1. General context

Vansjø-Hobøl is a complex lake-river system in south-eastern Norway (59024’N 100 42’E). The highest point of the catchment area is about 346 m a.s.l., the lowest is at 0 m a.s.l. Lake Vansjø is used as a drinking water source, with a raw water intake in the Eastern basin. The total catchment area is 690 km² and the Vansjø sub-catchment is 301 km². The main land management types are forest (79%) and agricultural land (17%). Surface water covers 4% of the catchment.

2. The particular case of Vansjø and its role in FAIRWAY

The drinking water source Lake Vansjø is located within four municipalities; Moss, Råde, Rygge and Våler, has a surface area of 35.6 km², and a legal water regulation height between 25.53 - 22.53 masl.

The water volume is about 73 million m³, the max depth is 37 m and the average depth is 7.4 m. The main water intake is in Storefjorden and there are intakes at both 12 and (normally) 25 meters depth. The intake is located in the part of Vansjø with the best raw water quality. The quality of the raw water varies constantly, mainly due to natural seasonal variations with varying weather and temperatures and associated variable loads of nutrients and other pollutants. The nitrogen concentration in both Storefjorden and Vanemfjorden is characterized by strong variations from year to year, but the long-term average does not show an increase or decrease. Nitrate may also be periodically limiting to algal growth, but the nitrate amount probably predominantly controls the relationship between blue-green algae Microcystis and Anabaena in Vansjø. Blue-green algae Microcystis is dependent on nitrate and Vanemfjorden has had some summers cleared for nitrates, favoring the nitrogen-fixing algae Anabaena (which has not been shown to be poisonous in Vansjø). This situation was not observed in Vansjø in the last 3-4 years.

The catchment has continental climate in the north and a more coastal climate in the south, with a growing season of around 200 days. The mean annual air temperature is 5.6° C and the annual precipitation is around 830 mm.     

There is currently no acute main drinking water quality concern regarding Vansjø. The concern is related to the long term loads of nutrients and subsequent inlake algae development, in particular, the occurrences of toxic blue green algae together with the browning of the drinking water will be in focus. This will vary some a consequence of climate change, land use change, in particular within the agricultural sector, but partially also as a consequence of the regulation of the water level in Vansjø.

The aim of the case study is mainly to elucidate for the various stakeholder the possible consequences upon (drinking) water quality as a consequence of modelled scenarios in which

1. climate change,
2. agricultural land use and
3. the water regulation scheme

are changed in the various scenarios. It will also be considered to further  A secondary objective is to assess the perception of uncertainties with respect to the modelled outputs.

3. Mitigation measures used

The main measures that will be applied in the decision support oriented modelling work is related to land use changes, predominantly agricultural change scenarios. Additionally there might also be introduced scenarios with respect to forest management measures, such as complementary nitrogen fertilization, and scenarios for the water regulation scheme regarding water levels.

Without having consulted with the actual stakeholders, these ideas on possible measures follows prior experience and knowledge from the study area, and the known driving forces influencing the water quality, notably the bluegreen algae development, of the drinking water source Vansjø.

There are a few other drinking water sources in Norway also affected by agricultural land use and for which the modelling work carried out at this case study could have bearing.

4. Current water governance system

Actors and stakeholders involved in water governance and their roles

Lake Vansjø is the main waterbody of concern in the inter-municipal water cooperation regarding the Morsa Catchment/area http://morsa.org/. This is also one out of 11 inter-municipal water cooperation areas within the RBD Glomma, the largest RBD in Norway. This inter-municipal cooperation was established as Norway included about 10 % of its catchment in a “trial” period for the implementation of the EU Water Framework Directive. It started as a project in year 2000. As for most other European water bodies, Lake Vansjø is governed within a multi-level governance system.

The municipalities involved are: Enebakk, Ski, Vestby, Ås, Frogn, Spydeberg, Hobøl, Våler, Moss, Rygge and Råde. Else, the County Governors of Østfold and Oslo/Akershus, respectively, are members, the County Councils of Østfold and Akershus, respectively, and the regional offices of the Norwegian Water Resources and Energy Directorate and the Norwegian Food Safety Authority. Additionally, the inter-municipal cooperation has some observers; Østfold & Akershus Farmers’ Association, Forum for Nature and Outdoor (FNF), the Moss-region Water,  Wastewater & Renovation Publ. Ltd (MOVAR), Vansjø Landowners og Moss Water Regulators Association.

The cooperation is described in the following manner: 

“A board (water area committee) consisting of mayors and regional representatives, as well as professionals from municipalities and county leaders in the thematic groups, has been and is absolutely essential to gain agreement on demanding and costly measures. 

In nutrient rich watercourses there are municipalities that have many of the means to do. They also have local ownership, knowledge and proximity to the residents. The municipalities therefore sit with the very key to the implementation. But the municipalities do not control all the instruments. Therefore, it is crucial that state regional authorities such as county councils, Norway's Water Resources and Energy Directorate (NVE) and the Norwegian Food Safety Authority participate actively in the work in the water area. 

Good cooperation that includes dialogue with farmers and other user interests is also important. There has been close dialogue with the farmer organisations and all farmers have been offered free agri-environmental advice.” 

Water quality control processes

Which body decides whether there is an issue with water quality and what measures should be taken is a complex question.

The cooperation is knowledge driven and monitoring and assessments have been carried out since the 90s. Thus, broadly speaking one might state that results from the monitoring and related source apportionement analysis is the trigger. Concerning the choice of measures within the agricultural sector, the thematic working group of agricultural is the main factual decision body, but given that most measures are triggered through voluntary measures, the actual decision-maker will be the individual farmer.

As Vansjø is one of the water bodies forming part of the Glomma River Basin District, the decision on the ecological objectives of the lake follows the WFD organization. Formally speaking, the targets for biological and chemical status are set by the Vannregionutvalget (RBD Council, following a proposal from the Competent Authority, following input from the inter-municipal water cooperation regarding the Morsa Catchment/area http://morsa.org/

Monitoring is organized and procured by the inter-municipal water cooperation, in concrete terms by the co-ordinator, regarding the Morsa Catchment/area http://morsa.org/. Throughout time the organizations and companies that have actually carried out the monitoring have differed; www.NIBIO.no and www.NIVA.no have often been responsible.  The parameters that are monitored are given in http://morsa.org/wp-content/uploads/2017/04/NIBIO-Rapp-38_2017-Skarb%C3%B8vik-et-al-Overv%C3%A5kning-i-Morsa-2015-2016.pdf (in Norwegian). Hydro-physical, chemical and biological parameters are monitored. Concerning monitoring of farm management, there is control and supervision conducted by the municipalities on the regulatory aspects and the measures conducted under voluntary agreements. The basis is self regulation, conducted by the farmers themselves.

Norway does neither form part of the EU Common Agricultural Policy (CAP) nor have implemented some of the environmental directives governing agricultural practices such as the Nitrates Directive and the Pesticides Directive. Still, Norway has its own legislation to a large extent matches that of EU.

The instruments used are essentially the same as for farmers within EU; legislation (with supervision and control), voluntary economic instruments in particular special support for carrying out of particular measures and knowledge & advisory.

So far there have not been any serious conflicts, thus there are not established any especial agreements on conflict resolution.

Engagement and multi-actor platforms

There is an already existing platform for engagement in the case study that will be conisdered as a MAP for FAIRWAY. The inter-municipal water cooperation regarding the Morsa Catchment/area has existed since about year 2000 http://morsa.org/ This will be the major MAP major platform used. In particular, the thematic group on Agriculture, one out of four thematic group, will be the operational sub-platform used.