Towards cost-efficient prospection and 3D visualization of underwater structures using compact ROVs

The deployment of Remotely Operated Vehicles (ROV) for underwater prospection and 3D visualization has grown significantly in civil applications for a few decades. The demand for a wide range of optical and physical parameters of underwater environments is explained by an increasing complexity of the monitoring requirements of these environments. The prospection of engineering constructions (e.g. quay walls or enclosure doors) and underwater heritage (e.g. wrecks or sunken structures) heavily relies on ROV systems. Furthermore, ROVs offer a very flexible platform to measure the chemical content of the water. The biggest bottleneck of currently available ROVs is the cost of the systems. This constrains the availability of ROVs to a limited number of companies and institutes. Fortunately, as with the recent introduction of cost-efficient Unmanned Aerial Vehicles on the consumer market, a parallel development is expected for ROVs. The ability to participate in this new field of expertise by building Do It Yourself (DIY) kits and by adapting and adding on-demand features to the platform will increase the range of this new technology. In this paper, the construction of a DIY OpenROV kit and its implementation in bathymetric research projects are elaborated. The original platform contains a modified webcam for visual underwater prospection and a Micro ElectroMechanical System (MEMS) based depth sensor, allowing relative positioning. However, the performance of the standard camera is limited and an absolute positioning system is absent. It is expected that 3D visualizations with conventional photogrammetric qualities are limited with the current system. Therefore, modifications to improve the standard platform are foreseen, allowing the development of a cost-efficient underwater platform. Preliminary results and expectations on these challenges are reported in this paper

Assessment of Levee Erosion using Image Processing and Contextual Cueing

Soil erosion is one of the most severe land degradation problems afflicting many parts of the world where topography of the land is relatively steep. Due to inaccessibility to steep terrain, such as slopes in levees and forested mountains, advanced data processing techniques can be used to identify and assess high risk erosion zones. Unlike existing methods that require human observations, which can be expensive and error-prone, the proposed approach uses a fully automated algorithm to indicate when an area is at risk of erosion; this is accomplished by processing Landsat and aerial images taken using drones. In this paper the image processing algorithm is presented, which can be used to identify the scene of an image by classifying it in one of six categories: levee, mountain, forest, degraded forest, cropland, grassland or orchard. This paper focuses on automatic scene detection using global features with local representations to show the gradient structure of an image. The output of this work counts as a contextual cueing and can be used in erosion assessment, which can be used to predict erosion risks in levees. We also discuss the environmental implications of deferred erosion control in levees

Freshwater Mussel Populations of the Monongahela River, PA and Evaluation of the ORSANCO Copper Pole Substrate Sampling Technique Using G.I.S. Interpolation with Geometric Means

Large river studies for freshwater mussel populations and habitat in the Monongahela River within Pennsylvania have been almost non-existent over the past century. Aquatic diversity and water quality have been impaired in the Monongahela River since the Industrial Revolution and early impoundments were constructed to control the river. To date, there have been no thorough mussel population studies conducted on the Pennsylvanian Monongahela River proper since A.E. Ortmann in 1919. The mussel population accounts for this large river system are invaluable accounts of the aquatic condition of the Monongahela River. Mussel populations and habitat within the river have diminished drastically during the 20 th century. Mussel populations and habitat were evaluated using SCUBA reconnaissance at 31 survey sites over 91 river miles. Survey methods included timed SCUBA searches for mussel populations and substrate consistency. Substrate habitat at each site was evaluated using diver reconnaissance and a modified version of the Ohio River Valley Water Sanitation Commission (ORSANCO) Copper Pole Substrate Sampling Protocol. Substrate sampling efficacy using the Copper Pole sampling technique was evaluated using benthic diagrams built using Inverse Distance Weighting with software ArcGIS 9.2. Results of this survey indicated seven (7) mussel species persist within the river with limited abundance compared to the 28 species accounted for in 1919. Habitat assessment techniques evaluated for use in large rivers illustrated an overestimation of substrate size. Paired T-test and Wilcoxon Signed-Rank analysis of Copper Pole Sampling versus diver reconnaissance of substrate size classes expressed significant differences of substrate geometric means. These data are presented to build on the ever growing research and evaluation of techniques used for large river ecosystem monitoring currently being developed in the field of river ecolog

Applying the DER rating system for the visual assessment of defects on concrete dams

NamWater is responsible for the management and maintenance of Namibia's main dams, amongst the many other infrastructure assets under their ownership. They have, as a result, devised asset management policies and practices with the aim of reaping the benefits of asset management. Additionally, they have aligned themselves with the current approaches to dam safety management in managing the dams. These current approaches do however not provide for a guided and standard approach when it comes to the visual assessment of surface defects on the dam elements. This may result in varying assessment outcomes from different individuals based on their differences in training and experience. The DER rating system used for the rating of defects on road structures, as input into the STRUMAN BMS used by SANRAL and other entities, provides for a standard approach to visually assessing the defects on these road structures. A study by Gombele (2017:79) has also demonstrated the possibility of using the DER rating system for the assessment of defects on cooling towers in a power generation environment. Additionally, the rating of defects can also play a role in dam risk determination, as demonstrated in the CIRIA 1 Project RP568 risk assessment methodology (Morris, Hewlett and Elliott, 2000:15). In quest for a standard and guided approach for visually assessing surface defects on dam elements, this study applied the DER rating on selected elements of three NamWater dams. The approach was by initially identifying dam elements that are deemed equivalent to the bridge items in the TMH19: Part A. There are variations in the design and functions of the dam elements versus those of bridge elements and thus the relevance of the defects may also vary for the two structure types. Thus, the focus of this study was on using the DER rating system to only assess the surface defects on the dam elements. This may be useful for the initial phase of a condition assessment for dams whereby it can provide a quantifiable indication of durability issues. While the study was able to demonstrate the possibility of using the DER rating system to assess defects such as cracks, spalling and erosion on the surfaces of dam elements, gaps where identified in its applicability. Only 33% of the bridge items in the TMH19: Part A were deemed relevant for the visual assessment of the dam items, coupled with the significant amount of U (unable to inspect) ratings given during the assessment. Furthermore, of the identified defects, a significant amount was given a low Relevancy rating (R) meaning that they are of a low relevance to the structural integrity of the dam structure. This may be due to the fact that the guiding tables used are originally for bridge items and thus not entirely suitable for dams. For the DER rating system to be applied extensively to dam items, defects that are specific to dam elements will therefore need to be incorporated into the guiding tables. Additionally, the weighting of the ratings for certain defects would need to be revised to specifically align with the consequence of the defect on the dam item. This process may require the compilation of a database of historical defects, guided by expert engineering judgement, to provide for guiding tables that are specific to dams. Assessment of more dams that vary in age, type, and performance may also be required to get a more diversified outcome of the applicability of the DER rating system on dams

Proceedings of 2008 Kentucky Water Resources Annual Symposium

This conference was planned and conducted as part of the state water resources research annual program with the support and collaboration of the Department of the Interior, U.S. Geological Survey and the University of Kentucky Research Foundation, under Grant Agreement Number 06HQGR0087. The views and conclusions contained in this document and presented at the symposium are those of the abstract authors and presenters and should not be interpreted as necessarily representing the official policies, either expressed or implied, of the U.S. Government or other symposium organizers and sponsors

Boston Harbor South Watersheds 2004 Assessment Report

This report includes assessments covering the four individual watersheds that discharge into Boston Harbor from south of the City of Boston — the Neponset, Weir, Fore and Back River Watersheds — plus an assessment for those portions of the City of Boston which border the Harbor itself south of the Charles River, hereinafter referred to as “Boston Inner Harbor Watershed.” The companion to this report is the “Boston Harbor South Watersheds 2004-2009 Action Plan,” which spells out a comprehensive set of responses needed to remedy problems identified here. This document does not cover the two major watersheds that discharge to the Harbor to the north of Boston — the Charles and Mystic River Watersheds - nor those sections of Boston that border or discharge into these watersheds. Therefore, it is not the purpose of the Assessment to analyze the health of the Boston Harbor itself, but rather to look at the environmental health of the individual watersheds from their headwaters to their discharge points into the Harbor, plus direct discharges into the Harbor from Boston. Since MWRA began pumping sewage from Deer Island to its outfall pipe in Massachusetts Bay, most of the pollution in the Harbor itself comes from the contributions of the various rivers discharging into the Harbor and Combined Sewage Overflows (CSOs) from the City of Boston. MWRA data indicate that it is the Charles and Mystic Rivers, and not the rivers covered in this report, which are the largest contributors to the Harbor’s pollution. In any case, extensive research by MWRA has been unable to pinpoint the exact pollutant contributions coming from each individual watershed. This report is based on a review of existing data and studies relevant to each of the watersheds, including water quality data reports, shoreline survey reports, EOEA’s Basin-wide Water Quality Strategy, relevant municipal plans, DEP reports, regional buildout analyses, Massachusetts Geographic Information Systems (MassGIS) data, and other relevant materials from non-governmental, academic, local, regional, state and federal sources

Recovering the Moca River: An Exploration through Sustainable Strategies for Developing Countries

Natural watercourses are being negatively affected by growing urbanization in different cities of the world. Within these circumstances the concept of river restoration has gained relevance, becoming a worldwide priority in water management. In developing countries, river restoration plans, conditioned by social and economic limitations, are mainly focused on a single approach, typically relying on short-term, low technology strategies. In the long term, these strategies tend to fail because they usually avoid integral solutions that address the interconnected factors contributing to river degradation. Therefore, the purpose of this study is to develop a framework of river restoration planning for developing countries that sustains the health of the river, the welfare of the ecosystem and the safety of the community. This framework develops three strategies with potential techniques to address the impacts of water pollution, flooding risk, and informal settlement in river ecosystems. Techniques responding to each of these strategies were described under a matrix that expresses their suitability with respect to a set of attributes or criteria selected for analysis. an explanatory case study approach in the Moca River, Dominican Republic, was used to apply the three strategies

Soil erosion and sediment control laws. A review of state laws and their natural resource data requirements

Twenty states, the District of Columbia, and the Virgin Islands enacted erosion and sediment control legislation during the past decade to provide for the implementation or the strengthening of statewide erosion and sediment control plans for rural and/or urban lands. That legislation and the state programs developed to implement these laws are quoted and reviewed. The natural resource data requirements of each program are also extracted. The legislation includes amendments to conservation district laws, water quality laws, and erosion and sediment control laws. Laws which provides for legislative review of administrative regulations and LANDSAT applications and/or information systems that were involved in implementing or gathering data for a specific soil erosion and sediment control program are summarized as well as principal concerns affecting erosion and sediment control laws