Rainfall is considered a major input in designing stormwater management measures, especially for any low-impact development (LID) control design. With the impact of climate change, rainfall frequency and its patterns are changing continuously. Quantification of these changes and their impact on the performance of LID design becomes crucial. This paper presents a methodology to quantify the change in rainfall patterns using the Coupled Model Intercomparison Project 5 (CMIP5) climate model and to select the most feasible LID for a catchment with haphazard development. Interconnected decentralization-based LID controls are evaluated with the objective of emulating a pre-urbanized scenario. The overall analyses indicated that green roof (GR) followed by infiltration trenches (IT), rooftop disconnection (RTD), and permeable pavement (PP) showed better performance. Furthermore, a combination of IT, PP, and RTD accomplishes better efficiency for extreme rainfall events. Implementation of the most feasible combination will provide the additional benefit of water recycle and reuse.

One of the challenges in urban stormwater management is to identify a suitable stormwater management method which will be socially, technologically and economically viable. In this paper, a study on the effectiveness of decentralized and interconnected percolation ponds as a stormwater harvesting technology, for a partially urbanized (semi-urban) catchment is presented. When applied to a case study region in Katpadi, Tamil Nadu, the results were encouraging. The investment required for implementing the proposed stormwater harvesting came to be about 555 Million for Option I and 714 Million for Option II. The annual volume of water that can be added to the groundwater system through infiltration from the ponds was found to be 1.22 Mm in the case of Option I and 0.74 Mm in the case of Option II. The percentage area under stormwater harvesting for the entire catchment was found to be 6.14% under Option I and 9.36 under Option II. The hydrologic performance of the proposed stormwater harvesting system indicated that for peak runoff values Option II is more efficient (in terms of minimizing runoff volume) compared to Option I; however, for daily rainfall values, Option I is hydrologically more efficient when compared to Option II.

Overcoming conventional stormwater management problems and finding appropriate control methods for safely discharging excess runoff from impervious areas is an essential part of any sustainable urban planning. This study aims to analyze the performance of different storm control measures (SCMs) applied to Vellore Institute of Technology (VIT) campus situated in Vellore, Tamil Nadu, which is a highly urbanized catchment. Different SCMs were designed for the VIT campus based on low impact development (LID) options available in stormwater management model (SWMM) software. The most suitable SCM was selected based on its ability to match pre-urbanized hydrographs as close as possible. The SCM location was identified by a localized survey, in such a way that there is least disturbance to the existing storm sewer network. The percentage reduction of peak flow under each proposed SCM were obtained as follows: bio-retention (19.8%), rain garden (18.69%), green roof (49.17%), infiltration trench (20.02%), permeable pavement (22.6%), rain barrel (12.95%), rooftop-disconnection (10.79%) and vegetative swales (17.23%). The results indicated that Option 9 (combination of permeable pavement and bioretention) and Option 10 (permeable pavement and infiltration trench) were better at reducing peak runoff and increasing infiltration. The peak runoff reduction for Options 9 and 10 were observed to be 32.05 and 39.81%, whereas the percentage increase in infiltration was observed to be 25.7 and 29.45% respectively.

Monitoring transformation of non-built-up area to urban spread via densely-stacked Land-Use-Land-Cover (LULC) classification offers a catalogue of spatio-temporal statistics to evaluate discrepancies instigated by transition factors. Impacts of major transition apparatuses in an area persuading the haphazard urbanization pattern are evaluated for Vellore acts a major contribution to Smart city project. Implications of causative factors: i) Population density; ii) proximity from rail-road-network; and iii) commercial areas are scrutinized with respect to urbanization upsurge. Multi-variate correlation is established using trend analysis and Multinomial Regression (MLR) technique for individual and homogeneous amalgamation of the aforementioned factors. Resulting equations obtained is formally used to detect closeness of urban extent from several landscapes. Research outcomes exhibited that the built-up straggling occurs from 30 to 232 m along the landscapes with a maximum of 336 m. Illustration of this study can also be assessed for various social and economic causative factors against urbanization for other smart cities.

In hydrological models, digital elevation models (DEMs) are being used to extract stream network and delineation of the watershed. DEMs represent elevation surfaces of earth landscape. Spatial resolution refers to the dimension of the cell size representing the area covered on the ground. Spatial resolution is the main parameter of a DEM. The grid cell size of raster DEM has significant effects on derived terrain variables such as slope, aspect, curvature, the wetness index, etc. Selection of appropriate spatial resolution DEM depends on other input data being used in the model, type of application and analysis that needs to be performed, the size of the database and response time. Each DEM contains inherent errors due to the method of acquisition and processing. The accuracy of each DEM varies with spatial resolution. The present paper deals with Shuttle Radar Topography Mission (SRTM), TerraSAR-X add-on for Digital Elevation Measurements (TanDEM DEMs) and compares their watershed delineation, slope, stream network and height with ground control points. It was found that the coarse resolution DEM-derived attributes and terrain morphological characteristics were strongly influenced by DEM accuracy. The objective of the present study is to investigate the impact of DEM resolution on topographic parameters and runoff estimation using TanDEM-12, TanDEM-30 and SRTM-90m with the Soil and Water Assessment Tool. The analysis of the results using different DEM resolutions gave a varied number of sub-basins, Hydrological Response Units (HRUs) and watershed areas. The results were optimum at a specific threshold value as extraction of drainage network has a significant influence on simulated results. The accuracy of DEM is important, as the source of construction of DEM is the main factor causing uncertainty in the output. The results showed variable amounts of runoff at the watershed level, which may be attributed to varied stream lengths, minimum and maximum elevations and sub-basin areas.

GIS technology is used to estimate the spatial heterogeneity of the hydrological parameters of a watershed. Hydrological models help to overcome the spatial variability and parameter uncertainties. Runoff is important parameter of hydrological cycle. Soil and Water Assessment Tool (SWAT) which is a physical distributed model developed to forecast runoff, sediment, erosion and nutrient transport from agricultural watershed helps to understand the hydrology of a watershed with rainfall, temperature, solar radiation, wind speed and relative humidity. SWAT simulates better results in both gauged and ungauged watersheds. In the present paper, Krishna river catchment area known as Jurala watershed in Mahabubnagar district, Telangana state of South India is taken to study surface runoff from agricultural areas as this area receives less annual rainfall and agriculture is mostly dependent on seasonal rainfall. Soil has less water infiltration capacity and bottom layer calcium carbonate deposits make soil alkaline due to bore well irrigation. To suggest proper water conservation methods, understanding hydrology of this watershed is important. To simulate runoff from this agriculture watershed SWAT model is used for 11 years from 2000 to 2010. The results are calibrated with observed values.

Assessment of crop condition is essential for crop monitoring and to predict productivity of the crops. The Remote Sensing data can provide near real time information about the seasonal crop status. A normalised difference vegetation index (NDVI) evaluates crop stages by inter-seasonal comparison with spatial and temporal variability. The present study is aimed to assess the crop condition of groundnut in Anantapur district for 2016. Phenological stage retrieval of crop growth is characterised by NDVI. It shows the growth stages for early to high growth period and harvesting period. NDVI images are generated using moderate resolution imaging spectroradiometer (MODIS) reflectance time series data and identified crop area. Composite seasonal NDVI images were classified into clusters using unsupervised classification (ISODATA) and crop temporal spectral response profiles were prepared from the NDVI images from June to November for 2010, 2012 and 2016. The specific NDVI changing patterns were observed with different crops, this indicates the feasibility of crop delineation with time series NDVI. The extent of groundnut cropped area was extracted in the study area using time series NDVI. The deviation of the NDVI is used to understand the crop growth in different stages and Season’s Max NDVI is used to assess the crop condition in the study area. The study revealed that crop productivity is showing a significant change from 2010 to 2016. In 2010, there were 6 mandals having poor or low condition, where as in 2016, 20 mandals were affected. By adopting this approach crop condition maps were generated.

In environmental and agricultural modelling soil moisture condition is one of the main parameter. To estimate surface soil moisture using an operational algorithm at fine spatial and temporal resolutions (thermal and optical sensors) with the help of Ts(Land Surface Temperature)/VI(Vegetation Index) space based triangle method. Theoretical solutions of dry and wet edges were derived from this method. Based on this method we calculated Soil Moisture Index using more than 8 images for year from 2007 to may 2011 for a part of Murrumbidgee catchment in southern new south wales, Australia. Insitu Soil moisture data for 20 agricultural stations were used for validating the satellite observed Soil Moisture Index. The Results indicated that the general pattern of the SMI variation follows the trend of field soil moisture measurement. Different soil backgrounds influenced the SMI computing using optical satellite image. Estimation of regional soil moisture in areas with less ground information (insitu observations) is achieved with the help of SMI model.

The scope of urbanization variation due to landscape alterations, profoundly affect the ecological features and decision-making process for built-up standards. In various parts of the globe, urbanization studies have identified a significant correlation between substantial human benefits on quality-of life, quantifiable resource utilization and local climatic parameters. Remote sensing environment has developed techniques to estimate change in spatio-temporal attributes in a georeferenced imagery. The intricate multi-signature classes and massive data interpretation for minute urban change detection for Kancheepuram, Tamilnadu. Supervised Land-use-and-Land-Cover (LULC) classification using Neural Network(NN), Minimum Distance, Support Vector Machine(SVM) & Maximum Likelihood technique to estimate change in urban class is performed. Unsupervised classification, inbuilt programmed distance learning algorithm, with ISO and K-means, is performed on preprocessed and enhanced PCAimage. Support vector machine and ISO classification techniques with enhanced imagery, on the prior basis shows more accuracy (80–85%) amongst mentioned techniques. Thus, following SVM to categorize attributes to classes and performing urban change detection. The discrepancy between new land and barren land via SVM practice remain uncertain.

Land use change is the main factor influencing watershed hydrology and could serve for developing better watershed management practices. The behaviour of each process in hydrology is influenced by its attributes and other processes. Present study analyses the impact of land use change on watershed hydrology in Nallamala forest watershed,India.The Soil and Water Assessment Tool (SWAT) is used to simulate runoff using different land use land cover (LULC) maps of 2000 and 2010. In present study land use changes and hydrological responses were quantified to investigate the runoff responses on annual basis time scale using SWAT to study the impacts of land use land cover change. A calibrated SWAT model simulated annual runoff processes for a period of 10 years i.e. 2000 to 2010. Sensitivity analysis for input parameters is analysed using the SUFI-2 algorithm in SWAT_CUP (Calibration Uncertainty Programme). Four SWAT input parameters are more sensitive including CN2.mgt, Delay.gw, sol_awc.sol and sol_k.sol. Hydrological model could simulate runoff for each sub-basin using two land use scenarios 2000 and 2010,soil map and DEM.It is observed that model results using optimised parameters, hydrological processes are better predicted with statistical evaluation methods like Nash-Sutcliffe Efficiency(NSE) and Coefficient of determination(R2). The results from present study help to quantify the potential impacts of land use land cover (LULC) change on total yield of water within watershed using SWAT model.

In this paper a novel approach for effective utilization of river assimilative capacity has been proposed. The method, referred to as waste load scheduling (WLS) is based on the principle that by restricting the effluent discharge into the river to only one polluter at any given day will allow us to utilize the available river assimilative capacity in a more efficient manner. This is achieved by scheduling the dischargeable waste load among the polluters, such that a waste load schedule once developed will specify two things: (1) which polluter has to discharge his/her effluent on a given day; and (2) what is the quantity of effluent that he/she can discharge. By scheduling the waste load discharge into the river thus, will considerably reduce the total effluent discharge into the river and hence a greater degree of water quality level can be achieved when compared to traditional waste load allocation methods. For the mathematical development of the model, the WLS problem was envisaged as analogous to a machine scheduling problem. In a simple single MS problem n number of jobs are required to be scheduled on a single machine to minimize/maximize a pre-defined performance measure. In a WLS problem, the river can be treated as a machine and the polluters discharging effluent directly into the river are analogous to the jobs to be scheduled. Treating the waste load scheduling problem in an analogous way to a MS problem enables us to apply the solution methods used for solving standard sequencing and scheduling problems to the proposed waste load scheduling problem. Although the present paper discusses the special case of waste load scheduling in which only one polluter can discharge effluent at any given day (suitable when the number of point load sources is small), it is however, possible to extend it to a more general case involving a large number of polluters as easily. In the accompanying paper, the application of the developed model to a case study has been explained in detail. The proposed model and its application proved that the model is highly efficient in solving the waste load allocation problem in a more comprehensive way.

Urban storm water management is an important aspect of any urban area development, planning and expansion. Urbanization of an area invariably leads to increase in overall imperviousness of the area. When land becomes impervious, storm water will stagnate on the surface thereby affecting the infrastructure, transportation and causing inconvenience to general populace. One way to minimize these effects is to provide a proper storm drainage system. In this paper, therefore, a small urban region was selected and for that region suitability of three different storms sewer systems were considered. The urban area considered for case study lies in the northern part of the Vellore town, and has a total area of about 25 km2 . For this region three different storm drainage systems were proposed, namely, construction of a new underground circular sewer system (Alternative 1), repair and expansion of existing surface sewer system (Alternative 2) and construction swales (Alternative 3). Of the three options, Alternative 2 was found to be economical; however it can be argued that from efficiency and aesthetics point of view 1 and 3 will be preferred alternatives. Alternative 3 can be used as a management measure for recharging groundwater aquifers, along with storm water drainage. The final selection of the option however, will depend on the suitability of the method, budgetary constraints and space availability. Keywords: Storm Water Management, Storm Sewer Design, Urban Hydrology

The present study deals with locally rotationally symmetric (LRS) Bianchi type III cosmological models representing massive string. The energy-momentum tensor for such string as formulated by Letelier [10] is used to construct massive string cosmological models. Exact solutions of the field equations are obtained with the help of: (i) proportionality relationship between rest energy density and tension density of strings; and (ii) a relationship between the metric coefficients. We have derived some models depending on different values of m. It is observed that in early stage of the evolution of the universe, the universe is dominated by strings. Our models are in accelerating phase which is consistent to the recent observations of Type Ia supernovae .The properties of the models are discussed at the end.

The field equations in scalar-tensor theory of gravitation are derived in the presence of cosmic strings .This model is used as a source of Bianchi type VI 0 cosmological model. To get a determinate model, we assume that the expansion (θ) in the model is proportional to the shear (σ).It is found that the cosmic string do exist with the scalar field. Some physical properties of the model are also discussed.

Explicit field equations of a new scalar tensor theory of gravitation proposed by the Sen-Dunn theory are obtained with the help of a five dimensional FRW metric in the context of cosmic strings. Assuming a functional relationship between the metric potentials, the solutions of the field equations are obtained in two cases: (i) geometric strings (i.e., λ = ρ) and (ii) massive strings (i.e., λ + ρ = 0). Some physical and geometric properties of the solutions are also discussed in each case.

The field equations are obtained in Sen–Dunn theory of gravitation with the help of LRS Bainchi type-I in the context of cosmic strings. We have solved the field equations when the shear σ is proportional to the scalar expansion θ. It is found that the cosmic do not exist with the scalar field except for some special cases and hence vacuum solutions are presented and discussed. c © Electronic Journal of Theoretical Physics. All rights reserved.