Groundwater monitoring can be understood as a continuous, methodologically and technically standardised programme of observations, measurements and analysis of selected physical, chemical and biological variables of groundwater. Its objectives are: 1/ to collect, process and evaluate groundwater quantity and quality data as a baseline for assessing the current status and forecasting trends in groundwater in time and space due to natural processes and human impacts; 2/ to provide data and information for planning, policy and management of groundwater resource protection and
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Figure 6.7. The influence of hydraulic short cuts (A) upstream of and (B) downstream from the production well with groundwater extraction at 225–275m depth. Shallow groundwater:
red, deep groundwater: blue; transition: yellow/green. Abstraction rate: 20% of groundwater recharge over a period of 30 years.
conservation; to address groundwater quality and quantity problems in relation to economic development and social and ecological needs, as well as to timely identify and to give advance warning of a disaster impact on groundwater supplies.
The objectives of each monitoring programme govern the extent of monitoring activities, such as the design of monitoring networks, the construction of monitoring wells, methods and frequency of measurement and sampling and the number of variables to be analysed. Clearly defined objectives of groundwater monitoring are essential to achieve the expected results. A groundwater monitoring programme is an important component of groundwater protection policy.
A groundwater monitoring programme is an important component of groundwater protection policy.
Monitoring of groundwater quantity and quality and collection and assessment of monitoring data help to clarify and analyse the potential risk and impact of disasters on groundwater systems and to formulate groundwater protection policy and management of emergency groundwater resources in areas affected by natural disasters. However, existing groundwater monitoring programmes are mostly concerned with the identification and control of the consequences of the impacts on groundwater and do not address preventive groundwater protection measures. The establishment and operation of site-specific and early warning groundwater monitoring programmes in disaster prone areas is therefore needed, to detect disaster impacts, particularly pollution, in the unsaturated zone before the aquifer is affected. Such monitoring strategy assists in the timely identification of natural or human impacts on a groundwater system while they are still controllable and manageable; also to better understand and predict processes leading to groundwater deterioration. Such a strategy also supports assessing risks to groundwater and designating effective groundwater preventive protection policy (Vrba and Adams, 2008).
The design of site-specific groundwater monitoring networks is predicated on the origin and risk of natural disasters, human impacts on groundwater, aquifer vulnerability and related time needed to take appropriate action with respect to the potential groundwater problem. They also control construction of monitoring wells – particularly the installation of well screens, selection and placement of monitoring devices, the frequency of groundwater measurements and sampling and the range of variables analysed.
Early warning monitoring allows one to identify and foresee the outcome of a process leading to groundwater deterioration both in quality and quantity, with enough leeway to put in place measures to mitigate the magnitude of the risk posed to groundwater by pollution still in the unsaturated zone.
The design of an early warning monitoring programme and selection of variables observed, therefore, depend on the time needed to take appropriate action with respect to the specifics of the impact of a disaster on groundwater.
There are differences between early warning and site-specific monitoring of shallow water table aquifers and deep, mostly confined, aquifers.
In shallow water table aquifersmonitoring of the unsaturated zone with respect to its ability to store, retain and attenuate the pollutants and delay their vertical downward influx to the saturated zone, is a crucial tool for protection and risk management of shallow aquifers in floodplains, coastal areas and river deltas. Such areas are often repeatedly affected by flood, tsunami and storm events producing groundwater salinity and other pollution problems. Protection of vulnerable shallow aquifers which contain groundwater with brief residence times and a rapid response to natural and human stresses require the operation of monitoring networks with specially designed monitoring wells that allow vertical profiling of both the unsaturated and saturated zone. Shallow aquifers rarely are a safe source of drinking water for emergency situations. On the other hand, they are technically and economically accessible by shallow wells and are developed for numerous domestic and public water supplies,
particularly in developing countries. To protect water supply wells against structural damage and pollution in a disaster and the need to rehabilitate their function as soon as possible after the event requires the formulation of protective measures in the preparedness and warning phases of the potential disaster (see chapter 7). Monitoring programmes linked with other protection activities such as hydrogeological and vulnerability mapping, delineation of inundation and other risk zones, inventorising and mapping existing water supply wells, drilling of new emergency wells, the appointment of emergency governance policy and community involvement and active participation are the basic activities which effectively support protection policy and management of such shallow groundwater supplies.
In contrast, deep, often confined aquiferswith a delayed hydraulic and quality response to natural and human impacts are usually a safe source of drinking water for emergency supplies. Groundwater exploitation of these aquifers should consider the transient hydraulic responses of deep groundwater systems to the changes in hydraulic boundary conditions as is described in greater detail above. To secure emergency groundwater resources protection site-specific monitoring programmes have to be combined with early warning monitoring such as proposed by Małoszewski et al. (1990), Ghergut et al.
(2001), and Vrba and Adams (2002). Monitoring of deep confined aquifers is focused on the timely identification of potential vertical downward or upward migration of pollutants and their lateral movement in the aquifer. The target zones for site-specific and early warning monitoring of deep aquifers are their recharge areas, associated surface water bodies interacting with the groundwater system, and other vulnerable areas of the aquifer e.g. vertical downward or upward influx from the overlying or underlying aquifers owing to fracturing in tectonically active zone. In these areas the operation of monitoring networks based on regular groundwater level measurements and sampling, analysis of basic chemical components and analysis of non-reactive environmental tracers (radioactive and stable isotopes, chloride) help to define the origin and age of groundwater and the groundwater flow net. The assessment of such data supports the establishment of a conceptual model or recalibration of a mathematical model. This allows for enhancing the predictability of pollution impact on emergency water supplies and formulating or modifying groundwater management strategies for a more efficient groundwater protection policy. As explained above, many runs of numerical models with different initial intrinsic and boundary conditions and different intrinsic parameters, show that the transient hydraulic behaviour of deep, emergency groundwater may retard the ingress of pollutants by decades or even centuries.
Monitoring and early detection of incipient pollutant fluxes in groundwater recharge areas, in the unsaturated zone and groundwater table before they are diluted in the aquifer, gives ample time for implementing protective and management measures before massive groundwater pollution can occur.
This stresses the importance of operation site-specific monitoring programmes.
For monitoring the vertical profile of the unsaturated zone sampling from lysimeters, extraction of interstitial water from core samples, suction caps, direct push sediment sampling are some of the available monitoring methods. These methods, in combination with soil gas monitoring and remote sensing (photographic imaging, geobotanical) methods facilitate early detection of groundwater quality problems and timely implementation of protective measures.
In the saturated zoneof the aquifer, various monitoring and sampling techniques may be employed depending on the nature of the disaster and its potential impact on the groundwater system. Such methods may employ horizontal monitoring wells, groups of monitoring wells each with a single screened segment in different depths, a nest of small diameter piezometers extending to different depths inside a monitoring well, the installation of multi-layered samplers, applying packer or separation pumping techniques, sampling under anaerobic conditions using a suction or the direct push sampling techniques.
Satellite techniquesprovide spatially and temporally coherent data and rapid coverage of large areas
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and have become an effective tool in groundwater monitoring and groundwater protection policy.
However, the spatial resolution and lower accuracy of satellite-based measurements, including the most promising gravimetric and radar altimetry methods, do not as yet provide sufficiently accurate data for evaluating groundwater level changes and storage. Space-based data therefore have to be calibrated and validated through data acquired from insitu observations in monitoring wells or other ground -water monitoring points.
Various international satellite based programmes (e.g. WHYCOS – World Hydrological Cycle Observ -ing Programme, IGWCO – Integrated Water Cycle Observation, IGOS – Integrat-ing Global Observ-ing System, GRACE – Gravity Recovery and Climate Experience, GOCE Gravity Field and Steady–State Ocean Circulation Explorer) provide spatially and temporally coherent data at the global and regional level and a view of major elements defining the water cycle independent of political boundaries. With respect to groundwater the most promising is the GRACE mission implemented particularly in studies focused on the assessment of variations in groundwater storage and their comparison with groundwater level changes measured in monitoring wells. Low spatial and temporal resolution results in an uncertainty in groundwater level measurements in the order of tens centimetres for aquifers with spatial extent lower than 200,000 km2. Satellite images of topography, geology, vegetation cover, land use and soil type, however, provide useful data for protection of emergency groundwater resources, particularly for delineation of inundation and recharge areas, location of paleochannels, underground buried streams and hydrogeologically important tectonic structures.
In areas prone to droughtgroundwater monitoring is directed to measurements of groundwater level and quality and isotopic composition. In areas affected by storms, floods and tsunamis groundwater level measurements and groundwater salinity (Cl, conductivity) monitoring is usually applied in coastal aquifers. Vertical multi-layer hydrochemical profiling of coastal aquifers helps to control the fresh water-salt water interface and manage sustainable groundwater pumping. In shallow water table aquifers in flood-prone areas often used for drinking water supplies groundwater level measurements and groundwater chemical analysis on drinking water standard level is usually applied.
Groundwater monitoring and early warning in areas affected by volcanic activity, earthquakes and landslides requires specific approaches in selecting monitoring variables, in particular groundwater quality variables. In volcanic areas groundwater temperature, turbidity and chemistry (Cl, HCO3, SO4, conductivity, pH), isotopic composition, dissolved gasses (Rn, CO2, He) as well as groundwater level measurements are the main variables observed. Groundwater monitoring in earthquake proneareas is directed at the measurement of groundwater level, spring discharge, groundwater environmental tracers, temperature, turbidity and chemistry mainly pH, SO4, Cl. Groundwater level and pressure are the leading variables which have to be carefully monitored in landslide prone areas as they have a direct bearing on landslide stability.
Site-specific and early warning groundwater monitoring is technically demanding, time consuming, and costly. However, with growing reliance on groundwater and natural and man-made impacts, threats to this resource are increasing. Establishing and operating specific and early warning monitoring networks is therefore justified socially, economically and environmentally. Governmental institutions, water stakeholders and local communities in many countries may not yet be prepared to accept the need to implement groundwater monitoring programmes. However, the reality in the field and the restoration costs of affected aquifers suggest that site-specific and early warning monitoring may be an important cost-benefit approach for preserving and protecting groundwater as a strategic source of drinking water particularly in emergency situations. Evaluated credible, and consistent groundwater monitoring data should be available and readily accessible to decision and policy makers, planners, regulators, managers, rescue teams and local governments and communities. Such data enables the forecast of disaster potential impact and mitigation of disaster risk and enhances management and protection policy of emergency groundwater resources in areas repeatedly affected by natural disasters.
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Introduction
There is no internationally agreed definition of water governance. However, it is widely accepted that it can be effective when it involves society as a whole and is not the exclusive domain of governments (Pierre, 2000). Generally, governance is based on multilevel and trans-sectoral approaches and activities and includes governmental authorities at all levels, the private sector, various civil society groups and communities. Effective water governance relies on catchment-based integrated water resources management (IWRM).
Several attributes of water governance stated in Agenda 21 (1992) are based on dynamic, interactive, iterative and multi-sectoral approaches, integration of all water users, strengthening of institutional structures and on the reform of water laws.
The Second World Water Forum held in the Hague in 2000 identified water governance as one of the key challenges and expressed the need to govern water wisely and involve the public and other water stakeholders in the governance policy.
The following criteria for effective water governance have been specified in the World Water Development Report I (2003):
• participation of all citizens directly or through intermediate organizations representing their interests and throughout the processes of policy and decision-making,
• transparency in the free flow of information within a society,
• opportunities for all groups in society to improve their well-being,
• accountability of governments, the private sector and civil society organizations to the public or the interests they represent,
• coherent, consistent and easily understood water policy and associated actions,
• institutions and processes should serve all stakeholders and respond properly to changes in demand and preferences, or to other, changed circumstances,
• water governance should enhance and promote integrated and holistic approaches,
• ethical principles of societies and their traditional water rights have to be respected.