even though the region receives an average annual rainfall of about 3,930 mm, it has nonuniform distribution with most of the rainfall confining to a few months of a year. In view of this, the region suffers from a prolonged dry period during February to May. The projected domestic water demand of the region for the next 25 years is estimated to be increasing from the present 0.09 mm3 to 0.25 mm3 per day because of rapid urbanization and industrialization. The purpose of this investigation is to highlight the effects of climate change and uneven distribution of rainfall in the river basin. This may assist in proper planning of the basin through strategies such as river water harvesting, which is investigated in the companion paper. Because the Netravathi River is a seasonal and tidal river, and saltwater intrusion along the river during the summer months is affecting the development of the basin. It was found that the river water is affected up to distance of about 22,000 m from the Arabian sea and the wells on the banks of the river are found to be highly vulnerable to saltwater intrusion during the summer period (March to May). © 2011 American Society of Civil Engineers.Item Tropical, Seasonal River Basin Development through a Series of Vented Dams(2011) Shetkar, R.V.; Mahesha, A.Tropical rivers are predominantly seasonal in nature, and managing water resources during the deficit period is becoming more difficult because of the rapidly increasing demand for water. The present investigation focuses on harvesting Netravathi River water in the southern Indian peninsula through a series of vented dams with an estimated storage capacity of 102 Mm3 for use during the deficit period. A brief hydraulic design of a vented dam at a specific location is presented. The spacing and capacity of these reservoirs were worked out on the basis of the dam height and the river characteristics. The proposed vented dams are seasonal dams, and the closure of the vents will be decided on the flow available (i.e., 95% dependable flow), the storage capacity, and the minimum water release required for the downstream ecosystem. The appropriate time to start storing water in the vented dams was estimated to be in the month of November, and the entire process of storing water in the vented dams may last for about 41 days. An operational protocol for the storing process is presented. The investigations of aquifer parameters were performed by using electrical resistivity, pumping, and soil tests. The results indicated that the aquifer is shallow, unconfined in nature, and had a depth ranging from 18 to 30 m and hydraulic conductivity ranging from 62.6 to 406 m/day. A multiple regression model developed to assess the groundwater recharge in the adjoining well fields indicated that water table fluctuations may be 30% of reservoir level fluctuations. Because the river is also tidal in nature, a saltwater exclusion dam is proposed at the lower reaches of the river to prevent the entry of saltwater along the river during the summer period. © 2011 American Society of Civil Engineers.Item Soil water fluxes under different land covers - A case study from Western Ghats, India(2011) Venkatesh, B.; Nandagiri, L.; Purandara, B.K.Knowledge of soil water fluxes is essential in hydrologic studies related to infiltration, runoff, ground water recharge and water uptake by vegetation. Previous studies have investigated the role played by soil and atmospheric factors on soil water fluxes in the unsaturated zone, but few studies have investigated the role played by vegetation or land cover. The present study was taken up understand the effect of land cover on soil water fluxes through long-term field measurements made in three experimental watersheds located in Western Ghats mountain ranges covering a portion of Uttara Kannada District, Karnataka State, India. Soil and climatic conditions were the same for the selected watersheds but they possessed different land covers - natural forest, degraded forest and acacia plantation. In addition to measurements of hydro-meteorological parameters, soil matric potential measurements were made at 4 locations in each of the watersheds up to a depth of 150 cm at an interval of 50 cm. Measurements were made for a period of 2 years (2007-2008) at weekly time intervals Depth-wise soil matric potential measurements were used to estimate soil water fluxes using Darcy's equation for unsaturated porous media. The estimated values of soil water fluxes were analyzed for their temporal distribution and stability. Results indicated that there is an improvement in soil moisture holding under the acacia plantation in comparison to degraded watershed. The estimated deviation of the soil water flux from the field average values indicate that the points located on milder slopes are representative of watershed mean soil water flux. Results also indicated the temporal persistence of soil water fluxes. © 2011 CAFET-INNOVA technical society. All right reserved.Item Morphometric evidences for neotectonism in the Mulki River basin of coastal Karnataka, India(2011) Radhakrishnan, K.; Lokesh, K.N.Mulki River basin, a rectilinear midland river draining the coastal Dakshina Kannada districts of Karnataka located in the Mulki-Pulikat Lake axis in south Indian Peninsula shield has been analysed for various morphometric characteristics to understand the tectonic conditions of the basin along with supporting evidences of geomorphology, geology and structural features using Remote Sensing and GIS technology. The regional neotectonism suggested by earlier workers evidenced through geomorphologic features and geology of the area has been established through morphometric analysis. Even though Mulki, a 6 th order river basin obeys the Horton's laws of stream order it disobeys the Horton's law of stream length, indicating the regional uplift due to neotectonic activities. Fluctuating stream length ratio of successive stream orders in the basin again stress upliftment and a late youth stage development of geomorphic features reflected in slope and topographic conditions. The range of varying bifurcation ratios and the low Form Factor along with Circularity and Elongation Ratios strongly suggest a geologically and structurally controlled drainage system with elongated basin shape and high relief pointing towards neotectonism. A very low relief ratio of 0.008342, with entrenched meandering plain and a steep structural ridge within the basin indicates a rejuvenation of the basin with regional uplift. A very coarse graded drainage texture of 7.84 with low stream frequency of 2.5 and a drainage density of 1.877km/km 2 suggest that the area is having highly resistant permeable subsoil in a low relief terrain indicative of neogene tectonic activities. © 2011 CAFET-INNOVA TECHNICAL SOCIETY. All rights reserved.Item Vegetation dynamics in a tropical river basin inferred from MODIS satellite data(2013) Laxmi, K.; Nandagiri, L.The objective of this study was to analyze temporal and spatial dynamics of vegetation and land use/land cover (LU/LC) characteristics in a humid tropical river basin originating in the forested Western Ghats mountain ranges using the Moderate Resolution Imaging Spectroradiometer (MODIS) satellite data. Both intra-annual and inter-annual variations in the parameters related to vegetation were analyzed in the Netravathi river basin (3314 km2) which is located in Karnataka State, India. MODIS data products on Land Surface Temperature and Reflectance were used as input to map the pixel-wise variations in albedo, Normalized Difference Vegetation Index (NDVI), Fraction of Vegetation (Fr) and Land Surface Temperature (LST) for two dates each (summer and winter) during the years 2002 and 2006. The fact that 2002 experienced a relatively wet summer followed by a relatively dry winter and 2006 experienced opposite conditions, proved useful in interpreting variations as influenced by wetness conditions. Overall results indicated significant variability in the parameters for major LU/LC classes of evergreen /semievergreen forest, scrub forest and agriculture. While albedo values appeared quite sensitive to wetness conditions, NDVI (and Fr) exhibited significant seasonal changes for some LU/LC classes but remained largely unaffected by wetness conditions. LST values corrected for elevation effects (LST*) were influenced by both LU/LC and wetness conditions. Differences in LST* values were as high as 70K between summer and winter of 2006 for some LU/LC classes. Lowest temperatures were recorded for the evergreen/ semievergreen forest class. Similar inferences could be drawn when variations in parameters were analyzed for 20 selected pixels located at different elevations and possessing each of the eight LU/LC classes. The methodology proposed in this research may prove to be useful in regional scale monitoring and mapping of tropical forests and other LU/LC categories in a convenient and cost-effective manner. MODIS satellite data products used in this study provides information on surface characteristics at a reasonable resolution. This permits identification of not only differences in LU/LC classes but also on changes in surface characteristics as influenced by season and wetness conditions. © 2013 CAFET-INNOVA TECHNICAL SOCIETY.Item Ground water potential assessment of Haladi River basin in Westernghat of Udupi district, Karnataka, India(2013) Mahadeve Gowda, S.K.; Nagaraj, M.K.For a sustainable development of water resources, it is imperative to make a quantitative estimation of the available water resources. It is necessary to maintain the groundwater reservoir in a state of Dynamic equilibrium over a period of time and the water level fluctuations have to be kept within a particular range over the monsoon and non-monsoon seasons. Groundwater is a dynamic system. The total annual replenishable resource is around 43 M ha-m. The development and over-exploitation of groundwater resources have raised the concern and need for judicious and scientific resource management and conservation. Among the two major water resources, surface and ground water, it is the ground water resource, which needs to be managed carefully, especially in drought prone areas. To assess the groundwater potential, a suitable and accurate technique is required for a meaningful and objective analysis. A critical study is carried out on the different methods of estimating the groundwater potential and compared to arrive the most suitable technique for practical utility. In this work, five methods of estimating groundwater recharge were studied viz., 1. Yearly water level fluctuation 2. Ten year average water level fluctuation 3. Fluctuation between the lowest and highest water levels over ten years 4. Relationship between rainfall and recharge Method. The results of this study helps in accurate prediction of groundwater availability, which in turn may avoid groundwater over exploitation and help to restore the eco-systems. © 2013 CAFET-INNOVA TECHNICAL SOCIETY.