The wake wash from passing ships can cause environmental damage. The wake wash is an important issue for naval architects and shipbuilders in concentrating on more environmentally friendly designs. This paper presents results of a parametric study of catamaran hull form to obtain low wake wash hull form configurations or low speed inland waterway boats. The study uses a Computational Fluid Dynamics (CFD) simulation, and model experiments were carried out for validation of the CFD software set-up. The study concentrates on the asymmetric catamaran hull form. The investigation is conducted on two configurations of hull form, Flat Side Inward (FSI) and Flat Side Outward (FSO) configurations. The investigation is conducted on a hull form with a Length to Beam (L/B) ratio of 12.2, 15.2 and 18.3 and a Separation to Length (S/L) ratio of 0.2, 0.3 and 0.4. The results based on wave height criteria at various longitudinal cuts have shown that the FSO configuration has a lower wake wash compared with the FSI configuration. Considering L/B and S/L ratios, hull forms with a larger separation or higher L/B ratios produce lower wave heights.

BACKGROUND AND OBJECTIVES: The Coronavirus 2019 pandemic has revealed significant shortcomings in the Philippines’ solid waste management system, particularly in addressing the surge of pandemic-related waste. Unreliable waste collection, insufficient public knowledge, and improper waste disposal practices have exacerbated risks to the environment and public health. Despite these concerns, the specific impacts of Coronavirus 2019 pandemic related waste on human health and the environment in the Philippines’ context remain underexplored. This study aims to quantify Coronavirus 2019 related waste generated from both household sources and non-household establishments, assess disposal practices, characterize waste composition, determine generation rates, and classify waste types. Moreover, a comprehensive waste flow analysis will be carried out to monitor the movement of both appropriately and inappropriately managed Coronavirus 2019 waste, examining its implications on terrestrial and aquatic environments, as well as public health. Insights from the Philippines can significantly contribute to the formulation of resilient and adaptive waste management approaches in response to future public health emergencies worldwide.METHODS: Coronavirus 2019 pandemic related waste generation from both household sources and non-household establishments was quantified through a 5-day at-source waste analysis and characterization study conducted in twenty-six urban and rural barangays of General Santos City. The determination of sample sizes was conducted using conventional statistical techniques, informed by the most up-to-date census data and business establishment profiles. Structured questionnaires and checklists were used to gather information from household respondents regarding Coronavirus 2019 related waste sources, generation rates, and disposal behaviors. To determine the degree of environmental contamination related to pandemic waste, further waste characterization was carried out in the Silway and Makar Rivers, two key urban WATERWAYS that pass through populated and commercial districts prior to their discharge into Sarangani Bay.FINDINGS: According to the Waste Analysis and Characterization Study, waste linked to the Coronavirus 2019 pandemic totals about 52,877.7 kilograms per day, which is equivalent to 1.57 percent of the city’s total daily waste. This equates to an estimated 4,654,720 discarded face masks from household sources and 633,050 from non-household establishments daily. Coronavirus 2019 pandemic related waste density in the Makar and Silway Rivers-tributaries of the Sarangani Bay Protected Seascape was recorded at 0.238 gram per square meters and 0.706 gram per square meters, respectively. Mainly consisting of plastic face masks, this waste poses environmental threats as possible microplastic sources, jeopardizing both marine environments and human well-being. Waste flow analysis illustrated the management pathways of Coronavirus 2019 pandemic-related waste, underscoring its significant environmental and social repercussions.CONCLUSION: The Coronavirus 2019 pandemic has highlighted critical gaps in waste management systems and the environmental and health hazards associated with emerging waste streams such as Coronavirus 2019. Mismanagement of this waste stream results in environmental damage and considerable threats to public health. The study emphasizes the pressing requirement for better waste governance, infrastructure enhancements, and public education to reduce the enduring effects of waste associated with the pandemic.

Ownership of natural WATERWAYS, including rivers, natural streams and canals, is one of the most important issues of the water law of the country; therefore, in this article, the evolution of the ownership of the mentioned WATERWAYS from the beginning of the legislation until now has been studied. For this purpose the fallowing articles were studied: the Civil Code (as the main law on ownership), paragraph 6 of Article 96 of the Municipal Law (as the first law governing the ownership of urban WATERWAYS), Article 2 of the Water Law and its nationalization, as well as Article 2 of the Law on Fair Water Distribution (as Specific laws in the water sector). In this research, the legal criteria for determining the waterway bed have been criticized and the legal effects of these criteria on the ownership of lands adjacent to natural WATERWAYS have been explained. Also, in the current article, an attempt has been made to mention the evolutionary stages of the ownership of WATERWAYS' bed. Therefore, taking into account the various divisions for property, ownership of WATERWAYS with the term "natural" or "public use" should be included in the category of public property. Reviewing the legal status of this type of property in the relevant laws from the beginning of the legislation until now, it was found that the legislator does not have the same approach to the ownership of WATERWAYS. The evolution of the relevant laws indicates that the legislator had three different approaches on the ownership of this category of property. Therefore in accordance with the circumstances of the time, the adoption of the law can be classified and reviewed in three historical important periods: 1-private property of WATERWAYS, 2-government ownership, 3-Water governance that considers WATERWAYS' property as public wealth and commonalities, at the disposal of the Islamic government. Study of the historical course of legislation showed that the Iranian legal system formed its first approach which was the protection of private property; and then gradually moved toward the governmentalization of these properties; and finally included them in the category of public property and natural resources, which are in the possession of the government. During the period of privet property of WATERWAYS (1906-1968), the WATERWAYS' bed was occupied by adjacent land owners and exploited according to the existing conditions. The article 23 of the Civil Code (1924) related the exploitation of ownerless property (including public properties) to relevant laws which had not been well developed until that time. Moreover, the article 25 of the Civil Code has forbidden the occupation of public properties. Paragraph 6 of Article 96 of the Municipal Law indicated that the WATERWAYS' beds within the cities are considered as public property that is owned by the municipality. Besides, any civil operations within the beds of WATERWAYS in cites is subjected to the permission of the Ministry of Power. The second period started in 1968 with the Water Law and its nationalization which introduced water ways as public properties. The Coastal Land Law described the conditions of construction, inside the bed or nearby the water bodies, with technical details. The third period of water governance started in 1983 with the Law on Fair Water Distribution. The results of this study showed that according to the current legal system of the country, the bed of natural WATERWAYS is not privately owned, and in addition the government does not own them; but the bed of WATERWAYS are among the public property and national natural resources. Although the bed of natural WATERWAYS is under the control of the government, it should be noted that this control is only to manage the use of water and protect national resources and the environment. This possession does not mean that the government owns them. Therefore, for example, the government does not have the right to sell or transfer them. Hence, the actions of the Ministry of Energy are purely administrative. The special emphasis of this article is on how to apply legal rules and standards in recognizing the bed of natural WATERWAYS and its final limit, as well as its stabilization in nature in order to protect public rights and prevent damage to adjacent landowners or limitation of their ownership.