Regionally approached groundwater management in Zwolle: preventing risks and utilizing opportunities
The approach of the contaminated groundwater in the surroundings of the railway station in Zwolle was the first ‘regionally approached groundwater management’ in the Netherlands. Abroad there is quite some scepsis about this approach, which is used in the Netherlands more and more. With this project we would like to demonstrate that this approach is much more than ‘letting the pollution flow’. It’s about making well considered, responsible decisions to prevent risks and to utilize opportunities.
The soil and the water in the surrounding of the railway station in the city centre of Zwolle are contaminated because of many industrial activities in the past. The various pollutions were too complex and too large to investigate and remediate each location separately. In 2003 a cooperation agreement between public and private partners was formulated, in order to protect drinking water and to remediate the existing groundwater pollution.
Measures, monitoring and results
This approach has been implemented over the past decade. The measures included the relocation of some drinking water wells, the interception of the contaminated groundwater and remediation of the soil. For the interception of the contaminated groundwater, existing infrastructure of the former drinking water extraction are used. In the polluted ‘source’ area, contaminated groundwater is extracted, thereby preventing it from flowing to the drinking water wells. The heat from the extracted groundwater is used as an energy source for office units nearby. After extracting the heat, the pumped groundwater is aerated and drained to an ditch. Because of the purifying effect of reed plants (constructed wetland) in this ditch, the pollution will be further biodegraded.
Goals achieved
Now, after 10 years, the remediation goals are achieved. The groundwater quality has significantly been improved and the drinking water wells are partly relocated , by which the supply of clean drinking water for the inhabitants of Zwolle can be guaranteed.
By making use of this approach, opportunities related to drinking water, energy and green urban development were utilized. Hereby, the municipality of Zwolle aimed to contribute to the sustainable development of the city centre. This approach turned out to be the most sustainable solution: the optimum for people, planet and profit.
Keywords: groundwater management, groundwater quality, risked based, urban and industrially contaminated land, sustainable development, integrated solution
Keywords: management plan, groundwater, volatile chlorinated hydrocarbons, feasibility study, remediation, priority, target values, natural degradation, numerical contaminant transport model Stuttgart is one of the few large cities in Europe, where mineral water springs and is widely used for spa and medical purposes. Nineteen springs discharge about 44 million liters of highly mineralized and carbogaseous water each day. Mineral springs of Stuttgart are, just after Budapest, the second largest European reservoir. Due to their vulnerability, they are protected as economical, natural and cultural assets.
In general, groundwater in urban areas is exposed to an anthropogenic influence and suffer from concentrations of contaminants. Stuttgart, as highly industrialized city, have more than 5,000 contaminated sites which might influenced the mineral water quality. Despite tremendous efforts and intensive single site orientated remediation since 1984 in downtown, the mineral springs were still affected with chlorinated hydrocarbons at low concentrations. Therefore, the applied practices of environmental management and measures for mitigation of pollution sources were not sufficient and had to be adjusted.
The main goal of this study is to define an integral remediation plan (management plan) for the project area, focusing on the key sources of chlorinated solvents which are relevant for the mineral springs,
including the fact that the pollution might originate from several sources. The management plan is generally consisting of:
detailed description of flow and contaminant situation, together with the processes that are taking place in the investigated area
scenario and prediction modelling
priorization and definition of remediation targets
remediation feasibility study and monitoring
definition of an implementation concept considering finances, legal aspects and securing transparency
For the large-scale investigated area of 26,6 km2 and eight aquifers, an extended data and information were available. At the begining of the project, 182 possible contaminated sites with a significant CHC concentration were identified. The integral investigation had indicated that 21 sites had an impact on the deeper layers. Therefore, a detailed investigation of those sites was performed and the results were summarized in 19 so-called “profiles”. Furthermore, the numerical model indicated that 9 contaminated sites affected the upper Muschelkalk aquifer, i.e. mineral water-bearing aquifer. Finally, the priorization characterised 4 contaminated sites with high priority and need for optimized or additional remediation efforts. For those four contaminated sites feasibility studies were performed and resulted in recommendation of remediation measures with total costs of more than 12.5 million euros.
The proposed strategy and approach are suitable for multiple sources of contamination. Only in this way, the contributions of single contaminated sites to the total groundwater contamination can be identifed and local remediation measures with their spatial impact simulated. Due to very complex geological
conditions, technically there is no alternative to this strategy in order to achieve the CHC purity in the mineral springs. Stuttgart is appoaching very closely to this goal.
This study was performed within MAGPlan Project (management plan to prevent threats from point sources on the good chemical status of groundwater in urban areas). The project is financially supported by the program LIFE+2008 environment of European Union from 01/01/2010 to 30/09/2015. Responsible project partners are the Municipal environmental Agency of Stuttgart as well as the Agency for environment, monitoring and ecology in Baden-Württemburg.
Background
Soil pollution poses a continuous threat to the Danish groundwater. The groundwater is the primary water resource suitable for drinking water in Denmark, and currently the only one used. Several years of infiltration through the ground has filtered the water, and thus a minimum of treatment is required in order to achieve drinking quality standards. If one or more contaminations are left unnoticed this could potentially affect entire drinking water catchments, and, worst case, shut down drinking water extraction from an entire catchment for years. Therefore, thorough mapping and prioritization of further action at possibly contaminated sites are crucial. This allows an optimal foundation for further actions, remediation and mitigation of contaminated sites to secure clean drinking water.
Using a large scale systematic approach to map and prioritize soil contamination, requires the authority to be able to control both funding and execution of exploration and investigation. In Denmark, the five Regions of Denmark, including the Capital Region, are the authorities of soil and groundwater, and at the same time fund the investigations and remediation of soil and groundwater. As of November 2014 additional funds have been allocated in order to obtain clean groundwater in the Capital Region more rapidly.
Every year the Capital Region of Denmark spends around 20 million EUR on contaminated soil and groundwater. There are approximately 12.000 potentially contaminated sites in the Capital Region. If the contamination threatens either groundwater or indoor climate, the Capital Region is obliged to remediate or mitigate, so prioritization is necessary to ensure that the funds allocated for protection of the environment and human health are spent optimally. The prioritization procedure includes all steps; from preliminary investigations of historical data through delineating investigations to design and execution of remediation and mitigation.
Strategy
Locating possibly contaminated sites through historical investigations is step one. A systematic examination of historic data identifies industrial activities that typically result in soil and groundwater contamination. The historical investigations are implemented in areas where groundwater has high priority due to high water quality and quantity and in catchment areas. Every tool at disposal is used, such as data from old phonebooks, municipal archives, aerial photos and directories. Several years of knowledge of various industries has been put into industry descriptions. These allow for pinpointing of possibly contaminated sites based on activities and industries found on sites in the historical investigations. There is a constant focus on keeping the industry-descriptions up to date. This is done through regional collaboration, exchange of experience and gathering new information. This knowledge is critical since every contamination not found will not be included in the subsequent prioritization and risk assessments, and will be left to possibly affect large quantities of groundwater.
The sites that are historically registered as possibly contaminated will be investigated in the field with an environmental preliminary survey. The sites are prioritized with regard to ground- and surface water threats, and indoor air quality threats. Thus industrial activities known to use chlorinated solvents are investigated first. The preliminary survey includes a predefined method for groundwater, soil and soil gas sampling. The sites with contamination that represent a threat to groundwater and/or indoor climate will be prioritized for delineating investigations, followed by prioritized remediation and mitigation.
All information on the possible and confirmed soil contaminations is registered in a national database, to maintain an overview. This database allows for a review of the registered sites, and future adaptation, should there changes in prioritization occur, or as more experience is gained or new methods developed. It also makes it possible to generate specific publically available databases on the contamination situation at individual sites, for citizens to use in i.e. property sales.
Conclusion
A large scale systematic approach such as this, is viable as long as the authority controls both funding and execution. The yearly budget does not enable the Capital Region to investigate all contaminated sites in the region at once. With the extra funding allocated in 2014, the current objective is to protect 80% of the groundwater within a 10 year timeframe, while still ensuring safe indoor climate. With this systematic approach it is possible to handle thousands of potentially contaminated sites, and through historical and environmental investigation, gradually reduce their number to a few hundred that ultimately need remediation, in order to meet the 10 year deadline.
Abstract Aquaconsoil 2015 – Success and failure factors area-wide groundwater management
Arne Alphenaar1 , Frank Swartjes2, Piet Otte2 and Reinder Slager2
Interfering and wide spread plumes of contaminated groundwater are hardly treated or controlled using conventional methods. An area-wide groundwater management approach seems to be more effective. Environmental policy in the Netherlands has been adapted to facilitate this approach. Innovators and early adaptors still faced technical, regulatory and organizational challenges. The application in practice stagnates. To overcome the barriers we started a study to investigate and interpret the factors lie beneath the success or failure off area-wide groundwater management
Area-wide groundwater management originally was developed as a tool to manage large scale and interfering plumes of contaminated groundwater. In those cases the usual case-oriented approach is limited in technical, practical and financial ways. Since then, the area-wide approach has evolved into a tool to tune most groundwater related challenges. Despite the effort taken to stimulate the implementation, the area-orientated and integrated approach of groundwater still gives rise to fierce debate.
We note that there are several reasons why the debate continues:
- In the Netherlands, the area-wide groundwater management approach appears to be a goal in itself. The parties involved have no clear picture why they choose the area-oriented approach.
- Linked to the debate on area-wide groundwater management, the discussion start whether groundwater should be protected, and if so, in what circumstances. As a consequence, some people see the area-wide approach being an excuse for doing nothing.
- The current standards, regulations, methods and demands does not proper fit with the area-oriented approach. As consequence early majority do not adopt the procedure.
During Aquaconsoil we will be able to present the definitive results of this study and we will be able to present tools and solutions that will support governments in managing their groundwater related problems.
A collaboration of four individual consulting companies, called the AGGb, and the RIVM analysed the factors that lie beneath the success and failure of the implementation of an area orientated approach of groundwater. Based on this research practical tools will be developed that will support (early) majority in implementing the area-wide groundwater management..
Keywords: Groundwater management, Contamination, Remediation, Area-wide and integrated approach, risk approach
1 AGGb. Adviescombinatie Gebiedsgericht grondwaterbeheer (TTE Consultants, Witteveen+Bos, Bioclear and 3Dimensies)
2 RIVM. the National institute of Public Health and Environment
- Arne Alphenaar, TTE Consultants, alphenaar@engineers.nl
- Reinder Slager, 3Dimensies, reinder@3dimensies.nl
- Frank Swartjes, RIVM, frank.swartjes@rivm.nl
- Piet Otte, RIVM, piet.otte@rivm.nl
Flowers 4 Brabant: excellent projects for an area oriented approach in North-Brabant
Cities are expanding
The traditional way of dealing with polluted soil and groundwater does not work in all cases. Cities are expanding, former gasworks, small scale industries are within present day city boundaries and left there polluted footprint behind. Many historical groundwater pollutions are intermingled and the polluter pays principle does not work in those cases, or they ask for endless legal procedures. The polluter is either bankrupt or buried in the graveyard. As a result in urban environments with complex contaminations spatial developments are at a standstill and neighborhoods at a social decline. An area oriented approach can be used to tackle the problems.
In the province of North Brabant in the south of the Netherlands policy makers from a different background try to look over there sectorial walls. In the project “Flowers 4 Brabant” specialists and pioneers who work on an area oriented approach are brought together and with the support of the ministry of Infrastructure and Environment they are sharing knowledge to stimulate an area oriented approach.
Area oriented approach and legislation
Area oriented groundwater approach is a policy framework in which the integral and sustainable design of the management of groundwater is performed within a restricted area. Groundwater activities and interventions in the groundwater system are linked to environmental objectives, (recovery) nature and spatial and economic developments are implemented and integrated in the groundwater system for the long term. The policy framework for area oriented groundwater approach will be determined by the relevant authorities (provinces, municipalities and/or waterboards) through an administrative arrangement. From that point, the governing bodies will manage the area oriented groundwater approach in the form of an implementation plan. This plan also operate as a reference for the authorisation and decisions within the existing laws and regulations aimed at soil, groundwater and the use of geothermal energy.
The Dutch soil protection act has been amended on 1 July 2012 to make an area oriented groundwater approach legally possible. The area oriented approach involves the polluted groundwater being allowed to freely move around inside the system area, providing that it does not engender risks to people or the ecology and does not spread outside the designated area. The area oriented approach therefore contributes in a general way to the realization of the objectives of the Groundwater Directive. According to article 5 plumes has to be monitored and article 6 prohibits the introduction of pollutants into the groundwater. The area oriented approach is par excellence made to prevent spreading of plumes outside the contaminated area and also addresses the pollution source as an essential part of the approach.
Sustainable urban development and soil quality are connected. A poor groundwater quality can form a risk and a limiting factor for desired urban developments. A badly designed urban development can form a long term risk for sustainable use of the subsoil, the environment and the health of its inhabitants. But the other way around urban re-developments are important triggers and a chance to restore soil quality. Also a good sustainable urban design concept can draw new customers and increase value and profit. So, groundwater quality, sustainability and urban development are connected. Can a win-win situation be reached? An area oriented approach which allows for more synergies through early connecting and overlapping different disciplines in urban planning is thought to be the most effective approach. But it is complex matter and actors involved have to collaborate and will need guidance to achieve an successful area oriented approach. In general local governments will take the role of director and organize the public private partnerships.
Lessons learned from Flowers 4 Brabant
The provincial government has in recent years actively stimulated the opportunity to apply the area oriented approach. There are essentially two reasons for the province to take this active position:
1. The province sees that many projects are bogged down because there is much unclear about finances, responsibility of the different actors (public and private), and who should pay for what.
2. An area oriented approach will achieve more than just solving a groundwater problem. The province, municipalities and other actors see advantages for sustainable re development.
The province of North Brabant recognises area oriented approach therefore as an effective tool to address soil and groundwater contamination, and it is also a tool to (re)start social and spatial developments which where stagnated due to groundwater contamination. Therefore the province developed an administrative Implementation Strategy for the area oriented approach.
Confidentiality and cooperation with other actors is an important key. Transparency and balancing the different interests, which leads to a broad-based approach for all actors is the foundation of the Implementation Strategy of Brabant. By placing assignments in a broader context, to restore confidence and link budgets new initiatives germinate. This can been seen at various places in the province where the area oriented approach is applied and solutions are developed to tackle long term stagnations and economic growth flourish. Flowers 4 Brabant has demonstrated that an area oriented approach is still human work. Enthusiastic pioneers are needed, people who have the courage to step out of there comfort zone.