Use constraints: Data can be used freely given that the source is cited (following creative commons license CC-BY). The source should be cited as:

“HELCOM HOLAS II Dataset: Watercourse modification (2017)”

The Estonian dataset has been collected from environmental permissions of the special use of available water via Republic of Estonia Environmental Board environmental services webpage ( https://eteenus.keskkonnaamet.ee/

?page=avalik_stat_koond&act=avalik_info&u=20160316143654)

Data reported by Finland and Poland as water course modification were interpreted as pipelines and were combined with HELCOM HOLAS 2 Pipelines dataset.

The Finnish dataset about underwater pipelines were extracted from the Finnish Transport Agency’s View & Download service (nautical charts). The data is based on information received from regional operators. The data quality is based on their individual quality specifications. The data set is created 7.4.2010, and in the original data year of construction is unknown.

The boundaries of the objects in the Polish dataset come from permissions given by Maritime Office Gdynia. Modification structure types were checked from the internet by their permission identification number.

The dataset was approved by all HELCOM Contracting Parties in the HOLAS II Human activities data review process during first quarter of 2017.

constructi: Year of construction (year/ under construction)

permission: Year of granted environmental permission for watercourse modification (year)

document_i: Permission id

Length: Length of modification structure (m)

Modificati: Modification structure type (trenching, canalisation/pipeline)

Estimated: Estimation of completion if constructi= under construction (date)

Lat_Start: x-coordinate point of line start

Long_Start: y-coordinate point of line start

Long_End: y-coordinate point of line end

Lat_End: x-coordinate point of line end

Lat_Mid: x-coordinate point of line midpoint

Long_Mid: y-coordinate point of line midpoint

Country: Country