INTERNATIONAL DECADE ON DRINKING WATER AND SANITATION1

ABSTRACT: The UN conference on Human Settlements (HABITAT) held in June 1976 at Vancouver, Canada, concluded that nearly two-thirds of the population of the developing world lacked access to safe drinking water and that a larger proportion lacked the means for hygienic human waste disposal. The conference urged governments to give priority to these two areas in their developement process. In March 1977, the UN Water Conference, held at Mar del Plata, Argentina, called for establishing the 1980's as the Decade for Drinking Water and Sanitation. The goal would be to bring clean water and sanitation to all peoples in the world by 1990. Since March 1979, four separate UN bodies have passed resolutions supporting the Decade and calling on all governments to support the Decade's goals. The U.S. Government, other OECD member states, and the private sector must combine to make this Decade a success.     

Local IWRM organizations for groundwater regulation: The experiences of the Aquifer Management Councils (COTAS) in Guanajuato, Mexico

Evidence of groundwater management by aquifer users emerging under Integrated Water Resources Management (IWRM) initiatives is presented, by analyzing the Consejos Técnicos de Aguas (COTAS; Technical Water Councils or Aquifer Management Councils) in the state of Guanajuato, Mexico, established between 1998 and 2000 by the Guanajuato State Water Commission (CEAG). Two contrasting models influenced this attempt to promote user self-regulation of groundwater extractions: locally autonomous aquifer organizations with powers to regulate groundwater extractions versus aquifer organizations with advisory powers only. The COTAS were conceived as locally autonomous IWRM organizations consisting of all aquifer users that would work together to reduce groundwater over-extraction and stabilize aquifer levels, at a later stage. CEAG followed an expedient IWRM approach to develop the COTAS, setting achievable targets for their development and explicitly focusing on active stakeholder participation. The article shows that, due to struggles between the state and federal levels, the COTAS have become advisory bodies that have not led to reductions in groundwater extractions. It concludes that achieving user self-regulation of groundwater extractions requires a fuller delegation of responsibilities to the COTAS which would not be possible without addressing the institutional struggles over water governance at the state and federal levels.     

Multi-Criteria Decision Analysis of Treated Wastewater Use for Agriculture in Water Deficit Regions1

Al-Juaidi, Ahmed E., Jagath J. Kaluarachchi, and Ungtae Kim, 2010. Multi-Criteria Decision Analysis of Treated Wastewater Use for Agriculture in Water Deficit Regions. Journal of the American Water Resources Association (JAWRA) 46(2):395-411. DOI: 10.1111/j.1752-1688.2009.00409.x Abstract: Coastal regions such as the Gaza Strip of Palestine with limited freshwater supply suffer significantly due to the rapid depletion of water levels, seawater intrusion, and increased water demands. In such regions, use of treated wastewater (TWW) is a viable option if public health issues are addressed. The goal of this paper is to address the use of TWW in agriculture while considering net benefit, economic efficiency of water use (EEWU), environmental goals, and public health risks. The proposed methodology considers public health risk assessment and multi-criteria decision analysis to assess the beneficial use of TWW in agriculture. The methodology was demonstrated for the Gaza Strip. The health risk assessment suggests that increasing the elapsed time between irrigation and consumption and switching from surface to sprinkler and drip irrigation are practical measures to reduce public health risks. The optimization and decision analyses show that proper allocation of freshwater and TWW and distribution of land area by crop type can significantly increase the net benefit and EEWU. In most cases, net benefit increased by 44%, groundwater use reduced 29% while increasing the EEWU by threefold compared with the existing conditions. The multi-criteria decision analysis with weighted goal programming can develop flexible management options that considers a given decision-maker preference. When groundwater abstraction for agriculture reduced from 57 to 36 Mm³ as per decision analysis, the corresponding area below mean sea level decreased by 58% indicating significant aquifer recovery.     

Parameter Uncertainty Reduction for SWAT Using Grace,Streamflow, and Groundwater Table Data for Lower Missouri River Basin1

Abstract: This study incorporates the newly available Gravity Recovery and Climate Experiment (GRACE) water storage data and water table data from well logs to reduce parameter uncertainty in Soil and Water Assessment Tool (SWAT) calibration using a SUFI2 (sequential uncertainty fitting) framework for the Lower Missouri River Basin. Model evaluations are performed in multiple stages using a multiobjective function consisting of multisite streamflow and GRACE water storage data as well as a groundwater component. Results show that (1) a model calibrated with both streamflow and GRACE data simultaneously can maintain the water balance for the whole basin, but may improperly partition surface flow and base flow. Additional inclusion of the groundwater constraint can significantly improve the model performance in groundwater hydrological processes. In our case, the estimation of specific yield of shallow aquifers has been increased to 10^?2 from previous much underestimated level (<10^?3). (2) The daily streamflow data are needed to confine the parameters related to water flow in channels such as the Manning’s coefficient, which are less sensitive to the monthly simulations. (3) Parameters are nonuniformly sensitive for different goal variables, and thus, proper specification of a prior distribution of parameters may be the key factor for global optimization algorithms to obtain stable and realistic model performance.     

Estimation of upper centile concentrations using historical atrazine monitoring data from community water systems

A survey sampling approach is presented for estimating upper centiles of aggregate distributions of surface water pesticide measurements obtained from datasets with large sample sizes but variable sampling frequency. It is applied to three atrazine monitoring programs of Community Water Systems (CWS) that used surface water as their drinking water source: the nationwide Safe Drinking Water Act (SDWA) data, the Syngenta Voluntary Monitoring Program (VMP), and the Atrazine Monitoring Program (AMP).The VMP/AMP CWS were selected on the basis of atrazine monitoring history (CWS having at least one annual average concentration from SDWA ≥ 1.6 ppb atrazine since 1997 in the AMP). Estimates of the raw water 95th, 99th, and 99.9th centile atrazine concentrations for the VMP/AMP CWS are 4.82, 11.85, and 34.00 ppb, respectively. The corresponding estimates are lower for the finished drinking water samples, with estimates of 2.75, 7.94, and 22.66 ppb, respectively. Finished water centile estimates for the VMP/AMP CWS using only the SDWA data for these sites are consistent with the results. Estimates are provided for the April through July period and for CWS based on surface water source type (static, flowing, or mixed). Requisite sample sizes are determined using statistical tolerance limits, relative SE, and the Woodruff interval sample size criterion. These analyses provide 99.9% confidence that the existing data include the 99.9th centile atrazine concentration for CWS raw and finished water in the Midwest atrazine high-use areas and in the nationwide SDWA dataset. The general validity of this approach is established by a simulation that shows estimates to be close to target quantities for weights based on sampling probabilities or time intervals between samples. Recommendations are given for suitable effective sample sizes to reliably determine interval estimates.     

Risk-based evaluation of Escherichia coli monitoring data from undisinfected drinking water

Drinking water regulations in the United States and elsewhere are based on the occurrence of fecal indicator bacteria. Though not meeting all the criteria of an ideal indicator, nonpathogenic strains of Escherichia coli (E. coli) are used worldwide as an indicator of potential fecal contamination for drinking water and for distribution systems. This is, in part, because real illnesses are related to human pathogens, such as E. coli O157:H7, whose presence may be predicted better by E. coli than by total coliform bacteria. Our objective was to estimate the number of E. coli O157:H7 illnesses attributable to drinking water exposures in the United States and the feasible relationships between positive occurrences of the indicator bacteria E. coli and E. coli O157:H7 in drinking water. Results of the modeling indicate that in undisinfected drinking water systems, the ratio of bacterial indicator E. coli positives to E. coli O157:H7 organisms is estimated to be between 6:1 and 90:1 with few model parameters accounting for the vast majority of the uncertainty. These results provide context for considering the potential public health implications of a positive E. coli result from routine monitoring of undisinfected drinking water.     

Mapping non-conventional atmospheric drinking-water harvesting opportunities in Central Eurasia: The case of Kazakhstan

Drinking water scarcity is becoming an urgent problem worldwide, and it affects developing and developed countries alike. Kazakhstan is not an exception and has its primary sources of drinking water (groundwater, rivers, and lakes) continuously depleted and polluted; moreover, the country will be close to its exploitation limits within the following decades. However, modern technologies allow us to harvest drinking water from unintegrated sources, like the atmosphere. Therefore, it is crucial to research which non-conventional technologies can be used to obtain drinking water from unintegrated sources for the country, considering the cost, viability of use through the year, and local climate conditions. Thus, the present assessment was performed for the 14 demographic regions in Kazakhstan and two city-states, and a map depicting the most feasible technology for each region is presented, including their levelized cost per liter. Seven mature technologies were found to be feasible in Kazakhstani year-round climates. However, Air AW₃ technology and Artificial Glaciers (AG) were the most cost-effective for family-size and village-size solutions, respectively. The water provided via utility pipelines proved to be the most cost-effective manner, when available, to supply drinking water at a family-size scale, but found a less expensive competitor in the AG technology for village-size solutions. Moreover, the lack of utility water pipelines in some Kazakhstani regions, principally countryside rural areas, makes it vital to deploy and implement these alternative water-harvesting technologies to guarantee the future water security of these regions.     

卢氏县集中式饮用水水源保护区划分研究

划分水源地保护区是保障饮用水资源可持续利用的重要措施。在卢氏县集中式饮用水水源保护区的划分工作中,根据《饮用水水源保护区划分技术规范》(HJ/T338-2007),采用现场调研和卫星遥感技术相结合的方法,结合饮用水水源保护区的地形、地标、地物的特点,科学地对卢氏县地下水型、河流型、湖泊型水源地进行保护区划分,并提出卢氏县饮用水水源保护区范围、面积及目标,为卢氏县饮用水源保护规划奠定了理论基础。针对卢氏县饮用水源的特点,提出可行的建议和措施,为下一步饮用水源的保护提供科学依据。     

Assessment of the Hydrogeochemistry and Groundwater Quality of the Tarim River Basin in an Extreme Arid Region, NW China

The concentrations of the major and trace elements in the groundwater of the Tarim River Basin (TRB), the largest inland river basin of China, were analyzed before and during rainy seasons to determine the hydrogeochemistry and to assess the groundwater quality for irrigation and drinking purposes. The groundwater within the TRB was slightly alkaline and characterized by high ionic concentrations. The groundwater in the northern sub-basin was fresh water with a Ca²⁺–HCO₃ ^? water type, whereas the groundwater in the southern and central sub-basins was brackish with a Na⁺–Cl^? water type. Evaporite dissolution and carbonate weathering were the primary and secondary sources of solutes in the groundwater within the basin, whereas silicate weathering played a minor role. The sodium adsorption ratio (SAR), water quality index (WQI), and sodium percentage (%Na) indicated that the groundwater in the northern sub-basin was suitable for irrigation and drinking, but that in the southern and central sub-basins was not suitable. The groundwater quality was slightly better in the wet season than in the dry season. The groundwater could be used for drinking after treatment for B³⁺, F^?, and SO₄ ^2? and for irrigation after control of the sodium and salinity hazards. Considering the high corrosivity ratio of the groundwater in this area, noncorrosive pipes should be used for the groundwater supply. For sustainable development, integrated management of the surface water and the groundwater is needed in the future.     

基于MODFLOW数值模拟法的地下水饮用水源保护区划分

我国城乡居民饮用水安全现状不容乐观,饮用水源污染已经成为较突出的社会问题,其中地下水饮用水源污染更为突出.饮用水源保护区划分是保证水质安全的重要措施,饮用水源保护区划分方法较多,其中数值模拟法能客观并详细地描述含水层结构与水文地质条件,适用于各种背景的地下水水源研究.本文以崇州市城区饮用水源为例,采用MODFLOW软件建立地下水渗流场,应用MODPATH对水源地抽水井进行粒子逆向示踪模拟,根据不同的时间标准确定一、二级保护区范围,并结合区域水文地质条件和地标、地界特点确定各级保护区的界线.     

Nitrate levels in shallow groundwater of upstate New York,USA

This paper summarizes research evaluating nitrate levels in shallow groundwater of upstate New York, USA. Water from abandoned dug wells in six different land-use categories was analyzed for nitrate. Findings indicate that regardless of overlying land-use, shallow groundwater is susceptible to high levels of nitrate. Over 60 percent of the water samples tested, including at least one sample from each land-use category, had nitrate levels in excess of the United States drinking water standard of 10 mg 1^–1. Due to the potential threat of elevated nitrate levels, efforts should be made to eliminate abandoned dug wells in shallow groundwater as a source of water supply.Glenn Harris is with the Environmental Studies Programme of St Lawrence University in Canton, New York. Brian Henry is with the Department of Entomology at the University of Georgia in Athens, Georgia. Jeffrey Deyette is with the joint International Relations and Resource and Environmental Management Programme at Boston University in Boston, Massachusetts. This research was performed as a Community Service Project sponsored by the Mergardt Fund while Mr Henry and Mr Deyette were students under the supervision of Dr Harris at St Lawrence University.     

Veterinary drugs in groundwater in a dairy region of central Argentina and risk assessment for human health

Veterinary drugs used in dairy production are potential contaminants of surface or groundwater sources, being able to affect human and environmental health. It is known that chronic exposure to antibiotics in low concentrations present in water can generate microbial resistance. This study aimed to evaluate the presence of veterinary drugs in 53 groundwater samples used for animal and human consumption, collected in dairy milking parlors, in an important milk-producing area of central Argentina, and to assess the risk to human health when they are used as drinking water. In 75% of the total samples analyzed, at least one veterinary drug was detected. The most frequently found drugs in water samples were the antibiotics tetracycline in 58.5% and oxytetracycline in 56.6%, and an anti-inflammatory, flunixin in 39.6%. In the water samples, the tetracycline and oxytetracycline concentrations were between 0.1 and 5.3 μg/L and flunixin concentrations were between 0.01 and 2.1 μg/L. The frequency of appearance and the concentration levels of the substances found in the water samples were evaluated according to the productivity, size, and production system (confined or pasture) of the dairy farms. Higher concentrations and proportions of water samples containing antibiotics were observed when the number of animals per dairy farm was >182 and when the productivity was high (>25 liters per animal per day). In the case of flunixin, the percentage of detection was similar in all evaluated categories. The risk assessment for children and adults, considering the intake of drinking water containing residues of these drugs, did not indicate a significant health risk. It would be advisable to evaluate other sources of drinking water, both surface and underground, in other regions of the country, to provide data to assess the impact of these substances and the other contaminants on environmental and human health.     

Groundwater characterization in major industrial and residential locations of Lagos metropolis

This study investigated the quality of groundwater collected from two industrial and residential locations, each within the Lagos metropolis. Prescribed standard procedures of the American Public Health Association (APHA) were used to measure the physicochemical parameters of each of the groundwater samples, which include pH, electrical conductivity (EC), dissolved oxygen, total dissolved solids (TDS), biological oxygen demand, chemical oxygen demand; the anions chloride (Cl^?), nitrate (NO₃^?), sulfate (SO₄^?), and phosphate (PO₄^?); and heavy metals copper (Cu), zinc (Zn), lead (Pb), manganese (Mn), iron (Fe), cobalt (Co), cadmium (Cd), and chromium (Cr). Based on the laboratory analysis, the physicochemical parameters that were measured were within the permissible ranges specified by the World Health Organization and the Nigerian Standard for Drinking Water Quality Standards Organization of Nigeria (SON), except for pH, TDS, EC, Pb, Mn, and Fe for groundwater samples from the industrial locations and for pH, Pb, Mn, and Fe for residential locations. The elevated concentrations of TDS and EC reported for groundwater samples from industrial locations were attributed to the heavy discharge of effluents from nearby industrial treatment plants as well as the dissolution of ionic heavy metals from industrial activities involving the use of heavy machines. Statistical analysis using Pearson's correlation revealed the physicochemical parameters to be moderately and strongly correlated with one another at either p < .05 or < .01. In conclusion, groundwater samples from residential locations are more suitable for drinking than those from industrial locations.     

THE ROLE OF AGRICULTURAL GROUNDWATER CONSERVATION IN ACHIEVING ZERO OVERDRAFT IN ARIZONA1

ABSTRACT: The elimination of groundwater overdraft was a key feature of the 1980 Arizona Groundwater Management Act. To achieve this goal, the Arizona Department of Water Resources identified several Active Management Areas and developed urban, industrial, and agricultural water conservation plans. This study examines the reductions in groundwater use through agricultural water conservation in the Phoenix Active Management Area (AMA). Linear programming models are developed to analyze changes in groundwater use and net returns to agriculture over a 38-year period, 1990 to 2025, for farming areas in the Phoenix AMA. Results indicate that the agricultural conservation program provides only modest groundwater savings under a wide range of scenarios. The low level of savings is partly due to the current economically efficient use of water. Other policy measures such as retiring agricultural land may be necessary if the Phoenix AMA is to meet its overdraft reduction goals; even if urban water conservation goals are met.     

A provider-based water planning and management model--WaterSim 4.0--for the Phoenix Metropolitan Area

Uncertainty in future water supplies for the Phoenix Metropolitan Area (Phoenix) are exacerbated by the near certainty of increased, future water demands; water demand may increase eightfold or more by 2030 for some communities. We developed a provider-based water management and planning model for Phoenix termed WaterSim 4.0. The model combines a FORTRAN library with Microsoft C# to simulate the spatial and temporal dynamics of current and projected future water supply and demand as influenced by population demographics, climatic uncertainty, and groundwater availability. This paper describes model development and rationale. Water providers receive surface water, groundwater, or both depending on their portfolio. Runoff from two riverine systems supplies surface water to Phoenix while three alluvial layers that underlie the area provide groundwater. Water demand was estimated using two approaches. One approach used residential density, population projections, water duties, and acreage. A second approach used per capita water consumption and separate population growth estimates. Simulated estimates of initial groundwater for each provider were obtained as outputs from the Arizona Department of Water Resources (ADWR) Salt River Valley groundwater flow model (GFM). We compared simulated estimates of water storage with empirical estimates for modeled reservoirs as a test of model performance. In simulations we modified runoff by 80%-110% of the historical estimates, in 5% intervals, to examine provider-specific responses to altered surface water availability for 33 large water providers over a 25-year period (2010-2035). Two metrics were used to differentiate their response: (1) we examined groundwater reliance (GWR; that proportion of a providers' portfolio dependent upon groundwater) from the runoff sensitivity analysis, and (2) we used 100% of the historical runoff simulations to examine the cumulative groundwater withdrawals for each provider. Four groups of water providers were identified, and discussed. Water portfolios most reliant on Colorado River water may be most sensitive to potential reductions in surface water supplies. Groundwater depletions were greatest for communities who were either 100% dependent upon groundwater (urban periphery), or nearly so, coupled with high water demand projections. On-going model development includes linking WaterSim 4.0 to the GFM in order to more precisely model provider-specific estimates of groundwater, and provider-based policy options that will enable "what-if" scenarios to examine policy trade-offs and long-term sustainability of water portfolios.     

AN EXTENSION INFORMATION PROGRAM TO IMPROVE RESIDENTIAL WELL WATER QUALITY1

ABSTRACT: Older inland lake communities in Wisconsin are more likely than many areas to have degraded water supplies. Many home sites are on sandy soils with high water tables and have shallow wells close to their own or a neighbor's septic system. Yet unless major rehabilitation is undertaken, these homes are relatively exempt from local codes and regulations. They also are beyond the application of the federal Clean Drinking Water Act. An Extension education program was created in response to the problem. At a community's request, home drinking water “screening tests” are conducted for at least coliform bacteria, chlorides, and nitrate/nitrite-N. Test results, together with explanations and recommendations are reported at a local meeting. Public response has been positive, and a surprising number of wells appear to be contaminated to some degree.     

Changes in Shallow Groundwater Quality Beneath Recently Urbanized Areas in the Memphis,Tennessee Area1

Barlow, Jeannie R.B., James A. Kingsbury, and Richard H. Coupe, 2012. Changes in Shallow Groundwater Quality Beneath Recently Urbanized Areas in the Memphis, Tennessee Area. Journal of the American Water Resources Association (JAWRA) 48(2): 336‐354. DOI: 10.1111/j.1752‐1688.2011.00616.x Abstract: Memphis, the largest city in the state of Tennessee, and its surrounding suburbs depend on a confined aquifer, the Memphis aquifer, for drinking water. Concern over the potential for downward movement of water from an overlying shallow aquifer to the underlying Memphis aquifer provided impetus for monitoring groundwater quality within the shallow aquifer. The occurrence of volatile organic compounds (VOCs), nitrate, and pesticides in samples from the shallow well network indicate a widespread affect on water quality from the overlying urban land use. Total pesticide concentration was generally higher in more recently recharged groundwater indicating that as the proportion of recent water increases, the occurrence of pesticides related to the current urban land use also increases. Groundwater samples with nitrate concentrations greater than 1.5 mg/l and detectable concentrations of the pesticides atrazine and simazine also had higher concentrations of chloroform, a VOC primarily associated with urban land use, than in other samples. The age of the water from these wells indicates that these concentrations are most likely not representative of past agricultural use, but of more recent urban use of these chemicals. Given that the median age of water represented by the shallow well network was 21 years, a lag time likely exists between changes in land use and the occurrence of constituents related to urbanization in shallow groundwater.     

Mason Valley Groundwater Model: Linking Surface Water and Groundwater in the Walker River Basin,Nevada1

Carroll, Rosemary W.H., Greg Pohll, David McGraw, Chris Garner, Anna Knust, Doug Boyle, Tim Minor, Scott Bassett, and Karl Pohlmann, 2010. Mason Valley Groundwater Model: Linking Surface Water and Groundwater in the Walker River Basin, Nevada. Journal of the American Water Resources Association (JAWRA) 46(3):554-573. DOI: 10.1111/j.1752-1688.2010.00434.x Abstract: An integrated surface water and groundwater model of Mason Valley, Nevada is constructed to replicate the movement of water throughout the different components of the demand side of water resources in the Walker River system. The Mason Valley groundwater surface water model (MVGSM) couples the river/drain network with agricultural demand areas and the groundwater system using MODFLOW, MODFLOW’s streamflow routing package, as well as a surface water linking algorithm developed for the project. The MVGSM is capable of simulating complex feedback mechanisms between the groundwater and surface water system that is not dependent on linearity among the related variables. The spatial scale captures important hydrologic components while the monthly stress periods allow for seasonal evaluation. A simulation spanning an 11-year record shows the methodology is robust under diverse climatic conditions. The basin-wide modeling approach predicts a river system generally gaining during the summer irrigation period but losing during winter months and extended periods of drought. River losses to the groundwater system approach 25% of the river’s annual budget. Reducing diversions to hydrologic response units will increase river flows exiting the model domain, but also has the potential to increase losses from the river to groundwater storage.     

Relative cancer risks of chemical contaminants in the great lakes

Anyone who drinks water or eats fish from the Great Lakes consumes potentially carcinogenic chemicals. In choosing how to respond to such pollution, it is important to put the risks these contaminants pose in perspective. Based on recent measurements of carcinogens in Great Lakes fish and water, calculations of lifetime risks of cancer indicate that consumers of sport fish face cancer risks from Great Lakes contaminants that are several orders of magnitude higher than the risks posed by drinking Great Lakes water. But drinking urban groundwater and breathing urban air may be as hazardous as frequent consumption of sport fish from the Great Lakes. Making such comparisons is difficult because of variation in types and quality of information available and in the methods for estimating risk. Much uncertainty pervades the risk assessment process in such areas as estimating carcinogenic potency and human exposure to contaminants. If risk assessment is to be made more useful, it is important to quantify this uncertainty.