Wellhead treatment costs for groundwater contaminated with pesticides: A preliminary analysis for pineapple in Hawaii

In Hawaii, trace concentrations of pesticides used in the production of pineapple were found in the groundwater supplies of Mililani Town in the Pearl Harbor Basin on the island of Oahu. Groundwater serves as the major source of drinking water and residents pay for wellhead treatment of the contaminated water, via their monthly water bill. The agricultural chemical users within the Pearl Harbor Basin do not include these wellhead treatment costs in their production costs. The agricultural industry benefits from using pesticides but does not pay the entire societal cost of using these chemicals. In this study we evaluate the specific financial cost of wellhead treatment, and not the economic value of groundwater. While wellhead treatment costs could conceivably be shared by several parties, this study focuses on the financial impact of the pineapple industry alone. This study factors annual wellhead treatment costs into annual pineapple production costs to measure the effect on annual financial return from pineapple production. Wellhead treatment costs are calculated from the existing granulated activated carbon (GAC) water treatment facility for Millilani Wells I and II. Pineapple production costs are estimated from previous cost of production studies. The inclusion of wellhead treatment costs produces different production-cost results, depending on the scale of analysis. At the local scale, the Mililani wellhead treatment costs can be factored into the production costs of the pineapple fields, which were probably responsible for contamination of the Mililani Wells, without causing a deficit in economic return. At the larger regional scale, however, the return from all of the pineapple grown in the Pearl Harbor Basin can not sustain the cost of wellhead treatmentfor the entire water supply of the basin. Recommendations point to the prevention of groundwater contamination as more cost-effective measure than wellhead treatment.     

Improving lake riparian source area management using surface and subsurface runoff indices

Sensitivity indices, which rank factors pertinent to surface and subsurface runoff pathways, were used to identify phosphorus source areas in riparian zones of 15 northern Minnesota lakes. Watershed models were first developed using a geographic information system (GIS). Empirical models were then developed correlating water quality with land use, lake morphometry, and riparian sensitivity. Base models of forested, cultivated, pasture/open, wetland and residential land use within 100, 200, 400, and 2000 m of the study lakes were regressed on total phosphorus and chlorophyll-a. Area-weighted groundwater and surface runoff sensitivity indices were then incorporated into each model and tested for significance. Within the 200-m buffer, the total phosphorus base model was improved by including the groundwater index alone. The chlorophyll-a base model at 200 m was improved by including: (1) the groundwater index alone, and (2) both the groundwater and surface runoff sensitivity indices. Results suggest that surface and subsurface runoff analysis of potential source areas can improve decision making for lake riparian management.     

Reducing groundwater pollution by toxic substances: Procedures and policies

One major source of water-related health problems is the improper disposal of toxic substances in the environment. Toxic materials leaching from unregulated and unlined pits, ponds, lagoons, and landfills have created a widespread environmental nightmare in the United States and many other parts of the world. At present, there are two major and interrelated components of this problem in the United States. The first is the issue of cleaning up abandoned disposal sites that pose actual or potential threats to water supplies. The second aspect of the problem concerns the necessity of siting proper management, treatment, or disposal facilities in the future. Priorities must be set to allow efficient, effective, and equitable allocation of the scarce resources that are available for accomplishing these tasks.This article examines a number of the issues involved in setting these priorities, and presents the results obtained from a study of risk estimation and evaluation in the context of groundwater contamination by toxic substances. The article introduces a new concept of risk estimation, which is shown to produce more accurate and credible risk analyses. Finally, the relationships between risk credibility and public perceptions of procedural fairness and equity are examined as these factors bear on the institutional aspects of implementing policies for site cleanup and/or facility siting.     

Evaluating the effects of spatial monitoring policy on groundwater quality portrayal

What size sample is sufficient for spatially sampling ambient groundwater quality? Water quality data are only as spatially accurate as the geographic sampling strategies used to collect them. This research used sequential sampling and regression analysis to evaluate groundwater quality spatial sampling policy changes proposed by California's Department of Water Resources. Iterative or sequential sampling of a hypothetical groundwater basin's water quality produced data sets from sample sizes ranging from 2.8% to 95% coverage of available point sample sites. Contour maps based on these sample data sets were compared to an original (control), mapped hypothetical data set, to determine at which point map information content and pattern portrayal are not improved by increasing sample sizes. Comparing series of contour maps of ground water quality concentration is a common means of evaluating the geographic extent of groundwater quality change. Comparisons included visual inspection of contout maps and statistical tests on digital versions of these map files, including correlation and regression products. This research demonstrated that, down to about 15% sample site coverage, there is no difference between contour maps produced from the different sampling strategies and the contout map of the original data set.     

Restoration ecology of riverine wetlands: II. An example in a former channel of the Rhône River

Riverine wetlands, which provide numerous valuable functions, are disappearing in floodplains of a channelized European river. A restoration project has been proposed by scientists to restore a former braided channel of the Rhône River by the removal of fine organic sediments in order to enhance groundwater supply. A precise and intensive prerestoration monitoring program during one year (including comparison with a reference channel) has taken into account several variables and ecological performance indicators measured at various spatial and temporal scales. Three restoration techniques were then suggested, taking into account two characteristics of ecosystem functions for increasing restoration success and self-sustainability: (1) the riparian forest as well as the shores must be preserved or disturbed as little as possible; and (2) the upstream alluvial plug must be preserved to prevent direct supply of nutrientrich water from the Rhône River. Among the three restoration options proposed, it was not possible to carry out the less ecologically disturbing one as it was considered too expensive, time consuming, and difficult to realize. A precise and intensive postrestoration monitoring program, conducted over two years, demonstrated restoration success but also unpredicted problems, such as a locally thick layer of fine organic sediment. As long as a self-sustainable state is not achieved, this monitoring should be continued. Afterwards, a less precise and less intensive long-term monitoring should enable the detection of future events that may influence ecosystem changes.     

Mobilising social energy against environmental challenge: understanding the groundwater recharge movement in western India

This paper explores a large-scale and growing popular movement to augment groundwater recharge in the Saurashtra region of western India, an area that has been facing acute water scarcity and other associated problems. As a social phenomenon, the movement is at an early stage of its development. However, it is interesting to study it for many reasons. First, even a decade after it began, it is still growing in scale and following. Second, it is entirely spontaneous and internally driven, necessitating no public resources or support. Third, early indications are that its social and ecological impacts are beneficial and highly significant. Fourth, the movement was catalysed and spearheaded by spiritual and religious institutions, which made ingenious use of non-economic messages and motivators in forging a new natural resource ethic based on a broad, collective rationality among movement members. It appears, however, that beyond a threshold, the movement acquired a logic and energy of its own which might fuel its future sustainability and growth. Finally, the movement has important lessons to offer because mobilising social energy on such a scale and intensity can perhaps be one of most effective responses to many of the environmental challenges the world faces today.     

双流区域地下水污染现状及评价

本文在双流区域地下水污染调查基础之上，选用了主要反映工业生活污染的综合指标ＣＯＤ、ＢＯＤ５和反映农业污染程度的ＮＨ３－Ｎ，ＮＯ３－Ｎ，ＮＯ２－Ｎ作为评价因子，研究了双流地下水污染现状，采用了综合指数法和点群分析法分类并评价了区域地下水污染对饮用水源地的影响程度。     

Sensitivity of Ozone Production to the Nmhc Composition, Aerosol Back-Scattering and High Chimney Emission

In this paper, three sensitivity studies are designed to analyze the effect of the NMHC (Non-Methane HydroCarbon) composition, the aerosol back-scattering and the high chimney NO_x emission to the photochemical prodution of ozone by using a one-dimensional photochemistry-diffusion model under a favourable meteorological condition. Measurements of the NMHC composition in Taipei indicated that the percentage of iso-butene, cis-2-butene, trans-2-butene and benzene in a unit volume was much higher than of those observed in other major cities. the high ratio of benzene was directly linked to its high percentage in gasoline. As to the unusually high amount of iso-butene, cis-2-butene and trans-2-butene, more researches are needed to identify their source. Concerns are raised as to how productive is NMHC composition is to the photochemical production of the surface ozone. A rough estimate shows that the total reactivity of the Taipei NMHC composition is about 1.21 × 10^-9 cm³ s^-1 which is 1.6 times that of the Los Angeles (LA) NMHC composition, while the simulated noon peak will be different by 28 ppbv, i.e. 18% more than that simulated with a LA composition.

Meanwhile, high aerosol loading is a serious problem in Taipei. the attenuation of the UV radiation by aerosols cannot be ignored. A numerical simulation shows that the noon ozone level will decrease from 178 to 141ppbv, i. e. about 21% reduction, with deterioration of the visual range from 85 to 5 km.

In the southern Taiwan, industry parks are mixed with the populated Kaohsiung city, hence the large emission of NO_x from high chimneys cannot be ignored. in this study, NO_x is assumed to be emitted in the layer between 235-460 m high with an emission rate of 0.05 or 0.145 ppbv/sec. the results show that the NO_x emitted from the elevated stack lead to a considerable reduction of surface ozone. Such conclusion is obtained due to the fact that a one-dimensional model is used in this paper. Whereas, if a three-dimensional regional model was used, then a higher productivity of ozone downstream would be simulated.     

A GIS Model of Subsurface Water Potential for Aquatic Resource Inventory,Assessment, and Environmental Management

Biological, chemical, and physical attributes of aquatic ecosystems are often strongly influenced by groundwater sources. Nonetheless, widespread access to predictions of subsurface contributions to rivers, lakes, and wetlands at a scale useful to environmental managers is generally lacking. In this paper, we describe a neighborhood analysis approach for estimating topographic constraints on spatial patterns of recharge and discharge and discuss how this index has proven useful in research, management, and conservation contexts. The Michigan Rivers Inventory subsurface flux model (MRI-DARCY) used digital elevation and hydraulic conductivity inferred from mapped surficial geology to estimate spatial patterns of hydraulic potential. Model predictions were calculated in units of specific discharge (meters per day) for a 30-m²-cell raster map and interpreted as an index of potential subsurface water flux (shallow groundwater and event through-flow). The model was evaluated by comparison with measurements of groundwater-related attributes at watershed, stream segment, and local spatial scales throughout Lower Michigan (USA). Map-based predictions using MRI-DARCY accounted for 85% of the observed variation in base flow from 128 USGS gauges, 69% of the observed variation in discharge accrual from 48 river segments, and 29% of the residual variation in local groundwater flux from 33 locations as measured by hyporheic temperature profiles after factoring out the effects of climate. Although it does not incorporate any information about the actual water table surface, by quantifying spatial variation of key constraints on groundwater-related attributes, the model provides strata for more intensive study, as well as a useful spatial tool for regional and local conservation planning, fisheries management, wetland characterization, and stream assessment.     

The Concept of Habitat Diversity Between and Within Ecosystems Applied to River Side-Arm Restoration

Since returning an ecosystem to its pristine state may not be realistic in every situation, the concept of habitat diversity is proposed to help decision-makers in defining realistic restoration objectives. In order to maintain habitat diversity and enhance the long-term success of restoration, process-oriented projects should be preferred to species-oriented ones. Because the hydrogeomorphological processes that influence biodiversity operate at different spatiotemporal scales, three scales are considered: river sectors, floodplain waterbodies, and mesohabitats within each waterbody. Based on a bibliographical review, three major driving forces are proposed for incorporation into the design of restoration projects: (1) flow velocity and flood disturbances, (2) hydrological connectivity, and (3) water supply. On the sector scale, increased habitat diversity between waterbodies can be achieved by combining various intensities of these driving forces. On the waterbody scale, increased habitat diversity within the ecosystem can be achieved by varying water depth, velocity, and substrate. The concept is applied to a Rhône River sector (France) where three terrestrialized side arms will be restored. Two were designed to be flood scoured, one having an additional supply of groundwater, the other being connected to the river at both ends. The third cannot be scoured by floods because of upstream construction and would be supplied by river backflow through a downstream connection. Habitat diversity within the ecosystem is exemplified on one side arm through the design of a sinuous pathway combined with variation of water depth, wetted width, and substrate grain size. Self-colonization of the side arms is expected owing to the restoration of connectivity to upstream sources of potential colonizers.