Abstract: | This report discusses the findings of an environmental impact study undertaken by Water Solutions Pvt.
Ltd in order to fulfill 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 Landhoo island, Noonu 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 socioeconomic
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
Landhoo in Noonu Atoll. The concept designed for Landhoo 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 Landhoo will be a gravity sewerage system where sloping pipelines will allow
waste water from the entire island to flow to three 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 center 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 Landhoo
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 some streets are very narrow and
congested, leaving limited space for mechanical excavation between buildings for the installation of
pipelines.
The lack of an approved land use plan for the island is also a draw back for Landhoo. The present design
is based solely on the existing populated area in the island. There are large areas of the island
undeveloped and unzoned due to lack of a proper land use plan. The island is a potential hot spot for
future tourism development due to the vase natural resources (beach, mangroves and thick forests and
plenty of land). Different types of developments such as guesthouses and restaurants may require
grease traps to prevent large influxes of unwanted material into the sewerage network. Therefore the
present design of the system has not considered these future developments and in the event of such
developments, the existing system will require upgrading. Requirements may need to be specified at a
policy level to counter this issue. Therefore this is a potential risk factor in this project.
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 in favor 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. |