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ENGLISH SUMMARY
TVERANGER, B., G.H. JOHNSEN & E. BREKKE 2007.
The municipality of Stord. Environmental impact assessment of the coastal waters.
Description of recipients, effluent treatement and ecological status 2007.
Rådgivende Biologer ltd., report 1038, ISBN 978-82-7658-565-0, 139 pages in Norwegian.
The Municipality of Stord is located on the western coast of Norway and has two coherent and densely
built-up urban areas; Sagvåg with 3.336 inhabitants along the westside and Leirvik with its 10.890
inhabitants situated at the south eastern part. The municipality of Stord operates 7 large and 30 smaller
wastewater outlets. The six largest outlets constitute 84 % of the wastewater, and this recipient
investigation focus upon these six largest outlets and the effects they constitute in the marine recipients.
The waste water effluents from two of these outlets, Sævarhagen and Grunnavågen, are released untreated
directly into the sea. In accordance with the Municipality Plan of Sewage Treatment and Water
Environment 2004-2015, these outlets will be upgraded to mechanically treatment. The effluents from the
other four large plants, Frugarden, Djupevika, Kjøtteinen and Kårevik, is mechanically treated before
discharges to the sea.
In accordance with the EEC Urban Wastewater Treatment Directive 91/271, and the Norwegian pollution
authorities, the municipality itself is responsible for authorizing effluents of maximum 10.000 pe to each
distinct recipient, even though it may be discharged from several treatments plants. The urban area of
Leirvik is inhabited by more than 10.000 pe, and will grow together with Sagvåg in the near future. If
these urban areas are regarded as one single unit, an extended level of waste water treatement will be
demanded, and the responsibility for the effluents will be transferred to the County Governour, unless
it can be documented that the effluents are released into several distinct recipients without any mutual
interference. This report presents documentation for this distinction.
According to the divison of water bodies according to the Water Framework Directive, the wastewater
from Stord is mainly discharged into four distinct coastal water bodies or recipients, each of which is
receiving effluents from less than 10.000 pe. These are: Husnesfjorden, receiving max 2.300 pe, Leirvik
harbour receiving max 5.000 pe, Klosterfjorden receiving max 6.000 pe and Stokksundet receiving max
3.500 pe (see figure 2 in the Norwegian summary on the subsequent pages).
In 2007, an extensive environmental impact assessment of the coastal waters of Stord was carried out to
evaluate both the distinction between the four separate recipients and to settle the approriate extent of
wastewater treatment in accordance to the Waste Water Directive. All results are summarized according
to the EEC Water Framework Directive and presented as classified Ecological Status both in figure 3 and
table 3 on the subsequent pages. The water bodies of Leirvik harbour are regarded as heavily modified
due to extensive physical modifications along ca 50 % of the shoreline, but this is not taken into
consideration when evaluating the Ecological Status.
The investigated water bodies of Husnesfjorden, Klosterfjorden and Grunnavågen in Stokksundet were
scarcely affected by supplies of nutrients, environmental pollutants, and were classified to high ecological
status of coastal surface waters, as well for the biological diversity of soft bottom fauna. Only Leirvik
harbour was classified to good ecological status with regard to occurrence of environmental pollutants
(PAHs and TBT) in the sediments due to adjacent industrial activity. Also the water quality of Leirvik
harbour was moderately affected by intestinal E. coli, and was classified to good ecological status. The
biological diversity of the soft bottom fauna quality in Leirvik harbour was classified to the highest quality
class, but the sediments were from moderately to substansially polluted by environmental pollutants
(PCBs, PAHs and TBT), originating from probably previous effluents from industrial activities as ship
yards and urban activites.
Rådgivende Biologer AS -3-
Rapport 1038