Calibration and Validation of ADAPT and SWAT for Field‐Scale Runoff Prediction1

Abstract: The pollutant reduction possible with a given agricultural best‐management practice (BMP) is complex and site‐specific. Water‐quality models can evaluate BMPs, but model results are often limited by the lack of calibrated parameters for a given BMP. This study calibrated runoff prediction of two models (ADAPT and SWAT) for individual field plots having one till and two no‐till management practices. The factors used for runoff calibration were curve number II (CN_II) and saturated hydraulic conductivity (Ksat) for ADAPT, and CN_II, Ksat, and available water capacity for SWAT. Results were evaluated using coefficient of determination (R²), Nash‐Sutcliffe efficiency (E_f), root‐mean square error, median‐based E_f, and sign tests. Results indicated that for ADAPT, the best‐fit CN_II was 66 for the NT/SB (no‐till plot with surface‐broadcast fertilizer) treatment, 68 for the NT/DB (no‐till with deep‐banded fertilizer) treatment, and 70 for the tilled plot, whereas for SWAT the best‐fit CN_II was much higher, 86, for all treatments. Neither agreed with the textbook CN_II, 78, for sorghum in silty clay loam soil. The best‐fit model parameters for both runoff calibration phases had excellent correlation to monthly totals and moderate correlation to individual events.     

Evaluation of the mutagenic potential of chlorpyrifos (CPF) using polytene chromosomes of Anopheles mosquito

Diverse cytogenetic tests are employed for short term screening of suspect environmental mutagens by using insects and mammals as models. In the present paper the polytene chromosomes of a mosquito Anopheles maculatus were used to evaluate the mutagenic potential of a widely used organophosphate pesticide chlorpyrifos-[o, o-diethyl-o-(3, 5, 6-trichloro-2-pyridyl) phosphothioate]. The results are based on the frequency of various structural aberrations encountered in the polytene chromosomes of the larvae treated with LC20 of chlorpyrifos (CPF). These aberrations were dominated by inversions, stickiness of the chromosomes, heterochromatinization of the bands and lack of polyteny. The frequency of various aberrations was highest in the left arm of chromosome number 2L followed by 2R, 3L, 3R, and X-chromosomes i.e. 2.10 +/- 0.44, 1.84 +/- 0.44, 1.57 +/- 0.54, 1.31 +/- 0.50, and 0.22 +/- 0.27 respectively. The susceptibility of different chromosomal arms to this pesticide was 2L > 2R > 3L > 3R > X and the regions prone to these aberrations have been marked on the polytene chromosome map of Anopheles maculatus.     

Assessment of Calibration Parameters for an Aerial Gamma Spectrometry System using Monte-Carlo Technique

During a radiation emergency subsequent to a nuclear accident orweapon fallout, quick assessment of the ground contamination andthe resulting exposure is of prime importance in planning and execution of effective counter measures. For an online assessmentof ground contamination, it is essential to calibrate the detector system for several parameters viz. the source energy,source deployment matrix, the flight altitude and position abovethe contaminated surface. This article discusses the methodology to predict all the necessary parameters like photon fluence atvarious altitudes, the photo-peak counts in different energy windows, Air to Ground Correlation Factors (AGCF) and the doserate at any height due to air scattered gamma ray photons. Themethodology includes generation of theoretically simulated gammaspectra at a required detector position for a given source distribution on the ground using Monte-Carlo method provided by general purpose coupled neutron/photon transport code (MCNP CCC-200). Thus generated gamma spectra are analyzed to arrive at the required parameters mentioned above.     

AN APPLICATION OF COMPUTER GRAPHICS TO ANALYSIS OF EXTREMES1

ABSTRACT: A convenient method for the statistical analysis of hydrologic extremes is to use probability papers to fit selected theoretical distributions to extremal observations. Three commonly accepted statistical distributions of extreme hydrologic events are: the double exponential distribution, the bounded exponential distribution, and the Log Pearson Type III distribution. In most cases, probability papers are distribution specific. But, for the Log Pearson Type III distribution, the probability paper is characterized by a population-specific parameter, namely, the coefficient of skewness. It is not practicable to procure probability papers for all possible values of this parameter. Therefore, a computer program is developed to generate population-specific probability papers and to perform statistical analysis of the data using computer graphics. Probability papers covering return periods up to 1000 years or more are generated for the three distributions mentioned above. Using a plot routine, available extremal observations are plotted on selected probability papers and a linear regression analysis is used to fit a straight line to the data. Predictions of hydrologic extremes for higher recurrence intervals can be made by extrapolating the fitted straight lines.     

Effect of salicylic acid on morphological and biochemical attributes in cowpea

Effects of salicylic acid (SA) on seed germination, seedling growth, flowering and biochemical activities were studied out in four cowpea (Vigna unguiculata) genotypes in control environments. The results revealed that both germination and seedling growth were negatively affected by 0.02%. SA application, however did not affect the size of full expanded buds, time of 50% flowering and date of flower initiation. A maximum increase in peroxidase (EC1.11.1.7) activity was observed in UPC 4200 over other genotypes. No significant change in the content of total soluble and intercellular fluid proteins was observed except in UPC 4200 genotype. SA induced accumulation of total soluble sugars more at flowering stage than at seed setting stage. It is evident from the present study that UPC 4200 genotype was more responsive to salicylic acid both in terms of increased peroxidase activity and less negative effect on morphological attributes, thus suggesting its wider use without negative impact on environment as salicylic acid has been reported in plants.     

Common procedural execution failure modes during abnormal situations

The Abnormal Situation Management^® Consortium¹ funded a study to investigate procedural execution failures during abnormal situations. The study team analyzed 20 publically available and 12 corporate confidential incident reports using the TapRoot^® methodology to identify root causes associated with procedural execution failures. The main finding from this investigation was the majority of the procedural execution failures (57%) across these 32 incident reports were associated with abnormal situations. Specific recommendations include potential information to capture from plant incident to better understand the sources of procedural execution failures and improve use of procedures in abnormal situations.     

N:P stoichiometry and transparent exopolymeric particles buffer ecological impacts of nutrients in the Ganga River: a mesocosm study

We investigated the possible drivers of the N:P stoichiometric shift and its relationship with micro-algal production of transparent exopolymeric particles (TEP) along a 35?km gradient of the Ganga River. The objective was to evaluate if the trade-off between N:P stoichiometry and production of TEP helps in maintaining water quality of the river. Mesocosm experiments were conducted to examine N:P-TEP linkages and its role in turbidity removal. In situ measurements did not show Si to be a limiting nutrient (N:Si?Aulacosira granulata and Fragilaria intermedia. Settling efficiency, turbidity removal and sedimentation of TEP, biogenic silica (BSi) and biomass all increased with decreasing N:P ratio proportionately to the amount of TEP produced in the mesocosm. The study demonstrates that trade-off between N:P stoichiometry and the production of TEP generates feedback to buffer the ecological impacts of nutrient pollution.     

Environmental concerns of desalinating seawater using reverse osmosis

This Critical Review on environmental concerns of desalination plants suggests that planning and monitoring stages are critical aspects of successful management and operation of plants. The site for the desalination plants should be selected carefully and should be away from residential areas particularly for forward planning for possible future expansions. The concerning issues identified are noise pollution, visual pollution, reduction in recreational fishing and swimming areas, emission of materials into the atmosphere, the brine discharge and types of disposal methods used are the main cause of pollution. The reverse osmosis (RO) method is the preferred option in modern times especially when fossil fuels are becoming expensive. The RO has other positives such as better efficiency (30-50%) when compared with distillation type plants (10-30%). However, the RO membranes are susceptible to fouling and scaling and as such they need to be cleaned with chemicals regularly that may be toxic to receiving waters. The input and output water in desalination plants have to be pre and post treated, respectively. This involves treating for pH, coagulants, Cl, Cu, organics, CO(2), H(2)S and hypoxia. The by-product of the plant is mainly brine with concentration at times twice that of seawater. This discharge also includes traces of various chemicals used in cleaning including any anticorrosion products used in the plant and has to be treated to acceptable levels of each chemical before discharge but acceptable levels vary depending on receiving waters and state regulations. The discharge of the brine is usually done by a long pipe far into the sea or at the coastline. Either way the high density of the discharge reaches the bottom layers of receiving waters and may affect marine life particularly at the bottom layers or boundaries. The longer term effects of such discharge concentrate has not been documented but it is possible that small traces of toxic substances used in the cleaning of RO membranes may be harmful to marine life and ecosystem. The plants require saline water and thus the construction of input and discharge output piping is vital. The piping are often lengthy and underground as it is in Tugun (QLD, Australia), passing below the ground. Leakage of the concentrate via cracks in rocks to aquifers is a concern and therefore appropriate monitoring quality is needed. Leakage monitoring devices ought to be attached to such piping during installation. The initial environment impact assessment should identify key parameters for monitoring during discharge processes and should recommend ongoing monitoring with devices attached to structures installed during construction of plants.