Lysimeter study to identify GPR response under different contaminant level in groundwater

Potentials of groundwater contamination due to different pollutant loads can be assessed using different technologies available through quality detection, mapping extend of the contaminant plume and migration of the plume. Real field situation is very complex and application of some techniques might be a challenging task especially with respect to data interpretation. Creating of controlled condition which represents the real field situation is very much important to understand the field situation and applicability of such techniques. Among the available geophysical methods, ground penetrating radar (GPR) technique is suitable for studying the subsurface features. A lysimeter (4.0 m x 1.0 m x 1.5 m (L x W x D)) study was conducted at the Meewathura farm of the Department of Agricultural Engineering, University of Peradeniya to verify the applicability of the GPR technique in detecting contamination level in groundwater. The lysimeter was filled with sand as a media and two iron bars (with a diameter of 5 cm) were placed at 1.0 m and 3.0 m length intervals at 0.2 m above from bottom of the lysimeter. GPR reflection surveys were carried out on lysimeter at different level of contamination. GPR wave response was studied under each situation and analyzed the reflected waves from bottom of the lysimeter and iron bars. 2D GPR wave simulations were carried out using GPRMAX2D for the same lysimeter conditions. For this purpose, a contamination plume with different EC values (to obtain different contaminant levels) in groundwater was introduced to the model domain. Both modeling result and lysimeter study were revealed that the energy of reflected wave attenuated and disappear the reflected event with increasing contaminant level (increasing EC)

Measuring and modeling of GPR ground wave depth penetration under transient soil moisture conditions in

Abstract-This study represents the first attempt to investigate the C;PR direct ground wave sampling depth by comparing GPR estimated soil moisture contents with data from horizontally and vertically installed TDR probes at different depths. The GPR direct ground wave method (200 MHz centre frequency) was used to estimate the temporal soil moisture dependence during uniform irrigation and drainage. Uniform irrigation and drainage experiments were conducted in an experimental pit (2.5 x 1.01 x 0.8 m) filled with repacked sandy loam soil. The GPR moisture contents measurements were more consistent with the moisture contents from vertically installed TDR than horizontally installed TDR. An analytical solution for onedimensional drainage of water was used to estimate the change in GPR ground wave sampling depth during drainage. The analytical solution was first fit to vertical TDR data to obtain an estimate of the soil hydraulic parameters and the GPR sampling depth was then estimated by fitting the drainage solution to the measured GPR data. The GPR direct ground wave sampling depth using the analytical solution during drainage varied from -20 cin at high moisture content to -50 cm at the lowest moisture conten

Field mapping of wetting front using ground penetrating Radar under uniform and non-uniform wetting

This research was carried out to develop 2D and 3D maps of a wetting front and to identify potential preferential flow areas using Ground Penetrating Radar (GPR). GPR grid data were collected during uniform and non-uniform wetting experiments. Maps were prepared for different depth profiles for each data set, collected at different time intervals after starting water application. The wetting front had reached a maximum depth of 0.45–0.50 m within 25 hours of continuous wetting based on 2D and 3D GPR images. In the uniform wetting experiments, potential preferential flow zones could be identified in 2D and 3D maps

Distinguishing Capillary Fringe Reflection in a GPR Profile for Precise Water Table Depth Estimation in a Boreal Podzolic Soil Field

Relative permittivity and soil moisture are highly correlated; therefore, the top boundary of saturated soil gives strong reflections in ground-penetrating radar (GPR) profiles. Conventionally in shallow groundwater systems, the first dominant reflection comes from the capillary fringe, followed by the actual water table. The objective of this study was to calibrate and validate a site-specific relationship between GPR-estimated depth to the capillary fringe (DCF) and measured water table depth (WTDm). Common midpoint (CMP) GPR surveys were carried out in order to estimate the average radar velocity, and common offset (CO) surveys were carried out to map the water table variability in the 2017 and 2018 growing seasons. Also, GPR sampling volume geometry with radar velocities in different soil layers was considered to support the CMP estimations. The regression model (R2 = 0.9778) between DCF and WTDm, developed for the site in 2017, was validated using data from 2018. A regression analysis between DCF and WTDm for the two growing seasons suggested an average capillary height of 0.741 m (R2 = 0.911, n = 16), which is compatible with the existing literature under similar soil conditions. The described method should be further developed over several growing seasons to encompass wider water table variability

Economic Analysis of Jatropha Bio-diesel Production in Sri Lanka

There has been an increasing trend in investments in renewable energy sources in the recent years. This study assesses the economic and financial feasibility of Jatropha production in Sri Lanka under the prevailing policy regime. The nominal protection coefficient and effective protection coefficients were employed to gauge the level of protection for bio-diesel production using Jatropha in Sri Lanka. The cost benefit analysis was performed to assess the feasibility of Jatropha bio-diesel production in Sri Lanka. The conventional measures like NPV, BCR, and IRR were used in financial and economic terms. Nominal Rate of Protection (NPR) was calculated by dividing the local Jatropha bio-diesel price by the border price of biodiesel. The NPR for Bio-diesel implies that nearly 47% of protection at local market level. Effective Protection Rate (EPR) for seed production is 90%, for oil extraction and bio diesel processing it is 128%. Implication of this is that the producers will be protected and they receive returns 47% greater than what they would have received under free market conditions for Jatropha cultivation. Except for the benchmark situation, all other considered scenarios produce a favourable NPV, BCR and IRR for Jatropha bio-diesel production. Economic benefits due to CO2 reduction were also considered in the analysis.KEYWORDS:Cost benefit Analysis, Jatropha Biodiesel, Protection Coefficien

Drinking Water and Sanitation Conditions of Households in Tea Estates A Case Study from the Giragama Estate

Safe drinking water and adequate sanitation are considered as basic human rigths. The understanding ofhow many people do not have access to drinking water and sanitation may help to assess the communitieswho do not have access to the fundamentals needs and facing spread of communicable diseases. In SriLanka, the estate sector has comparatively low health and sanitation condition than the rural and urbansectors. The population coverage for water and sanitation services for urban, rural and estate sectors are100%, 82% and 62% and 100%, 82% and 55%, respectively in 2012. The Millanium Development Goals andNational Development Plan targets 80%, 90% and 100% of water for estate, rural and urban areas,respectively. In the case of sanitation they target 75%, 85% and 95% for estate, rural and urban areasrespectively. This study was conducted to investiage the drinking water and sanitation situation of househodsin two villages of the Giragama tea estate in the Central Province of Sri Lanka. The required data werecollected through a structured questioner from a randomly selected 26 households from Kudaoya and 35households from Kirimetiya watta of the Giragama estate. The main source of drinking water is unprotectedspring in Kirimettiya watta and piped water in Kudaoya. The percentage of improved source of drinkingwater is 77.2% and 94.9% in Kirimettiya watta and Kudaoya, respectively. A 51.4% and 34.6% of watercollection is done by females in Kirimettiya watta and Kudaoya, respectively. A 96.8% of households inKirimettiya watta have access to safer drinking water while it was 78.3% in Kudaoya. Boiling is found to bethe major means of treatment of drinking water for 85.3% of the population tested. Kirimettiya watta has87.3% improved sanitation facilities while it is 85.6% in Kudaoya. With respect to sanitation, 81.1% disposechildren’s faeces safely in Kirimettiya watta and this was 100% in Kudaoya. According to the overallanalysis, it can be concluded that the two villages considered in this study has a fairly good improveddrinking water facility and water availability. The households in Kudaoya have less awareness with regardto making drinking water safer. More than 85% of the households are using improved sanitation facilitiesand most of them have improved methods of childen’s fecal removal.KEYWORDS: Kirimettiya watta, Kudaoya, sanitation, drinking wate

Оценка воздействия неблагоприятных факторов среды на морских двустворчатых моллюсков с помощью метода днк-комет: автореферат диссертации на соискание ученой степени кандидата биологических наук: специальность 03.02.08 - экология

Sri Lanka’s energy policy presumes that the country will be meeting 20% of its energy requirements by non-conventional renewable energy resources by 2020. This study attempts to assess diesel vehicle owners’ willingness to pay (WTP) for Jatropha biodiesel and the factors affecting their decisions. The Contingent valuation method (CVM) was used to elicit the WTP for the non-marketed biodiesel, which leads to a hypothetical allocation. For diesel vehicle users, a single bid approach was used at Rs.121/= per litre (€ 0.83). The study was carried out in Kandy region among diesel vehicle users. The factors affecting WTP were estimated using probit regression and WTP was estimated using nonparametric estimation techniques. The mean WTP for biodiesel by the diesel vehicle users was Rs.109 per litre (€ 0.74) for lower bound levels. The median WTP was Rs.124/= per litre (€ 0.85). Elderly respondents with higher education are less likely to pay for biodiesel in both samples. Married respondents with higher income are more likely to pay higher prices for biodiesel

Assessment of the Variability of Soil Properties for OFC Cultivation under Minor Irrigation Systems

Combined paddy and other field crops (OFC) fields are unique from other wetland or upland soils, because of seasonal alternation of wetting and drying conditions resulting anaerobic and aerobic conditions. Therefore, objective of this study was to assess spatio-temporal variation of soil properties in paddy fields under minor tanks with respect to OFC cultivation. Soil samples were collected at two soil depths from 24 locations covering the entire command area of the Bayawa Minor Irrigation Tank (MIT), Sri Lanka. Soil properties were analyzed and mapped using Arc GIS. Hardpan depth (HPD) was also determined by collecting undisturbed core samples at 0, 15, 25, 30, 45 and 60 cm depths from the same locations Statistical analysis was done to identify spatio-temporal variability of each property. Results revealed that, Bayawa command area showed low coefficient of variation (CV) for pH and bulk density, but high CV for saturated hydraulic conductivity (Ks). HPD was found to be varied in each section within the effective root zone. Overall, low Ks, high clay content, high field capacity, poor drainage and the presence of hardpan are major obstacles to introduce OFC. Therefore, introduction of site specific OFC by considering the variability of soil properties is very important for sustainability of the MIT system

Soil Moisture Mapping Using Multi-Frequency and Multi-Coil Electromagnetic Induction Sensors on Managed Podzols

Precision agriculture (PA) involves the management of agricultural fields including spatial information of soil properties derived from apparent electrical conductivity (ECa) measurements. While this approach is gaining much attention in agricultural management, farmed podzolic soils are under-represented in the relevant literature. This study: (i) established the relationship between ECa and soil moisture content (SMC) measured using time domain reflectometry (TDR); and (ii) evaluated the estimated SMC with ECa measurements obtained with two electromagnetic induction (EMI) sensors, i.e., multi-coil and multi-frequency, using TDR measured SMC. Measurements were taken on several plots at Pynn’s Brook Research Station, Pasadena, Newfoundland, Canada. The means of ECa measurements were calculated for the same sampling location in each plot. The linear regression models generated for SMC using the CMD-MINIEXPLORER were statistically significant with the highest R2 of 0.79 and the lowest RMSE (root mean square error) of 0.015 m3 m−3 but were not significant for GEM-2 with the lowest R2 of 0.17 and RMSE of 0.045 m3 m−3; this was due to the difference in the depth of investigation between the two EMI sensors. The validation of the SMC regression models for the two EMI sensors produced the highest R2 = 0.54 with the lowest RMSE prediction = 0.031 m3 m−3 given by CMD-MINIEXPLORER. The result demonstrated that the CMD-MINIEXPLORER based measurements better predicted shallow SMC, while deeper SMC was better predicted by GEM-2 measurements. In addition, the ECa measurements obtained through either multi-coil or multi-frequency sensors have the potential to be successfully employed for SMC mapping at the field scale