Please use this identifier to cite or link to this item: http://saruna.mnu.edu.mv/jspui/handle/123456789/4931
Title: Environmental impact assessment for the construction and setup of a sewerage system in Kaashidhoo Island, Kaafu Atoll, Maldives
Authors: Water Solutions
Keywords: Policy, legal and administrative framework
Project description
Methodology
Existing environment of Maldives
Environmental impacts
Stakeholder consultations
Alternatives
Environmental management and monitoring plan
Issue Date: Dec-2017
Citation: Water Solutions. (2017. Environmental impact assessment for the construction and setup of a sewerage system in Kaashidhoo Island, Kaafu Atoll, Maldives. Male': Maldives
Abstract: This report discusses the findings of an environmental impact study undertaken by Water Solutions Pvt. Ltd in order to fulfil obligatory requirements of the National Environment Protection and Preservation Act, Law No. 4/93 for the proposed setup of the sewerage system (hereafter referred to as the project) in Kaashidhoo island, kaafu Atoll, Maldives. The purpose of this EIA is to identify and minimize potential adverse environmental impacts related to this project and enhance the overall quality of the project. By examining the project location, the legal framework and the existing environmental components such as marine ecology and the socio-economic aspects, this EIA provides useful information regarding the extent, nature and the magnitude of impacts that are likely to occur. The EIA will also help to identify the long term socio-economic benefits to the community after implementing this project. It also provides a framework for future monitoring of the environment, so that changes can be monitored and corrective measures can be undertaken. The proposed project aims to establish a sewerage collection and disposal system in the island of Kaashidhoo in Kaafu Atoll. The concept designed for Kaashidhoo is a gravity type wastewater collection and disposal system. The existing systems are mainly based on septic tanks and small bore sewers. Without proper maintenance these systems are prone to damage and contamination of groundwater can occur. The contamination of the groundwater has occurred to the extent that it cannot be utilized for any potable use. Therefore, the current setup is not environmentally acceptable nor suitable. The sewerage system for Kaashidhoo will be a gravity sewerage system where sloping pipelines will allow waste water from the entire island to flow to nine zonal pumping stations. The sewage will be pumped from the pumping station to the treatment plant where it will be treated and discharged via a sea outfall pipeline into the sea. The sewerage system will comprise of elements of a given specification for sewer mains, cleanouts, manholes, vents, pump stations, outfall pipeline and diffuser that will ensure a 30 year design flow. The sewerage system therefore comprises of the following components: a) Household inspection chambers. b) A gravity sewerage reticulation network. c) Reticulation pumping stations and pressure main system. d) Construction of a sea outfall to discharge the sewage into deep sea. The proposed project will ensure that the groundwater of the island does not get contaminated through improper sanitation systems. It will also ensure that the surrounding marine environment will improve in terms of environmental quality and will ensure pollution from sewage does not occur on the near shore environments. The project is expected to bring several positive impacts on the environmental quality of the island and the surrounding reef. Particularly, the most significant benefit would be achieved through improvement in the bacteriological quality of the groundwater. The health benefits of the project are worthy of noting as the improvement in water quality are going to bring significant health benefits to the community. Environmental & social impacts and the mitigation measures Several environmental impacts of this proposed project have been examined through a number of processes. These include consultations with the project development team, field surveys, observations and assessment, and field experience gained from similar development projects implemented throughout the country. Potential positive and negative impacts on the environment have been considered. The assessment indicates environmental impacts, both during the construction and operation stage. During the construction period, impacts are likely to occur on the marine and terrestrial environment (groundwater). Most of the impacts during the construction period are impacts related to construction waste, dewatering, disruptions to the local traffic, dust emission, damage to the reef during sea outfall construction and noise. During the operational stage of this project, there will be both positive and negative impacts. Positive impacts include the improvement of the ground water quality of the island. Negative impacts include the increased in extraction of groundwater for toilet flushing that may increase the chances of groundwater salinization at a much accelerated rate. This project does foresee some negative impacts even during the construction stage but is geared towards improving the overall environmental quality of the island, most notably the environmental health. The project is presently planned to lay the sewer pipeline along the centre of the exiting road. During this process, dewatering and construction pose some challenges. Previous experience of sewer construction in the Maldives has indicated that excavation depths more than 3.5m are not recommended for conventional dewatering methods to avoid the risk of undermining and trench collapses as well as loss of structural integrity of the surrounding earth. For the purpose of the Kaashidhoo design, the maximum depth of excavation will not exceed 3.5m as per the Design criteria and technical specifications for conventional gravity sewerage systems guideline released by the Water and Sanitation Unit of the Environmental Protection Agency (Environmental Protection Agency, 2015). Strict reference to these criteria will be followed and necessary as the streets are very narrow and congested, leaving limited space for mechanical excavation between buildings for the installation of pipelines. Despite these shortcomings, the project does not pose serious threats to the natural environment (marine and terrestrial) and will directly benefit the environment and the community, both in the short and long term. Minor negative impacts with varying significance will occur as the project is implemented. They include dewatering and localized salinization, disruption to public transport, dust emissions during pipe laying work and reef damage during the process of outfall construction. The pump stations have not been placed around the periphery of the island, instead are located within the population zone. This could pose the issue of foul odour in the event of a system failure whereby the foul odour abatement mechanism is affected. Incorporating the pump stations in the populated areas is a necessity and this design factor will enhance the functioning of the overall system. The project will benefit the community and the island in the long term. It is important to ensure that the project implementation is carried in a sustainable manner and in such the sewerage system can be maintained in a cost effective manner as and when required. It is therefore in the opinion of the consultant that the project does not foresee significant negative environmental impacts and should be allowed. Although the project will benefit the community, the proposed design has a number of disadvantages. Construction of pump stations underground on the streets is seen as a design issue that could have operational difficulties. Instead, the pump stations could be located within the residential block boundary with a small plot of land allocated for the pump station. Selection of sites can be focused on places such as mosque, symmetry and from other public buildings or plots of land. With the present design, a number of operational difficulties are anticipated. Experience from similar systems setup elsewhere in the Maldives have been studied and reviewed for this project. The reviews and experiences from these systems are not infavour of the present design and this is something that needs to be considered before undertaking the project. Sanitation systems must be both environmentally and socially friendly and acceptable. As important as the design is the operation and maintenance. Operation and maintenance should be viewed as a key sustainable aspect of similar projects. No matter how good a design is, the sustainability and acceptability will depend on how good the system functions in the operational period. With the pump stations being located on the road itself, there are a number of such difficulties which are equally as important as the engineering design aspects.
URI: http://saruna.mnu.edu.mv/jspui/handle/123456789/4931
Appears in Collections:ތިމާވެށި
Environment A


Files in This Item:
File Description SizeFormat 
2017- 12-6 - Kaashidhoo Sewerage EIA final.pdf22.21 MBAdobe PDFView/Open


Items in Saruna are protected by copyright, with all rights reserved, unless otherwise indicated.