Wet Components Research Articles

Wildlife Population Dynamics in Human-Dominated Landscapes under Community-Based Conservation: The Example of Nakuru Wildlife Conservancy, Kenya.

Wildlife conservation is facing numerous and mounting challenges on private and communal lands in Africa, including in Kenya. We analyze the population dynamics of 44 common wildlife species in relation to rainfall variation in the Nakuru Wildlife Conservancy (NWC), located in the Nakuru-Naivasha region of Kenya, based on ground total counts carried out twice each year from March 1996 to May 2015. Rainfall in the region was quasi-periodic with cycle periods dependent on the rainfall component and varying from 2.8 years for the dry season to 10.9 years for the wet season. These oscillations are associated with frequent severe droughts and food scarcity for herbivores. The trends for the 44 wildlife species showed five general patterns during 1996–2015. 1) Steinbuck, bushbuck, hartebeest and greater kudu numbers declined persistently and significantly throughout 1996–2015 and thus merit the greatest conservation attention. 2) Klipspringer, mongoose, oribi, porcupine, cheetah, leopard, ostrich and Sykes monkey numbers also decreased noticeably but not significantly between 1996 and 2015. 3) Dik dik, eland, African hare, Jackal, duiker, hippo and Thomson’s gazelle numbers first increased and then declined between 1996 and 2015 but only significantly for duiker and hippo. 4) Aardvark, serval cat, colobus monkey, bat-eared fox, reedbuck, hyena and baboon numbers first declined and then increased but only the increases in reedbuck and baboon numbers were significant. 5) Grant’s gazelle, Grevy’s zebra, lion, spring hare, Burchell’s zebra, bushpig, white rhino, rock hyrax, topi, oryx, vervet monkey, guinea fowl, giraffe, and wildebeest numbers increased consistently between 1996 and 2015. The increase was significant only for rock hyrax, topi, vervet monkey, guinea fowl, giraffe and wildebeest. 6) Impala, buffalo, warthog, and waterbuck, numbers increased significantly and then seemed to level off between 1996 and 2015. The aggregate biomass of primates and carnivores increased overall whereas that of herbivores first increased from 1996 to 2006 and then levelled off thereafter. Aggregate herbivore biomass increased linearly with increasing cumulative wet season rainfall. The densities of the 30 most abundant species were either strongly positively or negatively correlated with cumulative past rainfall, most commonly with the early wet season component. The collaborative wildlife conservation and management initiatives undertaken on the mosaic of private, communal and public lands were thus associated with increase or no decrease in numbers of 32 and decrease in numbers of 12 of the 44 species. Despite the decline by some species, effective community-based conservation is central to the future of wildlife in the NWC and other rangelands of Kenya and beyond and is crucially dependent on the good will, effective engagement and collective action of local communities, working in partnerships with various organizations, which, in NWC, operated under the umbrella of the Nakuru Wildlife Forum.

Acid rain attack on outdoor sculpture in perspective

A major concern motivating research in acid rain materials effects has been the potential for damage to cultural heritage, particularly outdoor marble and bronze sculpture. However, a combination of field and laboratory studies has failed to show a correlation between rain pH and loss of materials. In order to understand this counterintuitive lack of acid rain effect, an aqueous geochemical modeling approach was used to analyze rain runoff chemistry for the relative importance of acid rain neutralization, dry deposition, and in the case of marble, natural carbonate dissolution. This approach involved the development of pH – SO42− phase diagrams for marble (calcium carbonate) and bronze (copper) under ambient environmental conditions. This then enabled reaction path modeling of the acid neutralization process using the pH range typically found in wet deposition (3.5–6). The results were for marble that the theoretical maximum amount of Ca2+ ion that could be lost due acid rain neutralization would be 0.158 mmol/l compared to 10.5 mmol/l by dry deposition, and for bronze, the Cu2+ ion losses would be 0.21 mmol/l and 47.3 mmol/l respectively. Consequently dry deposition effects on these materials have the potential to dominate over wet deposition effects. To test these predictions the geochemical models were applied to examples of data sets from mass balance (runoff vs rainfall) studies on a marble statue in New York City and some bronze memorial plaques at Gettysburg PA. Although these data sets were collected in the early 1980s they remain valid for demonstrating the mass balance method. For the marble statue, the mean Ca2+ losses by dry deposition was about 69% of the total compared 0.3% for acid rain neutralization, which was less than the natural carbonate dissolution losses of 0.8%. For the bronze, the mean Cu2+ losses were 70.6% by SO42− dry deposition and 23% by NO3− dry deposition compared to 6.4% by acid rain neutralization. Thus for both cases the wet deposition component was less than the variability of the dry deposition components, which explains the observed lack of correlation between the rain pH and the material losses. In addition, for the marble case, there was evidence for HCl acid vapor attack resulting from nitric acid/sea salt interactions and for bronze, ammonium ion may be important. In both cases, significant imbalances suggested that unmeasured organic acids may have a significant effect.

DETERMINING THE IMPACTS OF LAND COVER/USE CATEGORIES ON LAND SURFACE TEMPERATURE USING LANDSAT8-OLI

Abstract. Due to unplanned and uncontrolled expansion of urban areas, rural land cover types have been replaced with artificial materials. As a result of these replacements, a wide range of negative environmental impacts seriously impacting human health, natural areas, ecosystems, climate, energy efficiency, and quality of living in town center. In this study, the impact of land surface temperature with respect to land cover and land use categories is investigated and evaluated for Istanbul, Turkey. Land surface temperature data was extracted from 21 October 2014 dated Landsat 8 OLI data using mono-window algorithm. In order to extract land use/cover information from remotely sensed data wetness, greenness and brightness components were derived using Tasseled Cap Transformation. The statistical relationship between land surface temperature and Tasseled Cap Transformation components in Istanbul was analyzed using the regression methods. Correlation between Land Surface Temperature and Meteorological Stations Temperature calculated %74.49.

DETERMINING THE IMPACTS OF LAND COVER/USE CATEGORIES ON LAND SURFACE TEMPERATURE USING LANDSAT8-OLI

Due to unplanned and uncontrolled expansion of urban areas, rural land cover types have been replaced with artificial materials. As a result of these replacements, a wide range of negative environmental impacts seriously impacting human health, natural areas, ecosystems, climate, energy efficiency, and quality of living in town center. In this study, the impact of land surface temperature with respect to land cover and land use categories is investigated and evaluated for Istanbul, Turkey. Land surface temperature data was extracted from 21 October 2014 dated Landsat 8 OLI data using mono-window algorithm. In order to extract land use/cover information from remotely sensed data wetness, greenness and brightness components were derived using Tasseled Cap Transformation. The statistical relationship between land surface temperature and Tasseled Cap Transformation components in Istanbul was analyzed using the regression methods. Correlation between Land Surface Temperature and Meteorological Stations Temperature calculated %74.49.

Geomorphology as a first order control on the connectivity of riparian ecohydrology

Geomorphic controls on ecohydrological connections, while implicit in processes such as the derivation of transpired water from alluvial aquifers, have not been systematically investigated. In this article we test the hypothesis that geomorphic setting is an important control on groundwater-sourced riparian evapotranspiration (ET) through a statistical investigation of 30years of daily flow data, monthly precipitation data, and semimonthly satellite images at fourteen 1-km-long river reaches representing a range of geomorphic settings in the semiarid landscape of New Mexico, USA. We focus on correlations between vegetation greenness (as a surrogate for vigor and transpiration rates), interannual variability in flow and rainfall characteristics, and valley metrics such as width, slope, and concavity. Sites were considered individually and in groups based on classification as perennial or intermittent. Principal component analysis (PCA) was used to distill related metrics into significant, uncorrelated, interpretable, underlying variables. Components were interpreted in the same manner as a factor analysis and were found to include overall magnitude of greenness, within-summer variability of greenness, overall wetness, rain vs. flow dominance, snowmelt vs. monsoon dominance, and mountain vs. basin geomorphic setting, among others. To broadly test the hypothesis that geomorphology affects the relationship between wetness and greenness, best subset regressions were constructed for the full range of sites and groups using all wetness and geomorphic components as potential predictor variables and greenness metrics as response variables. From our analysis we draw two main conclusions: (1) including geomorphic parameters provides new information that is nonredundant with precipitation and flow parameters in predicting vegetation extent and vigor. The parameters, especially curvature, may indicate causal processes, such as increased soil moisture availability on concave surfaces with convergent flow paths, or they may provide correlative information on the groundwater setting (gaining vs. losing). (2) When considering groups of sites, the dominance of precipitation over stream flow in delivering moisture was a predictor of high greenness; but this was not the case for any individual sites. This indicates that while greener communities developed in sites with greater average precipitation, at any single site the vegetation was able to adapt to either local precipitation or streamflow delivery of moisture in a given year and only the magnitude of the moisture delivered affected vegetation vigor. These findings emphasize the versatility of riparian vegetation to utilize soil moisture in convergent geomorphic settings or wet time periods, moisture that may otherwise tend to evaporate.

Determination of Zenith Tropospheric Delay and Precipitable Water Vapor using GPS Technology

Abstract In order to be able to be process GPS data, the GPS signal it has to pass the entire terrestrial atmosphere – both neutral atmosphere and ionosphere – which may cause an alteration of the GPS receiver to perform, resulting in large errors in the final position estimate. The dual frequency GPS receivers are affected by the influence of the atmosphere, especially by the troposphere. To estimate the delay caused by the troposphere and to obtain a high degree of accuracy, mapping function has to be used in the estimation process, which opens the door for remote sensing the atmosphere. Because the wet component from the hydrostatic and non-hydrostatic part, is only 10% of the total neutral atmospheric part, its influence is considerate significant in the application of high-precision positioning in which GPS receivers are employed. The article presents the determination of the precipitable water vapor using relative using four permanent GPS stations. The estimation were done by using the Global Mapping Function - GMF and the apriori pressure and temperature from the GPT2 model.

An Immunology Course-Based Research Experience for Undergraduate Students that Introduces Computational and Modeling Skills

Abstract Previously, we developed a computational modeling lab for undergraduate immunology students that introduced them to the SIR model and the Vensim modeling program. In short, students modeled an epidemic of strep throat and were required to model the Susceptible (S), Infected (I) and Recovered (R) in order to find the best approach to decreasing the length of the epidemic and the number of people infected. While this lab experience was valuable in teaching some basic immunology and modeling skills, the short time frame for the lab provided limited exposure to the importance and potential of modeling skills in immunology. Here we developed a semester-long course-based research experience (CRE) where students develop their own hypothesis, design the experiments, conduct the studies, and analyze their findings. Moreover, in addition to the wet lab component that exposes students to immunology techniques such as flow cytometry, qRT-PCR, cell separation and tissue culture, the students model a signaling pathway providing them with experience in computational modeling. We developed a software package that generates a computational model in Netlogo from the specifications provided by the students. The computational approach allows students to model any type of cell signaling cascade providing a large number of possible hypotheses that can be tested. We piloted this approach with four first-year students with no immunology or modeling/programming experience and the students successfully generated and tested their own hypotheses, and using Netlogo they modeled several different G Protein Coupled Receptor signaling cascades in CD4 and CD8+ T cells. We are in the process of running this CRE with students enrolled in a 200 level immunology class.

Drying behaviour and microbial load after water damage

Purpose – The water damage in buildings because of leaking pipes and increasingly because of floods and severe weather require professional help. Methods for improved repair and remediation techniques have to be developed. The water damage in buildings because of leaking pipes and increasingly because of floods and severe weather require professional help. Methods for improved repair and remediation techniques have to be developed. The paper aims to discuss these issues. Design/methodology/approach – Therefore, large scale laboratory tests with four rooms, each with three types of masonry walls (Figure 2 and Plate 1) and typical floors for intermediate storeys with insulation were performed within a climate simulator. Artificial water damage was provoked through watering the floors, and the dispersion of water in the floors and the rising damp in the walls was measured. In the follow-up to the watering of the floors, a company specialized in drying wet buildings, installed systems for under floor drying and wall drying. Findings – The drying process of the different components and layers of the floor construction and walls was monitored by a measuring system with more than 300 sensors for moisture content, relative humidity and temperature accompanied by thermography and demonstrated so the advantages and disadvantages of the different tested drying systems. After providing an initial contamination that is typical for construction sites, the microbial load (mould infestation) within the wet components was monitored at different times by experienced biologists. So after three weeks under floor drying no mould growth could be asserted but more bacteria than expected were found. Originality/value – The aim of the research was to gain more confidence in selecting appropriate drying procedures and systems in order to identify the right moment for terminating the drying process. A further intent was to acquire data for computer simulations.

Atmospheric deposition as an important nitrogen load to a typical agro-ecosystem in the Huang-Huai-Hai Plain. 2. Seasonal and inter-annual variations and their implications (2008–2012)

Abstract Atmospheric nitrogen (N) deposition, an important N source to agro-ecosystems, has increased intensively in China during recent decades. However, knowledge on temporal variations of total N deposition and their influencing factors is limited due to lack of systematic monitoring data. In this study, total N deposition, including dry and wet components, was monitored using the water surrogate surface method for a typical agro-ecosystem with a winter wheat (Triticum aestivum L.) and summer maize (Zea mays L.) rotation system in the Huang-Huai-Hai Plain from May 2008 to April 2012. The results indicated that annual total N deposition ranged from 23.8 kg N ha−1 (2009–2010) to 40.3 kg N ha−1 (2008–2009) and averaged 31.8 kg N ha−1. Great inter-annual variations were observed during the sampling period, due to differences in annual rainfall and gaseous N losses from farmlands. Monthly total N deposition varied greatly, from less than 0.6 kg N ha−1 (January, 2010) to over 8.0 kg N ha−1 (August, 2008), with a mean value of 2.6 kg N ha−1. In contrast to wet deposition, dry portions generally contributed more to the total, except in the precipitation-intensive months, accounting for 65% in average. NH 4 + -N was the dominant species in N deposition and its contribution to total deposition varied from 6% (December, 2009) to 79% (July, 2008), averaging 53%. The role of organic N (O–N) in both dry and wet deposition was equal to or even greater than that of NO 3 − -N. Influencing factors such as precipitation and its seasonal distribution, reactive N sources, vegetation status, field management practices, and weather conditions were responsible for the temporal variations of atmospheric N deposition and its components. These results are helpful for reducing the knowledge gaps in the temporal variations of atmospheric N deposition and their influencing factors in different ecosystems, to improve the understandings on N budget in the typical agro-ecosystem, and to provide references and recommendations for field nutrient management in this region.

Impact of Tropospheric Delay Gradients on Total Tropospheric Delay and Precise Point Positioning

GPS signals are electromagnetic waves that are affected by the Earth’s atmosphere. The Earth’s atmosphere can be categorized, according to its effect on GPS signals, into the ionosphere (ionospheric delay) and neutral atmosphere (tropospheric delay). The first-order ionospheric delay can be eliminated by linear combination of GPS observables on different frequencies. However, tropospheric delay cannot be eliminated because it is frequency-independent. The total tropospheric delay can be divided into three components. The first is the dry component, the second part is the wet component, and the third part is the horizontal gradients which account for the azimuthal dependence of tropospheric delay. In this paper, the effect of modeling tropospheric gradients on the estimation of the total tropospheric delay and station position is investigated. Long session, one month during January 2015, of GPS data is collected from ten randomly selected globally distributed IGS stations. Two cases are studied: the first case, the coordinates of stations are kept fixed to their actual values and the tropospheric delay is estimated twice, with and without tropospheric gradients. In the second case, the station position is estimated along with the total tropospheric delay with and without tropospheric gradients. It is shown that the average bias of the estimated total tropospheric delay when neglecting tropospheric gradients ranges from ?1.72 mm to 2.14 mm while the average bias when estimating gradients are ?0.898 mm to 1.92 mm which means that the bias is reduced by about 30%. In addition, the average standard deviation of the bias is 4.26 mm compared with 4.52 mm which means that the standard deviation is improved by about 6%.

Publishing code is essential for reproducible flow cytometry bioinformatics.

Publishing code is essential for reproducible flow cytometry bioinformatics.

Вопросы повышения информативности измерения градиентных изменений температурных показателей атмосферы с помощью GPS

Abstract: It is well-known, that GPS system upon presence data on values of such parameters as total pressure at the surface and mean temperature of troposphere allow to determine the total amount of water vapors in atmosphere. Division of total delay of GPS signals on hydrostatic and wet components is carried out upon presence data on surface pressure. Upon presence data on mean atmospheric temperature and wet delay the total amount of water vapors can be calculated. It is shown, that in the theory of atmospheric temperature measurements the presence of data on such parameters as speed of changes of vertical gradient of mean atmospheric temperature and temperature of dry surface is important. The optimization task is formulated, according which between the speeds of changes of vertical gradient of mean atmospheric temperature and temperature of dry surface should be calculated such an interrelation function upon which the integral entropy of above said parameters reaches the maximum value. The solution of the optimization task does show that the optimum function between two above said parameters has an additive shift component.

Genetic origin of sour gas condensates in the Paleozoic dolomite reservoirs of the Tazhong Uplift, Tarim Basin

Twenty gas condensates, six oils and their associated formation water from the Tazhong Uplift in the Tarim Basin, NW China were characterized for their molecular and isotopic compositions and water chemistry to elucidate the origins of the sour condensates. Thermochemical sulfate reduction (TSR) is the main secondary alteration process relevant to the generation of sour gas condensates. Those condensates are slightly heavier than regular condensates with a wide range of physical property and chemical composition variations. The hydrogen sulfide (H2S) concentrations in gas phase show a strong positive correlation to gas/oil ratio, organosulfur compound (OSC) concentrations in the liquid phase. While methane isotopic values are mainly controlled by thermal maturity, wet gas components show unusual 13C enrichment at a low degree of thermal cracking. Geochemical anomalies occur mainly in the Lower Ordovician Yingshan Fm. where more H2S has been discovered, while the Upper Ordovician Lianglitage Fm. shows less irregularity and H2S concentration is much lower. Generation of sour gas condensate is most likely caused by TSR alteration, which could oxidize liquid hydrocarbons and form a large quantity of OSCs. Isotopic enrichment of 34S in formation water sulfate and elevated OSC concentrations provide supplemental evidence of TSR alteration. Both burial history reconstructions based on fluid inclusion analysis and PVT simulation indicate that in situ TSR reactions mainly occurred around last 10 Ma during the late Himalayan orogeny and overall TSR extent is relatively low in the Tazhong Uplift.

Diagnostics of atmospheric water vapor content according to GPS measurements

A continuously operating GPS network, comprising seven permanent observation sites, is created to study the geodynamic processes in the Baikal region. Processing of the initial GPS data provides continuous atmospheric data in the form of total zenith tropospheric delay, which can be used for meteorological and climatological studies. The total delay is the sum of “dry”, or hydrostatic, and “wet” components. The wet component determines the total water vapor amount and amount of precipitable water over the measurement site. Thus, GPS measurements make it possible to obtain initial data for creating new numerical models of zenith tropospheric delay and total precipitable water vapor for meteorological applications.

Microwave radiometer observations of interannual water vapor variability and vertical structure over a tropical station

AbstractThe intraseasonal and interannual characteristics and the vertical distribution of atmospheric water vapor from the tropical coastal station Thiruvananthapuram (TVM) located in the southwestern region of the Indian Peninsula are examined from continuous multiyear, multifrequency microwave radiometer profiler (MRP) measurements. The accuracy of MRP for precipitable water vapor (PWV) estimation, particularly during a prolonged monsoon period, has been demonstrated by comparing with the PWV derived from collocated GPS measurements based on regression model between PWV and GPS wet delay component which has been developed for TVM station. Large diurnal and intraseasonal variations of PWV are observed during winter and premonsoon seasons. There is large interannual PWV variability during premonsoon, owing to frequent local convection and summer thunderstorms. During monsoon period, low interannual PWV variability is attributed to the persistent wind from the ocean which brings moisture to this coastal station. However, significant interannual humidity variability is seen at 2 to 6 km altitude, which is linked to the monsoon strength over the station. Prior to monsoon onset over the station, the specific humidity increases up to 5–10 g/kg in the altitude region above 5 km and remains consistently so throughout the active spells.

Experimental study on the gas generation processes of lacustrine and marine shales in North China: Source implications for shale gas

Using a high pressure, semi-closed thermal simulation system, two organic-rich lacustrine and marine immature shales from North China were investigated to probe the dynamic processes and potential for the gas generation throughout the oil-gas window. The results identified at least two processes during gas generation, as revealed by changes of the gas dry coefficient (C1/ΣC1-5%) and carbon isotopic composition of methane (δ13Cmethane). The first process is associated with kerogen thermal degradation and occurs during the main phase of oil generation, showing an increasing trend of the dry coefficient and δ13Cmethane. The second process begins during the late phase of oil generation, accompanied by increasing yields of wet gas components and 13C depleted methane. Due to the lack of aliphatic carbon in kerogen in the highly to over mature stage, as demonstrated by FTIR analyses, the second process is mainly related to the cracking of kerogen-generated bitumen which is retained in the shale.The hydrogen content, a key parameter for petroleum generation, is then used to quantitatively evaluate the gas generation potential from kerogen thermal degradation and retained-bitumen cracking. Mass balance calculations show that kerogen-generated bitumen that is retained in lacustrine and marine shales is estimated to contribute 30% of the total gas yields at the stage of 1.5–2.0% Ro. This result is consistent with the theoretical calculations from Xia et al. (2013) and has important implications for the shale gas sources, and further the shale gas resource assessments before exploration in shale-gas petroleum systems.

Wet dark fluid with linearly varying deceleration parameter and type-V future singularity of the Bianchi type-I universe

This work deals with the study of the dynamics of a spatially homogeneous and anisotropic Bianchi type-I universe filled with two minimally interacting isotropic fluids: cold dark matter and wet dark fluid components. To obtain an exact solution of the Einstein’s field equations, we have used the assumption of linearly varying deceleration parameter. Under suitable conditions, it is observed that the solution describes effectively the current acceleration and indicates occurrence of a type-V future singularity in the late time evolution of the universe. As the solution shows that the universe has a finite lifetime and passes through a significant time when energy densities of both the dark components are nearly comparable, so considering the coincidence parameter r to be a free parameter and $\frac{1}{r_{0}} < r< r_{0}$ , where r 0 is any fixed ratio, we have calculated the important fraction f of total life time of the universe when it passes through the coincidental stage before the singularity. We have also discussed the consistencies of our results with the recent cosmological observational data.

Bionanocomposite Films from Resilin-CBD Bound to Cellulose Nanocrystals

This research explores the properties of bionanocomposite films prepared by binding recombinant resilin-like protein (res) consisting of the exon 1 resilin sequence from Drosophila melanogaster, engineered to include a cellulose binding domain (CBD), to cellulose nanocrystals (CNCs). The optimal binding of res-CBD to CNCs was 1:5 by mass, and the resulting res-CBD-CNCs remained colloidally stable in water. Res-CBD-CNCs were solventcast into transparent, free-standing films, which were more hydrophobic than neat CNC films, with water contact angles of 70–80° compared to 35–40° for the latter. In contrast to the multi-domain orientation typical of chiral nematic CNC films, res-CBD-CNC and CBD-CNC films exhibited long-range, uniaxial orientation that was apparently driven by the CBD moiety. Glycerol was studied as an additive in the films to determine whether the addition of a wet component to solvate the recombinant protein improved the mechanical properties of the res-CBD-CNC films. In comparison to the other films, res-CBD-CNC films were more elastic with added glycerol, in the range of 0.5–5 wt% (i.e., the films responded more elastically to a given strain and/or were less plastically deformed by a given mechanical load), but became less elastic at 25 wt% glycerol. Overall, films made of res-CBD-CNCs plus 0.5 wt% glycerol displayed improved mechanical properties compared to neat CNC films, with an increase in toughness of 150% and in elasticity of 100%.

Printed organic electronic device components from edible materials

ABSTRACTThe electrical and mechanical characteristics of ionic-covalent entanglement hydrogels consisting of combinations of the edible biopolymers gellan gum and gelatin were investigated. Impedance analysis and compression testing showed that these hydrogels (with water content = 97%) exhibited conductivity values of up to 13 mS/cm and compressive stress at failure values of up to 1.0 MPa. These are suitable characteristics for printed and mechanically robust wet device components.

Assessment of Surface Water Dynamicsin Bangalore Using WRI, NDWI, MNDWI, Supervised Classification and K-T Transformation

Bangalore, the IT capital of India, is one of the fastest growing city of Asia. Rapid urbanization of Bangalore during the last two decades has posed a serious threat to the existence of ecological systems, specifically water bodies which play a crucial part in supporting life. Remote Sensing Satellite images can play a significant role in investigation, dynamic monitoring and planning of natural surface water resources. Landsat-7 Enhanced Thematic Mapper(ETM+) imagery havehigh spatial, temporal and multispectral resolution and thereforeprovides reliable and accurate data to detect changesin extent of water bodies. In this paper, a study has been conducted to detect the changesin water body extent during the period of 2002 to 2014 using various methods namely Water Ratio Index (WRI), Normalised Difference Water Index (NDWI), Modified Normalised Difference Water Index (MNDWI),supervised classification and wetness component of K-T transformationand the results are presented.Several iterations were performed to determine a suitable threshold for effective water detection in urban areas for each of the methods. The performance of each of the algorithms was compared and verified via ground survey. This study indicates a considerable variation in water surface area of the city over a span of 12 years.