GUIDELINES FOR MITIGATION MEASURES AGAINST AGRICULTURAL WATER POLLUTION

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1 Photo: Grassed waterway. Svein Skøien GUIDELINES FOR MITIGATION MEASURES AGAINST AGRICULTURAL WATER POLLUTION Svein Skøien These guidelines for mitigation measures against water pollution from agricultural activities have been prepared to assist in the efforts to implement the EU Water Framework Directive in Norway.The guidelines have a general text and a menu bar with links to relevant information on specific topics. 1BioforskSoil and Environment 2011

2 Water Framework Directive TheEU Water Framework Directive was adopted in the EU in In 2007, Norway decided to implement the directive in Norwegian law as Regulation for the Framework for Water Management. Good ecological, chemical and hydromorphological status The main goal is that all water bodies should achieve good ecological, chemical and hydromorphological status. A water body may be a lake, a river stretch, a groundwater body or a marine, coastal area. The environmental objective is fairly strict since it implies that the water should achieve a state that does not deviate much from itsnatural state. To achieve this it is necessary to implement several measures in water bodies that do not have good ecological status. A national investigation has been carried out to characterize all the water bodies in order to know the current status. Norway is divided into 16 river basin district, with a number of local river basin sub-districts within each region. Each region is managed by an authority appointed by the Government. In Norway this authority lies with selected County Councils. The Regulation Framework for water management suggests that the river basin authority should be responsible for preparing action programmes with the river basin committee. Sector Authorities, counties and municipalities are responsible for assessing the necessary measures within their areas of responsibility. Management programmes and Programme of measures Aprogramme of measures must describe what measures are necessary within each sector to achieve the environmental goal of good ecological and chemical status in water bodies. The programmes should be included in river basin management plan. Evaluation of measures should be based on a cost effectiveness principle, and across sectors. This means that the costs and effects of measures in agriculture should be assessed against similar measures in other sectors, such as urban runoff and wastewater treatment plants. The measures should be ranked so that the most cost-effective measures are implemented first. Planning Tools There is prepared a number of tools that can be used in the work to implement measures in agriculture. In addition, there are other tools and resources that can be. We have tried to summarizethe ones we consider to be most useful. Here you will find useful links with information about the EU Water Framework Directive, as well as domesticand international sites. Below are links aimed at agriculture and measures against pollution. The official website for the implementation of the Water Framework Directive in Norway, is called Vannportalen. We recommend that you refer to this site for all official and updated information on implementation efforts. The Vannportalen also contains links to a guideline for planning of measures. This gives a review of all procedures, roles and deadlines for the implementation of action plans and the main measures in all sectors. This page focuses only on detailed information about the measures in the agricultural sector. 2BioforskSoil and Environment 2011

3 Measures in agriculture Here are summaries of relevant measures against pollution from agriculture. The measures are described in detail in fact sheets. Point sources In addition to erosion and runoff from the fields there is also loss of nutrients and pollutants in the form of leaks from silos, manure storage, waste piles, barns, washing facilities, farm buildings etc. Fertilizer planning Fertilizer planning is a systematic quantification of the need for plant nutrients for the individual agricultural crop at each field of a farm. The fertilizer requirement is calculated from a number of factors, primarily from the soil nutrient status and the crop's production potential foreach location. Conservation tillage Conservation tillage means that minimum tillage is performed before seeding, e.g. harrowing or direct seeding. It also means that no plowing is done in the autumn in order to preserve stubble or plant cover through the autumn and winter. Conservation tillage will reduce the loss of soil and nutrients and is also less timeand energyintensive. Hydrotechnical measures Control of surface runoff from agricultural land is important to minimize the loss of soil and nutrients. Hydrotechnical installations regulate and control the runoff from agricultural areas. Vegetated buffer zones A vegetation zone between the water body and farmland acts as an effective filter for soil particles, nutrients and particle-bound pesticides in surface runoff from agricultural land. Vegetation zones will also reinforce the stream and river banks and protect against landslides and excavation by the stream water. Sedimentation ponds, constructed wetlands Sedimentation ponds are constructed wetlands that capture and hold soil particles, nutrients and pesticides from diffuse sources such as agricultural land, roads and urban areas. The ponds also have anaesthetic quality in the cultural landscape. Re-opening of streams In the agricultural landscape many streams have been led into subsurface drains, while other streams have been straightened out or regulated in other ways. Wetlands and ponds have been drained in order to cultivate the land. This has resulted in a poorer cultural landscape, less biodiversity, pollution and increased flood peaks. In many places, it is desirable to reverse this trend, and one of the measures may be to reopen the closed streams. Grassed waterways Onerosion-prone soils where surface water is collected in natural depressions, erosion can be preventedby establishing grass-covered waterways. The waterways can be permanent grass cover or they can be sown every year. Other measures Under this heading, we have collected various reports and information leaflets dealing with other types of measures, as well as practical examples. Main measures in different agricultural areas Grain growing areas Programmes for measures for areas dominated by grain crops will be characterized by tillage methods and other measures that reduce particulate runoff from agricultural areas. 3BioforskSoil and Environment 2011

4 In areas with silt and clay soils and large agricultural areas it is a particularly challenging task to make plans. Measures that reduce the exposed soil in winter (such as reduced tillage and grass-covered waterways) have the best effect. Secondary measures will be vegetation zones and sedimentation ponds. Maintenance of hydrotechnical measures is also very important in some areas. General recommendations: A variety of measures is needed to achieve the desired reduction in particle and nutrient runoff from areas with grain. In most cases a combination of several measures will be required to achieve an adequate reduction. Firstly we recommended anti-erosion measures, ie measures that reduce detachment and transport of particles from agricultural land to surface waters. Such measures include reduced tillage and grasscovered waterways. Reduced tillage involves zero- or minimum tillage with harrowing as well as spring ploughing instead of autumn ploughing. Grassed waterways in depressions in the fields where there is surface water is recommended but not widely adopted. Other relevant measures will be measures that filter runoff water and sediment or bind particles and nutrients which are transported from agricultural areas. Such measures include vegetation zones and sedimentation ponds. These are recommended in most cases as a supplement to erosion prevention measures. In addition to the above measures it is in many cases necessary to control and repair existinghydrotechnical installations (manholes and drainage ditches) to reduce the direct transport of particles and nutrients through these systems and into rivers. Fertilizer planning is another relevant measure. By adapting the fertilizer application to the individual crop needs and by avoiding excess fertilization, the soil content of nutrients will also be reduced and consequently the risk of loss of nutrients to waterways. Priority of actions on action planning will depend on various conditions in the catchment area. Several factors affect runoff and the dominant transport processes in a catchment. Specific conditions that must be considered in each case include: Topography Soil type Operating practices and intensity Proximity to waterways Phosphorus levels in soil In the agricultural areas with vegetable production it is important to map the P status in the soil as this is generally very high. Measures which will bring long-term control over areas that have high soil P status values are important. The risk of particle runoff is high and vegetation zones and sedimentation ponds are appropriate secondary measures. It some areas installations for purification of drain water by means of filterbeds have also been built. Areas with vegetable crops In vegetable production much of the area is exposed without a good protective vegetation cover and is consequently highly vulnerable to erosion and loss of particles into watercourses. Relevant secondary measures in such cases are vegetation zones along rivers and sedimentation ponds. Both are measures that increase the retention of particles, so that a less enter directly into waterways. 4BioforskSoil and Environment 2011

5 General recommendations: In agricultural areas with intensive vegetable production, soil phosphorus content (measured as P-AL) is often very high due to strong fertilizationover a long time, with nutrient inputs in many cases far beyond what is taken out with crop. Through erosion and surface runoff large amounts of particles and phosphorus (both in solution and particle-bound) can be lost into the water systems. A long-term measure in such areas will therefore be to reduce the soil phosphorus content. It may take time before the effect of this measure can be registered, but the measure is absolutely necessary to reduce the loss of phosphorus to watercourses. If the need for reduced nutrient supply to the recipient is particularly important, it may be necessary to shift from intensive potato and vegetable crops to vegetables that are somewhat less phosphorus demanding. Regions with animal production In areas with high livestock production,manure handling, field application of manure and fertilizer planning are key points to include in a package of measures. Mapping of P status in soils and long-term measures that can bring control over areas that have high P values are important. In the livestock areas of the west coast region of Jæren, experience with sedimentation ponds are good, even if the ponds are a secondary measure in such areas. Timing of manure application on the fields, buffer zones along the watercourses and permanent vegetation zones are also relevant measures. General recommendations: In agricultural areas with intensive livestock production, soil phosphorus content (measured as P-AL) is often very high due to the addition of large amounts of manure (often in combination with mineral fertilizers) overa long time, with nutrient inputs in many cases far beyond what is taken out with crop. Large amounts of nutrients will be added to waterways in runoff from these areas. A long-term measure in such areas will therefore be to reduce soil phosphorus content by reducing fertilization, improve manure handling, as well as to maintain the requirements for manure per area unit. The area requirement for manure in Norway is 0,4 hectares per animal unit. These measures will primarily have a significant effect over time, but will also reduce the loss of dissolved nutrients to waterwaysin the short term. Control of the manure storage is important to avoid leakage into nearby waterways. Furthermore, it is important that the fertilizer planning take sufficient account of the nutrient content in manure, so that the supply of mineral fertilizers can be reduced. Time for spreading of manure is also of great importance. Manure should be primarily spread during the growing season, when the risk of runoff of nutrients is relatively low due to less precipitation, plant uptake and evaporation. The risk of runoff of nutrients is greatest when the manure is spread during periods of heavy runoff outside the growing season. Sedimentation ponds with vegetation filters have proven to be effective as secondary measures in the livestock regions, primarily in terms of retention of particles and particle-bound phosphorus. The ponds have generally less effect on the retention of nitrogen. Other important measures are unfertilized buffer zones between meadows / pastures and waterways and permanent vegetation zones between open fields and rivers. A central point in any action plan is to assess the costs and effects of actions. This is perhaps one of the hardest to draw up management plans. For some measures it may be easy to calculate the costs and assess the effects, while for others it can be very complicated. Survey - calculation of cost effectiveness NILF and Bioforsk has conducted a survey to get a better estimate of the cost effectiveness of the implementation of measures in agriculture (NILF report no ). 5BioforskSoil and Environment 2011

6 Administrative tools Here is an overview of the administrative measures to reduce environmental impacts from agricultural operations. These are instruments for the government, the counties and municipalities with responsibility for agriculture and environment. The emphasis is on measures that affect water quality, and the tools are divided into legal instruments, economic instruments and other tools. Legal instruments Several laws and regulations govern the agricultural operation from an environmental perspective. These can be laws and regulations under the Ministry of Agriculture and Food but also several laws under the Ministry of the Environment. Economic instruments Economic measures include schemes with subsidies for environmental measures where the user receives financial compensation for active environmental efforts. They also include environmental requirements that are related to other financial arrangements, and where it is essential that environmental requirements are met for the grant to be paid in full. Other tools A range of means other than economic and legal instrumentsare widely applied to promote more environmentally friendly agriculture and encourage measures to reduce pollution of water from agricultural operations. This includes advice, information, monitoring, research and development. 6BioforskSoil and Environment 2011