In the loess area of the southern part of Limburg soil erosion is responsible for damage in the agricultural area and the associated runoff leads to flooding of urban areas and deposition of mud on the infrastructure. Since the second half of last century erosion hazards and damage have increased, due to more intensive tillage of the soil. With a general use of artificial fertilizers, organic matter content of the soil dropped to critical levels. Besides that, activities in agriculture like enlargement of fields, use of heavy machinery and activities outside the agricultural area like the extension of the built-up area and infrastructure led to less infiltration and consequently to more runoff. The expected change of the climate – more intensive rain showers – may even aggravate the erosion problem in the future. Moreover, the general policy of protection of the urban areas against flooding is developing to a higher protection level. The public sector is responsible for general policies to control erosion and to bring the damage of flooding back to acceptable levels. The basic principle is to tackle the erosion problem at the source, on the farmer's field with measures among others by the introduction of non-turning-ploughing and mulching and preservation and expansion the area of grassland. At local level, specific erosion control measures and financial arrangements are made. Municipalities are supposed to prepare and guide local level erosion plans, where measures are taken to complement the individual on-farm erosion control measures. Municipalities have to solve small-scale problems (bottlenecks) with local flooding and sedimentation of mud, especially on infrastructure. To prevent flooding the Water Authority has the task to develop the water infrastructure mainly to buffer water and to convey runoff at a safe discharge (grass strips, grassed waterways). In the combat against erosion the farmers and the farmer's organizations took their responsibility. The efforts resulted in 1990 in an Erosion Ordinance (EO) lately revised in 2003. The EO is primarily a responsibility of the farmer's organisations. In 2000 authorities involved in erosion and flood control signed a covenant in which generic and specific interventions were agreed upon to realize in a period of 4 years. Tough the agreed measures are only partly realized in this period, the intentions of the covenant are still valid. In 2003 the farmer organizations introduced in the revised EO a new instrument: the Farm Erosion Management Plan (FEMP) in which a farmer can take its own responsibility to keep erosion risk at an acceptable level and to organize his own farm strategy. By taking enough measures in the FEMP, the farmer gets dispensation of several measures otherwise due to the EO. Farmers can rely on EU-subsidies when applying erosion control measures (cross-compliance). Both the EO and the FEMP are part of the EU Common Agricultural Policy (CAP). In spite of legislation, accepted responsibilities at different levels and financial support (incentives), erosion control interventions do not (yet) cover the whole area and not all stakeholders are equally motivated to implement and maintain the measures. In practice monitoring of the fulfilment of the EO and the FEMP is quite complicated, because of scattered land property, the complexity of the instruments and lack of (trained) controllers. At the moment the Water Authority is evaluating the effectiveness of measures taken by the FEMP in relation to general legislation of the EO. At municipality level several plans to solve the problems at locations where flooding and mud deposition occurs frequently are ready, but lack of funds will postpone execution of some of them.
- soil-erosion model
- drainage basins