Water and marine management models

LLR, or Lake Load Response, is a browser-based modelling tool developed at the Finnish Environment Institute for assessing the impacts of nutrient loading on lakes. LLR helps in evaluating the need for load reduction and thus in planning water management. LLR calculates how external loading and its changes affect the total nutrient and a-chlorophyll concentrations in the water body. LLR is particularly suitable for calculating load reduction targets for lakes in poor condition or on the border between good and moderate status, and for supporting the assessment of ecological status.

LLR calculations are based on simple relationships between nutrient loading and water quality. Using a nutrient retention model based on known nutrient balance equations, the total nutrient concentration can be calculated when the area, loading, flow, and sedimentation rate of the lake or water body are known. The phosphorus model in LLR also includes the effect of internal loading. The total nutrient concentrations calculated using nutrient loadings are used to calculate the a-chlorophyll concentration of the water body. The relationship between nutrient and a-chlorophyll concentrations is then used to derive the connection between loading and a-chlorophyll concentration.

All calculations in LLR are based on Bayesian probability statistics methods, which provide a full probability distribution for unknown variables instead of a single value. This allows for the assessment of the uncertainty associated with model predictions, whether due to natural variability or, for example, unrepresentative data.  

As a result, the user receives:

• The necessary nutrient load reduction to achieve good status
• Critical load
• Distributions of total nitrogen, total phosphorus, and a-chlorophyll concentrations for given loadings
• The most probable ecological status of the lake for given loadings

LLR can be found at http://lakestate.vyh.fi/. The site contains more information about the models and user instructions. A similar modelling tool for coastal areas, CLR (Coastal Load Response), is under development but is not yet publicly available.
 

Publications

• Kotamäki, N., Pätynen, A., Taskinen, A. et al. Statistical Dimensioning of Nutrient Loading Reduction: LLR Assessment Tool for Lake Managers. Environmental Management 56, 480–491 (2015). (link.springer.com)
• Olli Malve, Turo Hjerppe, Sirkka Tattari, Sari Väisänen, Inese Huttunen, Niina Kotamäki, Kari Kallio, Antti Taskinen, Pirkko Kauppila, Participatory operations model for cost-efficient monitoring and modeling of river basins — A systematic approach, Science of The Total Environment, Volume 540, 2016, Pages 79-89. (sciencedirect.com)

Keywords: 
Modeling, lake modeling, water quality, nutrient balance, phytoplankton, water management

More Information 
Group Leader Niina Kotamäki, Finnish Environment Institute (Syke), firstname.lastname@syke.fi
 

VIHMA is an Excel model developed at the Finnish Environment Institute. It has been used particularly in projects and assessments related to water management planning. The model can estimate the amount of nutrient loads from fields to water bodies and assess how the load would change if tillage methods were altered. The use and calculation results of VIHMA are based on specific load figures produced for the tool and the characteristics of the arable land in the area under consideration.

Specific load figures (kg/ha/year) describe the average annual sediment and nutrient load from fields with different characteristics and cultivation practices. The tool includes specific load figures for various cultivation methods in five slope classes, four soil type groups, and three phosphorus classes.

The figures are based on long-term measurement results from Finnish runoff test fields and values derived from these test field results. The minimum and maximum values of the specific load figures represent the long-term average minimum and maximum loads depending on the hydrological year type.
 

The slope classes of the fields are:

• < 0,5 %
• 0,5–1,5 %
• 1,5–3,0 %
• 3,0–6,0 %
• > 6,0 %

The soil types of the fields are classified into four groups: clays, silts, coarse mineral soils, and organic soils.

The phosphorus classes of the fields are:

• < 6 mg/l (soil),
• 6–9,9 mg/l
• 10–14,9 mg/l
• 15–25 mg/l
• > 25 mg/l

The classification of cultivation methods is based on the quality of the field surface left by tillage during winter:

• Autumn plowing
• Shallow stubble cultivation (depth < 10 cm)
• Deep stubble cultivation (depth 10–15 cm)
• Winter cereal (traditional plowing and sowing cultivation)
• Direct sowing of winter cereal
• Winter stubble
• Direct sowing of spring cereal
• Permanent grass

The model operates at the catchment and water body level. Primarily, the model is suitable for assessing the impacts of various agricultural water protection measures and combinations of measures, as well as the potential impacts of different scenarios. In practice, the model is used to estimate the amount of measures needed to achieve the target level of agricultural load. The necessary input data include the area of fields in the target areas, soil type, slope, and phosphorus distribution, as well as the implemented tillage measures and the possibilities to implement buffer zones and wetlands.

The effects of buffer zones are calculated in VIHMA for an average-sized field plot. The effects of buffer zones are based on the differences in load between fields with and without buffer zones in different slope classes and various tillage and vegetation cover treatments. The effects of wetlands are calculated per hectare of the upstream catchment area, influenced by the relative size of the wetland and the percentage of arable land in the catchment area.
 

Publications

• Puustinen, M., Turtola, E., Kukkonen, M., Koskiaho, J., Linjama, J., Niinioja, R., Tattari, S. 2010. VIHMA—A tool for allocation of measures to control erosion and nutrient loading from Finnish agricultural catchments. Agriculture, Ecosystems & Environment. (sciencedirect.com)

More Information 
Researcher Sari Väisänen, Finnish Environment Institute (Syke), firstname.lastname@syke.fi

KUTOVA is an Excel tool developed at the Finnish Environment Institute to assess the cost-effectiveness of various water protection measures and the achievable reduction in phosphorus load from agriculture, forestry, scattered settlements, and peat production. The tool can also form cost-effective combinations of measures and calculate the costs and combined effects of selected measures on the load.

The tool has been applied and developed in various projects in the Temmesjoki, Kalajoki, Lapuanjoki, Karvianjoki, Paimionjoki, and Vantaanjoki river basins, as well as in the catchment areas of Hiidenvesi, Vanajanselkä, and Western Pien-Saimaa.

Publications

• Hjerppe, T. & Väisänen, S. 2015. A practical tool for selecting cost-effective combinations of phosphorus loading mitigation measures in Finnish catchments. International journal of river basin management 13(3):1-14 (tandfonline.com)

More Information 
Researcher Sari Väisänen, Finnish Environment Institute (Syke), firstname.lastname@syke.fi

The VIRVA model is an Excel calculation model developed at the Finnish Environment Institute to assess the impact of water quality, particularly eutrophication, on the recreational value of water bodies. It can be used to determine the current recreational value of a water body and the benefits that can be achieved if the water quality improves to a level indicating good ecological status or excellent usability.

Information on the impact of water quality on recreation must first be collected through surveys or interviews. VIRVA is applied separately to waterfront properties and users of non-waterfront properties to determine their recreational value. The recreational value of waterfront properties consists of swimming, fishing, boating, taking water for washing and sauna, and enjoying the water landscape and staying on the shore. The importance of different uses is taken into account using use-specific weighting factors. The recreational value for users of non-waterfront properties in the model consists of swimming, fishing, and boating. VIRVA has been applied and developed in several water bodies.

In VIRVA, the starting point is the assumption that a change in water quality affects the perceived benefit of recreation, which is examined through the quality and quantity of the recreational experience. For example, as water quality deteriorates, the pleasantness of recreation decreases, additional work or costs may be incurred for the user, the amount of use decreases, and in extreme cases, the water body may no longer be usable for recreation at all.

Publications

• Hjerppe, T., Seppälä, E., Väisänen, S. & Marttunen, M. 2016. Monetary assessment of the recreational benefits from improved water quality – description of a new model and a case study. Journal of environmental planning and management. (tandfonline.com)

More Information 
Researcher Sari Väisänen, Finnish Environment Institute (Syke), firstname.lastname@syke.fi

COHERENS (COupled Hydrodynamical Ecological model for REgioNal Shelf seas) is an open-source modeling tool developed in Belgium for three-dimensional modeling of coastal seas, lakes, and other basins. The model is used, for example, to study the dispersion of substances entering water bodies.

At the Finnish Environment Institute, the COHERENS model is used for detailed transport modelling of lakes and is adapted as needed to address the specific characteristics of our northern location and numerous lakes, such as winter ice cover, fragmentation, and shallow depth. The model can also be used for flood assessments and in suitable river sections. In marine areas, the COHERENS model is used in the Archipelago Sea as part of the coastal total load model (FICOS).

The model's approach is mechanistic, meaning calculations are performed step by step based on equations derived from the laws of physics. Input data for the model include depth and weather data for the basins, as well as flow data for rivers entering and leaving the basin. The water area is divided into segments in the model, which are small enough to investigate the matter at hand. In lake areas, the size of the segments, or the resolution of the calculation grid, is typically between 20 meters and 250 meters horizontally, and the water column is divided into five to twenty layers vertically. Within each segment, the water flow velocity and temperature, as well as salinity or nutrient concentration if necessary, are calculated. The quantities calculated by the model can be modified on a case-by-case basis, or other external models can be linked to the model.

Of Finland's thousands of lakes, about twenty have been modelled using the COHERENS tool in various projects, often related to water construction (e.g., the effects of pumping stations in Pien-Saimaa) or research (e.g., local wind effects in Tuomiojärvi and Palokkajärvi in Jyväskylä). Modeled lakes include Pien-Saimaa, Onkivesi, Northern Päijänne, the southern parts of Näsijärvi, Tampere's Pyhäjärvi, and Säkylä's Pyhäjärvi.

The COHERENS model does not have a user interface; instead, it is used by defining input data and model settings either directly in the model code or through separate input files.
 

Links  
COHERENS model developer's homepage (odnature.be)

More Information 
Researcher Janne Ropponen, Finnish Environment Institute (Syke), firstname.lastname@syke.fi

The Vemala model is an operational, national-scale nutrient loading model for water bodies developed at the Finnish Environment Institute. It simulates nutrient processes, leaching, and transport on land, in rivers, and in lakes. The model simulates the total nutrient load to water bodies, retention, and the load from Finnish water bodies to the Baltic Sea.

More information can be found on the Vemala webpage. 

The Finnish Environment Institute uses a nationwide Watershed Simulation and Forecasting System to forecast, among other things, water levels and flows in water bodies, groundwater levels, flood warnings, and roof snow loads, as well as to calculate nutrient loads from water bodies to the Baltic Sea.

More information can be found on the Watershed Simulation and Forecasting System's own webpage.

The Finnish coastal nutrient load model, or FICOS model, helps researchers and authorities in planning, evaluating, and monitoring water management measures. It can easily calculate and compare the effects of load changes on coastal water quality. The model covers the entire Finnish coast up to the economic zone, with some exceptions.

More information can be found on the Finnish coastal nutrient load model's own page.