Quantification of suspended solids in Dal lake, Srinagar using remote sensing technology

Nature of suspended solids and IRS1A-LISSI data: A case study of Tawa reservoir (Narmada Basin)

Water depth estimation using optical remote sensing offers a reliable and efficient means of mapping coastal zones. Here, we aim to find a suitable model for fast and practical bathymetry of an estuary using Indian Remote Sensing Satellite (IRS) Linear Imaging Self Scanning Sensor (LISS-3) images. The study examines three different models; (1) least square regression model, (2) spectral band-ratio method and (3) multi-tidal bathymetry model. The findings are supported with in situ observed depth values and statistical estimates. Although the least square regression model has provided best results with root mean square error (RMSE) of 0.4 m, it requires a large number of observed data points for absolute depth estimation. Spectral band-ratio and multi-tidal model provides results with RMSEs 2.1 and 0.9 m, respectively. The present investigation demonstrates that multi-date imagery exploitation at disparate tide levels is the best estimation technique for recursive shallow water bathymetry where in situ observation is not possible.

In-flight sensor Modulation Transfer Function (MTF) can be measured using ground based targets (natural/artificial) which satisfy the basic criteria. Meeting the specific conditions all the time is practically difficult. In this paper, we have explored Bi-resolution method to measure ResourceSat (RS)-2 Linear Imaging Self Scanner (LISS)-III sensor MTF. LISS-III sensor MTF was measured for three spectral bands (B2, B3 & B4) with corresponding LISS-IV bands as reference. MTF values determined for all three data sets found to meet the specifications and their variation were within 6.1% over the mean.

This paper reports the bandpass solar exoatmospheric irradiance and Rayleigh optical thickness for six categories of sensors, namely, the linear imaging self scanning sensor (LISS)-I, -II, -III, the wide field sensor (WiFS), the panchromatic (PAN), and the ocean color monitor (OCM) which have been flown on Indian Remote Sensing Satellites (IRS)-1B, -1C, -1D, and -P4 platforms, based on laboratory measurements of relative spectral response (RSR) of each band. These estimates have been compared with similar contemporary international sensors.

Land consumption is increasing rapidly with the exponential growth of population. The built-up environment configuration influences the management processes for development and other municipality works. Population growth also affects the availability of land for different purposes in its spatial distribution. The present study was conducted using satellite remote sensing data Landsat MSS (Multi-spectral Scanner), ETM+ (Enhanced Thematic Mapper), IRS P-6 (Indian Remote Sensing Satellite), LISS IV (Linear Imaging Self-Scanner), and IRS P-5 Cartosat-1 for the assessment of urban area change dynamics between years 1976 and 2008 in Bhagalpur city in the state of Bihar in India. The ground truth and coordinate points were collected using a Global Positioning System (GPS) for the location of the built-up themes prepared in the Geographic Information System (GIS). Land Consumption Rate (LCR) and Land Absorption Coefficient (LAC) were introduced to aid in the quantitative assessment changes. The results show a rapid growth in land consumption rate till 1976, reduction in 1999 and again increase in 2008.

Background & objectives: Subalpine valley along the Sutlej River has been identified as an endemic focus for Cutaneous Leishmaniasis (CL) in Himachal Pradesh (H.P.). The present study was undertaken with aim to find out the climatic and ecological determinants responsible for distribution of sand flies and occurrence of Cutaneous Leishmaniasis in Himachal Pradesh. Methods: Collections of sand flies were made in the Shimla, Kullu, and Nichar districts of H.P. during 2017 and 2019. The climatic data were procured from Indian Meteorological centre, Shimla (H.P). The satellite images (Indian remote sensing satellite (IRS)-Linear imaging self-scanner (LISS)-IV sensor multispectral data) having resolution of 5.8m were procured from National Remote Sensing Centre Hyderabad, India. The relationship between the incidence of CL and Land use was analysed. Results: A total of 332 sand flies were collected. The transmission of CL was favoured by temperatures exceeding 20°C over a period of six months, specifically from April to September. The valley with an elevation ranging between 1000 to 1250 meters reported 90% of the CL cases. The correlation between CL incidence and land use patterns revealed a notable rise in barren land (8%) and scrub land (5%) from 2013 to 2017. Interpretation & conclusion: The findings reveals that specific meteorological conditions and land cover play significant role in determining the presence of sand flies in Himachal Pradesh. To effectively control CL, it is recommended to implement control programs primarily between June and September, focusing particularly on regions with elevations ranging from 1000 to 1250 meters.

In this study an attempt is made for studying the Himalayan glacier features using TerraSAR-X and Indian Remote Sensing Satellite, Linear Imaging Self Scanning System III (IRS LISS –III) images. New generation, synthetic aperture radar (SAR) data from TerraSAR-X (TS-X) sensor provide opportunity for glacier feature studies in Himalayan rugged terrain. Spot Light High resolution mode TS-X data give idea about glacial features which remained untraceable from other existing SAR system. However, presence of speckle noise in SAR images degrades the interpretability of the glacier features. Speckle suppression filters (Lee, Frost, Enhanced Lee, Gamma-Map) are applied on SAR intensity images. On the basis of field sight seeing and insitu observations it is observed that still features are not clear. Hence attempt has been made for fusing multitemporal multispatial speckle reduced TS-X SAR data and multispectral IRS LISS-III data for extracting the glacial features such as crevasses, exposed ice and superaglacier lakes. Principal component analysis (PCA) represents the high spectral resolution data in a linear subspace with minimum information loss. Herein, PCA based image fusion technique is adopted for this study and comparison is made between IHS fusion technique and PCA based technique for glacier studies in the Himalayan region.

Indian Remote Sensing Satellite-1A Linear Imaging Self Scanning System (IRS-1A-LISS-I) multispectral digital data acquired over the Tawa reservoir region have been analysed to evaluate the turbidity in the surface water. Tawa reservoir water samples were collected on 20 October 1988 concurrent with an IRS-1A overpass. The turbidity was measured at each sampling point in the field with a nephelometer. Reservoir water samples were analysed for total suspended matter, grain size and mineralogy. IRS-1A-LISS-I computer-compatible tapes were obtained from the National Remote Sensing Agency (NRSA), India. The relationship between the LISS-I digital data of 20 October 1988 and the measured values of turbidity was established. The results indicate that, in the turbidity range between 15–45 NTU (nephelometric turbidity units), a positive relationship exists between the turbidity and the visible wavelength band 1, 2 and 3 (0.45 to 0.68 μm) mean pixel values. Shorter wavelengths, especially in band 3 (0.62–0.68 μm), are more useful than longer wavelengths (near infrared) in quantifying turbidity. The concentration, mineralogy and grain size of the suspended matters are the main factors which influence the reflected radiance at low concentration levels (15–45 NTU) of turbidity. There is a positive correlation between reflectance, turbidity and suspended sediment concentration. It can be concluded that, as turbidity increases in the 15–45 NTU range, the spectral response increases. It appears that IRS-1A-LISS-I data could be developed as a practical tool in water quality monitoring.

Behavior of suspended solids in supernatant of containment area

The article presents information on open-air overflow swimming pools and their water exchange systems. It defines the principle of open-air swimming pool operation and shows the developed mathematical model of its water regime describing the change in concentration time of suspended solids in the pool basin water depending on the qualitative composition of the feed water (drinking or circulating water after cleaning). A number of design parameters (building volume of the pool basin, the water-surface area), technological indicators (initial concentration of suspended solids in water, feed water consumption and concentration of suspended solids), standard ratios (average number of pool users, the amount of pollution coming from one person, the maximum permissible concentration of suspended solids in the pool water), as well as meteorological conditions at the pool location (rain intensity and hours of rainfall, dustiness, and the volume of atmospheric air above the pool basin) have been analyzed as basic elements of pool operation. The article also provides information about a computer program for calculating the water regime of the pool and the results of an automated calculation of the pool performance period (in days) when the technological and regulatory parameters of its operation, designed to provide the required sanitary standards for the concentration of suspended solids in the pool basin water, change. Based on automated calculation, four alternative cases of the pool operation have been reviewed, in which the average number of pool users is used as a variable value of the standard parameter. The change dynamics of the duration (in days) of safe user stay in the pool have been determined and analyzed, indicating the need to reduce the time of its operation in proportion to the number of users, all other things being equal.

Sustainable practices require that manure nutrients be reused within the agricultural sector. Reverse osmosis (RO) is one of the few technologies capable of producing nitrogen and potassium concentrates that can be transported to fertilize distant cultivated fields. However, solid-liquid separators produce a liquid fraction that could significantly foul RO membranes because of high colloidal and particulate concentrations. This project investigated the effect of high suspended solids (SS) concentrations, ranging from 258 to 3897 mg L-1, in pretreated manure on the performance of a spiral-wound RO membrane. The effluents were first concentrated to 47% of the initial volume. The concentrates, containing from 453 to 6893 mg SS L-1, were then filtered in full-recycle mode for a total of 22.5 h. Permeate flux stabilized during the full-recycle filtration period at SS levels up to 4000 mg L-1 in RO concentrate, but it was 13% lower at 4016 than at 453 mg SS L-1. At the highest SS level of 6893 mg L-1 in concentrate, flux decreased throughout the full-recycle filtration period, and it was 27% below that measured at 453 mg L-1 after 22.5 h. Lower flux was attributed to the formation of a concentrated gel layer at the membrane surface. While the thickness or density of the gel layer appeared to stabilize below 4000 mg SS L-1 in concentrate, it kept increasing at the highest tested SS level. However, with all effluents, the gel layer was easily removed by rinsing the membrane with tap water, and water flux recovery after rinsing (82.3% 1.6%) and chemical cleaning (99.1% 1.2%) were similar at all SS concentrations. Results thus suggested that spiral-would RO membrane systems could be used to directly process swine manure pretreated by physically based solid-liquid separators, but permeate flux will be significantly reduced at SS concentrations above 4000 mg L-1 in the membrane element.

Application of a membrane bioreactor for treating explosives process wastewater

Chlorophylla (chl-a) and suspended solid concentrations are two frequently used water quality parameters for monitoring a lake. Traditional measurement of chl-a and suspended solids, requiring laborious laboratory work, which is often expensive and time consuming. Hyperspectral remote-sensing measurement provides a fast and easy tool for estimating water trophic status.In situ hyperspectral data on March 7–8, July 6–7, September 20 and December 7–8, 2004 and the corresponding water chemical data were used to regress the algorithm of water quality parameters. Results showed that the peak of water leaving radiance around 700 nm (R700) varied proportionally with chl-a concentration, and moved to infrared when algal bloom occurred. The reflectance ratio ofR702/R685 was well correlated with chl-a when water surface in no algal bloom case and the correlation coefficient was better if absorption of phycocyanin was considered. The reflectance ratioR620/R531 was highly correlated to the concentration of suspended solids. The relationship between suspended solids and other band groups were also compared. Secchi disk depth could be calculated by non-linear correlation with suspended solids concentration.

The paper presents a geospatial modeling approach for the assessment of plant richness in Barsey Rhododendron Sanctuary in Sikkim, a Himalayan State of India located in the “Indo‐Burma” biodiversity hotspot. Remotely sensed data from Indian Remote Sensing Satellite IRS‐1C Linear Imaging Self‐Scanner (LISS‐III) and field‐based methods were synergistically used to model plant richness on 1:50,000 scale. It was found that the sanctuary is dominated by East Himalayan Moist Temperate Forest (55.50%), followed by Rhododendron Forest (23.77%), Degraded Forest (6.66%) and Hemlock Forest (0.78%). The vegetation map prepared through digital interpretation of satellite imagery was subjected to landscape analysis and assessment of biotic disturbance in terms of disturbance index. The disturbance index together with species richness, ecosystem uniqueness, total importance value and terrain complexity was modeled to assess the plant richness in this unique sanctuary. Out of the 120 km2 of the total geographical area of the sanctuary, 28.45 per cent was found to possess very high plant richness followed by high (50.84%), medium (6.96%) and low richness (13.75%). It was noted that plant richness assessment at ecosystem level presents a more realistic picture than at landscape level. The study demonstrated that remote sensing coupled with landscape analysis, ground inventory data and geospatial modeling holds good potential for rapid and operational assessment of plant richness.

Investigating the transport of suspended solids by water sampling usually leads to an underestimation of loads and an unrealistically high sampling frequency is required to properly characterize temporal trends. An alternative method is to use in situ optical turbidimeters to estimate the suspended solids concentration; however, the relationship between turbidity and suspended solids concentration is potentially confounded by variations in particle size, particle composition and water colour. Field measurements, and laboratory measurements using the type of natural material suspended in streamwater, were made to quantify the influences of these factors on nephelometric turbidity (Hach 2100A) and attenuance turbidity (Partech 7000 3RP MKII). The attenuance turbidity was approximately 2.5 times higher than nephelometric turbidity. The turbidity instruments were most sensitive to dispersions with a median diameter of 1.2‐1.4γm. Particle size variation can cause the turbidity to vary by a factor of four for the same concentration of suspended solids. However, the numerous close correlations between turbidity and suspended solids concentration reported previously suggests that either the particle size variations are not usually great, or that particle size variations are often associated with variations in suspended solids concentration. For the same concentration and particle size, organic particles gave attenuance turbidity values two to three times higher than mineral particles. However, shortterm temporal variations from purely organic to purely mineral particle loads are rare in nature, so variations in the percentage of organic matter in the paniculate load will not confound turbidity to this extent. Coloured dissolved organic matter is unlikely to alter the turbidity reading by more than 10%. An adequate relationship between turbidity measured in the field and suspended solids concentration should be expected in most situations. Some variance can be tolerated because a continuous estimate of suspended solids concentration overcomes the problem of infrequent sampling, which is the greatest source of error in the estimation of stream sediment loads.