Urban Groundwater Management and Sustainability

Urbanization modifies underlying groundwater systems. This may lead to adverse hydrological, water quality, geotechnical, or socio-economic effects, jeopardizing sustainability. To avoid these effects, management is required irrespective of whether the groundwater is to be used or not. This management must be based on a sound technical understanding of the interacting processes involved. The papers in the present volume explore the state of this understanding in the context of a wide range of countries, climates, and geologies.

Urban water supply problems are not limited to depletion of reserves, but include issues such as surface and groundwater contamination, deterioration of distribution systems, water table rise or decline, landslides, land subsidence, and increased seismic hazard. These problems often have social implications that can lead to serious economic damage. Analysis of the situation associated with the use and protection of urban groundwater in Azerbaijan, and of the Absheron peninsula in particular (where in our view there are major issues to be resolved), suggests that special approaches are necessary within urban hydrogeology. Evaluation of both static and time variant factors has allowed the setting up of a hydrogeological zoning system which has been trialled in the Absheron Peninsula, with encouraging results. It is hoped that this approach will form a sound basis for prognostic evaluation in urban areas elsewhere.

The historical development of water supply sources for the populations of Baku and the Absheron peninsula are described and their water-quality status indicated. The area is an intensely populated part of Azerbaijan subject to the pressures of the urbanization and increasing population densities. As such there are significant pressures on existing water resources and a need to identify supplementary supplies from groundwater sources. It is proposed that future supplies should come from the good quality groundwaters within the Quaternary deposits of the Greater Caucasus foothills of the Samur- Devechi plain. A further possible supply is from the Ganyh-Agrichai Plain.

Azerbaijan’s environment is under pressure. Flooding from irrigation canal leakage, irrigation return, blocked drainage systems, and leaking water pipes / sewers are the most significant problems. Associated phenomena include groundwater level rise, salinization, and fertilizer contamination. Since the start of the Samur-Absheron irrigation canal project, groundwater level has risen by up to 20 m. Rise in Caspian Sea level has also caused flooding. Landslides are triggered by slope erosion, irrigation, engineering works, and increased loading. Soil contamination is a major problem in the oilfields of the Absheron Peninsula. Mud volcanoes, deflation, internal erosion, and abrasion are widely developed. This evaluation marks the start of a geoenvironmental monitoring project within the Republic.

This paper focuses on the reasons underlying the continuing derogation of surface-water quality in Azerbaijan. Surface (river) water has been one of the main sources of fresh water. The major river systems used have their sources in neighbouring countries. There is, however, proven advantage of utilizing groundwater rather than surface water as a supply source for urbanized territories in Azerbaijan. The overarching reason being the greater natural protection of groundwaters from pollution relative to surface waters. An overview of water resources present and contamination problems observed is presented. A case for increased groundwater supply in Azerbaijan is presented as a solution to these challenging problems.

The discovery of new water sources, including groundwater, acquires great importance in states with a deficit of general water resources. This paper examines the scientific and technical aspects of evaluating the resources of hydrogeological structures, such as the alluvial cone deposits present in some mountain rivers, in the context of Azerbaijan. It also investigates the feasibility of diverting some of the sources of fresh groundwater in the Ganja and Agrichai regions, with the aim of providing a centralized water supply to all cities within the Republic.

Groundwater pollution in Turkey is examined. Important natural sources of groundwater pollution identified include seawater intrusion, discharges from contaminated lakes and streams, geothermal waters, and dissolution of minerals. The major sources of anthropogenic groundwater contamination identified are: agricultural pesticides and fertilizers; mining waste products; industrial waste; on–site septic tank systems; and pollution from poorly constructed wells. Although industrial waste and on–site septic tanks are important sources of anthropogenic pollution, because agricultural activities are very significant contributors to the Turkish economy, pollution from pesticides and fertilizers poses the larger threat.

The sustainability of the clastic Tertiary aquifers supplying the Corlu region of Turkey has been examined. It is found that: (i) with recharge of 194 million m

3/

year and abstraction of 271 million m

3

/year, groundwater levels are declining annually by about 1 m; (ii) serious pollution has not been recorded in the region, and groundwater quality is satisfactory for industrial applications at least. Water quality is therefore less of a concern than water quantity. The latter, however, requires active intervention.

This study examines the effects of rapidly increasing industrial activities on groundwater levels in the Trakya Region of Turkey where groundwater is the main resource for industrial, agricultural, and domestic water supply. The Ergene River Basin (11,325 km

2

) is the most important catchment, around half of which is underlain by the unconfined 600 m thick Çorlu/Ergene aquifer of Miocene / Pliocene age. Using water-table monitoring data from 13 monitoring wells the relation between potential pumping and water table fluctuation was evaluated. The average aquifer reserve and the total discharge of the area per year were determined as 340 and 460 Mm

3

respectively. The annual recharge was calculated as 123 Mm

3

. The results show that the total amount of discharge (outflow + withdrawal) is much higher than the groundwater recharge, i.e. the system is not sustainable.

Romania is the beneficiary of an important complex of water resources. The underground waters are estimated to contain about 9.6 x 10

9

m

3

as a resource that can be exploited, such that supply is greater than demand. However, as various forms of water pollution are present in Romania, some sources of water have become unusable, giving the demand/supply ratio a more complex significance. Generally, fertilizers, livestock industry waste, and household effluents can be regarded as the main sources of groundwater pollution by nitrate. The Romanian environmental authorities have established provisional guidelines concerning the controls on discharge of three substances, including trichloroethene. The principles for the sustainable management of water resources, recommended at the Rio de Janeiro Conference (1992), also lie at the foundation of the concept of integrated water management in Romania, where the problems of water usage have to be balanced with the need to protect natural ecosystems.

This paper describes the application of integrated surface-groundwater (ISGW) models in regard to the planning of urban water supplies, basin water management, sustainability of natural resources, and ecosystem preservation. A brief description of the integrated models is provided to illustrate their flexibility in assessing various schemes used in the management of urban water supply systems and basin water resources. A more detailed discussion of one of the most functional and widely used integrated models (MIKE SHE) and its applications at a rapidly urbanizing site in southwest Florida is also presented.

Quantifying evapotranspiration (ET) rates in urban environments is paramount for understanding and modeling other hydrologic fluxes such as runoff and recharge. Large impermeable fractions of land in urban areas may only experience evaporation following rainfall events. Pervious fractions are believed to support most of the ET burden. Point measurements of land-cover ET in pervious areas can provide better estimates of the overall urban ET budget. These can be made by examining changes in the total soil moisture above the seasonal low water table or the ET extinction depth. Soil moisture can be determined by summing the average soil moisture content measured at various depths with capacitance sensors on a vertical probe. Graphs of total soil moisture above the water table for a riparian area in west-central Florida display two distinct slopes, a flattened slope during the overnight period and a steeper slope between approximately 9:00 am and 6:00 pm. The overnight slope is believed to correspond to a process removing moisture continually from the soil, such as gravity drainage. The daylight portion of the slope corresponds to ET plus the continuing downward gravity drainage. Daylight ET is the cause of the difference between the two slopes. Different plant communities exhibit measurably different ET rates and can be estimated using this methodology.

Reliance on vadose zone models to estimate groundwater recharge in arid and semiarid regions of the United States is increasing due to limited groundwater supplies and continued urbanization. The success of vadose zone models in providing reliable estimates of urban recharge and other fluxes depends on the information content used to constrain the calibration process. In this study, a numerical experiment of artificial recharge through a three-layered vadose zone system revealed several findings related to coupled model calibration. First, the extension of vadose zone model calibration to three dependent variables added information content that enhanced parameter sensitivities. Second, predictive analysis using the calibration-constrained Monte Carlo approach was time-prohibitive because of the tendency toward local minima when using the gradient algorithm. Third, despite a perfect match to historical data, the affect of alternative starting calibration parameters sets on condition number illustrated the limitations of information quality on model uncertainty. Fourth, perfect observed / simulated profiles correlation coefficients for all calibration parameter sets, were, by themselves, poor indicators of model success. Fifth, the range of predictive recharge uncertainty, and uncertainty in energy and solute mass entering the groundwater system, estimated using the likelihood-type approach, is attributed to parameter non-uniqueness due to limited calibration information. For a calibration of a field system, the estimated range of predictive uncertainty would be larger because of additional uncertainty from errors in measurements and/or the conceptual model.

The town of Domodedovo, Russia, is used here as a case study to test a recently developed flow structure modelling method for the delineation of urban well-field capture zones. A three-dimensional capture zone was determined for the well fields used for the town’s water supply. Significant differences in the size of the capture zone intersecting the ground surface and the size of the entire sub-surface capture zone projection were found, suggesting that accurate understanding and prediction of contaminant movement within urban systems cannot ignore the third dimension. The modelling procedure used here performed well.

Leaky sewers have to be considered as potential sources for groundwater contamination in urban areas. The medium-sized city of Rastatt in SWGermany with 50,000 inhabitants was subject of a series of investigations on sewer leakage which are summarized and discussed in this paper. Amongst others factors, the degree of pollution depends on the chemical composition of the wastewater and the amount of exfiltration. The groundwater underneath the city area showed anthropogenic influence resulting in elevated concentrations especially of boron, potassium and sodium as well as a generally increased electrical conductivity. Groundwater in the close vicinity of broken sewers showed typical sewage indicators such as iodated X-ray contrast media and microbiological parameters. Contamination with pharmaceutical residues and gadolinium could not be found in groundwater, despite significant concentrations of pharmaceuticals in wastewater. In autumn, the contents of boron and microbiological pollution were higher than in spring, indicating a higher ratio of wastewater in groundwater during times of less natural recharge. Groundwater monitoring wells near prominent leaks showed short-time fluctuations of EC and groundwater levels which could be correlated to changes of the wastewater composition and the flow regime in the pipe.

Oslo Airport is located on a large unconfined aquifer. It follows strict governmental regulations regarding spills of de-icing chemicals. During winter, de-icing of aeroplanes and runways is necessary for safety reasons: propylene glycol (aeroplanes) and potassium formate (runways) are used. During melts releases to the subsurface may potentially occur. The Pollution Control Authority allows Oslo Airport to use the unsaturated zone for remediation. Biodegradation potential although significant is strongly dependent on retention time. If necessary, pump & treat is implemented. Chemical analyses of the groundwater demonstrate capacity for microbial biodegradation. Locally this sometimes changes the composition of inorganic compounds in the groundwater. A simple box-model was created to estimate oxidation potential in the groundwater. The model indicates that the degradation potential is exceeded west of the western runway, but this is not supported by chemical analyses. Estimates of spatial distribution zones of electron-acceptors and estimates of physical spread of contamination and its residues are not fully supported by the box-model.

Clay units have often been assumed to provide good protection for underlying aquifers from contamination. This assumption, however, is rarely proved. The capacity of clays to resist contaminant invasion in urban areas is of significant interest, especially where underlying aquifers are used for supply. We report the initial findings of an on-going field study to investigate organic contaminant penetration of clay strata below a former petrochemical site in the UK. The clay is a thin, relatively continuous unit 6- 7.5m below ground surface within a shallow sandy aquifer contaminated with aromatic hydrocarbons (benzene, toluene, ethylbenzene, and styrene). Concentration/ depth profiles were obtained from cores at four locations and demonstrated transport of aromatic hydrocarbons into the clays with significant penetration in places. Preliminary modelling suggests that the clay penetration cannot always be explained by simple diffusion; advective transport through preferential pathways appears probable. Clay thin sections indicate the presence of palaeo-root holes and worm burrows. These potentially explain the enhanced solute penetration, and suggest that the presence of unconformities should be considered when assessing the protection afforded by thin clay beds.

A study of baseline groundwater chemistry has been carried out in the pristine areas around Eastern Shores, Lake St Lucia, North-eastern South Africa. The study aims to provide a quality baseline against which anthropogenic (urban) impacts elsewhere may be evaluated. In general, groundwater in the Eastern Shores region is of low conductivity, and a vital freshwater source to both Eastern Shores and Lake St Lucia itself. Two distinct groundwater types are recognized in the aquifer, one dominated by sodium and chloride and the other by calcium and bicarbonate. The two are spatially distinct, corresponding to separate groundwater mounds. Variation in electrical conductivity is thought to be related to evapotranspiration. The study provides valuable background data on coastal aquifer natural quality and a suitable baseline to judge impacts upon that aquifer, both from historic and future urbanization.

This investigation of urban groundwater problems in the city of Évora is one of the first in Portugal, its main objective being to develop a hydrochemical knowledge of the city’s groundwater. Thirteen water points, represented by 7 large diameter wells and 6 deep wells, were selected for sampling. The major ions were analysed, as well as temperature, EC, pH and total hardness. The results show that most of the waters are HCO

3

-Mg-Ca-Na type, but some of the samples are Cl in type and one is clearly Cl-Na in type. The EC varies between 230 and 2500 μS/cm. The nitrate content varies between 0.5 and 310 mg/L, but over 50 % of the samples exceed the 25 mg/L maximum recommended by Portuguese Law. The absolute permitted maximum of 50 mg/L is also exceeded in 30 % of the samples. When compared with water quality elsewhere in Alentejo, the results are clearly high in terms of EC, nitrates and chlorides. The high content of nitrates and chlorides may be an indication of urban contamination.

This paper examines the issue of radioactivity within urban groundwater systems in Russia. Since the atomic industry began, the enterprises associated with different elements of the nuclear fuel cycle have become industrially advanced and helped drive the development of satellite cities. However, the groundwater systems of these cities were affected, especially in terms of water balance and quality. Radioactivity as a specific contaminant is a source of concern for both the public and scientists. This paper examines data concerning radioactive pollution produced by nuclear power plants, research reactors, and the Chernobyl accidents. The main conclusion is that radiation pollution is much less of a risk to the health of the Russian population than social and economic factors.

Poorly regulated landfill disposal is a worldwide problem. This study aimed to assess the risks posed by unsanitary landfill leachates to groundwater quality. The case study presented examines the town of Çorlu in the Tekirdağ Province of Turkey, where various types of waste are disposed into unsanitary landfill sites without any separation or classification of hazardous and non-hazardous waste. The leachate from unsanitary landfill in Çorlu has complex characteristics that are dependent on the composition of solid waste in the landfill. Contamination risks posed to groundwater vary and depend upon the quantity of leachate generated (in this case ~13 m

3

/day) and its specific physico-chemical characteristics. Considerable public attention has recently been focused on the environmental and potential human health risks of unsanitary landfill in Çorlu. The potential risk of leachate contamination of groundwater resources in Çorlu Town is assessed from waste quality, soil characteristics and leachate composition data. General recommendations to facilitate improved future protection of groundwater quality are indicated.

Assessment and mapping of groundwater vulnerability remains foundational to the effective protection of groundwater resources. A combined approach for assessing the vulnerability of groundwater to different types of contamination is suggested. Preliminary results of a groundwater vulnerability assessment for one of the most hazardous pollutants, the organochlorine pesticide lindane, are given. These calculations were based on typical piedmont territory in the Caucasus Mineral Water region, which is characterized by complicated geological and hydrogeological conditions.

Azerbaijan is rich in oil and gas, deposits of various minerals, and mineral waters. Thermomineral waters, present in 5 regions, are very important economically: their occurrence, properties, and environmental impacts are reviewed. Overall, it is concluded that Azerbaijan has a very considerable potential for further development of its thermal waters; although this development will necessitate care if environmental problems are to be avoided, its use could save about 1.5 million tonnes of conventional fuel every year.

To prove the hydraulic connection between the urban Rózsadomb recharge area (Buda Thermal Karst System, Budapest, Hungary) – through its hydrothermal inactive caves – and the springs at the foothills has been an important question since the 1980s. These cold and lukewarm springs have been utilized as thermal baths since Roman times, and in modern times, occasionally, chemical and bacterial contaminants of human origin have been detected in them. It is hence of considerable importance to know whether these contaminants originated from the Rózsadomb recharge area or from close to the discharge points. According to the results of a previous test in a cave passage high upon the hill, it was tempting to suppose direct connection between the Rózsadomb area and the Boltív Spring in the foothills. The expected breakthrough-time predicted from this previous study was between 10 hours and 42 days. The tracer test documented in this present work showed that no breakthrough occurred. It is proposed therefore that the risk of the Boltív Spring being contaminated by infiltration in the Rózsadomb recharge area is low as compared with the possible contamination from sources near the discharge area. We suggest that in this case the negative tracer test clearly helped to prove and to understand better the role of “natural attenuation” in the Rózsadomb area. The efficient dilution observed in the tracer test facilitated the prediction of a hitherto unknown, large, phreatic cave-system as well.

Monitoring of urban aquifers has highlighted faecal contamination in both developed (UK) and developing (Mozambique) country settings. This has underlined gaps in our knowledge of not only the flux of contaminants through the complex urban water system but also the fate and transport of pathogens once in the subsurface. Research aiming to achieve a better understanding of these issues is described here along with potential management strategies looking at water reuse in urban areas.

In May 2000, the town of Walkerton, Ontario suffered one of Canada’s worst outbreaks of waterborne disease. In the final toll, 2,300 people became ill and seven people died. The principal pathogens were

Escherichia coli

O157:H7 and

Campylobacter jejuni

, both found in the town’s municipal well-water supply. The outbreak sparked intensive hydrogeological investigations and a nine-month long independent commission of inquiry. Two reports were issued. Part 1 focused on Walkerton and identified a cattle farm adjacent to the primary pumping well as the most probable cause of the outbreak. Part 2 delved deeply into all aspects of water supply in the Province and documented 93 commission recommendations concerning the Province-wide delivery of safe drinking water. The very first recommendation highlighted the need for adequate groundwater management and protection. To its credit, the government responded well to many of the issues raised, mostly as they relate to infrastructure, the operation of municipal water sources, the training of operators and data collection. However, from a hydrogeological perspective, the government’s response has been disappointing, particularly with regard to its prescribed methodologies for groundwater protection. A program for mapping groundwater vulnerability and wellhead protection areas was hastily assembled following the Walkerton outbreak but is seriously under-funded, piece-meal in approach, and in several cases scientifically ill-conceived. Ultimately, there are no simple solutions and no easy short cuts, and the successful implementation of groundwater protection measures in Ontario will demand a serious commitment of funds and resources to advance significantly our basic understanding of the Province’s groundwater resources and provide key input data.

Urban groundwater is commonly recharged artificially by stormwater runoff. This paper focuses on the effects of artificial stormwater infiltration on groundwater ecosystems using data from a specific study site. It is demonstrated that at this site artificial stormwater infiltration increased local fluxes of organic matter into the groundwater ecosystems. An insufficient residence time of stormwater in the vadose zone resulted in organic matter reaching the water table and subsequent oxygen consumption. The invertebrate assemblages in the underlying urban groundwater system were enhanced, probably because organic matter enrichment stimulated microbial production. Thus, urban groundwater biodiversity was higher under stormwater infiltration basins for shallow water-table conditions. Furthermore, groundwater biodiversity peaked at the water table, and decreased with depth. Invertebrate assemblage composition showed a vertical shift with depth below the water table, thereby suggesting that competition processes occur among taxa. This work highlights interesting ecological issues in groundwater and provides several recommendations for urban stormwater management.

The historical development and current status of groundwater organic contaminant remediation is reviewed. Such development awareness underpins effective implementation of current and future remediation strategies. Significant remediation has been attempted since the 1980s with the US initially pre-eminent following a widespread programme of pumpand- treat that later developed to more innovative

in situ

technologies aimed at accelerating source mass removal or control. The emergence of the NAPL (non-aqueous phase liquid) paradigm in the 1980s was critical to both understanding the failings of pump-and-treat and later remediation strategies that recognized the importance of separate remedial strategies for source and dissolved plume zones. A plethora of

in situ

technologies have emerged over the past two decades or so including vapour-based methods, enhanced mass removal chemical-based methods, monitored and enhanced natural attenuation (bioremediation) and more passive technologies such as permeable reactive barriers. A summary of remediation issues is presented that requires on-going consideration for remediation efforts to remain central to the sustainable management of urban groundwater resources.

Groundwater protection and pollution prevention must be based on an integrated and conclusive protection and safety philosophy. Out of this philosophy a uniquely integrated concept for protection standards can be developed and implemented into technical and legal standards. State-of-the-art technical standards and regulations for the storage and handling of hazardous material, as well as state-of-the-art groundwater protection, have to refer to the complete spectrum of physical, chemical and biological properties of potential contaminants. Hydrogeologists have to integrate the latest research results and developments of material science, chemistry, physics, biology and the life sciences into their conceptual models and must even include the “green technologies” which start to produce new underestimated hazards. Remediation of soil and groundwater contamination can only be successful, if all the aspects of science and technology are professionally integrated in the planning of the remediation process. In most pollution cases only a well-balanced combination of various methods can guarantee a successful remediation, depending on the geological conditions, the specific properties of the aquifer itself and the extent of the contamination. Finally transboundary aquifers and rivers and the development of international public utility companies urge hydrogeologists to work together on an international basis for the solution of common problems.

Results are presented of an experimental study of bacterial leaching of tailings and wastes from mining industry enterprises. From the examples of Chiatura city and the industrial centre of Kazreti, it is shown that use of the suggested method for the leaching of ores can reduce significantly the pollution risk to water and soils in urban areas. The method also promotes both the improvement of the ecological system in general, and a more rational use of natural resources.

A water-saturated biological denitrification system was employed to remove selected pesticides and nitrate from drinking waters. In the study, approximately 99% nitrate removal was observed, but most of the samples included nitrite. Up to 95% removal of pesticides was also observed. The lowest removal efficiency of nitrate (63%) was observed when the temperature dropped sharply from 18 °C to 14 °C. Despite such oscillations, high removal efficiencies for trifluralin, fenitrothion and endosulfan (α+ β) were observed and the highest nitrite concentration was 16 mg/l in the effluent of the reactor.

The Tbilisi reservoir (Georgia) represents an important water supply for the city of Tbilisi, but has suffered considerable problems over the past 50 years. Initially the problems related to leakage of stored water via the schistose bedrock. It contains soluble gypsum and is highly sensitive to particulate removal by the process of suffusion. To some extent the leakage problems were ameliorated by the construction of vertical grout curtains but they have never been fully resolved. In recent times, an additional problem has appeared related to the inflow of saline groundwater from the bedrock host during times when reservoir levels are low. This groundwater locally contains as much as 16,000 mg/l total dissolved solids due primarily to gypsum dissolution. This release of groundwater to the reservoir has impaired reservoir water quality, increasing total dissolved solids from about 250 mg/l in 1988 to almost 500 mg/l in 2002. This has important implications for the long-term viability of the reservoir as a supply of potable water for the city.

Buildings in the Varkethili ‘Sleeping District’ of Tbilisi are often affected by subsidence. They are underlain by the extensive third left bank terrace of the River Mtkvari, formed by products of erosion of the flat-lying slopes above and cut by natural drainage channels. Geotechnical and chemical analyses of the sediments suggests that the main reasons for subsidence are chemical and pore water pressure changes in the reactive sediments brought about in part by changes in the recharge regime which in turn was the result of urbanization.

Bridging the gap between a need for preserving unique historic cities and a requirement for modern infrastructure development is one of the major challenges for sustainability of urban areas. Many historic cities around the world have complicated ground conditions, commonly represented by weak soils and a high groundwater table. Natural, or historically formed, hydrogeological conditions need to be maintained carefully in such ground conditions, since even insignificant variations of groundwater level and gradient may affect valuable historic buildings. This paper discusses an integrated evaluation program for the assessment of causes and consequences of variations in hydrogeological parameters within urban historic environments. An analytical quantitative method based on hierarchy structures is used for the program. Some examples of the potential use of the assessment program in Hamburg and St.Petersburg are given.

Investigations were carried out on hydrothermal resource exploitation in the Tbilisi hydrothermal reservoir, Georgia, using a multidisciplinary approach involving geophysical, geological, and hydrogeological techniques. Highresolution monitoring of temperature and pressure in several boreholes was carried out over a long period of time using an innovative geophysical tool. The system was numerically modelled, being calibrated against both the hydraulic and thermal monitoring data. It was found that the oil and thermal fields are connected hydraulically, that the thermal resource is of the order of 2-4 x 10

4

m

3

/day, and that the hydraulic system responds to the stresses associated with seismic events.

In a number of cities in Uzbekistan, infiltration from irrigation and surface drainage structures, leakage from water supply pipelines and sewers, and discharges of waste water all contribute to rising groundwater levels. To prevent damage to buildings, well fields have been installed to act as vertical drainage systems. These vertical drainage systems need to be managed properly if they are to achieve their purpose. This paper presents a calculation scheme for estimating the requirements for basic materials and other resources for urban areas where drainage by well systems is necessary. The scheme takes into account many different types of pumping failure, and is supported by empirical relationships developed from a large data set collected across the country. The principles of the approach could be adapted for other management issues concerned with urban water development.

This study describes the hydrogeological conditions of the coastal urban areas of Poti and Batumi, Georgia. A clear hydrogeological zonation can be mapped out. The hydrological influence of the rivers Rioni and Chorokhi on the environment of Poti and Batumi is evaluated. Infilling of the coastal zone with inert material has proven to be, and will remain, the most effective method of rehabilitation of the areas where coastal erosion is occurring.

Based on a literature review, the paper analyses groundwater management problems in the urban and the agricultural setting in the developing world. It is argued that in both settings groundwater rights can neither be established nor enforced. Groundwater rights are based on land rights and the economic capacity of the user to follow the falling groundwater table. The connection of groundwater access rights to land rights and economic capacity may cause social instability and could lead to further depletion of the resource.

This paper presents an economic approach towards urban groundwater in the context of a fast growing metropolis. It attempts to understand the current role of groundwater in the urban water supply for the city of Delhi, India, and proposes possible scenarios of future evolution. The main insight of this paper is that in spite of the public neglect of groundwater as a resource for urban water supply, groundwater plays a central role in meeting urban needs through a variety of private and uncontrolled systems. The potential role of these systems in the future and their impact on urban sustainability is questioned.

This paper concerns the bringing together of the science of hydrology and the socio-economics of water supply in order to deliver a high degree of human security to those people who have diminished, or complete loss of access to their water supply. Human security is measured in a number of ways, but one underlying factor for all humanity is access to adequate water (quality and quantity) at an affordable cost. In Azerbaijan there are over 50 secondary towns with populations in the range 10,000 - 100,000. While the larger towns had a well developed industrial and infrastructure base during the former Soviet Union, with its collapse and shut down of industry in the early 1990s, the town infrastructure has significantly deteriorated and water supply and sanitation systems are anticipated to collapse by the middle of this century. The situation in the smaller towns, where the economic base was more fragile, having been founded on agriculture and processing of agricultural products, the situation is no less dire. For a combined population of 1.45 million in secondary towns, the systems originally designed to a capacity of 179.6 Mm

3

/y, actually delivers only 48.2 Mm

3

/y. As a consequence, the population resident in these towns suffers considerable hardships incurring high personal costs, thus further impacting their incomes, and reinforcing widespread poverty. The water related health and environmental problems add to the burden, trapping some people into a vicious cycle of poverty.

While the public water supply organization Suvokava claims that there are no problems of public water supply to the urban households in the Khorezm province of Uzbekistan, water shortages occur, particularly during the summer. During this period, urban households utilize groundwater as an alternative source to the public water supply. The data suggest that there are two common pool resource problems: first, between the agricultural and the urban sector; and secondly between upstream and downstream cities.