Biosolids recycling : a proposed methodology for the assessment of the impact on groundwater

A groundwater risk assessment protocol is needed for land restoration schemes using recycled biosolids. A hydrogeological risk assessment for the Darnconner site in East Ayrshire [NS5723 to NS5823] has been used as a case study to develop the protocol. The proposed outline for developing the protocol included the following components: 1. Gather available geological information for the site and environs from 1: 50 000 scale geological maps and more detailed information where available. 2. Interrogate the BGS borehole database (Wellmaster) to establish existing groundwater users in the vicinity and available information regarding depth to water, water quality, etc. 3. Identify the catchment Baseflow Index (HOST) to establish the degree to which surface water courses are groundwater dependent. 4. Bring the three strands of information together to create a preliminary conceptual groundwater flow model for the vicinity of the site. This is presented as a three dimensional schematic supported by cross sections if details are available. 5. Identify pathways from the site to the water table, such as former adits, local faulting etc., in addition to likelihood of any intergranular ingress. 6. Access BGS HiRES airborne geophysics images to see if existing pollution plumes derive from or cut across the recycling sites. 7. Evaluate the potential risk to groundwater from the site and likely flow path any contaminated groundwater may take, including emergence to surface water. 8. Advise on any further work that may be required, e.g. drilling and monitoring. The time estimate for each assessment was aimed at four man days (including Coal Authority input to access mine abandonment plans for former collieries in the vicinity, and time for accessing the HiRES data where appropriate, to evaluate pollution egress from treated sites), plus the walkover site of all four sites, a further one day. Bacteria are largely attached to soil particles, are not easily mobile and die-off is rapid in the soil profile. Bacterial risk to groundwater is, therefore, low unless there is direct transport from the soil via a fracture or existing mine adit to the water table. The risk from metal contamination of groundwater is also low as metals are bound to the sludge organic matter and the receiving soil provided the pH is maintained at a near neutral environment. The main potential pollution risk from biosolids is nitrate derived from the oxidation of ammonium and nitrite species leaching from the topsoil. Risk assessment hinges on the potential for transport of nitrogen species to groundwater. A scorecard system to assess the nature of the pathway and its potential to transport nitrogen rich infiltration to the water table is presented. The use of sewage sludge as a primer for vegetative growth and as a humic foundation for soil development at mine sites is not new. It was common practice in the 1980s and 1990s to mix biosolids with the more shaley rock wastes from colliery and opencast sites to attempt to recreate a soil cover. The technique was, for example, applied repeatedly and successfully during post-closure procedures of numerous opencast sites in South Wales. There are no recorded instances of bacterial, metal or nitrogen contamination of local groundwaters, although background levels of all three potential contaminant groups were likely to have been elevated during the initial post-closure period due to intensive mining and industrial activity taking place at that time. Detailed descriptions of this work may be available in the records of the Coal Authority at Mansfield, but there is otherwise little reliable information reported in the open literature. Biosolids were also used at a number of Scottish reclamation sites including Heathland Forest (Bye Law Hill) near Forth (see Section 4)

Integrating sciences in sustainable development of natural resources and poverty alleviation : workshop manual, Colombo, November 2003

This manual was prepared for the Training Workshop on Integrating Sciences in Sustainable Development of Natural Resources and Poverty Alleviation in South Asia, held at Colombo, 4-6 November 2003, by the British Geological Survey (BGS). It comprises a series of six BGS presentations. The first four have been specially prepared for the Colombo workshop by Nick Robins: 1. Needs of society in the 21st century, environment, natural resources, hazards and needs of the poor 2. The role of the Geological Surveys 3. Water - the future 4.The BGS - some contributions to sustainable development The last two are technical presentations: 5. The Bangladesh groundwater arsenic problem - prepared by David Kinniburgh and others 6. Minimising fluoride in drinking water in problem aquifers – prepared by Pauline Smedley The four main presentations draw on two source documents, The British Geological Survey’s Responses to the Terms of Reference of the 2003 Science and Management Audit, September 2003, and the internal BGS report of the BGS Horizon Scanning Group. Additional information is drawn from a variety of sources including the internet. The British Geological Survey through its parent body the Natural Environment Research Council, owns the Intellectual Property Rights of all the material in this manual. The manual and the presentations have been designed for use by the United Nations Economic and Social Commission for Asia and the Pacific, but are retained under BGS ownership, and must not be issued for use by a third party

Groundwater dependence and drought within the southern African development community

A groundwater situation analysis of the SADC region has been undertaken as part of the World Bank GEF Programme as a basis for ensuring equitable use of groundwater resources, particularly during periods of drought, both for human needs and for sustaining ecosystems. Much of the groundwater in the region occurs in weathered crystalline rocks suitable for dispersed supply to rural communities, although there are several aquifers capable of sustaining urban demand that contribute to the supply of several major cities and towns. A number of SADC Member States, such as Botswana, Namibia and South Africa, are very dependent on groundwater, whereas the Democratic Republic of Congo is least dependent. Groundwater dependence and groundwater demand, together providing an indication of drought vulnerability, have been assessed from the availability and coverage of groundwater data, but it is very apparent that reliable and comprehensive groundwater data are major deficiencies throughout the SADC region. Few attempts have thus been made to calculate renewable groundwater resource volumes or develop optimum use of groundwater, despite the fact that susceptibility of many Member States to drought requires them to consider mitigation strategies to lessen the hardships imposed largely on their rural population. Such strategy requires long-term intervention and not short-term emergency responses, a process that is directly related to availability of comprehensive groundwater datasets. Considerable effort in groundwater assessment and monitoring and the accumulation, evaluation and dissemination of essential datasets will thus be required to maintain population livelihoods in future years when water supply is projected to be in deficit in over half of the SADC Member States

The SADC Groundwater Data and Information Archive, Knowledge Sharing and Co-operation Project. Final report

The Southern African Development Community (SADC) Groundwater Data and Information Archive, Knowledge Sharing and Co-operation Project, funded by the German Development Cooperation (GIZ) and Department for International Development, UK (DFID), was initiated in September 2009 to identify, catalogue and subsequently promote access to the large collection of reports held in the UK by the British Geological Survey (BGS). The work has focused on a wealth of unpublished so-called “grey” data and information which describes groundwater occurrence and development in Southern Africa and was gathered by the BGS over its many decades of involvement in the region. The project has four main aims: To catalogue and describe the "grey data" documents on SADC groundwater held by the BGS within a digital metadatabase. To identify a sub-set of scanned documents to be made freely available to groundwater practitioners and managers in the SADC region by electronic distribution. To link the metadatabase and digital sub-set of documents via a web portal hosted by the BGS, to enable download of documents by SADC groundwater workers. To strengthen links between BGS hydrogeologists with counterparts in SADC, and provide an example of groundwater data sharing which could be emulated by other European Geological Surveys with substantial data holdings on SADC groundwater. The project has successfully met these aims. The assessment of BGS archived material produced an electronic meta-database describing 1735 items held in hard copy. Of these, 1041 have been scanned digitally to searchable Portable Document Format (PDF) format. A subset of 655 PDFs including partial documents related to groundwater development from the colonial and post independence period as well as BGS internal project reports and reports approved for web dissemination by host countries are now available to download (free of charge) at http://www.SADCgroundwaterarchive.com . Initial results indicate a good deal of interest both from within SADC and elsewhere, accessed by directly addressing the website and via a search engine such as Google. The information presented has already been used by in-region projects such as the SADC Hydrogeological Mapping project and the Malawi Water Assessment Project. This is essentially a pilot project providing an example of how Web delivery of the archive is an important step forward for the well-being of the SADC region. It permits access to documents few even new existed and will, it is hoped, provide a valuable dataset that should inhibit the temptation to waste scarce resources by ‘re-inventing the wheel’

Hydrogeology of Wales

Wales enjoys a humid westerly airstream which provides a plentiful source of water. Public supply largely depends on upland gathering and surface storage, but groundwater is also supplied. Approximately 250 Ml d-1 (91 Mm3 a-1) or about 8 per cent of the total water in public supply in Wales derives from groundwater and a further 95 Ml d-1 (34 Mm3 a-1) is abstracted for private consumption from about 21 000 boreholes, wells and springs. Private abstraction is limited and of a local scale because of the indurated and fractured nature and modest permeability of many of the aquifers. It is nevertheless of significant social and economic importance and is used for drinking water, farming, and light industry. Development of groundwater remains patchy due to a perception that it is unlikely to be present in useable quantities in areas such as the hard rock terrains typical, for example, of much of central and west Wales. Groundwater is also important as it maintains low river flows during dryer periods. The traditional perception of groundwater in Wales is as an insignificant resource that has been a hazard to the mining communities. The Water Framework Directive (European Community, 2000) has brought new impetus to the understanding of groundwater in Wales as the Directive requires that the physical and chemical status of even the smallest producing aquifers be reviewed and remedial targets set. There are also several significant innovative groundwater schemes in Wales, including the Clwyd Augmentation/Abstraction Scheme and hydrogeological investigations carried out during the development of the Cardiff Bay Barrage. Wales has a wide range of aquifers that reflect its diverse geology. These include the Triassic sandstone aquifer in the Vale of Clwyd in north Wales, the only aquifer designated as Principal A type by the Environment Agency Wales, the ‘Old Red Sandstone’ of the Brecon area and large areas of Carboniferous Limestone. Quaternary and alluvial deposits also provide some resource potential. Much of central and upland Wales comprises Lower Palaeozoic and older bedrock. There are large areas of metasedimentary strata, typified by rocks such as mudstone, siltstone and sandstone which offer shallow fracture porosity and storage with no supporting intergranular storage. The Silurian and Ordovician rocks of west Wales, for example, sustain small springs and shallow boreholes enough to supply rural demand. The alluvial deposits that floor most valleys provide additional storage if they are in hydraulic continuity with the fractured bedrock. Deeper circulation occurs in the Llandrindod Wells area of central Wales where a number of chemically mature spring sources were used as Victorians spa resorts

Tension over equitable allocation of water : estimating renewable groundwater resources beneath the West Bank and Israel

Competition for water resources between Palestine and Israel is an ongoing cause of tension. The Western Aquifer Basin forms a major part of the complex, largely karst, limestone system of the West Bank Mountain Aquifer. The aquifer crops out and is recharged solely in the semi-arid uplands of the West Bank and groundwater flows west beneath Israel to discharge at the Yarqon and Nahal Taninim springs near the Mediterranean coast. Annual recharge to the aquifer is not easy to quantify but lies within the range 270×106 to 455×106 m3 a−1, and current uncertainties do not support definition of a single value of long-term average recharge. The resource is heavily exploited and abstraction is directly controlled and apportioned between Israel and the West Bank by Israel. The key to equitable apportionment is the determination of the long-term average recharge to the basin, which also requires definition of the eastern boundary of the basin to confirm the recharge area. Calculations include empirical formulae and process-based models that are likely to constrain the best estimate provided that there is appropriate, ongoing monitoring. Improved understanding can then be fed back into the model

Southern African development community regional situation analysis

The Southern African Development Community (SADC) groups fourteen sovereign states in the southern and eastern Africa region for the main purpose of fostering co-operation for mutual benefit from development of the resources of the whole region. The region accounts for almost 70% gross domestic product of sub-Saharan Africa and is home to almost a third of its people. In the context of water resources, conditions in the SADC region are highly variable with respect to the relative reliance of each of the Member States on surface or groundwater sources. However, studies already indicate that water resources will be scarce in 9 of the 14 Member States within the next 10 to 30 years, most especially in the southern and eastern portion of the SADC region. Clearly, water resource conservation and comprehensive national and regional planning is going to be crucial. SADC recognised the critical importance of water to regional integration and economic development and established its own Water Sector in 1996. A SADC Protocol on Shared Watercourse Systems was adopted to set the rules for joint management of resources. A Regional Strategic Action Plan for Integrated Water Resource Development and Management has been compiled; this is being implemented to address key water management issues, concerning both surface water bodies and aquifers (groundwater). The region is also characterised by rapid population growth. Extremes of climate bring frequent drought and substantial flood events that impact on rural populations as well as national productivity. The region is already highly dependent on groundwater for rural water supply, and it is clear that groundwater is a key element in the alleviation of the effects of drought on rural communities. However, policy responses to drought have, in the past, been based on short-term crisis reactions, which have generally proved to be inefficient or ineffective. To address this undesirable situation, proactive, sustainable and integrated management of groundwater resources needs to be instigated, but with due sympathy to the requirements of ecosystems

A conceptual snapshot of a big coastal dune aquifer: Magilligan, Northern Ireland

The Magilligan sand spit dune field is situated on the eastern mouth of Lough Foyle in County Londonderry, Northern Ireland. It is a large triangular-shaped site some 7 km by 4 km by 1.5 km wide (about 800 hectares) and maintains areas, particularly in the eastern part, with slacks that regularly flood in winter. The size of the system acts as a buffer to external drivers due to the large volume of groundwater stored, the longer travel distances and lower hydraulic gradients. However, unlike many other coastal dune sites with humid dune slacks in the British Isles the sand is not wholly underlain by silt and clay, as raised beach sand and gravel deposits are in contact with the sand aquifer in some places. A preliminary water balance suggests that the majority of the discharge from the sand aquifer occurs via the underlying raised beach deposits and only a small amount discharges directly from the sand aquifer beneath the foredunes. Available water level monitoring is skewed towards the wetter end of the dune system; no significant short-term water level trends are apparent. The data also indicate that recharge regularly takes place within the sand aquifer interspersed by periods of groundwater level recession

The Upper Devonian Sandstone aquifer of Fife

The Devonian sandstone aquifer of Fife has long been recognised as one of the most important hydrogeological units in Scotland. Its importance was first acknowledged by Earp and Eden (1961), and the aquifer was later described by Foster et al (1976). Data were subsequently gathered together in map form (BGS, 1986) but little analysis of the aquifer was carried out other than a dissertation prepared by Barker (1981), occasional reports on specific issues such as nitrate pollution (e.g. Frost and Sargent, 1993; MacDonald, 1993; Ball, 1994), and the preparation of the 1: 100 000 scale Aquifer Vulnerability Map of Fife (SEPA, 1999). The aquifer currently supplies some 20 Ml/d during the winter, rising to 40 Ml/d in the summer months, when irrigation boreholes are put into use. Groundwater provides an important back up to public water supplies, particularly during dry years when river abstraction is restricted. Despite this, relatively little is known about the overall renewable resource potential of the aquifer. It is also only in recent years that means of safeguarding groundwater from pollution have been investigated in any detail. Renewed interest in the aquifer is now being driven on two fronts. The first is that the East of Scotland Water Authority (ESWA) needs to expand its source provision due to increasing demand. The second is that the Scottish Environment Protection Agency (SEPA) needs to look more closely at the aquifer potential if in the future groundwater abstraction licensing is introduced in significant aquifers (Robins and Ball, 1998). In addition, the requirements of the proposed EU Water Framework Directive indicate that a greater understanding of the aquifer and the sources it supplies will be needed in order to implement properly integrated surface and groundwater management on a catchment basis. With these goals in mind, the East of Scotland Water Authority, Scottish Environment Protection Agency and NERC have jointly commissioned this preliminary study of the Eden valley aquifer