Dam - Seepage Analysis

This research paper focuses on conducting a steady state seepage analysis along with the downstream slope factor of safety using the Modified Bishops method in a poorly compacted earthen embankment and optimizing the same reservoir earthen embankment in a case study located near Sadiyavav village in Junagadh district in Gujarat, India. The study site, situated at 21°32'06.5"N and 70°37'26.7"E, is renowned for its Asiatic lions. The analysis and optimization were performed with a double-textured High-Density Polyethylene (HDPE) Geo-membrane barrier. Previously, designs and numerical solutions proposed homogenous embankments and too poorly compacted with no drainage arrangements, which led to anisotropic conditions within the section and water seeping out, cutting the phreatic line. The paper presents the documented improvements in the factor of safety achieved through the seepage analysis and the optimization of the HDPE Geomembrane barrier. Two improvement techniques were studied using the "Limiting Equilibrium-Finite Element Method" (LS-FEM). The first using (HDPE) Geo-membrane stabilized with gabions, and the second alternative using HDPE Geomembrane with gabions in addition to rock toe. The study results showed improvements in the downstream slope stability for the two alternatives by 3% and 10%, respectively.

Abstract: In this study, a program was built to simulate the sudden and complete collapse of the Mosul and Badush Dams behavior towards this
collapse and predict the level at which the water will balance in the two dams after the collapse, compared to different levels at the Mosul Dam
before the collapse. Two mathematical models were built as inputs to this program. The first predicted the water level in the Mosul Dam reservoir in terms of its storage volume before the collapse, and the second predicted the water level in the Badush reservoir after the collapse, according to the level in the Mosul reservoir before the collapse. For each collapse scenario, the program was organized according to sequential steps summarized assuming the water level in the Badush Dam reservoir when the level stabilizes, and from it determining the water volume in Badush reservoir based on the geometric analysis of the reservoir, then the volume of water transferred from Mosul reservoir to Badush reservoir, and thus the
volume of water inside Mosul reservoir before the collapse. From the first mathematical model, the level of the Mosul Dam reservoir was determined before the collapse. The second mathematical model determined the level of the Badush Dam reservoir after the collapse. The results showed that the program has high flexibility in predicting what will happen in the Badush Dam reservoir after the collapse based on the water level in the Mosul Dam reservoir before it collapses and that the limits of the program's work extend from the minimum to the maximum level in Mosul Dam at which the failure can occur. Also, the storage volume in Mosul Dam will be distributed to the two reservoirs after the failure until the level stabilizes. Badush Dam, at a level of 330.4 m (a.s.l), can expand the maximum flood wave resulting from the total and sudden collapse of Mosul Dam at its maximum level of 333 m (a.s.l).

Agricultural wastes are generated in rural areas can be effectively utilized for production of mushroom as food supplements as well as for income generation. The present research explored some of the unexplored locally available lignocellulosic substrates such as paddy straw, reeds, banana stem, sugar cane bagasse milled and crushed, sugar cane leaves, coir pith, sorghum husk and sun flower stem for field scale production of Pleurotus florida and Calocybe indica. The field level cultivation was carried out by 137 farmers and produced totally 15.33 tonne of P. florida and C. indica with an aggregate bioefficiency of 58.52 % and 60.38 % respectively. The produced mushrooms generated an additional income and also consumed as nutritional supplement.

The soil is a heterogeneous and anisotropic medium. Hydraulic conductivity, an intrinsic property of natural alluvial deposits varies both deterministically and randomly in space and has different values in various directions. In the present study, the permeability of natural deposits and its influence on the seepage flow through a natural alluvial deposit is studied. The 2D Finite Difference code, FLAC 5.0, is used for modeling permeability as a random variable with lognormal distribution and correlated structure. Effect of spatially varying permeability on the seepage flow through deposit is investigated for both isotropic and anisotropic conditions. Results show that in isotropic condition, the mean discharge flow rate calculated from stochastic analyses is less than the equivalent deterministic value and this reduction depends on the coefficient of variation, COV of permeability and the correlation length. The directionality of permeability introduced as mechanical anisotropy was also studied along with the heterogeneity. It was found that increasing the anisotropy ratio of permeability leads to the formation of horizontal flow canals and increasing the seepage flow consequently at a constant vertical permeability. Variation of permeability coefficient was found to have almost no impact on mean discharge flow rate for anisotropic fields in comparison to the isotropic condition.

Groins are one of the most important facilities used to protect coastal regions. In this research, groins made from a concrete cube were tested experimentally. This research investigates the impact of groin length (Lg) of 105, 135, and 165 cm and groin angle with the normal axis of the shoreline (h) of 0 °, 10 °, 20 °, and 30°under different dimensionless wave numbers (khg), from 0.34 to 1.26, with the beach slope of 8:1. The units used to indicate erosion and deposition are dimensionless erosion depth (Smax/h), dimensionless deposition height (Dmax/h), and dimensionless erosion hole length (lsmax/h). The sandy bed changes and wave reflection from the groin were monitored. The results showed that the angle of 30°h ad more impact on beach stability than that of 0°, and more sediments were eroded by short groins than by long ones. The reflection of waves from groins was also studied as a function of the reflection coefficient (kr). As concluded, short groins reflect higher waves than long ones.

Seepage is one of the main causes of dams and some other hydraulic structures' failure. Water movement beneath the dam's base creates piping and uplift pressure under the structure, potentially leading to improper dam operation. This current study focuses on the utilization of a special technique to restrict the transfer of movement water via soil which includes sheet piles under the dam foundation. Sheet pile walls are interlocking pile segments that are embedded in soil to resist horizontal pressure, classified as a flexible retaining system, and capable of tolerating relatively large deformations. Sheet piles are made of various materials, such as wood, concrete, steel, and aluminum, which are suitable for different applications. The role of seepage can be affected by the cutoff utilization. In this study, some Iraqi dam issues due to seepage are explained, also the geological stratum beneath the dam is briefly discussed. the potential use of sheet piles with different configurations has been reviewed to detect the optimum situation for seepage parameters reduction based on their numbers, interval distances, inclinations, and places.

Yung-Tse Hung, Lawrence K. Wang, Mu-Hao S. Wang, Nazih K. Shammas, Jiaping Paul Chen (2017).  Waste Treatment in the Service and Utility Industries, CRC Press, Boca Raton, Florida, USA; ISBN:  9781315164199; DOI:  https://doi.org/10.1201/9781315164199    ....    ABSTRACT:  This book volume provides in-depth coverage of environmental pollution sources, waste characteristics, control technologies, management strategies, facility innovations, process alternatives, costs, case histories, effluent standards, and future trends in the process industries. It delineates methodologies, technologies, and the regional and global effects of important pollution control practices. The authors focus on new developments in innovative and alternative technologies, design criteria, effluent standards, managerial decision methodology, and regional and global environmental conservation specific to process industries.

An alternative approach to assist the environmental engineer in his care for the geoenvironment is described in the stochastic continuum modelling of seepage from waste facilities. The prediction of seepage can be conducted for typical soil and protective layers around the containment to investigate possible contaminant movement under steady state conditions. An important parameter controlling the transport of these contaminants is the hydraulic conductivity of the soil. This paper looks at a fresh approach to the application of stochastic continuum modeling in generating hydraulic conductivity by kriged simulation. Flow and transport were computed numerically for the model. Results show that the approach is well suited for the simulation of seepage of contaminants around waste containment facilities.

In groundwater flows, if the force exerted by the flow on the soil particles is greater than the force exerted by gravity on the soil
particles, boiling occurs in the area where the water exits the ground. The main methods recommended to prevent this are increasing
the flow path length or using a gravity filter in the area where there is a risk of boiling. In impermeable dams, it is possible to increase
the length of the flow path by creating an impermeable layer in the upstream (entrance) section of the dam or by constructing an
impermeable sheet pile curtain under the dam. However, the construction of sheet pile walls under an impermeable dam is costly
and difficultIn this study, the sheet pile wall under the dam wall was placed in various positions between the upstream region and
the downstream (outlet) region of the dam, and the leakage rate value at the downstream was analyzed by the finite difference
method. Vertical seepage rate values and safety numbers against vertical boiling have been found by taking the gradient of the
hydraulic head. It has been seen that the sheet pile wall placed in the exit zone of the dam is the solution that minimizes the leakage
rate, and, therefore, maximizes the vertical safety number against boiling.

There are several methods to represent the beach changes around the composite coastal protection systems at the coastal zone. This research try to investigate and predict shoreline changes around composite shore protection systems using LITPACK software. The model represents the movement of sandy soil sediment transport under the effect of wave and current interaction. The morphological changes development along quasi-uniform beaches are investigated. The model was applied on the natural bathymetry of area which located in the neighboring of El-Hammra port at the north western coast of Egypt. The numerical model was applied to clarify the predicted rates of erosion and accretion around the existing structures and the proposed additional protection structures. The model results were calibrated with the measured shoreline from 2015 to 2017 and verified with shoreline data from 2017 to 2019. The model was performed to predict the morphological changes from 2015

CSIRO advises that the information contained in this publication comprises general statements based on scientific research. The reader is advised and needs to be aware that such information may be incomplete or unable to be used in any specific situation. No reliance or actions must therefore be made on that information without seeking prior expert professional, scientific and technical advice. To the extent permitted by law, CSIRO (including its employees and consultants) excludes all liability to any person for any consequences, including but not limited to all losses, damages, costs, expenses and any other compensation, arising directly or indirectly from using this publication (in part or in whole) and any information or material contained in it. OEH advises that this report was prepared by CSIRO in good faith exercising all due care and attention, but no representation or warranty, express or implied, is made as to the relevance, accuracy, completeness or fitness for purpose of this document in respect of any particular user's circumstances. Users of this document should satisfy themselves concerning its application to, and where necessary seek expert advice in respect of, their situation. The views expressed within are not necessarily the views of the Office of Environment and Heritage (OEH) and may not represent OEH policy.

SYNOPSIS: The paper describes the distress caused to a minor earth dam const:ructed at a high elevation in a mountainous area to conserve water. The distress related to instability of the dam and also due to high percolation underneath the dam coupled with foxmation of piping. The remedial measures taken to rectify instability and reduce percolation are described in this paper.

This research paper focuses on conducting a steady state seepage analysis along with the downstream slope factor of safety using the Modified Bishops method in a poorly compacted earthen embankment and optimizing the same reservoir earthen embankment in a case study located near Sadiyavav village in Junagadh district in Gujarat, India. The study site, situated at 21°32'06.5"N and 70°37'26.7"E, is renowned for its Asiatic lions. The analysis and optimization were performed with a double-textured High-Density Polyethylene (HDPE) Geo-membrane barrier. Previously, designs and numerical solutions proposed homogenous embankments and too poorly compacted with no drainage arrangements, which led to anisotropic conditions within the section and water seeping out, cutting the phreatic line. The paper presents the documented improvements in the factor of safety achieved through the seepage analysis and the optimization of the HDPE Geomembrane barrier. Two improvement techniques were studied using the "Limiting Equilibrium-Finite Element Method" (LS-FEM). The first using (HDPE) Geo-membrane stabilized with gabions, and the second alternative using HDPE Geomembrane with gabions in addition to rock toe. The study results showed improvements in the downstream slope stability for the two alternatives by 3% and 10%, respectively.

There are several methods to represent the beach changes around the composite coastal protection systems at the coastal zone. This research try to investigate and predict shoreline changes around composite shore protection systems using LITPACK software. The model represents the movement of sandy soil sediment transport under the effect of wave and current interaction. The morphological changes development along quasi-uniform beaches are investigated. The model was applied on the natural bathymetry of area which located in the neighboring of El-Hammra port at the north western coast of Egypt. The numerical model was applied to clarify the predicted rates of erosion and accretion around the existing structures and the proposed additional protection structures. The model results were calibrated with the measured shoreline from 2015 to 2017 and verified with shoreline data from 2017 to 2019. The model was performed to predict the morphological changes from 2015

evaluate the performance of the model are found to be 2.445ft, 1.413 ft, 1.379% and 99.442% respectively. Additionally verifiability of the model is also made by comparing observed and simulated values of piezometeric heads; such graph is illustrated in Fig. 6. The slope of the line is observed to be approximately at 45 degree; thus the Fig. indicates no considerable difference between observed and simulated head values.

The present research work is designed to
model seepage analysis of an earthen dam
by using finite element approach. For this
purpose a research study was conducted on
Hub dam, which is a small earthen dam
located at about 35 km, north-east of
Karachi city, Pakistan. In the study the
amount of seepage through and under body
of the main dam is computed, profile of
phreatic line is simulated for different
scenarios and compared with the observed
data. For the purpose of this study, SEEP/W
the sub-program of Geo-Slope software is
used. Data pertaining to design parameters
and dam geometry are given as input to the
software to compute the unknown
parameters. Finally results are validated by
comparing them with the observed data. The
main dam is composed of three different
kinds of reaches; therefore in this research
only one reach with core wall i.e. Zoned
Embankment Section at CH: 48+75 is
studied. Computations are carried out for
three different scenarios, that is: maximum
pool level, normal pool level, and minimum
pool level.

In this study, a homogeneous section of an earthen dam (Hub dam) with and
without cut-off wall was analyzed by using FEM based software SEEP/W. The
FEM model was run to compute the behavior of the dam in terms of seepage
flux and exit gradient for three different scenarios i.e. maximum (346 ft),
minimum (270 ft), and normal pool level (339 ft) respectively. The simulated
results for case (i) with cut-off wall showed that the dam is safe against piping, at
its original design with overall minimum seepage flux of (2.513 x 10-4 ft3/sec/ft)
and exit gradient (0.351) at downstream toe respectively. However, for case (ii)
without cut-off wall, the dam showed abnormal behavior as an overall extremely
high exit gradient (1.879) along with the maximum overall seepage flux of order
17.182 x 10-4 ft3/sec/ft respectively. The comparison showed that seepage flux
(29.382% – 76.946%) and exit gradient (68.604% – 75.845%) through the dam
and its foundation was found more when there are no cut-off walls. Which is the
result of continuous movement of the water within the dam especially in the
foundation, as there is no any barrier installed to control internal pore water
pressure, due to which the water seeping from the upstream and foundation
finds its way moving towards the downstream and cuts the toe to make its way
out respectively.

In this research paper, a seepage flow through a non-homogeneous earth dam at various hydraulic heads was computed by using finite element-based software (SEEP/W) and the simulated results were compared with the field observation respectively. The research work was executed on a Fontaine Gazelles dam, which is an embankment dam situated at about 35 km, northeast of Biskra province, Algeria. The outcome of the simulated results showed that the dam is safe against piping for all the scenarios, at its original design as the installation of a cutoff wall found working effectively in reducing internal pore water pressure within the dam and its foundation. The overall maximum and minimum seepage flow was recorded at the pond level 383m (5.04920 LPS) and 374m (2.100 LPS) respectively. The performance efficiency of the model was founded as 99.924%. The RMSE, MAE, and AMRE were found (0.0342015 LPS), (0.00511668 LPS), and 1.06667% respectively; which indicates that there was no major variation between observed and simulated seepage values.

In this study, a weir section of Runpur bund located in Sindh province of Pakistan
was examined. A 2-dimensional model was generated using finite element based
software Geo-Slope, SEEP/W. The model was run for two different cases i.e. (i)
original design, and (ii) without sheet piles respectively. The study aims to calculate
the amount of seepage (q) underneath the weir foundation and to calculate exit
gradient (GE) for five different hydraulic heads i.e. EL 25m, EL 25.7m, EL 26.7m, EL
27.7m, and EL 28.7m respectively. The seepage results showed that at original
design a normal behavior of the weir for various hydraulic heads was observed. The
overall maximum resultant seepage quantity (q) 7.21x10-6 m3/sec/m and exit
gradient (GE) 0.57 for the hydraulic head EL 28.7m respectively. However, abnormal
behavior of the weir without sheet piles was observed with maximum resultant
seepage quantity (q) 78.20x10-6 m3/sec/m and exit gradient (GE) 2.27 for the
hydraulic head EL 28.7m respectively. It has been found that without the provision
sheet piles the internal pore water pressure underneath the weir foundation was
increased and the overall seepage and exit gradient will increase up to 90.78% and
74.88% respectively. Therefore, the weir is not safe without the installation of sheet
piles.

Embankment dams have better stability than homogeneous earth dams, resulting in
a slimmer design in volume. The core zone, which serves as an impermeable zone,
is where embankment dams are weak. Zonal core embankment dams are a
composite of several material characteristics. Due to the intricacy of the geometry,
the material parameters, and the boundary conditions, drainage and geometric
design will have an impact on seepage and phreatic line properties. In this study
three geometric models of a non-homogenous earth dam (Hub dam) depict along
with three different scenarios i.e. (i) original design, (ii). Dam with a partial cutoff
wall, (iii). Dam with a full cutoff wall was numerically analyzed by using Geo-Slope
(SEEP/W) software. The results indicate that the cutoff wall at its original shape and
design performs better as the minimum seepage value of order 2.2117 x 10-4
(ft3/sec/ft) with an exit gradient of (0.099) and minimum seepage velocity 1.0020 x
10-6 (ft/sec) at 270 ft reservoir level. Any increment in the length of cutoff wall will be
uneconomical as it does not make much difference to minimize seepage flux,
seepage velocity, and exit gradient. For the majority of flow characteristics, the
cutoff wall's length plays a very limited role therefore, it can be said that the Hub
Dam has operated efficiently since its construction in accordance with its original
form and design.

It is not so common in dam engineering to design and construct earthfill dams with waterproof geomembrane liners instead of using clay cores. Since any dam failure cause catastrophic results and disasters over large areas located on the downstream side of the dams, dam design engineers generally avoid using geomembrane liners wherein any holes on the liners may cause seepage forces within the embankment materials. Therefore, engineers mostly prefer to use with well known traditional materials such as concrete face, clay fill, and asphalt membrane to provide water tightness for embankment dams. However, in recent years, in the World, there is an attempt to use geomembranes on the upstream faces of embankment dams as water barriers. There are recently some small dams with geomembrane water barriers constructed less than 30 meter heights in Turkey and in the World. In this study, for dam design engineers, it is shown that critical slope loading cases for dam slopes with geomembrane liners are different than those for conventional embankment dams with clay cores. So, this study will provide a technical source and a guide for dam engineers by the way of explaining some important criterions to analyze and design the slope of the geomembrane faced embankment dams along with Kızık dam. In addition this study briefly discusses also some other design principles of geomembrane faced dams. Moreover, the study shows how to optimize the outer slopes of geomembrane faced embankment dams in terms of safety and economy.

Seepage-induced erosion is one of the main reasons leading to the catastrophic failure of earth dams, levees, and dykes. Mitigation measures include grouting or mixing additives with the soil. In the present study, nanoclay (NC) was investigated as an additive for silty sand soil, considering 1 and 1.5 wt.% NC additions, employing curing periods of 1, 7, 14, and 28-days for the soil–NC mixtures. Homogeneous model dams were then prepared by compaction of the unamended and cured -amended soil materials to the same cross-sectional profile in a laboratory flume apparatus. Once the upstream water level had reached the required water depth, the internal erosion process was initiated by opening a 6-mm dia. preformed hole created through the base width of the model dams next to the flume’s glass sidewall panel. To track the entire erosion process, side-view video recordings of the eroding dam cross-section were taken, employing a novel digital image-processing technique (previously developed by the authors) to track the progression of piping that ultimately lead to breach failure occurring. Original experimental results presented herein show the positive effect of the NC addition on erodibility reduction. From the NC content and curing ranges examined, the 1 wt.% NC and minimum 7-day curing period combination were tentatively identified as producing the best improvement in internal erosion resistance for the investigated soil.

The paper presents authors’ contribution to the improvement of the manufacturing technique of foam glass using the microwave energy. Due to the physical and mechanical characteristics, this material, obtained by the sintering process of waste glass at high temperature, constitutes a viable replacer of existing similar materials, used especially in construction. Unlike the conventional heating methods used worldwide, the company Daily Sourcing & Research SRL Bucharest tested lately microwave heating techniques in the manufacturing process of foam glass. In the paper it is presented an original method based on the feature of the powder mixture composed by waste glass (over 97 wt.%) and the foaming agent (calcium carbonate) to absorb the microwave energy and convert it to heat since the ambient temperature, using a silicon carbide and silicon nitride (80/ 20 weight ratio) crucible with thin wall (2.5 mm), which allows both a preponderantly direct heating and partially an indirect heati...

The stepped spillway design has been used for more than 3,300 years. A simple structure is the gabion stepped weir. A laboratory study was performed herein in a large size facility. Three gabion stepped weirs were tested with and without capping, as well as a flat impervious stepped configuration. For each configuration, detailed air-water flow measurements were conducted systematically for a range of discharges. The observations highlighted the seepage flow through the gabions and the interactions between seepage and overflow. The air-water flow properties showed that the air concentration, bubble count rate and specific interface data presented lower quantitative values in the gabion stepped weir, compared to those on the impervious stepped chute, while higher velocities were measured at the downstream end of the gabion stepped chute. The re-oxygenation rate was deduced from the integration of the mass transfer equation using air-water interfacial area and velocity measurements. The aeration performances of the gabion stepped weir were lesser than on the flat impervious stepped chute, but for the lowest discharge. For the two configurations with step capping, the resulting flow properties were close to those on the impervious stepped configuration.

In the last decades the design of stepped spillways regained some interest because of their suitability with new construction methods including gabions. The hydraulic performances of gabion stepped weirs were investigated experimentally in terms of the flow patterns, air-water flow properties, and energy dissipation. A laboratory study was conducted in a 26.6°slope (1V:2H) and 0.10-m step height facility, with both smooth impervious and gabion steps. The visual observations highlighted the seepage flow through the gabions, inducing a modification of the cavity flow especially in the skimming flow regime. In skimming flows, higher velocities were measured at the downstream end of the gabion stepped chute, associated with smaller energy dissipation rates and lower friction factors, compared to the smooth impervious stepped chute data.

On a gabion stepped chute, the steps contribute to the dissipation of turbulent kinetic energy, free-surface aeration may be intense, and there are complex interactions between the free-surface flow and seepage motion. Detailed measurements were conducted in a relatively large gabion stepped spillway model. Using a combination of high-speed movies and phase-detection probe measurements, the air-water flow properties in the step cavities and in the gabions were documented. Strong air-water exchanges between seepage and stepped cavity flows were observed. The data showed a complex bubbly seepage motion in the gabions associated with a high level of interactions between seepage and free-surface flows, leading to a modification of the step cavity recirculation and lesser flow resistance.

Gabion stepped spillways are presented as a viable option for low to medium head designs. The material contributes to stability, low cost, flexibility, porosity and noise reduction. The steps also enhance energy dissipation, and reduce the requirement of a stilling basin. This paper constitutes a systematic study of the free-surface and seepage bubbly flows using a combination of phase-detection probe and high-speed video camera. The two-phase flow properties and turbulence characteristics in the free-surface flow were documented. The bubbly motion through the gabion material was analysed. The results demonstrated evidence of strong air-water mixing between the free-surface and seepage flows, and highlighted a modified cavity flow pattern as a result.

On a stepped spillway, the steps contribute to some dissipation of the turbulent kinetic energy, while free-surface aeration can be very intense. The aim of this study is to investigate the two-phase flow properties on a gabion stepped spillway, including both free-surface and seepage flows, as well as the bubbly flow interactions at the gabion interface. Detailed measurements were conducted in a relatively large-size gabion stepped chute model. Using a combination of high-speed video movies and phasedetection probe measurements, the aeration processes in the step cavities and within the gabions were documented. The observations showed some very strong air-water interactions between seepage and step cavity flows. The results indicated a high level of interactions between two-phase seepage and cavity flows.

The suitability of a centerline or upstream design as a sustainable option for construction of future raises for the existing Life of Mine (LoM) downstream Tailings Storage Facility (TSF) at Adamus Resources Limited (ARL) was investigated using Slope/W in GeoStudio Software. Review of technical information, evaluation of the performance of the existing Stage 6 dam, and geotechnical investigations of available construction materials were undertaken in this research. Insights were gained about the TSF’s life cycle and current bearing capacity for intended future raises. Viable geotechnical parameters were established to define construction material specifications as well as input data for modelling the new designs. The British Standards Institute (BSI) standards were adopted for all the material testing protocols carried out at the Council for Scientific and Industrial Research-Building and Road Research Institute (CSIR-BRRI) laboratory in Kumasi. The scope of modelling covered the or...

The present study is concerned with the characteristics and quality of Tigris water passing through in Mosul city. Twelve samples were collected from the river in the area between upstream and down stream of the city. Six samples in Summer and (6) samples in Winter, as well as, sample of the rain water falling on the city were collected. The

Hydrogeological parameters of coherent and incoherent deposits are deeply dependent of their granulometric characteristics. These relations were shaped in formulas and defaultly used for calculation of hydraulic conductivity, and are valid only for uniform incoherent materials, mostly sands. In this paper, the results of analyses HESSD

Determination of soils permeability on the basis of their grains size is definitely very interesting because it allows to predict the permeability from easily measured and routinely obtainable data. The article has a great value also because the investigations were carried out on a large number of samples. Although I do not agree with all conclusions I think that the article is worthy for publication. AUTHOR'S ANSWER: We thank the reviewer for swift and prompt review. Also, we are glad to hear that reviewer 1 agrees with our opinion that this is an interesting and useful topic. Specific comments: The question is if Kozeny-Carman equation also applies to clays or sands with a larger amount of clay minerals. For example: the studies of Carman C1 HESSD Interactive comment Full screen / Esc

Pharmacognostic standardisation of the fresh, powdered and anatomical sections of the stems of Dendrophthoe falcata Linn. Was carried out to determine its macro- and microscopical characters and also some of its quantitative standards. Externally, the stems are circular in shape, woody, yellowish green in colour when fresh and become greenish black on drying. Fresh material is having characteristic and slightly astringent in taste. When transversely cut surface of stems shows yellowish brown circles of woody matter with pith. The yellowish brown circle of wood is major part and covered by dark brownish black cork. Dried stem when cut longitudinally, faint brownish, solid pith is clearly visualized. Surface of young stem part is glabrous when fresh. The chemo-microscopy revealed the presences of lignin, starch, proteins and calcium oxalate crystals. Physicochemical evaluation includes ash values, extractive values, moisture content and fluorescence analysis. These findings will be us...

Agricultural wastes are generated in rural areas can be effectively utilized for production of mushroom as food supplements as well as for income generation. The present research explored some of the unexplored locally available lignocellulosic substrates such as paddy straw, reeds, banana stem, sugar cane bagasse milled and crushed, sugar cane leaves, coir pith, sorghum husk and sun flower stem for field scale production of Pleurotus florida and Calocybe indica. The field level cultivation was carried out by 137 farmers and produced totally 15.33 tonne of P. florida and C. indica with an aggregate bioefficiency of 58.52 % and 60.38 % respectively. The produced mushrooms generated an additional income and also consumed as nutritional supplement.

Agricultural wastes are generated in rural areas can be effectively utilized for production of mushroom as food supplements as well as for income generation. The present research explored some of the unexplored locally available lignocellulosic substrates such as paddy straw, reeds, banana stem, sugar cane bagasse milled and crushed, sugar cane leaves, coir pith, sorghum husk and sun flower stem for field scale production of Pleurotus florida and Calocybe indica. The field level cultivation was carried out by 137 farmers and produced totally 15.33 tonne of P. florida and C. indica with an aggregate bioefficiency of 58.52 % and 60.38 % respectively. The produced mushrooms generated an additional income and also consumed as nutritional supplement.

Tanami Mine, located within the Tanami Desert of the Northern Territory, approximately 670 km northwest of Alice Springs, is one of the most remote mine sites in Australia. The site comprises 45 open pits, eight backfilled pits, 11 in-pit tailing storage facilities (TSF), 24 waste rock landforms, two above ground TSF, a processing plant and on-site village accommodation scattered over 70 km in length. The mine site, including TSF, has been subject to a systematic closure process over the last five years. The large Three Cell above ground paddock style TSF was seen by previous mine closure planners as a major challenge to rehabilitate, and accordingly had attracted the largest portion of the closure budget. Deposition of tailings into the TSF occurred between 1992 and 2001, and from this time the cells were allowed to dry and consolidate. The decommissioning process for the facility began in 2004, and a staged and logical approach was employed. Early in the process a review of literature and prior investigations was undertaken to identify gaps in information. The resolution of identified gaps required geochemical investigations for acid base chemistry and multi-elements, surveys of density of deposited tailings, compaction reduction studies through ripping trials with different dozers, ripper depth and configurations, geotechnical assessment of the existing walls, and an extensive upper surface closure option review, followed by a field trial to determine optimum cover designs for rehabilitation and closure. Planning for tailings closure can often be a two to three year process, or longer for more problematic tailings stored in complex facilities, or facilities located on mine sites that have competing resource requirements. At the time of writing this paper, the closure earthworks for the Three Cell TSF were in the final stages, resulting in an active closure process of five years duration. It is expected that by late 2009 all earthworks will be complete and an "as-built decommissioning report" will be prepared. The site will then move into the monitoring phase. The closure of the TSF has not been without challenges and included a one in 910 year annual exceedance probability (AEP) rainfall event which produced large-scale surface water flow and erosion. Other challenges included drought conditions, cold winters, extreme summer temperatures and perceived edaphic difficulties. This paper presents the process employed for the closure of the Three Cell TSF, the investigations, the issues encountered and the final closure strategy.

The interpolation finite difference method (IFDM) can be used in the numerical analysis of steady-state seepage problems over arbitrary domains. In such analyses, by providing the coordinates of change points considering the polygonal domain and boundary conditions, a grid is automatically generated and a numerical solution is promptly obtained. Homogeneous, isotropic dams without tail drains have been investigated in a previous study. However, to consider dams with tail drains, we must alter the previous system slightly. This paper describes the altered system. In earlier times, when computation power was limited and before modern numerical calculation methods had been established, it was highly important for dam engineers to estimate the seepage discharge and the location of the free surface. Several empirical methods were proposed, and these have retained their functionality. For instance, the basic parabola method is an exemplary work that builds on classic empirical methods. In this work, the results obtained using A. Casagrande's method are compared with those obtained by IFDM, and it is confirmed that there are considerable deviations between them. The so-called ''equivalent KZ flow method" is proposed and shown to significantly improve the calculation accuracy for the discharge and free surface location.

A wide range of chemical engineering research challenges face the pulp and paper industry. Many of these are motivated by a desire to understand, improve, and better control pulp and paper processes. They are also motivated by forces of change from within and outside the industry. These forces include increased demand on limited fibre resources, increased global competition that favours lowcost producers, development of new value-added and higher performance paper products, and an acute awareness of the environmental impact of all industrial processes. Research directed at these issues includes improving and optimizing existing processes to make higher quality products with less fibre at reduced cost, development of new products to meet consumer demands for increased performance, and modification of pulping, bleaching and papermaking processes to make them environmentally benign. The twenty-six papers that comprise this thematic issue on "Chemical Engineering Research in Pulp and Paper" give an overview of the many interest areas and technical challenges facing the pulp and paper community. The papers have been arranged according to area of research: pulping and bleachmg processes, mechanical pulp refining, environmental improvement, process control, and new products and developments. Diffusional processes occurring within chips and fibres during kraft pulping affect the yield, selectivity, and ultimate degree of delignification attainable. This is true for both the diffusion of chemicals to reaction sites within the chips as well as for removal of solubilized lignin from the fibre. Agarwal and Gustafson model the diffusional transport and

The paper discusses an RCC dam project where an exposed geomembrane system was installed in 2002 and has been successfully performing for now 13 years. The RCC dam, Miel I, is located in Colombia and when constructed it was the highest RCC dam in the world. 188 m high, the dam is used for power production. The RCC mix has a cement content of 85 to 160 kg/m 3. To meet contractual schedule, the original design of an upstream face made of slip formed reinforced concrete was changed to a Carpi drained exposed PVC geocomposite system, placed on a 0.4 m thick zone of RCC material enriched with cement grout and vibrated. Placement of the geocomposite system in horizontal stages allowed starting dam impoundment while RCC placement was still ongoing at higher elevation. The geocomposite system was completed in 2002, before complementary concrete works were finished. ISAGEN, the owner of the dam, constantly monitors the dam and the geocomposite system. The measured leakage has never surpassed the historical values, or overcome the maximum allowed drainage design values. After 11 years of good performance, in 2013 ISAGEN decided to have a comprehensive monitoring of the general conditions and weathering behaviour of the geocomposite system. Objectives of the investigation were to assess the reason of small cuts that had been detected and repaired (in total 15 in 11 years on a 31,000 square meters surface), to assess the conditions of the PVC geocomposite, ascertaining at which extent its characteristics had changed over service, and to evaluate if the weathering behaviour was in accordance with the expected durability. Inspection at the upstream face and in the drainage galleries was followed by sampling and testing of the exposed geocomposites in the laboratory, to compare the physical and chemical properties of the aged geocomposite sample collected at the dam with those of the same geocomposite as manufactured. Evaluation of test results, based also on most recent research on geomembrane weathering mechanisms, completed the investigation. Results confirmed that the behaviour of the PVC geocomposite is extremely good and fully in line with expectations. The performance of the dam in 2015, after 13 years of service, keeps being extremely satisfactory. The paper will describe the geocomposite system installed at the dam, and then discuss all steps of the investigation, and detail the test results and the conclusions drawn..

The aim of this work was to study the effect of ozone, either alone or combined with an activated sludge system, on the reduction of the recalcitrant COD in the effluent of a chemimechanical pulping (NaOH-Na 2 SO 3) integrated mill. Several alternative schemes involving ozonation were tested on liquors and effluents of the pulp mill, and on two kinds of effluents were taken at different points of an activated sludge pilot plant. The largest decrease in COD was 33%, whereas that in aromatic compounds (absorbance at 232.5 nm) was of 73%. The most obvious result of the ozone treatment was effluent decolorization. It was not possible to use ozonation as tertiary treatment, as ozone was necessary to treat the BOD generated, and therefore the effluent must necessarily pass through a biological treatment. With a scheme including an intermediate ozonation between two secondary treatments (postactivated sludge and pre-aeration lagoon), the maximum reductions achieved were of 70% in COD, of 93% in aromatics, and of 96% in color. The limits of COD allowed by the environmental regulations (<250 mg/L) could be achieved with the following stages: 1) primary clarifier, 2) activated sludge system, 3) ozonation, 4) aeration lagoon, and 5) stabilization lagoon.

Many communities in northern Nigeria are in serious need of supplementary water supply systems to augment the
scanty rainfall in the region with a population of majorly farmers who face a lot of hardship due to acute shortage of water in most
part of the year. The aim of this study is to provide a well-designed and reliable dam for irrigation water supply. To achieve this aim,
this study focused on the analysis of the stability of an earth dam embankment and its seepage, which is very vital for the safety,
stability and economic (optimal) design of the dam. The conventional methods of slope stability analysis have major limitations
which were addressed by numerical modelling techniques. This study was carried out using some analytical methods and then
SLOPE/W and SEEP/W numerical modelling programs. The stability of the embankment slope was also modelled for rapid
drawdown conditions based on worst case scenario. The safety factor results show that the embankment is safe from slope failure
having a minimum safety factor value of 2.302. A minimum safety factor result of 1.416 was observed after a worst case scenario of
rapid drawdown from the maximum anticipated flood water height of 7.6 m to 0 m in 24 hours which is satisfactory. The results of
maximum hydraulic velocity and rate of seepage of 4.15E-04 m/sec and 1.27E-04 m3/sec respectively were indication of need for
sufficient compaction and careful selection of core material with a very low permeability for adequate design against piping failure.

An uncontrolled leakage and piping in embankment dams may cause breaching and slope slides. Clarification of the cause of an embankment leakage is also crucial to determine the effective and economical treatment method. However, identification of the source of a leakage in embankment dams is a difficult task since site investigations and computation methods may vary significantly depending on the site geology, topography, and embankment material properties. This paper presents an exemplary distinctive study and treatment methods of a leakage problem of an embankment dam located on seismically active region wherein the site is under the risk of 89 active faults capable of producing magnitudes over 6.0. Calculated slope failure probability of the dam due to the leakage-related saturation of the downstream zone is significantly high as 0.89. Numerical seepage analyses were also performed to determine whether the leakage was related to a piping incident or a filter deficiency. Particularly, bottom outlet valve on/off operations and satellite image approaches and their interpretations enabled the finding that the leakage on the dam occurred due to the bottom outlet deterioration. The deterioration of the bottom outlet resulted in high water uplift pressure into and saturation of the downstream sandyfill beyond the chimney filter. Finally, the study discusses two different treatment techniques: (1) the application of a geomembrane on the upstream face that did not prevent the leakage, and (2) driving an HDPE pipe into the existing steel bottom outlet pipe, a rapid, economical, and effective solution that prevented the leakage. This study provides different evaluations of the reason of the leakage problem and effective treatment process of a bottom outlet which can be useful for other embankment dams having such leakage problems.

Very long dry seasons due to high temperature and decrease of rainfall rate, may threaten the stability of dams and dikes, and make them more sensitive to internal erosion. This vulnerability raises a question of how such hydraulic structures could behave after the degradation of soil properties. This research investigated the susceptibility of three zoned dams in Morocco to internal erosion, particularly after the dam's core soil was submitted to the drying effect due to the drought, causing desiccation. For this purpose, Hole Erosion Tests (HETs) carried out on core soils collected from the three dams aimed to assess their vulnerability to erosion after desiccation. The materials have been also analyzed in order to assess their suitability to dam construction using the usual engineering guidelines. The erosion results, analyzed through the erosion kinetics and soil resistance classification, showed an initial high resistance to internal erosion of tested soils, but the desiccation makes the core soils more vulnerable to erosion, especially for Mazer dam whose core soil is a lean clay. So,

There are several methods to represent the beach changes around the composite coastal protection systems at the coastal zone. This research try to investigate and predict shoreline changes around composite shore protection systems using LITPACK software. The model represents the movement of sandy soil sediment transport under the effect of wave and current interaction. The morphological changes development along quasi-uniform beaches are investigated. The model was applied on the natural bathymetry of area which located in the neighboring of El-Hammra port at the north western coast of Egypt. The numerical model was applied to clarify the predicted rates of erosion and accretion around the existing structures and the proposed additional protection structures. The model results were calibrated with the measured shoreline from 2015 to 2017 and verified with shoreline data from 2017 to 2019. The model was performed to predict the morphological changes from 2015

Failures can occur from seepage failure in the downstream slope of an earth-fill dam. The excessive pore pressures and seepages must be controlled to achieve the desired safety level in such dams. This safety can be provided with a horizontal drainage cover design. The essential goal of drainage system design is to increase system efficiency in reducing pore water pressures and seepage. Several calculations were made with a downstream slope cover design and downstream horizontal drainage length for homogeneous earth-fill dams. The minimum and maximum effective length of the filtered drainage system was obtained after the analyses. Moreover, the factor of safety regarding the downstream slope was calculated for the drainage system with different geometries. The results showed that the horizontal drainage length affects system performance and the seepage behavior of the dam.

In this study, the 2D steady-state seepage analysis of the dam body and its base is investigated using the finite element method based on the Galerkin’s approach. The body and foundation soil are considered as homogeneous isotropic and anisotropic materials and the effects of horizontal drainage length and cutoff wall on seepage are investigated. The differential equation governing the response of water in the soil is obtained with the help of Darcy&#39;s law and continuity equations. A program has been prepared in Fortran programming language to find the hydraulic load, pressure values and phreatic line pressure values at the points inside the dam body and the quantity of seepage on the bottom of dam. It has been shown that the obtained values are in good agreement by comparing them with the results of existing studies in the literature.