Godavari River Basin Research Articles

A new Bagrid catfish species, Rita bakalu (Siluriformes: Bagridae), from the Godavari River basin, India

Rita bakalu, a new species, is described from the Godavari river system in peninsular India. With this finding, the genus Rita is enlarged to include seven species, comprising six species found in South Asia, R. rita, R. macracanthus, R. gogra, R. chrysea, R. kuturnee, R. bakalu, and one species R. sacerdotum from Southeast Asia. R. bakalu is distinguished from its congeners by a combination of the following characters: eye diameter 28–39% HL and 20–22 caudal fin rays; teeth in upper jaw uniformly villiform in two patches, interrupted at the midline; palatal teeth well-developed villiform, in two distinct patches located at the edge of the palate. The mtDNA cytochrome C oxidase I sequence analysis confirmed that the R. bakalu is distinct from the other congeners of Rita. Superficially, R. bakalu resembles R. kuturnee, reported from the Godavari and Krishna river systems; however, the two species are discriminated due to differences in the structure of their teeth patches on upper jaw and palate, anal fin originating before the origin of adipose fin, comparatively larger eye diameter, longer mandibular barbels, and vertebral count. The results conclude that the river Godavari harbors a different species of Rita, R. bakalu which is new to science.

Case Study: A Real-Time Flood Forecasting System with Predictive Uncertainty Estimation for the Godavari River, India

This work presents the application of the multi-temporal approach of the Model Conditional Processor (MCP-MT) for predictive uncertainty (PU) estimation in the Godavari River basin, India. MCP-MT is developed for making probabilistic Bayesian decision. It is the most appropriate approach if the uncertainty of future outcomes is to be considered. It yields the best predictive density of future events and allows determining the probability that a critical warning threshold may be exceeded within a given forecast time. In Bayesian decision-making, the predictive density represents the best available knowledge on a future event to address a rational decision-making process. MCP-MT has already been tested for case studies selected in Italian river basins, showing evidence of improvement of the effectiveness of operative real-time flood forecasting systems. The application of MCP-MT for two river reaches selected in the Godavari River basin, India, is here presented and discussed by considering the stage forecasts provided by a deterministic model, STAFOM-RCM, and hourly dataset based on seven monsoon seasons in the period 2001–2010. The results show that the PU estimate is useful for finding the exceedance probability for a given hydrometric threshold as function of the forecast time up to 24 h, demonstrating the potential usefulness for supporting real-time decision-making. Moreover, the expected value provided by MCP-MT yields better results than the deterministic model predictions, with higher Nash–Sutcliffe coefficients and lower error on stage forecasts, both in term of mean error and standard deviation and root mean square error.

Revised diagnosis of the genus Gonorhynchus McClelland (Teleostei: Cyprinidae: Labeonini) with redescription of G. latius (Hamilton) and revalidation of G. wattanah (Sykes).

A new diagnosis of the genus Gonorhynchus McClelland 1838 from South Asia is proposed. Seven species are contained in the genus: G. latius (Hamilton 1822), G. diplochilus (Heckel 1838), G. wattanah (Sykes 1839), G. macmahoni (Zugmayer 1912), G. burmanicus (Hora 1936), G. bicornis (Wu 1977), and G. periyarensis (Menon & Jacob 1996). Gonorhynchus latius, a senior synonym of the type species G. brevis M'Clelland 1839 is redescribed. Crossocheilus gohama (M'Clelland 1839) and Crossochilus rostratus Günther 1868 are considered junior synonyms of G. latius, and a neotype is designated for G. latius. Gonorhynchus wattanah (Sykes 1839) from the Krishna and Godavari River basins in western India is revalidated and redescribed with the designation of a neotype. Akrokolioplax Zhang & Kottelat 2006 is a junior synonym of Gonorhynchus.

Climate change impact assessment on hydrology of a small watershed using semi-distributed model

This study is an attempt to quantify the impact of climate change on the hydrology of Armur watershed in Godavari river basin, India. A GIS-based semi-distributed hydrological model, soil and water assessment tool (SWAT) has been employed to estimate the water balance components on the basis of unique combinations of slope, soil and land cover classes for the base line (1961–1990) and future climate scenarios (2071–2100). Sensitivity analysis of the model has been performed to identify the most critical parameters of the watershed. Average monthly calibration (1987–1994) and validation (1995–2000) have been performed using the observed discharge data. Coefficient of determination (R^{2}), Nash–Sutcliffe efficiency (ENS) and root mean square error (RMSE) were used to evaluate the model performance. Calibrated SWAT setup has been used to evaluate the changes in water balance components of future projection over the study area. HadRM3, a regional climatic data, have been used as input of the hydrological model for climate change impact studies. In results, it was found that changes in average annual temperature (+3.25 °C), average annual rainfall (+28 %), evapotranspiration (28 %) and water yield (49 %) increased for GHG scenarios with respect to the base line scenario.

Hydrologic sensitivity of Indian sub-continental river basins to climate change

Climate change may pose profound implications for hydrologic processes in Indian sub-continental river basins. Using downscaled and bias corrected future climate projections and the Soil Water Assessment Tool (SWAT), we show that a majority of the Indian sub-continental river basins are projected to shift towards warmer and wetter climate in the future. During the monsoon (June to September) season, under the representative concentration pathways (RCP) 4.5 (8.5), the ensemble mean air temperature is projected to increase by more than 0.5 (0.8), 1.0 (2.0), and 1.5 (3.5) °C in the Near (2010–2039), Mid (2040–2069), and End (2070–2099) term climate, respectively. Moreover, the sub-continental river basins may face an increase of 3–5°C in the post-monsoon season under the projected future climate. While there is a large intermodel uncertainty, robust increases in precipitation are projected in many sub-continental river basins under the projected future climate especially in the Mid and End term climate. A sensitivity analysis for the Ganges and Godavari river basins shows that surface runoff is more sensitive to change in precipitation and temperature than that of evapotranspiration (ET). An intensification of the hydrologic cycle in the Indian sub-continental basins is evident in the projected future climate. For instance, for Mid and End term climate, ET is projected to increase up to 10% for the majority of the river basins under both RCP 4.5 and 8.5 scenarios. During the monsoon season, ensemble mean surface runoff is projected to increase more than 40% in 11 (15) basins under the RCP 4.5 (8.5) scenarios by the end of the 21st century. Moreover, streamflow is projected to increase more than 40% in 8 (9) basins during the monsoon season under the RCP 4.5 (8.5) scenarios. Results show that water availability in the sub-continental river basins is more sensitive towards changes in the monsoon season precipitation rather than air temperature. While in the majority of the sub-continental river basins, water availability is projected to increase, spatial and temporal (interannual) variability in the monsoon season precipitation under the projected future climate may play a significant role. Changes in the hydrologic processes under the projected future climate indicate that substantial efforts may be required to develop water management strategies in the Indian sub-continental river basins in the future.

Assessment of Climate Change for Precipitation and Temperature Using Statistical Downscaling Methods in Upper Godavari River Basin, India

In the present study SDSM downscaling model was used as a tool for downscaling weather data statistically in upper Godavari river basin. Two Global Climate Models (GCMs), CGCM3 and HadCM3, have been used to project future maximum temperature (Tmax), minimum temperature (Tmin) and precipitation. The predictor variables are extracted from: 1) the National Centre for Environmental Prediction (NCEP) reanalysis dataset for the period 1961-2003, 2) the simulations from the third-generation Hadlycentre Coupled Climate Model (HadCM3) and Coupled Global Climate Model (CGCM3) variability and changes in Tmax, Tmin and precipitation under scenarios A1B and A2 of CGCM3 model and A2 and B2 of HadCM3 model have been presented for future periods: 2020s, 2050s and 2080s. The scatter-plots and cross-correlations are used for verifying the reliability of the simulation. Maximum temperature increases in future for almost all the scenarios for both GCMs. Also downscaled future precipitation shows increasing trends for all scenarios.

Comparison of Estimators of Gumbel Distribution for Assessment of Seasonal and Annual Rainfall

Estimation of seasonal and annual rainfall for a river basin is of importance in planning and management of water resources projects. This study illustrates the use of six different parameter estimation methods for Gumbel distribution for assessment of seasonal and annual rainfall for Krishna and Godavari river basins. Goodness-of-Fit tests involving Anderson–Darling and Kolmogorov–Smirnov are used for checking the adequacy of fitting of Gumbel distribution to the recorded rainfall data. Model performance indicators such as correlation coefficient, model efficiency and root mean square error are used for the selection of suitable method for estimation of rainfall. The study shows that the probability weighted moments are better suited for determination of parameters of Gumbel distribution for assessment of seasonal and annual rainfall for Krishna and Godavari basins.

Site-specific ground motion simulation and seismic response analysis for microzonation of Nanded City, India

We study strong ground motion characteristics and ground response analysis of different sites in Nanded City, India. Synthetic strong ground motion records are obtained for two scenario earthquakes of magnitude M 5.2 and M 6.8 in southern Peninsular India using the finite fault model. Shear-wave velocity averaged over top 30 m of the soil is obtained from multichannel analysis of surface wave survey at 60 sites at depths of 20–50 m below the ground surface. The sites in different parts of the city are characterized by peak ground acceleration (PGA) at the surface and bedrock level, 5 % damped response spectra at the ground surface and the amplification factor defined as the ratio of ground motion at the surface to that at the bedrock. The area east to the lineament is characterized by low V S30 values (<200 m/s), probably associated with Godavari River basin sediments with alluvial deposits, composed of brown clay with intercalated bands of sand and gravel. A relatively high PGA value at the surface of about 0.24 g for the M 5.2 target event and hence high ground motion amplification indicative of major damage are observed at sites E-NE to the lineament in the area that are associated with the top soil column consisting of unconsolidated river basin sediments with very low V S30 values (<200 m/s). The amplification factor for the city ranges from 3 to 8 for the highest target event of magnitude M 6.8. There is a strong lateral variation in PGA values at the surface for the part of the city lying to the east of the lineament and parallel to its trend, where a relatively high amplification factor of 6–8 is found at a dominant frequency of 1.5–2.5 Hz, which can be considered as a significant zone of amplification and hence areas with high seismic hazard. The site-specific response spectra show that the peak of spectral acceleration for different sites occurs around 3 Hz. There is a large spatial variation of spectral acceleration at any given frequency for the city. For example, site nos. 9 and 50 are characterized by a peak in spectral acceleration of 0.55 and 0.9 g, respectively, at 3 Hz frequency.

Assessing the adequacy of the parameter estimation methods of the Gumbel distribution for modelling the seasonal and annual rainfall

The assessment of seasonal and annual rainfall for a river basin is of utmost importance for the planning, design, and management of water resources projects. This paper compares the six parameter estimation methods of the Gumbel distribution for modelling the seasonal and annual rainfall of the Krishna and Godavari river basins. Goodness-of-Fit (GoF) tests of Anderson–Darling and Kolmogorov–Smirnov are used for checking the adequacy of fitting the Gumbel distribution to the recorded data. A diagnostic test of root mean square error is used for the selection of a suitable method for the estimation of rainfall. Based on GoF and diagnostic tests results, probability weighted moments is identified as a better suited method for modelling the seasonal and annual rainfall for the Krishna and Godavari basins.

A dual role of dams in fragmentation and support of fish diversity across the Godavari River basin in India

ABSTRACTFreshwater systems are among the habitats most sensitive to environmental changes and human interference. The increasing needs in India for supplies of both fresh water and fish as a food source under the pressure of a rapidly growing population mandate identification of ways to conserve natural resources while meeting these human needs. Dams provide a partial solution for both water and food fish supplies, especially in monsoonal areas, although disruption of natural fish habitats may offset these benefits. To examine this phenomenon, the Godavari River basin in India was sampled at 32 sites, and the effects dams might have on fish species assemblages and distribution at these sites were analysed. Although the river basin was rich in species, their representation and distribution was fragmented. The surveyed fish fauna included 114 species that were classified into 12 orders. Cyprinids dominated the fauna. Few introduced and cultured species were widely distributed in the river. Some native species were barely captured, suggesting they might be at risk of loss. The presence of the Godavari dams, as has been the case elsewhere, does appear to have disturbed the species distribution. However, here, the dams also appear to have positive effects. Some dam reservoirs supported the highest levels of species diversity, and as low as five dam sites contained over 95% of all species found. The dam reservoirs may therefore represent preferred sites for conservation, and the proper management of such reservoirs may be critical to balancing human needs with sustainable conservation of fish biodiversity. Copyright © 2014 John Wiley &amp; Sons, Ltd.

Trends in temperature over Godavari River basin in Southern Peninsular India

ABSTRACTThere is little dispute that global surface air temperature has increased and the anthropogenic‐induced global warming is likely to play an important role in the management of water resources of a river basin. Therefore, this study was undertaken for Godavari River basin, a large southern peninsular river basin in India. After removing the effect of significant lag‐1 serial correlation by pre‐whitening procedure, the Mann–Kendall (MK) test was employed to investigate trends in maximum temperature (Tmax), minimum temperature (Tmin) and mean temperature (Tmean) at 35 stations in the basin. At seasonal (monthly) time scales, a majority of the stations exhibited no trends in Tmean, Tmax and Tmin in any of the four seasons (12 months) with the exception of post‐monsoon (December) for Tmax and monsoon (July and September) for Tmin. About 60% (45%) of the stations exhibited increasing trends in Tmax (Tmin) in different durations: the month of December and post‐monsoon season (the months of July and September and monsoon season) indicating the presence of an element of seasonal cycle in temperature over the Godavari basin. Results of tests of spatial and temporal homogeneity of trends by the Van Belle and Hughes method showed that trends in temperature over the Godavari basin were not homogeneous for different months or at different stations. In spite of the warmer climate in the basin, the evaporation (Epan) has been found to decrease significantly over the Godavari basin. Strong decreases in wind speed and increases in relative humidity may have actually caused the Epan decreases over the southern peninsular region of India.

Mapping agricultural responses to water supply shocks in large irrigation systems, southern India

Irrigated agriculture experienced a water supply shock during a drought in southern India in 2002–2003. In this paper, hotspots of agricultural change were mapped and put in the context of hydrology and water management. Time series of MODIS imagery taken every eight days before (2001–2002) and during (2002–2003) the supply shock were combined with agricultural census data to document changes in cropping patterns in four large irrigation projects in the downstream sections of the Krishna and Godavari River basins (total command area 18,287 km 2 ). The area cropped in rice in the four irrigated command areas decreased by 32% during the drought year, and rice production in the two districts that experienced the largest flow reductions fell below production levels of 1980. The irrigation project that showed the largest change in double cropped area (−90%) was upstream of the Krishna Delta. In the Krishna Delta, large areas changed from rice–rice to rice–gram double cropping. Historical water management contributed to the vulnerability of rice production to drought: the main reservoir in the system was drained to dead storage levels by the end of each growing season over 1968–2000, with little carryover storage. The land cover change maps suggested that the lower Krishna Basin has experienced a “hard landing” during basin closure, and revised management strategies that account for the new flow regime will be required to maintain agricultural production during droughts.

Adapting to climate change in the Godavari River basin of India by restoring traditional water storage systems

Food, climate and water crises are interrelated and interdependent. Climate change is projected to significantly alter rainfall patterns, with implications for the annual runoff for the Godavari River basin of the Indian subcontinent. Agriculture, especially rain-fed agriculture, will be particularly affected, due to changes such as periodicity and intensity of rainfall. This paper describes field interventions in 2005–2007 designed to restore traditional water management systems (in the form of water tanks; that is, wetlands embedded in a semi-arid region), with the aim of mitigating the effects of increased climate variability and the frequency of weather extremes. Our findings suggest that traditional water management methods can be both socially and economically effective in coping with variability in precipitation patterns, decentralizing management institutions, improving crop productivity and increasing groundwater recharge. This approach is preferable to large projects for increasing water storage capacity or expanding areas under irrigation, which are expensive, and can displace people and degrade ecosystems.

Chemical weathering and associated CO 2 consumption in the Godavari river basin, India

The study gives insight into the source of major ions concentration and their seasonal variability, chemical weathering rates and associated CO 2 consumption in the Godavari River Basin (GRB). The results show that the Godavari river basin water was mildly alkaline, with a wide range of TDS (40 to 550 mgL − 1 ). The most dominant anion was HCO 3 − followed by Cl − and the most dominant cation was Ca 2+ followed by Na + for all three sampling seasons. The average molar ratio of Cl −/Na + was 0.59 in pre-monsoon, 0.51 for post-monsoon and 0.66 in monsoon, which is lower than the values, reported in earlier studies. The range of precipitation corrected molar ratio for (Ca 2+/Na +) was 0.20 to 1.84 in pre-monsoon, 0.59 to 1.59 in post-monsoon and 0.35 to 2.09 in monsoon season, (Mg 2+/Na +) was 0.26 to 1.18, 0.24 to 0.62 and 0.17 to 1.42 in pre-monsoon, post-monsoon and monsoon respectively, while (HCO 3 −/Na +) was 2.08 to 7.0 in pre-monsoon,1.98 to 4.05 in post-monsoon and 1.67 to 5.79 in monsoon, which indicated the influence of basalt weathering on river water chemistry. Factor analysis indicated the vital role of silicate and carbonate weathering along with atmospheric and anthropogenic input that govern the water chemistry of the GRB. The chemical weathering rate of GRB varied from 17.61 to 68.16 tkm − 2 y − 1 with an average of 39.49 tkm − 2 y − 1 in pre-monsoon, from 27.94 to 65.67 with the average of 42.02 tkm − 2 y − 1 in post-monsoon season and from 17.53 to 62.95 tkm − 2 y − 1 with an average value of 34.69 tkm − 2 y − 1 in monsoon. The associated CO 2 consumption rate due to chemical weathering in the GRB was ∼ 0.25 × 10 12 mol y − 1 which is ∼ 1.04% of the annual global CO 2 consumption (24 × 10 12 mol y − 1 ) by chemical weathering of silicate and carbonate rocks. The average annual CO 2 drawdown by Deccan trap (area 5 × 10 5 km 2) based on CO 2 consumption rate due to silicate weathering determined in this study was 0.29 × 10 12 mol y − 1 , ∼ 2.48% of the annual global CO 2 consumption (11.7 × 10 12 mol y − 1 ) by silicate weathering [Gaillardet, J., Dupre, B., Allegre, C.J., 1999. Global silicate weathering and CO 2 consumption rates deduced from the chemistry of large rivers. Chemical Geology 159, 3–30.]. The present study was the first attempt to calculate weathering rate of Deccan trap using major ion chemistry of the Godavari River water, the third largest river in India. The study further provides the inventory for CO 2 consumption on river basin scale, which is an important consideration from the point of view of global warming.

Distribution of iron in the surface and groundwaters of East Godavari district, Andhra Pradesh, India

With the progradation of Godavari delta in the east coast of India, increase in iron (Fe) concentrations in the groundwater was observed. High concentrations of Fe (>10 mg/l) were observed in khondalite and charnockite formations. A lower portion of the Godavari river basin, viz. East Godavari district was chosen for the study of the distribution of iron with special reference to the existing geological formations and the geomorphology of the area. The concentration of iron was observed to vary from below detection limit to 69 mg/l in the groundwater while it was less than 1 mg Fe/l in river and spring waters. The Fe of river water was reduced due to seawater mixing and the electrical conductivity (EC) was increased approximately to half of the seawater conductivity. Unlike the mixing of seawater at the surface, the same seawater mixing with groundwater yielded a water having similar order of EC with relatively high Fe. Fe was inversely related with nitrate in the groundwater. Fe was found to correlate considerably better with manganese in fluvial and coastal alluvium zones. The locations having higher Fe in delta are suspected to be related to palaeo channels. The association between Fe and Mn and their negative association with NO3 may be due to the possible autotrophic denitrification that might have taken place in the subsurface.

Nature of sedimentary organic matter in the lower reaches of the Godavari River basin, India

The distribution and nature of sedimentary organic matter (OM) have been examined in sediment cores collected from the lower reaches, including estuary, of the Godavari River in order to understand sedimentation patterns, sources, and diagenesis of OM. The samples were analyzed for organic carbon (Corg), total nitrogen, amino acids and hexosamines. The observed irregular trends in Corg distribution with depth indicate the unstable nature of bed sediment in the lower reaches of the river. Yet, in the lower estuarine region, regular trends in Corg distribution with depth reflect the deposition of sediment. The atomic ratio of Corg and total nitrogen (C/N; 10.5–16.1) also supported this observation. The distribution of amino acids and diagenetic indicators (β-ala+γ-aba mol.%, AA/HA and Glc-NH2/Gal-NH2) in individual cores revealed the post-depositional changes in the OM. In the core sediment from the lower reaches, there was no clear cut trend in amino acid content with depth. In the estuarine region, however, amino acid content was very low (50.5 and 186.5μgg−1) in the upper layers compared to that in the lower layers (558.5 and 1099.3μgg−1). Reactivity index (range 0.3–3.7) revealed that OM in the upper few centimeters, especially in the lower estuarine region, was more reactive relative to that in the deeper layers.

Monsoon rainfall and its variability in Godavari river basin

Rainfall variability over a river basin has greater impact on the water resource in that basin. With this in view, the variability of the monsoon rainfall over the Godavari river basin has been studied on different time scales. As expected, the monsoon rainfall in Godavari basin is more variable (17%) than the all-India monsoon rainfall (11%) during the period of study (1951–90). Similarly, inter-annual variability of the monsoon rainfall on smaller time scales is found to be still higher and increases while going on from seasonal to daily scales. An interesting observation is that the intra-seasonal variability of the monsoon rainfall has a significant negative relationship (CC= −0.53) with the total seasonal rainfall in the basin.

Interannual Variations of Monsoon Rainfall in Godavari River Basin—Connections with the Southern Oscillation

Abstract Interannual variations of the monsoon rainfall in one of the central Indian river basins, Godavari, are studied for the 40-yr period 1951–90. It is observed that the departures from the normal of the monsoon rainfall in excess and deficient rainfall years are larger in the plain areas than in the hilly regions. The connections between the monsoon rainfall in this basin and the Southern Oscillation are also examined. The winter to spring Darwin pressure tendency is found to have a significant negative connection with the monsoon rainfall in the basin as a whole. However, this connection is weak in hilly regions, where the rainfall is influenced by the orography. It is also observed that this connection is consistent throughout the entire period of study and suggests the use of Darwin pressure tendency as a parameter for long-range forecasting of the monsoon rainfall in this basin.

Heavy metal distribution in the Godavari River basin

Suspended and bed sediments collected from the entire region of the Godavari River basin were analyzed for Fe, Mn, Cr, Cu, Ni, and Zn. There are pronounced temporal and spatial variations in the heavy metal distributions. The concentrations of heavy metals in the suspended sediments are significantly higher than the bed sediments.

Sediment transport of the Godavari River basin and its controlling factors

The mean annual water flow and sediment transport of the Godavari River are estimated to be 92 km 3 and 170 × 10 6 ton (t), respectively. In terms of sediment transport and the rate of physical erosion (555 t km −2yr −1), the position of the Godavari would be ninth and fifth respectively among the world rivers. Geology of the basin is the main controlling factor of the sediment transport. The sedimentary rocks located in the lower part of the basin and constituting 7% of the total basin area are responsible for 33% of the sediment load. More than 67% of sediment load is silt and clay. Annual, monthly and daily variations in sediment transport indicate that a few selected days in the hydrological year control the annual sediment budget. Our latest estimates are nearly twice that of our earlier values. The presently available global estimates on sediment transport need to be re-evaluated.