THE NATIONAL WATER COMMISSION REVISITED1

ABSTRACT: In 1973 the National Water Commission concluded its five-year study of national water policy by issuing a massive report containing over 200 recommendations for improvements in the way the Nation deals with its water resources. The Carter Administration is now engaged in another water policy review which incorporates many of the policies espoused by the National Water Commission. In this paper, presented at the 13th American Water Resources Conference in Tucson in November of 1977, the author describes the work of the National Water Commission and the actions taken on its recommendations.     

UV peroxidation with air stripping for optimized removal of VOCs from groundwater

No one remedial technology is best suited to treat every groundwater contaminant plume. This article describes how pilot testing and analytical evaluation targeted selection of two treatment technologies, UV peroxidation and air stripping, to be used in series to create a synergistic, cost-effective pump-and-treat system for the removal of VOCs from groundwater. Pilot plant size equipment was employed to treat the VOC-contaminated groundwater in order to obtain site-specific reaction rates and to develop full-scale design parameters. It was found that by using the two treatment technologies in combination, the influent concentration of 2,000 ppb total VOCs could be reduced to less than 1 ppb, thus meeting drinking water standards.     

Environmental gradients in northwest freshwater wetlands

Wetland environmental characteristics are examined to determine their spatial and temporal relationships. Two very different Oregon freshwater wetlands provided a range of wetland types. Results are evaluated to determine the possible use of environmental characteristics in defining wetlands and their boundaries. Representative physical, hydrological, and edaphic properties were periodically measured in microplots along upland/wetland transects. A multivariate approach is stressed in the data analysis; correlation, cluster analysis, and principal components analyses were used. The results indicate the environmental characteristics change in a quantifiable manner both spatially and temporally. The controlling mechanism is moisture, spatially in terms of the upland/wetland transect and temporally with respect to seasonal response. These changes do not correlate well with vegetation. Several hypotheses are offered as an explanation. Correlation within environmental characteristics is variable but definite patterns are discernible. These data suggest both single and combinations of environmental characteristics that could serve as keys in wetland identification and boundary determination. However, before extensive use is made of this information additional long-term monitoring of wetland environmental characteristics will be required.     

Book reviews

Common Property Economics: A General Theory and Land Use Applications

Glenn G. Stevenson

Cambridge, Cambridge University Press, 1992, XIV + 256pp., £35

Controversial Issues in Environmental Policy: Science vs Economics vs Politics

Kent E. Portney

London, Sage, 1992, 181 pp. £22.00 hb., £10.95 pb.

Economics of Natural Resources and the Environment

E. Kula

London, Chapman & Hall, 1992, 287 pp., £40

Policy Implications of Greenhouse Warming: Mitigation, Adaptation and the Science Base

Committee on Science, Engineering and Public Policy (US), Panel on Policy

Implications of Greenhouse Warming

Washington, DC, National Academy Press, 1992, xxiii + 918 pp., $89.95 hb.

Contemporary Rural Systems in Transition, Volume 1: Agriculture and Environment, Volume 2: Economy and Society

I. Bowler, C. Bryant & M.Nellis (Eds)

Wallingford, CAB International, 1992, 288 pp. + 336 pp., £35 + £40 (2 vols. £70) hb.

Third World Cities: Problems, Policies and Prospects

John Kasarda & Allan Parnell (Eds) London, Sage, 1993, 310 pp., £19.50 pb.

Pricing the European Environment

Stale Navrud (Ed)

Oxford, Oxford University Press/Scandinavian University Press, 1992, 288 pp., £30.00 hb.     

Hydro-geochemical aspects of Mediterranean temporary ponds in western Crete

The hydrologic and geochemical conditions that prevail in Mediterranean temporary ponds (MTPs), create a unique environment for many rare and endangered species. Mediterranean temporary ponds are habitats of high ecological value, which are vulnerable to imminent climatic changes, as well as to human activities. This article examines the hydrology and the nitrogen and phosphorous geochemical cycles of four MTPs in Crete. Field and laboratory studies provided the necessary information for the development of a conceptual understanding of the hydrologic and biogeochemical processes that affect the fate of nitrogen and phosphorous in these MTPs. Their hydrology was driven by deposition, infiltration, and evaporation. The hydroperiod of the ponds varied between 40 and 160 d. Mineralization and nutrient release capacity experiments illustrated the significant role that MTP sediments played in enhancing the geochemistry of the aqueous phase. Such ecosystem functions (i.e., mineralization, nutrient release) exhibited high variability among MTPs necessitating site-specific studies with immediate implications to management. It is very important to understand the local hydrogeochemical and climatic conditions to ensure appropriate environmental measures for their management and conservation.     

Field Validation of a Conservation Network on the Eastern Shore of Maryland,USA, Using Breeding Birds as Bio-Indicators

Maryland’s Green Infrastructure (GI) is a network of large, intact natural areas (hubs), interconnected by linear swaths of riparian or upland vegetation (corridors). The GI serves significant ecological functions and provides the bulk of the state’s natural support system. This study examined whether the GI as mapped does, in fact, identify Maryland’s most ecologically valuable forested lands, using forest interior dwelling birds (hereafter called “forest birds”) as bio-indicators. We conducted bird point counts within forest both inside and outside of hubs on Maryland’s Eastern Shore. We also collected a wide variety of habitat data. We found that both the condition of a forest and its surrounding landscape influenced the bird communities. On average, forest bird richness was significantly higher within hubs; furthermore, almost all sites with at least five forest bird species present were in hubs. Forest bird richness and abundance were highest in undisturbed, mature broadleaf forest with wetlands and streams nearby. We detected a significant relationship between forest bird richness and the ecological score of a finer-scale landscape assessment, focused on “cells” of about 0.1 ha in size. This field study also validated the Rapid Field Assessment (RFA) protocol developed in 2001 to assess, on the ground, the relative condition of individual sites or properties within the GI. Forest bird richness and abundance were positively correlated with the RFA community scores. Our results underscore the importance of maintaining regional biological diversity by retaining large blocks of forest, especially mature forest containing streams and wetlands.     

Coal-Mine Hollow Fill and Settling Pond Influences on Headwater Streams in Southern West Virginia, USA

The influences of coal-mine hollow fills and associated settling ponds in three headwater streams were assessed in southern West Virginia, USA. Fill drainage waters had elevated conductivities and metal concentrations, compared to a regional reference. Benthic macroinvertebrate richness was not affected consistently by the hollow fill drainages, relative to a regional reference, although a more tolerant community, lacking in Ephemeroptera taxa at most locations, was evident. Collector-filterer populations were elevated at monitoring stations directly below the settling ponds, indicating that the ponds’ presence influenced macroinvertebrate community structure by means of organic enrichment. Corbicula fluminea growth was enhanced in monitoring locations directly below the settling ponds, also an apparent result of organic enrichment. Results of acute water column toxicity testing with Ceriodaphnia dubia, sediment chronic toxicity testing with Daphnia magna, and in-situ ecotoxicological assessments with C. fluminea demonstrated no mortality or toxic influence at most of the sites tested below the ponds. The settling ponds appear to serve as sinks in collecting some, but not all, trace metals.     

Factors affecting aural detections of songbirds.

Many factors affect the number of birds detected on point count surveys of breeding songbirds. The magnitude and importance of these factors are not well understood. We used a bird song simulation system to quantify the effects of detection distance, singing rate, species differences, and observer differences on detection probabilities of birds detected by ear. We simulated 40 point counts consisting of 10 birds per count for five primary species (Black-and-white Warbler Mniotilta varia, Black-throated Blue Warbler Dendroica caerulescens, Black-throated Green Warbler Dendroica virens, Hooded Warbler Wilsonia citrina, and Ovenbird Seiurus aurocapillus) over a range of 15 distances (34-143 m). Songs were played at low (two songs per count) and high (13-21 songs per count) singing rates. Detection probabilities averaged across observers ranged from 0.60 (Black-and-white Warbler) to 0.83 (Hooded Warbler) at the high singing rate and 0.41 (Black-and-white Warbler) to 0.67 (Hooded Warbler) at the low singing rate. Logistic regression analyses indicated that species, singing rate, distance, and observer were all significant factors affecting detection probabilities. Singing rate x species and singing rate X distance interactions were also significant. Simulations of expected counts, based on the best logistic model, indicated that observers detected between 19% (for the worst observer, lowest singing rate, and least detectable species) and 65% (for the best observer, highest singing rate, and most detectable species) of the true population. Detection probabilities on actual point count surveys are likely to vary even more because many sources of variability were controlled in our experiments. These findings strongly support the importance of adjusting measures of avian diversity or abundance from auditory point counts with direct estimates of detection probability.