ADMINISTRATION OF GROUND WATER AS BOTH A RENEWABLE AND NONRENEWABLE RESOURCE1

ABSTRACT: Ground water is intended to be administered in many western states as a flow or renewable resource. In Idaho, this administration is based on the appropriation doctrine of water rights. Two generalizations may be made concerning ground water. First, water artificially discharged from an aquifer system must deplete the total resource by that amount; water consumptively pumped from a well must be derived from either increased recharge, decreased discharge or a decrease of water in storage. Second, the annual rate of recharge to a ground-water system is often only a small percentage of the total resource in storage. Ground water may be divided into flow and stock portions. In those basins where the second generalization is true, most ground water may be classified as stock. However, only the flow portion of ground water may be developed if utilization of the resource is to be enjoyed over an infinite period. Data from the Raft River Basin in Idaho indicate that the flow and stock characteristics of ground water are time dependent. The resource exhibits the characteristics of both a renewable and nonrenewable resource. As a result, present administrative techniques do not provide for effective management of the resource.     

Electricity price and Southern California’s water supply options

This paper evaluates the impact of fluctuating electricity prices on the cost of five options to increase the water supply to urban areas in Southern California—new surface storage, water purchases, desalination, wastewater recycling, and conservation.We show that the price of electricity required to produce and transport water influences the cost of water supply options and may alter the decision makers economic ranking of these options. When electricity prices are low, water purchase is the cost effective option. When prices exceed US$ 86/MWh, conservation of electricity and water through installation of high efficiency clothes washers is the most effective option.     

Design and cost estimation of permeable reactive barriers

Cost-effective use of permeable reactive barriers for groundwater treatment requires properly estimating the amount of reactive material required and choosing the best means of emplacing it. The weight of reactive material per unit cross section of the plume can be estimated from laboratory reaction kinetics data and basic knowledge of the plume and the remediation goals. This parameter has implications regarding the choice of permeable barrier design and emplacement method. The use of tremie tubes, trenching machines, high-pressure jetting, and deep soil mixing may be appropriate for different situations depending on the amount of reactive material required, the dimensions of the plume, and other factors. The specific application considered here is the use of granular iron to treat groundwater contaminated with chlorinated solvents.     

Playing chicken on the Nile? The implications of microdam development in the Ethiopian highlands and Egypt's New Valley Project

How Egypt and Ethiopia will defend or promote their interests in the Nile basin has recently become clearer. Egypt will again seek to create 'facts on the ground', this time a large new land reclamation and settlement scheme called the New Valley Project. Ethiopia too will create facts by proceeding with water resources development in the Blue Nile basin, including the construction of low-cost microdams. If Egypt and Ethiopia pursue these two unilateral initiatives, they may find themselves on a collision course that both may have difficulty changing. The challenge facing the Nile riparian countries is to find a balance between the upstream countries' support for the principle of 'equitable use', and Egypt's and Sudan's support for the principle of 'no appreciable harm'. Of all the riparian states, Egypt has the most to gain from the establishment of a basin-wide framework for water resources development. It can ill afford a future in which upstream riparians take unilateral action with respect to water development projects. If Egypt would reduce its existing water use by 5 billion m³ and scale back or abandon the plans for the New Valley Project, there would be enough water available to strike a deal that would bring Ethiopia and other upstream riparians into the framework of a comprehensive Nile Waters Agreement.     

Contributions of Acid Deposition and Natural Processes to Cation Leaching from Forest Soils: A Review

Methods of quantifying the roles of atmospheric acid inputs and internal acid generation by carbonic, organic, and nitric acids are illustrated by reviewing data sets from several intensively studied sites in North America. Some of the sites (tropical, temperate deciduous, and temperate coniferous) received acid precipitation whereas others (northern and subalpine) did not. Natural leaching by carbonic acid dominated soil leaching in the tropical and temperate coniferous sites, nitric acid (caused by nitrification) dominated leaching In an N-fixing temperate deciduous site, and organic acids dominated surface soil leaching in the subalpine site and contributed to leaching of surface soils in several other sites. Only at the temperate deciduous sites did atmospheric acid input play a major role in soil leaching. In no case, however, are the annual net losses of cations regarded as alarming as compared to soil exchangeable cation capital.

These results were used to illustrate the methods of quantifying the effects of atmospheric inputs and internal processes on soil leaching rates, not to draw broad generalizations as to acid rain effects on soils. However, there are predictable patterns in natural soil leaching processes which relate to climate, soil properties, and vegetation that may help in predicting the relative importances of natural vs. atmospheric acid inputs to soil leaching.     

Homophily and Agency: Creating Effective Sustainable Development Networks

Community networks are self-organized groupings that form for many different reasons. Some networks, connected mainly through bonding ties, are based on personal interests and relationships; others, based mainly on bridging ties, centre around broader interests. These networks form to create collective agency for engaging with social, environmental, and other issues through the concentration of social capital. The multi-scaled and evolutionary nature of sustainable development issues requires that community groups dedicated to engaging with such issues be particularly diverse, resilient, and flexible. As such, they must build a large number of bridging ties leading to external resources and limit the potential for bonding ties to impose constraining norms upon the group. Over time, however, volunteer groups tend towards a state of homophily, the tendency of groups to form from similar actors and then become more similar with time. This tendency leads to a decrease in the number of the bridging ties that help to provide group agency. Homophily must be actively recognized within community sustainable development groups if they are to remain effective over the long term. This paper suggests methods to prevent and control group homophily drawn from experience in forming small, time-limited sustainable development networks. Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue     

DETECTING CILANGES IN THE SPATIAL DISTRIBUTION OF NITRATE CONTAMINATION IN GROUND WATER1

ABSTRACT: Many studies of ground water pollution in general and nitrate contamination in particular have often relied on a one-time investigation, tracking of individual wells, or aggregate summaries. Studies of changes in spatial distribution of contaminants over time are lacking. This paper presents a method to compare spatial distributions for possible changes over time. The large-scale spatial distribution at a given time can be considered as a surface over the area (a trend surface). The changes in spatial distribution from period to period can be revealed by the differences in the shape and/or height of surfaces. If such a surface is described by a polynomial function, changes in surfaces can be detected by testing statistically for differences in their corresponding polynomial functions. This method was applied to nitrate concentration in a population of wells in an agricultural drainage basin in Iowa, sampled in three different years. For the period of 1981–1992, the large-scale spatial distribution of nitrate concentration did not show significant change in the shape of spatial surfaces; while the magnitude of nitrate concentration in the basin, or height of the computed surfaces showed significant fluctuations. The change in magnitude of nitrate concentration is closely related to climatic variations, especially in precipitation. The lack of change in the shape of spatial surfaces means that either the influence of land use/nitrogen management was overshadowed by climatic influence, or the changes in land use/management occurred in a random fashion.     

Mine capacity and mineral price

The loss of foreign mineral supplies may affect domestic supply and price. To investigate the assumption that prices, a simple mine investment model that relates mine capacity to deposit attributes is used. A test of the model to see how well it approximates industry investment practice illustrates its accuracy. The model suggests that price changes can substantially affect the optimal capacity of planned or existing mines as well as the mineral supply in the USA.