Dataset description: The assessment dataset contains data on water flow and annual nutrient inputs (total nitrogen and phosphorous loads) from catchments and from point sources (municipal, industrial and aquaculture) directly discharging to the Baltic Sea sub-basins. The dataset is produced by regional experts (PLC implementation group) through statistical analysis and filling data gaps in the data reported by national experts to the HELCOM PLC-water database. The dataset includes actual (non-normalized), and water flow normalized annual inputs of total nitrogen (TN) and total phosphorus (TP) from monitored and unmonitored areas per Balic Sea sub-basin. It also contains data on total nitrogen (TN) and total phosphorus (TP) annual inputs from point sources (industrial, municipal and aquaculture) aggregated per country and per sub-basin discharging directly into the Baltic Sea sub-basins. The dataset is published as MS Excel workbook, consisting of several sheets. The sheets provide assessment data for flow, total nitrogen and total phosphorus, as well as background information on data treatment and aggregation. Spatial delineation of catchments is provided in the catchment dataset accessed through HELCOM Metadata Catalogue - (PLC) Assessment catchments (spatial data). Datasets can be related using Source_Code field. The dataset is used in HELCOM Baltic Sea Environmental Fact Sheet (BSEFS) on Waterborne nitrogen and phosphorus inputs and water flow to the Baltic Sea published annually. Dataset content: Excel workbook contains the following tables: AggregationsOfIncompleteRiverTi – the table enlists aggregation of monitored areas of sub-catchments with incomplete time-series with unmonitored areas (country specific), UnmonitoredAreasMergedInMonitor – the table enlists aggregation of unmonitored and monitored areas into unified catchments (country specific). OriginalRivers_Flow, OriginalRivers_TN, OriginalRivers_TP – time series of flows (m3/s) and total N and P (tonnes/year) inputs as reported to PLC-Water database for monitored rivers OriginalUnmonitored_Flow, OriginalUnmonitored_TN, OriginalUnmonitored_TP - time series of flows (m3/s) and total N and P inputs (tonnes/year) as reported to PLC-Water database for unmonitored areas Rivers_Flow (m3/s), Rivers_TN (tonnes/year), Rivers_TP (tonnes/year) - non-normalized inputs from rivers and unmonitored areas, Rivers_NormTN (tonnes/year), Rivers_NormTP (tonnes/year) - normalized inputs from rivers and unmonitored areas, Industry_TN (tonnes/year); Industry_TP (tonnes/year) – aggregated input from industrial point sources discharging directly into the Baltic Sea, Municipal_TN (tonnes/year); Municipal_TP (tonnes/year) – aggregated input from municipal WWTPs discharging directly into the Baltic Sea, Aquaculture_TN (tonnes/year); Aquaculture_TP (tonnes/year) – aggregated input from aquaculture discharging directly into the Baltic Sea. Tables under items 3-6 contain the following fields: Source_Code, Name, Country code, Basin code, 1995, …, 20XX Where water flow is given in m3s-1 and TN/TP tonnes year-1 for each year. Tables under items 7-9 contain the following fields: Country code, Basin code, 1995, …., 20XX Where TN/TP is given in tonnes year-1 for each year. Data update: Metadata is updated by HELCOM Secretariat annually by 1 July. The dataset is updated by HELCOM Secretariat annually by 1 July.

Dataset description: This dataset contains data on water flows, actual waterborne (riverine plus direct) inputs and atmospheric deposition of nutrients. Furthermore, it includes normalized total (atmospheric and waterborne) inputs of nitrogen and phosphorus into the Baltic Sea. The data are used in the HELCOM core indicator of nutrient inputs (nitrogen and phosphorus) to the Baltic Sea marine ecosystem (Inputs of nutrients - HELCOM indicators). The data is presented in the format of MS Excel workbook consisting of 3 sheets. Sheets of nitrogen inputs and phosphorus inputs integrate 4 tables each. These tables contain time series, starting from 1995, of assessed nutrient input values: waterborne actual (riverine+direct), atmospheric deposition (actual), total actual input (air+water), normalize total input (air+water). Nitrogen and phosphorus inputs are assessed for the following Baltic Sea sub-basins: Bothnian Bay (BOB), Bothnian Sea (BOS), Baltic Proper (BAP), the Gulf of Finland (GUF), the Gulf of Riga (GUR), Danish Straights (DS), Kattegat (KAT) and the whole Baltic Sea (BAS). All input data is given in tonnes per year (tonnes/year). The Flow sheet contains only one table with an annual water flow data time-series for each sub-basin of the Baltic Sea given in cubic meters per year (m3/s). The river input data is based on riverine monitoring data and estimation of loads from unmonitored areas by countries in the frame of national monitoring programs. Data on waterborne inputs and water flow is reported by Contracting Parties to the PLC-Water database. The data are verified and quality assured using the PLC water database verification tools and national expert quality assurance. Atmospheric deposition of nitrogen for all Baltic Sea sub-basins is computed using the latest version of EMEP MSC-W model and data on official emissions reported by EMEP Contracting Parties. Dataset content: Excel workbook contains the following sheets: Nitrogen inputs – time-series of waterborne actual (riverine+direct), atmospheric deposition (actual), total actual input (air+water), normalized total input (air+water) (tonnes/year) . Phosphorus inputs – time-series of waterborne actual (riverine+direct), atmospheric deposition (actual), total actual input (air+water), normalized total input (air+water) (tonnes/year). flow - annual water flow data time-series (m3/s). Visualization: MS Excel workbook. Data update: Metadata is updated by HELCOM Secretariat annually after adoption of indicator report. The dataset is updated by HELCOM Secretariat annually after adoption of indicator report.