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Academic literature on the topic 'Ponding'

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Published: 4 June 2021
Last updated: 29 January 2023

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Journal articles on the topic "Ponding"

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Dunbabin, J. S., I. H. Hume, and M. E. Ireson. "Effects of irrigation frequency and transient waterlogging on the production of a perennial ryegrass - white clover pasture." Australian Journal of Experimental Agriculture 37, no. 2 (1997): 165. http://dx.doi.org/10.1071/ea96057.

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Summary. Perennial ryegrass–white clover swards were irrigated for 3 years every 50, 80 and 120 mm of crop evapotranspiration minus rainfall (ETc–R) and water ponded on the soil surface for either 4, 12 or 24 h at each irrigation. Pasture production and clover content were highly seasonal, peaking in spring and autumn. Frequent irrigation increased dry matter production by an average of 56%. When irrigating at 50 mm ETc–R, dry matter production was decreased by ponding water on plots, 17% for 12 h ponding and 14% if ponded for 24 h. However, when irrigating at an interval of 80 mm ETc–R ponding increased dry matter production by 7% for 12 h ponding and by 25% for 24 h ponding. Ponding also increased production at an irrigation interval of 120 mm ETc–R by 25% for 12 h ponding but only by 2.4% for 24 h ponding. While these increases in dry matter production are large in relative terms the absolute increase in production is small. More water infiltrated per irrigation at longer irrigation intervals, and at longer ponding times. Frequently irrigated, rapidly drained swards used irrigation water most efficiently. The small gain in dry matter production achieved by prolonging ponding at longer irrigation intervals is an inefficient use of water and likely to recharge regional groundwater systems. Oxygen diffusion rate measurements suggested that ponding for as short as 4 h was likely to cause waterlogging stresses and that these stresses were higher when irrigating frequently. The relative increase in waterlogging stress by extending the period of ponding from 4 to 24 h was small.
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Chen, Shuaihua, and Xiaoping Wang. "Design of Monitoring System for Urban Low-Lying Water." Journal of Physics: Conference Series 2029, no. 1 (September 1, 2021): 012128. http://dx.doi.org/10.1088/1742-6596/2029/1/012128.

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Abstract The Internet of things technology is applied to establish a low-lying ponding monitoring system, which includes information acquisition system and information management system. This GPRS, 4G, Java, Internet of things and large database technology are applying to build a data acquisition hardware platform. On this basis, the basic database of road ponding and the monitoring and early warning system of road ponding in low-lying land are established. Thus, the application requirements of road ponding information query, management, monitoring, water level change analysis and water level overrun alarm based on map are realized. At the same time, the control of relevant drainage facilities has been integrated. The modern management means of road low-lying land ponding monitoring has been improved. And the management and control level of municipal road ponding has been comprehensively improved.
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Shoemaker, E. M. "On the formation of large subglacial lakes." Canadian Journal of Earth Sciences 28, no. 12 (December 1, 1991): 1975–81. http://dx.doi.org/10.1139/e91-179.

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The role of subglacial water storage beneath continental ice sheets is investigated, primarily for a deformable bed. Subglacial ponding is shown to occur under most regions of warm-based ice sheets, and large subglacial lakes can become established, for example in the Hudson Bay basin. The formation of large lakes depends upon the fact that the ice-surface gradient is reduced once subglacial ponding occurs and upon the feedback between the reduced ice-surface gradient and increased subglacial ponding. Subglacial ponding likely played a large role in determining the ice-sheet topography during late deglaciation and in speeding up the deglaciation process.
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Hashim, Ahmad Ezanee, Mohd Ikmal Fitri Maruzuki, Norngainy Mohd Tawil, Mohd Zulhanif Abd-Razak, and Adi Irfan Che-Ani. "Flat Roof Defect: Preliminary Condition Survey for Water Ponding Monitoring." Applied Mechanics and Materials 747 (March 2015): 351–54. http://dx.doi.org/10.4028/www.scientific.net/amm.747.351.

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Roof is among defect-prone building part as it exposed to natural factor especially rainfall and sunlight. Thus, the inspection on roof part must be done more frequent compare to other parts of building. However, roof is the most difficult part to inspect because of limited access and safety concern. This paper presents the result of preliminary condition survey for water ponding monitoring on flat roof surface and discussion on the solving method. The survey has been carried out on flat roof of an academic building in Penang, Malaysia on a rainy day. Based on the condition survey, we found that water ponding occurs on some parts of the flat roof. Water ponding on flat roof will cause moisture problem that trigger severe problem on building. Since water ponding problem ineffectively do monitor by traditional method, we proposed to design an intelligent system to monitor water ponding problem on flat roof. By using an intelligent system, water ponding existence can be detected at a real-time. Furthermore, the system is time saving, manpower saving and the data can be manage systematically without the presence of surveyor on site.
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Hidayati, I. K., Suhardjono, D. Harisuseno, and A. Suharyanto. "Ponding time in infiltration process for different land use." IOP Conference Series: Earth and Environmental Science 930, no. 1 (December 1, 2021): 012054. http://dx.doi.org/10.1088/1755-1315/930/1/012054.

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Abstract Ponding time is the period from the beginning of rainfall/infiltration until the occurrence of ponding. This paper aims to determine the infiltration rate and ponding time on different land uses, such as open fields, residential, agriculture, and vegetation. This research was conducted in one of the watersheds in the Brantas River Basin, namely the Lesti River Basin, which is administratively included in the Malang Regency, East Java. The Lesti River is one of the tributaries of the Brantas River, which originates around Mount Semeru, a very intensive area for planting rice, sugar cane, and coffee. Infiltration data were collected at 35 points using a double-ring infiltrometer spread across the Lesti watershed with Andosol, Mediterranean, and Regosol soil types. At the same time, ponding time was obtained from infiltration measurements in the field using the flooding method. The physical properties of the soils were tested in the laboratory to obtain water content, porosity, and bulk density values. This study resulted in the infiltration rate and ponding time for each land use and shows how the physical properties of the soil affect the ponding time.
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Yang, Dan, Mengzhou Xiong, Tao Wang, and Guangtao Lu. "Percussion-Based Pipeline Ponding Detection Using a Convolutional Neural Network." Applied Sciences 12, no. 4 (February 18, 2022): 2127. http://dx.doi.org/10.3390/app12042127.

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Pipeline transportation is the main method for long-distance gas transportation; however, ponding in the pipeline can affect transportation efficiency and even cause corrosion to the pipeline in some cases. A non-destructive method to detect pipeline ponding using percussion acoustic signals and a convolution neural network (CNN) is proposed in this paper. During the process of detection, a constant energy spring impact hammer is used to apply an impact on the pipeline, and the percussive acoustic signals are collected. A Mel spectrogram is used to extract the acoustic feature of the percussive acoustic signal with different ponding volumes in the pipeline. The Mel spectrogram is transferred to the input layer of the CNN and the convolutional kernel matrix of the CNN realizes the recognition of pipeline ponding volume. The recognition results show that the CNN can identify the amount of pipeline ponding with the percussive acoustic signals, which use the Mel spectrogram as the acoustic feature. Compared with the support vector machine (SVM) model and the decision tree model, the CNN model has better recognition performance. Therefore, the percussion-based pipeline ponding detection using the convolutional neural network method proposed in this paper has high application potential.
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Mirjat, M. S., D. A. Rose, and M. A. Adey. "Desalinisation by zone leaching: laboratory investigations in a model sand-tank." Soil Research 46, no. 2 (2008): 91. http://dx.doi.org/10.1071/sr07112.

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We report a laboratory study in a model sand-tank to investigate improvements using partial ponding over the common method of leaching salts from soils by flooding the entire area above equally spaced subsurface drains. The physical basis of the theory developed by E. G. Youngs and P. B. Leeds-Harrison was demonstrated in the model. We traced the streamline patterns for complete ponding and 3 situations of partial ponding of the soil surface to demonstrate the flow paths. We also leached saline water, initially uniformly distributed in the sand, with sweet water and recorded the breakthrough curves of the leaching water for the same situations of complete and partial ponding. The results demonstrate that partial ponding is more effective than complete ponding in that it requires less time to carry solute towards the drain and saves water of good quality needed to leach salts through drains. They also confirm the theoretical findings that more uniform leaching with less water can be achieved by constraining the infiltrating area with bunds, initially flooding only the region midway between the drains and then progressively increasing the flooded area until the entire surface above the drains is ponded.
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Nerantzaki, Maria S., and John T. Katsikadelis. "Ponding on floating membranes." Engineering Analysis with Boundary Elements 27, no. 6 (June 2003): 589–96. http://dx.doi.org/10.1016/s0955-7997(02)00114-5.

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Tuan, Christopher Y. "Ponding on circular membranes." International Journal of Solids and Structures 35, no. 3-4 (January 1998): 269–83. http://dx.doi.org/10.1016/s0020-7683(97)00076-0.

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Zhang, Lei, Lin Xu, Yong Xiao, and NingBo Zhang. "Application of Comprehensive Geophysical Prospecting Method in Water Accumulation Exploration of Multilayer Goaf in Integrated Mine." Advances in Civil Engineering 2021 (September 24, 2021): 1–12. http://dx.doi.org/10.1155/2021/1434893.

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A coal mine in Datong is an integrated mine. At present, there is goaf in the upper and lower part of the mining coal seam. There is a lot of ponding in the goaf, which has great potential safety hazards for production. In order to find out the scope and location of ponding in goaf, the comprehensive geophysical exploration method combining transient electromagnetic method and high-density resistivity method is used to carry out the research. Firstly, the time-base, turn-off time, receiving delay, current, superposition times, and other parameters of the instrument are tested on the surface of known goaf to obtain the best instrument parameters, and the parameters are used to verify the feasibility of the research scheme; then, the transient electromagnetic method is used for large-area exploration on the surface of the mine, the suspected goaf ponding area is found through comprehensive analysis, and the high-density resistivity exploration is arranged in the suspected goaf ponding area. According to the obtained results, the scope and location of the goaf ponding area are accurately located through comprehensive analysis. The results show that there are two goaf ponding areas in the exploration area, which are located above the 8# coal seam currently mined; the range and location of goaf ponding area can be accurately obtained by using the comprehensive geophysical method of high-density electrical method and transient electromagnetic method. This method can provide reference for mine water prevention and control in Datong area and has great practical significance to ensure coal mine safety production.
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Dissertations / Theses on the topic "Ponding"

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Wells, Charles Digby. "Tertiary treatment in integrated algal ponding systems." Thesis, Rhodes University, 2005. http://hdl.handle.net/10962/d1006162.

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Inadequate sanitation is one of the leading causes of water pollution and consequently illness in many underdeveloped countries, including South Africa and, specifically, the Eastern Cape Province, where cholera has become endemic. As modern wastewater treatment processes are often energy intensive and expensive, they are not suitable for use in these areas. There is thus a need to develop more sustainable wastewater treatment technologies for application in smaller communities. The integrated algal ponding system (IAPS) was identified as a possible solution to this wastewater management problem and was investigated for adaptation to local conditions, at the Rhodes University Environmental Experimental Field Station in Grahamstown, South Africa. The system was monitored over a period of nine years, with various configuration adjustments of the high rate algal pond (HRAP) unit operation investigated. Under standard operating conditions, the system was able to achieve levels of nutrient and organic removal comparable with conventional wastewater treatment works. The mean nitrate level achieved in the effluent was below the 15mg.l-1 South African discharge standard, however, nitrate removal in the IAPS was found to be inconsistent. Although the system was unable to sustain chemical oxygen demand (COD) removal to below the 75mg.l-1 South African discharge standard, a removal rate of 87% was recorded, with the residual COD remaining in the form of algal biomass. Previous studies in the Eastern Cape Province have shown that few small wastewater treatment works produce effluent that meets the microbial count specification. Therefore, in addition to the collation of IAPS data from the entire nine year monitoring period, this study also investigated the use of the HRAP as an independent unit operation for disinfection of effluent from small sewage plants. It was demonstrated that the independent high rate algal pond (IHRAP) as a free standing unit operation could consistently produce water with Escherichia coli counts of 0cfu.100ml-1. The observed effect was related to a number of possible conditions prevailing in the system, including elevated pH, sunlight and dissolved oxygen. It was also found that the IHRAP greatly enhanced the nutrient removal capabilities of the conventional IAPS, making it possible to reliably and consistently maintain phosphate and ammonium levels in the final effluent to below 5mg.l-1 and 2mg.l-1 respectively (South African discharge standards are 10mg.l-1 and 3mg.l-1 in each case). The quality of the final effluent produced by the optimisation of the IAPS would allow it to be used for irrigation, thereby providing an alternative water source in water stressed areas. The system also proved to be exceptionally robust and data collected during periods of intensive and low management regimes were broadly comparable. Results of the 9 year study have demonstrated reliable performance of the IAPS and its use an appropriate, sustainable wastewater treatment option for small communities.
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Peña-Ramos, Carlos Enrique 1962. "CONCRETE PONDING EFFECTS IN COMPOSITE FLOOR SYSTEMS." Thesis, The University of Arizona, 1987. http://hdl.handle.net/10150/276421.

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Murrie, W. Trevor. "Infiltration and surface ponding on a sand-based sportsfield." Thesis, University of British Columbia, 1987. http://hdl.handle.net/2429/26502.

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The thesis addresses the problem of ponding as it pertains to sand-based sportsfields. The Lower Premier Sportsfield, in the District of North Vancouver, was specifically studied. It is located in a high rainfall location. The hypothesis is that a 'surface layer' at the top of the soil profile was directly responsible for the reduced surface infiltration necessary for the ponding observed. The accumulation and compaction of detrital organic matter within the pore space of this layer was assumed to be the source of the ponding problem. Pond depth hydrographs were derived from field measurements to illustrate the behaviour of the pond in response to various rainfall conditions. Furthermore, a semi-empirical model was devised to determine the water balance of the pond for an incident rainfall event. Results from the model show that overland flow from the area concentrically adjacent to the pond contributed approximately four times as much water to the pond as was contributed directly by rainfall. From the analysis, it was determined that a low 'surface layer' saturated hydraulic conductivity, of the order of 10⁻⁸ m.s⁻¹ was necessary for this to occur. Recommendations emphasize preventative management that limits the accumulation of detrital plant matter and the employment of groundskeeping techniques to control the formation of the hydrologically restrictive 'surface layer'. Furthermore, to avoid the concentration of surface runoff, it is essential that surface.
Land and Food Systems, Faculty of
Graduate
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MacMillan, Robert A. "Modelling depressional storage and ponding in a Canadian prairie landscape." Thesis, University of Edinburgh, 1994. http://hdl.handle.net/1842/20657.

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There is a need for accurate information on patterns of distribution of surface water in agricultural landscapes in western Canada. Artificial drainage on agricultural land has become widespread as farmers attempt to maximise their available land and minimise obstacles to efficient cultivation. There is a shortage of appropriate methods for describing, analysing and simulating the flow of surface water and its accumulation in shallow closed depressions in agricultural landscapes. Such capabilities are increasingly needed to assess the benefits and impacts of both on- and off-farm drainage. The goal of the present study is therefore to develop and test procedures to quantify the capacity to store runoff in depressions in agricultural landscapes and to estimate the extent to which this depressional storage is filled at any given time. Analyses of the conditions controlling runoff were conducted at a single site characterised by low relief, glaciated terrain and a non-integrated drainage system. Field measurements of soil hydrological properties and observed ponding were collected for the farm-scale site during a period of spring snow melt and runoff in 1989. Automated extraction of geomorphological features from digital elevation data was used to delineate the location , extent and maximum volume of all depressions and to establish the sequence in which they would be expected to fill, overspill and drain. A highly-distributed, physically-based hydrological model (DISTHMOD) was assembled and used to simulate runoff and ponding for the selected site for the same period. Field studies confirmed that the formation of shallow ponds in the spring was almost wholly related to rapid melting of snow and surface runoff of snowmelt. Runoff was observed to collect in all depressions of any significant size. Ponds less than 40 cm deep disappeared by mid June through a combination of evaporation and infiltration. Ponds greater than 40 cm deep generally persisted throughout the summer. Such ponds occupied lower positions in the landscape and most were in contact with a water table.
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Then, Stephanie Rose. "A hydrologic assessment of surface ponding in a drained prairie pothole wetland." Thesis, University of Iowa, 2016. https://ir.uiowa.edu/etd/2154.

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This thesis evaluates the surface water hydrology in an artificially drained and farmed prairie pothole wetland located in north-central Iowa as part of the Iowa DNR Wetland Program Development (WPD) project. The purpose of the WPD project was to begin documentation of basic hydrology, wildlife value, and water quality to improve understanding of ecosystem services provided by drained prairie pothole wetlands. The surface water hydrology was evaluated using a daily water balance (PPWB) model. The model development, validation, and applications are described in detail in this thesis. The PPWB model estimates the water depth and duration in the drained wetland. Several sensitivity analyses were performed to evaluate how site-specific factors affect the frequency, depth, and duration of surface ponding in the drained wetland. In the absence of surface inlets, infiltration was found to have a significant impact on ponding, second only to the amount of precipitation in importance. The topography also plays an important role in surface water ponding, with higher ponding durations occurring for larger catchment-to-pothole area ratios. However, the presence of a surface inlet in a drained prairie pothole wetland significantly alters the hydrology and all other ponding factors become negligible. In addition, long-term ponding was evaluated for historic and future hydrologic trends. The long-term simulation showed increasing trends for precipitation and ponding duration. The possible implications of continued farming of drained wetlands were explored using PPWB model sensitivity analysis and long-term simulation results. Agricultural implications include mitigation strategies to balance ecosystem needs with crop production and impacts of the projected future outlook with regards to climate. Environmental implications include insight on impacts of wetland restoration.
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Ho, Alvin Felix. "Experimental and numerical investigation of infiltration ponding in one-dimensional sand-geotextile columns." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape3/PQDD_0018/MQ52994.pdf.

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Cilliers, Anneke. "The treatment of brewery effluent using an integrated high rate algal ponding system." Thesis, Rhodes University, 2012. http://hdl.handle.net/10962/d1005177.

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The application of high rate algal ponds (HRAP) in the treatment of brewery effluent that met the South African Department of Water Affairs and Forestry's (DWAF) general limits for discharge into a natural water resource of 1998 were tested during a lO-month baseline phase, followed by an 11-month optimization phase. The objective of the baseline phase was to monitor the seasonal performance of HRAPs. The hydraulic retention time (HRT) fluctuated between 11.16 d and 12.00 d in HRAPs. The chemical oxygen demand (COD) increased from 130.12 ± 6.94 mg/L (post-AD), to 171.21 ± 7.99 mg/L (post-HRAP) . The presence of algal cells and evaporation contributed towards an increase in post-HRAP COD. The ammonia (NH₄-N) concentration decreased from 46.59 ± 2.47 mg/L (post-AD), to 1.08 ± 0.12 mg/L (post-HRAP). The nitrite (NO₂- N) concentration remained below 1.00 mg/L in post-pilot plant AD, post-PFP and post-HRAP effluent. The phosphate (PO₄-P) concentration decreased from 29.81 ± 1.39 mg/L (post-AD) to 17.30 ± 1.16 mg/L PO₄-P. The objective of the optimization phase was to manipulate the HRT to achieve the maximum treatment rate that met the DWAF general limits for discharge into a natural water resource of 1998. Nitrogen (as NH₄-N, NO₃-N, NO₂-N) removal efficiency was used as an indicator of nutrient removal success. HRT was influenced by season. The optimal HRT for autumn was 4.30 d at a temperature of 20.53ºC in HRAP A2 (heated) and 18.96ºC in HRAP B2 (ambient). The optimal HRT for summer was 2.74 d at 29.90ºC in HRAP A2 (heated) and 26.36ºC in HRAP B2 (ambient). The COD decreased from 152.33 ± 4.85 mg/L (post-AD) to 95 .00 ± 3.75 mg/L (post-HRAP A2), and to 100.82 ± 5.93 mg/L (post-HRAP B2). The incoming NH₄-N concentration decreased from 42.53 ± 1.38 mg/ L (post-AD), to 1.70 ± 0.81 mg/ L (post-HRAP) . The nitrate (NO₃-N) concentration post-HRAP was 12 - 14 mg/L. The main methods for NH₄-N removal were probably NH₄-N volatilization through algal uptake. HRAPs were able to lower nitrogen and phosphorous concentrations to within the DWAF limits under normal operating conditions. It is recommended that HRAP treated brewery wastewater be used for irrigation after salt removal, or alternatively, for groundwater recharge . Regulatory exemptions would be required for higher than permitted COD and EC concentrations to enable these actions.
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Dekker, Leendert Gideon. "Development of integrated algal ponding systems in the treatment of wine distillery wastewaters." Thesis, Rhodes University, 2003. http://hdl.handle.net/10962/d1004530.

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In South Africa, wastewater disposal in the wine and distilling industry is undergoing a profound transformation as a result of fundamental changes in regulations and license requirements. To deal with this problem conventional Waste Stabilisation Ponding systems have been used by the industry together with irrigation and evaporation disposal practises. Although effective in the evaporation and containment disposal functions, these pond systems are generally not properly designed and/or managed, resulting in overloading and, at times, the generation of seriously offensive odour problems. Preliminary studies on the feasibility of utilising the Advanced Integrated Wastewater Ponding System as a core treatment technology in winery wastewater treatment were conducted. Results indicated that specific problems had to be addressed before successful ponding treatment could be achieved. This research programme undertook an investigation of the performance of a demonstration ponding system treating household sewage, which formed the basis of the research due to limited experience reported on ponds treating wine industry wastewaters. Malfunctions identified were in correlation with the preliminary winery waste ponding survey, which included unstable fermentation pit functions and inadequate nutrient removal. Retrofitting the fermentation pit with a nylon net across the rising water column resulted in improved retention of active anaerobic sludge, especially during periods of system start-up and/or organic overloading. An investigation into nutrient removal utilising algal biomass provided a valuable contribution towards development of an independent nutrient removal system. Harvested algal biomass was passively manipulated to release polysaccharides under anoxic conditions, with subsequent use as a carbon source by denitrifying organisms. Following denitrification, the still viable algal cells were introduced into a High Rate Algal Pond raceway for photosynthetically produced alkalinity. This high pH environment resulted in induced calcium phosphate mineral formation and subsequent precipitation, as well as effective ammonia stripping from the water. Based on the novel positive research outcomes a decision was made to proceed to the construction of a pilot-scale integrated ponding system treating wastewater from a wine lees factory. The system linked the Anaerobic Baffle Reactor, for pre-treatment, with the improved Advanced Integrated Wastewater Ponding System. The potential of this system has shown that a Waste Stabilisation Ponding system can be engineered to treat wine industry wastewaters and thereby effectively reduce the organic and nutrient loads, by using low-cost retrofitted upgrading unit operations. Valuable algal biomass may also be recovered as a by-product of the treatment process.
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Dunn, Kevin Matthew. "The biotechnology of high rate algal ponding systems in the treatment of saline tannery wastewaters." Thesis, Rhodes University, 1998. http://hdl.handle.net/10962/d1004066.

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Salinisation has been identified as a major cause of the progressive deterioration in the public water system in South Africa. To deal with this problem Waste Stabilisation Ponding systems have been used by the Leather Processing Industry as zero-dischaJ;ge wastewater evaporation disposal processes in water-limited inland regions of the country. While effective in the evaporation disposal function these systems are plagued by the generation of serious odour nuisance creating intractable environmental problems relating to adjacent residential communities. High loading to ponds of organic compounds, sulphides and ammonia results in strongly reducing anaerobic conditions prevailing in early parts of pond cascades. These are characterised by bright red colours due to the predominance of purple photosynthetic bacteria. Sporadic micro algal blooms of Spirulina sp. and Dunaliella sp. had been previously noted to occur on the latter ponds in these cascades, and were associated with their conversion to facultative function, with aerobic surface layers, and a marked reduction in odour release. This research programme undertook an investigation of the microbial ecology of a tannery waste stabilisation ponding system to describe factors which give rise to these blooms, and to determine whether microalgal growth may be manipulated to achieve a reliable oxygengenerating capping of the anaerobic ponds. The predominance of near pure cultures of Spin/lina platensis was demonstrated for the blooms and factors restricting its growth in the system were described. These include the interaction of ammonia and sulphide toxic effects and laboratory studies were undertaken to show how effluent loading may be regulated to enable effective growth of the cyanobacterium. At appropriate dilutions of tannery effluent an enhancement of growth was noted, compared to growth in defined mineral medium. An investigation of this phenomenon provided preliminary evidence for organic uptake by the pond micro algae and a possible contribution to heterotrophic nutrition. The manipulation of Spirulina sp. growth in a High Rate Algal Pond raceway was undertaken in outdoor pilot plant studies and the effect of microalgal capping of the anaerobic ponds in the cascade was demonstrated by activating a recycle loop from a blooming facultative pond. Heavy metal contaminants were effectively eliminated by an optimisation of the primary anaerobic pond function and precipitation as metal sulphides. Biomass was harvested and dried, during which a range of methods were evaluated. Toxicological studies were undertaken on the dried biomass using Artemia and chick assays, and feed studies showed its useful application in rations for the abalone Haliotlls midae and rainbow trout Onchorhynchlls mykiss. Based on positive independent assessment of research outcomes, a decision was made by the tanning company operating the Waste Stabilisation Ponding system, to proceed to the construction of a full-scale 2 500 m2 High Rate Algal Pond raceway. This would be used for controlled Spirlilina biomass production to effect a practical capping of the anaerobic ponds in the system, and to evaluate its commercial potential in the feed market. The Advanced Integrated Wastewater Ponding System described by Oswald (1991) provided the conceptual basis for the Algal Biotechnology process development undertaken. The studies of the microbial ecology and the biotechnological potential of this system have shown that a Spirulina-based High Rate Algal Ponding process can be engineered in such a way that saline tannery effluents may be treated to effect a significant reduction in overall pollution load, that biomass may be recovered as a value added product of the treatment process and that the operational performance of Waste Stabilisation Ponding systems, and hence their immediate environment, may be improved by the use of the High Rate Algal Pond as a retrofitted upgrading unit operation.
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Geeves, Guy William, and not available. "Aggregate Breakdown and Soil Surface Sealing under Rainfall." The Australian National University, 1997. http://thesis.anu.edu.au./public/adt-ANU20010702.142014.

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Aggregate breakdown is an important process controlling the availability of fine soil material necessary for structural sealing of soil surfaces under rainfall. It may be caused by slaking resulting from rapid soil wetting and by physical dispersion resulting from direct and indirect energetic raindrop impacts. Relationships have been proposed by others predicting steady infiltration rate and saturated hydraulic conductivity from final aggregate size following high energy rainfall on initially dry, uncovered soil surfaces. Under these extreme conditions, both rapid wetting and energetic raindrop impact result in maximum aggregate breakdown and surface sealing. Knowledge of the relative importance of these two agents under less severe conditions and knowledge of how increased aggregate stability due to conservative soil management may ameliorate them should improve prediction and management of aggregate breakdown and surface sealing. ¶ This study has isolated and quantified effects of rapid soil wetting and energetic raindrop impact on aggregate breakdown and surface sealing. Simulated rainfall was applied to re-packed soils from differing tillage treatments on light textured soils from near Cowra and Condobolin in New South Wales, Australia. Aggregate breakdown was assessed using aggregate size distribution, determined by wet sieving and summarised by a range of statistics. The degree of breakdown was assessed after 66 mm of simulated rainfall whilst the rate of change in aggregate size distribution was assessed by sampling after 5, 10, 15, 30 and 60 mm. The degree of surface sealing was assessed using final surface hydraulic conductivity after 66 mm rainfall calculated from inferred infiltration and measured sub-seal soil water potential. The rate of surface sealing was assessed prior to ponding using cumulative rainfall volume at ponding and throughout the post-ponding phase by decline in surface hydraulic conductivity as a function of cumulative rainfall kinetic energy. Two levels of raindrop kinetic energy flux and three wetting treatments were used to isolate effects of these agents of aggregate breakdown and surface sealing. ¶ Significant surface aggregate breakdown was observed when either rapid soil wetting or highly energetic raindrop impact were allowed to occur. The majority of the data suggest a negative interaction between the two agents. When soil was initially dry rapid soil wetting was the dominant agent causing rapid aggregate breakdown, generally within the first 5 mm of rainfall. When rapid soil wetting was prevented by tension pre-wetting, energetic raindrop impact was the dominant agent and was able to cause aggregate breakdown of an almost equivalent degree. This breakdown occurred over a period lasting for up to 30 mm of rainfall. In contrast, the rate and degree of surface sealing were influenced primarily by raindrop kinetic energy with highly energetic impact leading to significant surface sealing, irrespective of soil wetting. For the soils studied, it was concluded that structural sealing of surface soil, could be significantly reduced by protecting the soil surface from energetic raindrop impact but that prevention of surface aggregate breakdown required amelioration of both processes. ¶ In addition to the negative interaction referred to above, a positive interaction was observed whereby energetic raindrop impact occurring concurrently with rapid soil wetting caused a greater degree of aggregate breakdown and a greater degree of surface sealing than energetic raindrop impact occurring subsequent to rapid soil wetting. The effect on surface sealing may be explained by the effect of lower sub-seal water potential that necessarily results from initially dry soil condition required for concurrent rapid wetting. However, the effect on aggregate breakdown remains unexplained. ¶ Notwithstanding the above, permeability was reduced under high kinetic energy rainfall even when soil wetting was reduced to very slow rates by tension pre-wetting. Likewise, surface sealing did occur under low kinetic energy rainfall for the least stable soil following rapid soil wetting. It was concluded that threshold soil wetting rates and threshold rainfall energy levels, proposed by others, are either not applicable to these soils or are negligible. ¶ The rate and degree of aggregate breakdown was also dependent on the soil with the Cowra soil being more stable than the Condobolin soil. Greater aggregate stability brought about by conservative tillage treatments at both soil locations retarded and reduced surface sealing. Unvalidated simulation modelling was used to illustrate possible effects for the soil water balance. In contrast to the conclusions of Loch (1994b), that were based on soils throughout eastern Queensland, the soil water balance simulations predicted that the residual benefits in ameliorating surface sealing resulting from improved aggregate stability could significantly reduce point runoff under the lower intensity winter rainfalls experienced in southern New South Wales. ¶ Limited testing with Condobolin soil following tension pre-wetting showed that rainfall intensity, varying over the range from 16.5 to 66 mm h-1, had little effect on the decline in surface hydraulic conductivity as a function of cumulative rainfall kinetic energy. This contrasts with greater seal permeability under higher rainfall intensities observed by Romkens et al. (1985) and others. It is proposed that an alternative explanation exists for the observations of Romkens et al. based on reduction in seal permeability due to lower sub-seal water potential under lower intensity rainfall. ¶ Post-ponding reduction in K[subscript sat] under high kinetic energy rainfall exhibited exponential decline as a function of cumulative raindrop kinetic energy as proposed by Moore (1981b). However, inferred rates of decline prior to ponding were more rapid than measured post-ponding rates suggesting that infiltration models using only a single exponential rate of surface K[subscript sat] decline based on post-ponding measurements may be in error. Potential for error is greatest at early times for loose soil that is highly susceptible to sealing. ¶ Pre-ponding decline in surface aggregation was also relatively more rapid than post-ponding decline. This discrepancy was evident irrespective of soil pre-wetting. From this it was concluded that the more rapid initial aggregate breakdown and surface sealing was due, at least in part, to processes other than aggregate slaking due to rapid soil wetting. An explanation has been proposed as follows. Raindrops initially fall on aggregates that have not been subjected to rainfall and therefore each drop has the capacity to cause greater aggregate breakdown than subsequent raindrops that fall on aggregates or soil fragments that have been strong enough to survive preceding rainfall impacts. Such a mechanism could provide an alternative explanation of the findings of Baumhardt et al. (1991) who found that less cumulative raindrop kinetic energy was necessary to achieve a given reduction in surface conductance when the cumulative energy was supplied through lower energy drops. ¶ Relationships predicting rates of surface sealing using aggregate breakdown under rainfall and aggregate stability were evaluated. Post-ponding infiltration rate and surface K[subscript sat] were related to aggregate size by exponential functions. The proportion of surface aggregates less than 0.125 mm in diameter provided slightly more consistent relationships. Parameters of fitted relationships differed among wetting pre-treatments suggesting that the influence of sub-seal water potential on surface K[subscript sat] must be considered whenever such relationships are developed or applied. Aggregate stability determined by wet sieving was related to rainfall volume required for ponding, final K[subscript sat] and final aggregate size but only for initially dry soil suggesting that such relationships may be unique to the rainfall, soils and flow conditions used to develop them. ¶ This study has established the relative importance of rapid soil wetting and energetic raindrop impact in both aggregate breakdown and surface sealing over a range of antecedent soil water and rainfall conditions. It has quantified the effectiveness of culturally induced aggregate stability in ameliorating effects of these two important agents and illustrated the potentially significant consequences for the soil water balance. It has quantified temporal patterns of surface sealing and aggregate breakdown and proposed an alternative mechanism explaining more rapid aggregate breakdown during the initial stages of rainfall. It has identified possible explanations for effects of rainfall intensity on surface sealing observed in other studies. It has also partially evaluated a mechanism proposed to explain important effects of subseal water potential on seal permeability found in this and other studies. These significant findings have been used with the findings of other studies to amend the conceptual model proposed by Le Bissonnias (1990). The amended model gives a more complete description of the relationships between parameters and processes determining aggregate breakdown and structural surface sealing under rainfall.
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Books on the topic "Ponding"

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Cho, Hŏn-su. Pondang osimnyŏnsa. Yŏngchʻŏn-si: Yŏngchʻŏn Chʻŏnju Kyohoe, 1986.

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Changan Pondang Simnyŏnsa Pʻyŏnchʻan Wiwŏnhoe. Changan Pondang simnyŏnsa. Sŏul: Chʻŏnjugyo Changandong Kyohoe, 1992.

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Korea) Chʻŏnjugyo Apkujŏng Kyohoe (Seoul. Apkujŏng Pondang simnyŏnsa. Sŏul: Chʻŏnjugyo Apkujŏng Kyohoe, 1989.

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Catholic Church. Archdiocese of Seoul (Korea). Tonam-dong Kyohoe. Tonam Pondang samsimnyŏnsa. Sŏul Tʻŭkpyŏlsi: Chʻŏnjugyo Tonam-dong Kyohoe, 1985.

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Pondick, Rona. Rona Pondick. New York, N.Y: Fiction/nonfiction, 1991.

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Pondering pollution. Ann Arbor, Michigan: Cherry Lake Publishing, 2014.

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Sejongno pondang sasimnyŏnsa, 1946-1986. Sŏul Tʻŭkpyŏlsi: Chʻŏnjugyo Sejongno Kyohoe, 1987.

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Mallayya, Kāluva. Nēlatalli: Bahumatulu pondina kathānikala saṃpuṭi. Haidarābād: Sri Vedagiri Kamyunikesans, 2011.

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Mallayya, Kāluva. Nēlatalli: Bahumatulu pondina kathānikala saṃpuṭi. Haidarābād: Sri Vedagiri Kamyunikesans, 2011.

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(Seoul, Korea) Chʻŏnjugyo Ŭngam-dong Kyohoe. Ŭngam-dong pondang 25-yŏnsa. Sŏul Tʻŭkpyŏlsi: Chʻŏnjugyo Sŏul Taegyogu Ŭngam-dong Kyohoe, 1993.

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Book chapters on the topic "Ponding"

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Parlange, J. Y., and R. Haverkamp. "Infiltration and Ponding Time." In Unsaturated Flow in Hydrologic Modeling, 95–126. Dordrecht: Springer Netherlands, 1989. http://dx.doi.org/10.1007/978-94-009-2352-2_4.

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Kubo, Naritaka, Toshiaki Iida, and Masaru Mizoguchi. "Reduction of Air Radiation Dose by Ponding Paddy Fields." In Agricultural Implications of the Fukushima Nuclear Accident, 189–204. Tokyo: Springer Japan, 2016. http://dx.doi.org/10.1007/978-4-431-55828-6_15.

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Bertolini, Luca, Federica Lollini, and Elena Redaelli. "Comparison of Resistance to Chloride Penetration of Different Types of Concrete through Migration and Ponding Tests." In Modelling of Corroding Concrete Structures, 125–35. Dordrecht: Springer Netherlands, 2011. http://dx.doi.org/10.1007/978-94-007-0677-4_8.

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Barry, D. A., and J. Y. Parlange. "Infiltration Subject to Time-Dependent Surface Ponding: Exact Results and Correspondence to Solute Transport with Nonlinear Reaction." In Water Science and Technology Library, 33–48. Dordrecht: Springer Netherlands, 1996. http://dx.doi.org/10.1007/978-94-011-0391-6_3.

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Sherif, Mohsen, Abdel Azim Ebraheem, Ampar Shetty, Ahmed Sefelnasr, Khaled Alghafli, and Mohamed Al Asam. "Evaluation of the Effect of the Wadi Bih Dam on Groundwater Recharge, UAE." In Natural Disaster Science and Mitigation Engineering: DPRI reports, 509–27. Singapore: Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-16-2904-4_21.

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AbstractIn Ras Al Khaimah, UAE, groundwater from the alluvial aquifer in Wadi Bih was the only source of freshwater for various uses prior to the construction of a seawater desalination plant in 1998. This study was conducted to evaluate the effect of the Wadi Bih dam on groundwater resources and to increase knowledge of the hydrodynamics of the aquifer. A local-scale numerical groundwater flow model was developed and used to investigate the impacts of different groundwater management options on groundwater resources. The calibrated and validated model was defined as the base case, and subsequently, simulations were performed to analyze different management scenarios. The simulations indicated that maximum recharge occurred during years of high rainfall (1995–1998). Minimum recharge occurred in 2000, 2002, and 2004. The major contribution to the water balance was from subsurface inflows from the upper wadi zone and the two tributaries. Overall, the annual water balance was negative in most years, with an average net decline of 0.6 MCM per year, indicating a slow but continuous depletion of groundwater resources. At the end of the simulation, the total groundwater recharge due to rainfall and water storage in the ponding area was 9.81 MCM.
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He, Z., T. Maeshima, M. Hosotani, and I. Iwaki. "Study on the fatigue resistance of precast road bridge deck with the newly developed joint under ponding water." In Bridge Safety, Maintenance, Management, Life-Cycle, Resilience and Sustainability, 245–52. London: CRC Press, 2022. http://dx.doi.org/10.1201/9781003322641-26.

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Catry, Thibault, Cécile Vignolles, Serge Olivier Kotchi, Stéphanie Brazeau, Antoinette Ludwig, Nicholas H. Ogden, Dominique J. Bicout, Richard A. Fournier, and Dirk Werle. "Mosquito-borne diseases." In Earth observation, public health and one health: activities, challenges and opportunities, 11–92. Wallingford: CABI, 2022. http://dx.doi.org/10.1079/9781800621183.0002.

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Abstract The World Health Organization (WHO) has highlighted identification and monitoring of vector populations as an important component of global vector-borne disease surveillance efforts. EO and RVF map data could play a crucial role in identifying risk locations for mosquito-borne diseases globally on the basis of habitat and climate variables. EO and RVF map data are also useful for measuring or mapping a range of environmental parameters that help determine mosquito vector occurrence and abundance and the rate of development of mosquito-borne parasites and pathogens in mosquito vectors. The EO and RVF map data have been sufficiently high spatial and temporal resolution, applied research could develop weather-based and environment-based forecasting of high-risk locations and time periods for mosquito-borne diseases using statistical models. The maps generated by this project indicate and outline the RVF risk areas associated with surface water ponding, mosquito breeding, and cattle grazing for a test area in Senegal. This strategy could include the following recommendations to effectively mitigate the exposure of cattle to RVF, and thus to minimise infection risk for humans: establish a joint communication strategy by integrating information of the forecasted risk bulletins into the National Information System of Surveillance of Epidemics used by the Ministry of Livestock in Senegal and the Headquarters of the Directorate of Veterinary Services of Senegal and its local representatives in rural districts, relocate livestock grazing areas away from risk zones, with warning signs in local languages posted near the ponds to inform breeders to keep their animals at least 500 m away from the ponds, and issue regular bulletins so the Directorate of Veterinary Services of Senegal can organise and optimise vaccination campaigns in the riskiest zones.
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McIntosh, Jason S. "Pondering Our Progress." In Microscopic Monsters and the Scientists Who Slay Them Grades 4-5, 159–63. New York: Routledge, 2021. http://dx.doi.org/10.4324/9781003236627-31.

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Stebbins, Robert A. "How We Manage Everyday Life." In Pondering Everyday Life, 1–20. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-35922-5_1.

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Stebbins, Robert A. "Work." In Pondering Everyday Life, 21–36. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-35922-5_2.

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Conference papers on the topic "Ponding"

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Snijder, H. H. (Bert), and S. N. M. (Simon) Wijte. "Rainwater Ponding on Roof Structures with Interaction between Main Girders and Purlins." In IABSE Congress, New York, New York 2019: The Evolving Metropolis. Zurich, Switzerland: International Association for Bridge and Structural Engineering (IABSE), 2019. http://dx.doi.org/10.2749/newyork.2019.0150.

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<p>Rainwater causes flat roofs to deflect resulting in ponding. Due to the deflection, extra rainwater flows to the lower area of the roof, resulting in a larger loading with a larger deflection, resulting in more rainwater flowing towards this area, etc. Failure of flat roof structures due to ponding under heavy rainfall frequently happens in The Netherlands with an average of 15 incidents each year in the last decades. An increase in rain intensity due to climate change is expected to increase these numbers in the near future. Nevertheless, ponding on light roof structures is still underestimated as a significant load case in design. Moreover, the design calculations necessary are complex due to geometrical non-linear behavior. A number of software programs are available, but to keep insight in the process of rainwater ponding, a simple analytical design method for ponding of flat (steel) roof structures was developed including the interaction between main girders and purlins. The paper presents this method which avoids an iterative calculation procedure. Subsequently, this method is used to analyze a roof structure concluding that the interaction between main girders and purlins cannot be neglected.</p>
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Baber, Thomas T., and Eric D. Rigsbee. "Noniterative Finite Element Analysis of Ponding." In Structures Congress 2010. Reston, VA: American Society of Civil Engineers, 2010. http://dx.doi.org/10.1061/41130(369)105.

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Sputo, Thomas, Perry S. Green, and Ananda Bergeron. "Improved Ponding Criteria for Cantilever Framing Systems." In Structures Congress 2004. Reston, VA: American Society of Civil Engineers, 2004. http://dx.doi.org/10.1061/40700(2004)111.

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Nasab, Mohsen Tahmasebi, and Xuefeng Chu. "Topo-Statistical Analyses of Ponding Area versus Ponding Storage of Depression-Dominated Regions for Macro-Scale Hydrologic Modeling." In World Environmental and Water Resources Congress 2018. Reston, VA: American Society of Civil Engineers, 2018. http://dx.doi.org/10.1061/9780784481400.039.

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Sanabria, Ricardo Alfonso, Carlos Felipe Gomez, Francisco Javier Vaca, Juan David Sanchez, Diego Aldana, and Angie Franco. "Communication Architecture for the Ponding Flood Prediction Model." In 2021 International Symposium on Computer Science and Intelligent Controls (ISCSIC). IEEE, 2021. http://dx.doi.org/10.1109/iscsic54682.2021.00042.

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Tae-Gon Kim and Jeong-Jae Lee. "Estimation of a Ponding Depth Using a Dynamic Simulator." In 2006 Portland, Oregon, July 9-12, 2006. St. Joseph, MI: American Society of Agricultural and Biological Engineers, 2006. http://dx.doi.org/10.13031/2013.20714.

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Gossen, Paul, David Chen, Wenxiao Shan, and David Campbell. "Snow Induced Ponding of Toyota Pavilion Canopy, Montage Mountain, PA." In Structures Congress 2008. Reston, VA: American Society of Civil Engineers, 2008. http://dx.doi.org/10.1061/41016(314)238.

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Dejun Yang and Zhengfu Bian. "Study on modeling infiltration responses of different soils under ponding conditions." In 2011 International Conference on Remote Sensing, Environment and Transportation Engineering (RSETE). IEEE, 2011. http://dx.doi.org/10.1109/rsete.2011.5965241.

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Narayanan, N., R. Wüchner, and J. Degroote. "Comparison of Monolithic and Partitioned Approaches for Ponding Analysis On Membrane Structures." In 14th WCCM-ECCOMAS Congress. CIMNE, 2021. http://dx.doi.org/10.23967/wccm-eccomas.2020.092.

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Kodunthirappully Narayanan, N., R. Wüchner, and J. Degroote. "Simulation of wind induced excitation of a membrane structure with ponding water." In 8th European Congress on Computational Methods in Applied Sciences and Engineering. CIMNE, 2022. http://dx.doi.org/10.23967/eccomas.2022.254.

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Reports on the topic "Ponding"

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Morse, P. D., T. L. McWade, and S. A. Wolfe. Thermokarst ponding, North Slave region, Northwest Territories. Natural Resources Canada/ESS/Scientific and Technical Publishing Services, 2017. http://dx.doi.org/10.4095/300531.

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Dowling, Adam. Adaptation Resources for Agriculture A Case Study: Organic Dairy in Wisconsin. USDA Midwest Climate Hub, November 2018. http://dx.doi.org/10.32747/2018.6893742.ch.

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Like many producers in Wisconsin, R & G Miller & Sons is already seeing an increase in intense precipitation events particularly in spring. This delays planting and prevents early season grazing due to possible damage/compaction from cow traffic on saturated pastures. Extended wet periods (e.g. 5 in of rain or more/week) and big deluge rains also lead to ponding in some areas of fields, which in turn leads to reduced productivity of pastures.
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Bhattarai, Rabin, Yufan Zhang, and Jacob Wood. Evaluation of Various Perimeter Barrier Products. Illinois Center for Transportation, May 2021. http://dx.doi.org/10.36501/0197-9191/21-009.

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Construction activities entail substantial disturbance of topsoil and vegetative cover. As a result, stormwater runoff and erosion rates are increased significantly. If the soil erosion and subsequently generated sediment are not contained within the site, they would have a negative off-site impact as well as a detrimental influence on the receiving water body. In this study, replicable large-scale tests were used to analyze the ability of products to prevent sediment from exiting the perimeter of a site via sheet flow. The goal of these tests was to compare products to examine how well they retain sediment and how much ponding occurs upstream, as well as other criteria of interest to the Illinois Department of Transportation. The products analyzed were silt fence, woven monofilament geotextile, Filtrexx Siltsoxx, ERTEC ProWattle, triangular silt dike, sediment log, coconut coir log, Siltworm, GeoRidge, straw wattles, and Terra-Tube. Joint tests and vegetated buffer strip tests were also conducted. The duration of each test was 30 minutes, and 116 pounds of clay-loam soil were mixed with water in a 300 gallon tank. The solution was continuously mixed throughout the test. The sediment-water slurry was uniformly discharged over an 8 ft by 20 ft impervious 3:1 slope. The bottom of the slope had a permeable zone (8 ft by 8 ft) constructed from the same soil used in the mixing. The product was installed near the center of this zone. Water samples were collected at 5 minute intervals upstream and downstream of the product. These samples were analyzed for total sediment concentration to determine the effectiveness of each product. The performance of each product was evaluated in terms of sediment removal, ponding, ease of installation, and sustainability.
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Wallach, Rony, Tammo Steenhuis, Ellen R. Graber, David DiCarlo, and Yves Parlange. Unstable Flow in Repellent and Sub-critically Repellent Soils: Theory and Management Implications. United States Department of Agriculture, November 2012. http://dx.doi.org/10.32747/2012.7592643.bard.

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Water repellency causes unstable wetting fronts that result in water moving in preferential flowpaths through homogeneous soils as well in structured soils where macropores enhance the preferential flow pattern. Water repellency is typically associated with extended water ponding on the soil surface, but we have found that repellency is important even before the water ponds. Preferential flow fingers can form under conditions where the contact angle is less than 90o, but greater than 0o. This means that even when the soil is considered wettable (i.e., immediate penetration of water), water distribution in the soil profile can be significantly non-uniform. Our work concentrated on various aspects of this subject, with an emphasis on visualizing water and colloid flow in soil, characterizing mathematically the important processes that affect water distribution, and defining the chemical components that are important for determining contact angle. Five papers have been published to date from this research, and there are a number of papers in various stages of preparation.
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Kerr, D. E. Reconnaissance surficial geology, Clarke River, Northwest Territories, NTS 65-M north. Natural Resources Canada/CMSS/Information Management, 2022. http://dx.doi.org/10.4095/329416.

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The Clarke River map area (north half) comprises isolated areas of glacially and meltwater scoured bedrock, till veneers and blankets, locally fluted, and strongly fluted (mega-scale glacial lineations) streamlined till in the northeast. Ridged till may overlie fluted till blanket and streamlined till. Glaciofluvial esker complexes and associated meltwater outwash sediments trend westward (some may parallel pre-glacial valleys), southwestward, and northwestward. Glaciolacustrine sediments are a minor component. An early regional warm-based diverging southwestern and southern ice flow is well preserved in the central regions across the map area. The youngest late deglacial ice flows, in the extreme southwest and broader northeast region, are both northwesterly. The latter represents the Dubawnt Lake ice stream. During ice retreat, ridged till was deposited with minor moraines and larger recessional moraines locally. Ponding meltwater formed pro-glacial lakes with deltas, beaches, and trim lines from 355 m elevation, in the southwest, to 155 m, in the northeast.
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Wolfe, S. A., H. B. O'Neill, C. Duchesne, D. Froese, J M Young, and S. V. Kokelj. Ground ice degradation and thermokarst terrain formation in Canada over the past 16 000 years. Natural Resources Canada/CMSS/Information Management, 2022. http://dx.doi.org/10.4095/329668.

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Thermokarst results from thawing of excess ground ice in permafrost sediments. Thermokarst processes and landforms are controlled by ground ice type, amount and distribution, as well as the patterns of ground ice loss over time. Recent acceleration of varied thermokarst processes across diverse Canadian permafrost terrains make for a challenging task in predicting landscape-scale thaw trajectories. Using existing ground ice models, we examined the modelled amounts and spatial extent of ground ice loss relative to ground ice maxima in the last ca. 16 ka BP for relict, segregated and wedge ice. We relate observed thermokarst features to the nature of ground ice development and loss in different environments (cold continuous permafrost, discontinuous permafrost, and no current permafrost). In cold, continuous permafrost areas where ground ice loss has been limited over the last 16 ka BP, thermokarst processes include active layer detachments and slumps in segregated and relict ice, gullying and ponding in ice wedge troughs, and the cyclical development of shallow thermokarst ponds in segregated ice. With ground ice loss in discontinuous permafrost, thermokarst processes are wide-ranging. Slumps, subsidence, and collapse of lithalsas, palsas and peat plateaus occur from thawing of segregated ice, thermokarst ponds from melting wedge and segregated ice, and involuted terrain from melting and creep of relict or segregated ice. In former permafrost terrain, evidence of thermokarst includes former ice wedge polygons, collapsed lithalsas, and irregular hummocky terrain. The relations between modelled ground ice loss and observed thermokarst landscapes assist in understanding present-day processes and in predicting future thermokarst landform evolution with a changing climate.
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Leeper, Eric. Fiscal Policy and Inflation: Pondering the Imponderables. Cambridge, MA: National Bureau of Economic Research, February 2003. http://dx.doi.org/10.3386/w9506.

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