Analysis of macroplastic transport in a river regulated by groynes

The transport of buoyant macroplastic litter in the presence of concrete groynes and vegetation in a straight channel was investigated. Four variants of channel configuration were tested during laboratory measurements. Water velocity fields were measured using ADV current meter, while floating plastic particles' paths were registered using PTV (Particle Tracking Velocimetry) technique. Preliminary research using numerical model Delft3D was carried out to reproduce the observed physical phenomena

Fuzzy simulation of forest road surface parameters

The problem of construction of forest roads with the use of local low-strength substandard materials and industrial waste is considered. To solve the problem, the primary task is to develop a method for estimating the parameters of road surfaces taking into account the conditions of uncertainties in the data. This technique allows us to reasonably clarify some of the regulatory parameters and improve the technology of construction of forest roads, which was the goal of the work. To formalize the task, experimental studies were performed and on the basis of these results, the statement of the task of fuzzy derivation of the function for estimating the bearing capacity of the coating was performed. The synthesis of the output function is performed by means of Matlab. © 2019 IOP Publishing Ltd. All rights reserved

Understanding Moisture Dynamics in the Vadose Zone: Transcending the Darcy Scale

Soil moisture forms the interface at which the partitioning of the energy, carbon and water budget for the land-surface occurs. Its variability impacts different fields of application at varying extent scales like agriculture at the field scale, meteorology at the regional scale and climate change assessment at the global scale. However, past literature has focused on understanding soil moisture dynamics at this diverse range of extent scales using soil moisture data at the Darcy support scale which cannot effectively cater to soil moisture dynamics for the current eco-hydrologic models that describe complex heterogeneous domains at remote sensing footprint scales. This dissertation serves to push the envelope of our understanding of soil moisture dynamics and its dependence on land-surface heterogeneity at the coarse remote sensing scales. The research questions answered in this dissertation include 1) determining the dominant land-surface controls of near-surface soil moisture dynamics at scales varying between the Darcy (of the order of a few centimeters) support and satellite footprint scale (25.6 km); 2) generating a framework for quantifying the relationships between antecedent wetness, land-surface heterogeneity and near-surface soil moisture at remote sensing scales and 3) evaluating variability in the root zone moisture dynamics as evaluated through evapo-transpiration estimates at different remote sensing footprint scales. The dominant land-surface factors controlling soil moisture distribution at different scales were determined by developing a new Shannon entropy based technique and non-decimated wavelet transforms. It was found that the land-surface controls on soil moisture vary with hydro-climate and antecedent wetness conditions. In general, the effect of soil was found to reduce with coarsening support scale while the effect of topography and vegetation increased. A novel Scale-Wetness-Heterogeneity (SWHET) cuboid was developed to coalesce the relationship between soil moisture redistribution and dominant physical controls at different land-surface heterogeneity and antecedent wetness conditions across remote sensing scales. The SWHET cuboid can potentially enable spatial transferability of the scaling relationships for near-surface soil moisture. It was found that results from the SWHET cuboid enabled spatial transferability of the scaling relationships between two similar hydro-climates (Iowa, U.S.A and Manitoba, Canada) under some wetness and land-surface heterogeneity conditions. Evapotranspiration estimates were computed at varying scales using airborne and satellite borne remotely sensed data. The results indicated that in a semi-arid row cropped orchard environment, a remote sensing support scale comparable to the row spacing and smaller or comparable to the canopy size of trees overestimates the land surface temperature and consequently, underestimates evapotranspiration

Use of Large Lysimeters to Monitor Unsaturated Hydraulic Properties of Amended Soils

The design and construction of large $1.2$~$m$ diameter lysimeters has been implemented to monitor the soil water retention behaviour and permeability characteristics of contaminated soils under remediation. The work was carried out as part of a larger project focussing on the sustainable remediation of low value brownfield land. Three lysimeters have been filled with lead contaminated soil: one control; one with a \ac{WTR} amendment; and one with a \ac{WTR} and compost amendment. A new software system was built to control the \ac{TDR} point water content measurement and irrigation system, which could log data to an online unified data repository; provided an interface for connectivity to any serial port device; deal with templating for simplified setup; and realtime feedback for the end user. High capacity tensiometers were used in conjunction with the \ac{TDR} point water content measurement system to read volumetric water contents and suctions in the large control lysimeter over a series of wetting and drying cycles, each lasting several months. The results demonstrate that there was a difference between small scale laboratory tests and the data obtained from the lysimeters, particularly in the near surface soil due to cracking. Where cracking was not present, the agreement was stronger, but differences suggested that the drying curves in the lysimeter was predominantly scanning behaviour whereas the element tests were likely more representative of primary drying behaviour

Evaluation of AnnAGNPS for simulating the inundation of drained and farmed potholes in the Prairie Pothole Region of Iowa

Closed surface depressions, also known as “potholes” play an important role in the hydrologic cycle and provide multiple environmental services including flood mitigation, water quality improvements and wildlife habitat. In the Prairie Pothole Region, which covers approximately 715,000 km2, including parts of three Canadian provinces (Saskatchewan, Manitoba, and Alberta) and five states in the U.S. (Minnesota, Iowa, North and South Dakota, and Montana), these potholes are typically farmed and are a dominant feature in the landscape. In this study, we evaluate the Annualized Agriculture Non-Point Source (AnnAGNPS) model for simulating the inundation behavior of two farmed potholes, termed Bunny and Walnut, in Prairie Pothole Region (PPR) of Iowa. Performance analysis considered the entire growing season (GS), corresponding to the span in which there was observed data, and only days in which water storage (WS) was observed. Results show that AnnAGNPS predicted pothole water depth acceptably but not pothole water volume because of the model’s inability to accurately represent the depth-volume relationship of a pothole. When calibrated to depth, Nash-Sutcliffe efficiency (NSE) values were 0.77 and 0.24 in the Walnut pothole and 0.56 and 0.30 in the Bunny pothole, for the GS calibration and validation periods, respectively. Our results demonstrate that the AnnAGNPS model can be used to predict the inundation depth of drained and farmed potholes, which is useful for assessing landscape impacts of these features. Appropriate applications of this model could include impact of inundation on crop yield or simulations of alternative farm management strategies to compare water delivery to the potholes

The use of Unmanned Aerial Vehicle based photogrammetric point cloud data for winter wheat intra-field variable retrieval and yield estimation in Southwestern Ontario

Precision agriculture uses high spatial and temporal resolution soil and crop information to control the crop intra-field variability to achieve optimal economic benefit and environmental resources sustainable development. As a new imagery collection platform between airborne and ground measurements, Unmanned Aerial Vehicle (UAV) is used to collect high spatial resolution images at a user selected period for precision agriculture. Most studies extract crop parameters from the UAV-based orthomosaic imagery using spectral methods derived from the satellite and airborne based remote sensing. The new dataset, photogrammetric point cloud data (PCD), generated from the Structure from Motion (SfM) methods using the UAV-based images contains the feature’s structural information, which has not been fully utilized to extract crop’s biophysical information. This thesis explores the potential for the applications of the UAV-based photogrammetric PCD in crop biophysical variable retrieval and in final biomass and yield estimation. First, a new moving cuboid filter is applied to the voxel of UAV-based photogrammetric PCD of winter wheat to eliminate noise points, and the crop height is calculated from the highest and lowest points in each voxel. The results show that the winter wheat height can be estimated from the UAV-based photogrammetric PCD directly with high accuracy. Secondly, a new Simulated Observation of Point Cloud (SOPC) method was designed to obtain the 3D spatial distribution of vegetation and bare ground points and calculate the gap fraction and effective leaf area index (LAIe). It reveals that the ground-based crop biophysical methods are possible to be adopted by the PCD to retrieve LAIe without ground measurements. Finally, the SOPC method derived LAIe maps were applied to the Simple Algorithm for Yield estimation (SAFY) to generate the sub-field biomass and yield maps. The pixel-based biomass and yield maps were generated in this study revealed clearly the intra-field yield variation. This framework using the UAV-based SOPC-LAIe maps and SAFY model could be a simple and low-cost alternative for final yield estimation at the sub-field scale. The results of this thesis show that the UAV-based photogrammetric PCD is an alternative source of data in crop monitoring for precision agriculture

Using urban climate modelling and improved land use classifications to support climate change adaptation in urban environments: A case study for the city of Klagenfurt, Austria

This study outlines the results of current and future climate scenarios, and potentially realizable climate adaptation measures, for the city of Klagenfurt, Austria. For this purpose, we used the microscale urban climate model (MUKLIMO_3), in conjunction with the cuboid method, to calculate climate indices such as the average number of summer and hot days per year. For the baseline simulation, we used meteorological measurements from 1981 to 2010 from the weather station located at Klagenfurt Airport. Individual building structures and canopy cover from several land monitoring services were used to derive accurate properties for land use classes in the study domain. To characterize the effectiveness of climate adaptation strategies, we compared changes in the climate indices for several (future) climate adaptation scenarios to the reference simulation. Specifically, we considered two major adaptation pathways: (i) an increase in the albedo values of sealed areas (i.e., roofs, walls and streets) and (ii) an increase in green surfaces (i.e., lawns on streets and at roof level) and high vegetated areas (i.e., trees). The results indicate that some climate adaptation measures show higher potential in mitigating hot days than others, varying between reductions of 2.3 to 11.0%. An overall combination of adaptation measures leads to a maximum reduction of up to 44.0%, indicating a clear potential for reduction/mitigation of urban heat loads. Furthermore, the results for the future scenarios reveal the possibility to remain at the current level of urban heat load during the daytime over the next three decades for the overall combination of measures