Background The management of groundwater resources in areas that have been subject to extensive coal mining is a major international problem due to the difficulty of predicting the hydrological characteristics of groundwater drainage regimes and the potential impact on groundwater quality, surface water flow and quality, stability of structures and public safety. Under the EC Water Framework Directive it will become increasingly important to incorporate large-scale groundwater drainage networks such as those in former coalfield areas into River Basin Management Plans. Without improved understanding of the opportunities for integrated management of coalfield groundwater systems they will remain a major environmental risk and a significant barrier to the successful implementation of fully integrated river basin management systems. The project aimed to support the development of effective integrated management strategies by considering the relationships and linkages between coalfield groundwater systems and all other catchment water resources including abstractions, discharges, flowcontrols and land development issues. Objectives The objective of the project was to demonstrate and evaluate innovative techniques and procedures for integrated management of groundwater resources in former coal mining areas. The overall aim is to develop a methodology to reduce the risks and uncertainties associated with strategic approaches to integrated management of water resources at a river basin scale. Research by the project partners had suggested that groundwater systems that interact with mine workings can be managed to minimise public and environmental risk in the following ways: • Internal balancing of system flows to ensure optimum dilution of contaminated water and controlled discharge to receiving waters. • Identification of hydrological trends related to underground drainage system instability and the potential for catastrophic groundwater impacts. • Establishment of integrated management and response systems that allows real-time control oversystem flows. • Co-ordination with water management systems at river basin scale to optimise opportunities to support low river flows and alleviate flooding. It was anticipated that the project would provide significant support to the implementation of the EC Water Framework Directive in the many regions of Europe where coalfield drainage is a major consideration. The project was based on catchment scale demonstration programmes in the UK and supporting activities in Romania together with evaluation of applicability in all major European coal mining regions. The UK site was the primary focus of the demonstration activity due to the large amount of data that was already available. The Romanian demonstration activity was based in a single coalfield containing a number of abandoned mine workings, considered to be most representative of mine drainage in the region. The majority of the management and control procedures were demonstrated in the UK and subsequently tested at the Romanian site. Results The INWATCO project met its primary objective of demonstrating and enabling innovative techniques and procedures for integrated management of groundwater resources in former coal mining areas’. A basic demonstration test plan was developed at the UK site to include the following core components: - Long-term waster quality and flow monitoring throughout the catchment area; - Large-scale pumping tests at Hope Shaft and Woolley Shaft; - Tracer testing to determine key flow paths within the system; and - Analytical studies based on monitoring data. A baseline catchment-wide water quality sampling and analytical programme was undertaken in order to allow establishment of background hydrochemical variation across the catchment. This data was added to a central database for comparative analysis in relation to rainfall, minewater flow and level information collected from the prototype real-time monitoring and management system. This study was followed by a water quality monitoring and discharge rate monitoring programme. The data was used in detailed analytical assessment of potential minewater management options and the relationship between minewater systems and the wider surface water and groundwater content. Drawdown tests were carried out to establish the hydrologic connectivity of the other monitoring points within the water catchment area. Additional flow balancing and tertiary treatment systems were installed at Hope Shaft. A continuous monitoring and evaluation scheme was operational. The data accumulated during the entire demonstration phase of the project will form the basis for detailed analysis aimed at establishing the influence of a variety of pumping and water management strategies on water flow and quality within the system. The knowledge and data collected was subject to detailed evaluation and analysis in the context of integrated catchment management. The results from these components of the project produced the main technical outputs from the INWATCO project and provided the basis for development of guidance on integrated water resource management in former coal mining regions. This was one of the key project successes. In addition to this, and the acquisition of a large amount of valuable technical information, the main project highlights were a prototype real-time minewater monitoring and data transfer facility, and a minewater exhibition and Visitor Centre at the National Coal Mining Museum for England, to promote dissemination of information relating to minewater management to the general public. The project has generated substantial interest from many parts of Europe.