Coping with variability and change: Floods and droughts

Floods and droughts are natural phenomena for which the risks of occurrence are likely to continue to grow. Increasing levels of exposure and insufficient adaptive capacity are among the factors responsible for the rising vulnerability. The former is conditioned by anthropopressure (e.g., economic development of flood–prone areas) and adverse effects of climate change; scenarios for future climates indicate the possibility of amplified water–related extremes. This article presents the current situation of coping with extreme hydrological events within the pressure–state–response framework. Among promising response strategies, the role of forecast and warning, and of watershed management are reviewed. Sample success stories and lessons learnt related to hydrological extremes are given and policy implications discussed.     

Coping with Change: The Small Experiment as a Strategic Approach to Environmental Sustainability

The patterns of living, planning, and resource utilization as practiced in Western countries for decades are not sustainable; change of some sort is essential. But what changes are appropriate, and, perhaps more important, will people accept them? The small experiment framework provides a strategy for meeting the challenge of change. By encouraging participation, limiting the scale of initial change, and incorporating some aspects of the familiar, many of the difficulties that make change so problematic can be mitigated or even eliminated. An exploration, from a psychological perspective, of the characteristic difficulties surrounding potential change provides the context for a discussion of the components of the small experiment and an analysis of how these elements address these characteristic challenges. A comparison to adaptive management is drawn, and several concrete examples illustrate how the strategy has been used successfully to address a variety of environmental problems.     

An explanation of the behavioral origin of moderation in the use of natural resources: a meta-synthesis study

Environment Systems and Decisions - Natural resources are a type of good whose individual utility maximization is not desirable, as it could lead to their depletion. This problem, raised several...     

Phosphorus loss from an agricultural watershed as a function of storm size

Phosphorus (P) loss from agricultural watersheds is generally greater in storm rather than base flow. Although fundamental to P-based risk assessment tools, few studies have quantified the effect of storm size on P loss. Thus, the loss of P as a function of flow type (base and storm flow) and size was quantified for a mixed-land use watershed (FD-36; 39.5 ha) from 1997 to 2006. Storm size was ranked by return period (<1, 1-3, 3-5, 5-10, and >10 yr), where increasing return period represents storms with greater peak and total flow. From 1997 to 2006, storm flow accounted for 32% of watershed discharge yet contributed 65% of dissolved reactive P (DP) (107 g ha(-1) yr(-1)) and 80% of total P (TP) exported (515 g ha(-1) yr(-1)). Of 248 storm flows during this period, 93% had a return period of <1 yr, contributing most of the 10-yr flow (6507 m(3) ha(-1); 63%) and export of DP (574 g ha(-1); 54%) and TP (2423 g ha(-1); 47%). Two 10-yr storms contributed 23% of P exported between 1997 and 2006. A significant increase in storm flow DP concentration with storm size (0.09-0.16 mg L(-1)) suggests that P release from soil and/or area of the watershed producing runoff increase with storm size. Thus, implementation of P-based Best Management Practice needs to consider what level of risk management is acceptable.     

Applied landscape economics: a personal journey of discovery

Putting cash values on the environment facilitates commoditization and political capture of evaluation. However, individual citizens may also wish to know the appropriate trade‐off of values, in order to use political power properly. Willingness‐to‐pay offers insight into consumers’ valuation of landscape, but routine application of economic methods to land use decisions meets major problems, especially the data needs of cost — benefit analysis in face of the urgency of decisions, and the insensitivity of conventional methods to subtle landscape changes. These problems require the citizen‐as‐consumer to make personal judgements of value, but to link those values to a cash scale for the purpose of making trade‐offs. Such judgements can be entered into an orderly framework, in which the judgements can be exposed for comment, which itself exposes the assumptions of commentators. The decision about routing electricity transmission lines in Scotland provides an example. Recent interest in environmental economics gives the opportunity to broaden the scope of the method.     

Metal prices as a function of ore grade

The authors are both with the Systems Analysis Research Unit, Department of the Environment, London, England. The views expressed in this paper are those of the authors and do not necessarily coincide with those of the Department of the Environment.     

Nuclear crisis relocation: Issues for a host community-the case of Greenfield,Massachusetts, USA

US civil defense planning for nuclear attack since 1974 has emphasized the doctrine of crisis relocation. Under this doctrine, some 150 million people would evacuate from urban areas and other probable targets to rural host communities. The population of the latter would stay put to assist the relocatees. Local communities would be responsible for the welfare of up to ten times their normal population for an indefinite period of time.This study examined certain implications of crisis relocation for the town of Greenfield, Massachusetts, USA, a typical host community. Various assumptions were articulated regarding the timing of events, the season of year, weather, and social behavior. Assumptions were favorable to the success of crisis relocation. Nevertheless, Greenfield would face impossible burdens in attempting to provide fallout protection, water, food, medical care, and civil order. Additional pressures would arise from adjoining communities which are functionally dependent upon Greenfield for normal goods and services, but which would receive their own allotment of relocatees. Crisis relocation is not taken seriously in Greenfield and virtually no preparations have been made to implement it.     

Energy effects associated with e-commerce: a case-study concerning online sales of personal computers in The Netherlands

The introduction of e-commerce is changing purchase and distribution patterns dramatically. One of the observed effects is that logistics become more efficient as products are directly shipped from a manufacturer or wholesaler to an end-user. Another effect is that market transparency increases, which has a downward pressure on prices of many products sold via the Internet. This article addresses the energy implications of e-commerce at the micro level. This is done by quantifying the transport related energy savings in the case of a Dutch online computer reseller and by assessing the extra energy expenditure associated with increased buying power of online buyers. It is found that energy use per article sold by the online computer reseller is lower. However, taking into account indirect effects such as increased consumer buying power, there are scenarios that lead to an overall increase in energy use.     

Guild management: an evaluation of avian guilds as a predictive tool

The use and applicability of the guild concept to management is evaluated and questioned. Ecological problems are never as simple as implied in using one or two guild axes. A close examination of bird communities in a ponderosa pine forest reveals little relationship between guilds or guild blocks and the responses exhibited by individual bird species or bird species groups. Response guilds changed from year to year without any obvious changes in vegetation. A three-year composite analysis shows a clearer picture of the responses of ponderosa pine forest birds to the overall interactions between structure, weather, competition, and so on. The six response groups in the composite analysis are species that (1) were absent in 1973 on most or all study plots and showed no preference for any forested site; (2) had their highest densities on the medium cut and light cut plots; (3) were absent in 1973 on most or all study plots and had their highest densities on the medium cut and light cut plots; (4) had their highest densities on the untreated, light cut, and medium cut plots; (5) had their highest densities on the untreated and light cut plots and were either absent or had greatly reduced densities on all other plots; and (6) were present only on the clearcut, except for the Rock Wren which was also on the medium cut and heavy cut plots. The overall correlation between species density and guild density was significantly higher for response guilds ( <0.05) than for any of the structural or functional guilds. The whole concept of guild management needs much more research and development before it can be recommended as a management tool.     

Ramifications of solid waste disposal site relocation in urban areas of developing countries: a case study in Tanzania

Sanitary landfilling is considered to be the most appropriate means of final disposal of solid wastes. Currently in Tanzania, the cheapest method of developing a landfill is by making use of natural depressions or former borrow pits and mine pits. This paper examines the impacts associated with the relocation of a waste disposal site from a crude disposal site at Vingunguti to a new landfill site at New MECCO quarry in Kunduchi area, both in Dar es Salaam, Tanzania. The paper focuses on the fate of scavenging and solid waste recycling which are currently taking place at Vingunguti site and mining as well as food vending activities at the proposed new landfill site. Scavenging and waste recycling were found to be important sources of income for some individuals in the city. Various items collected for recycling were found to be an important source of raw materials for some industries in Dar es Salaam. A total of 94% of all the miners were entirely dependent on stone mining and crushing as a sole means of income generation, and 68% of the miners had practised this activity for between 1 and 9 years. Finally the paper recommends that, selection of a waste disposal site should favour abandoned mines or borrow pits rather than operational ones. It also recommends that, waste recycling and scavenging be accommodated in other stages of the waste stream since they can not be practised at a sanitary landfill.     

Economic costs of extratropical storms under climate change: an application of FUND

Extratropical cyclones have attracted some attention in climate policy circles as a possible significant damage factor of climate change. This study conducts an assessment of economic impacts of increased storm activities under climate change with the integrated assessment model FUND 3.5. In the base case, the direct economic damage of enhanced storms due to climate change amounts to US$2.8 billion globally (approximately 38% of the total economic loss of storms at present) at the year 2100, while its ratio to the world GDP is 0.0009%. The paper also shows various sensitivity runs exhibiting up to 3 times the level of damage relative to the base run.     

Evaluation of wetland methyl mercury export as a function of experimental manipulations

Mercury associated with natural enrichment, historic mining, and ore processing is a contaminant of concern in watersheds of the western USA. In this region, water is a highly managed resource and wetlands, known to be important sites of methyl mercury production, are often an integral component of watersheds. This study applied controlled manipulations of four replicated experimental wetland designs with different water and soil mercury concentrations to determine the potential impacts on methyl mercury export. Wetlands were manipulated by drying and wetting, changing hydraulic retention time, and adding sulfate and nitrate to influent waters. In a summer drying and wetting manipulation, an immediate increase in total methyl mercury release was observed with rewetting, however, concentrations decreased quickly. Drying all wetlands over the winter and rewetting in the spring resulted in high net methyl mercury output relative to that observed before drying. Net methyl mercury output was not influenced by changes in hydraulic retention time from 4 to 8 h or to 30 min, or by increasing the nitrate concentration from 0.1 to 10 mg L(-1). The addition of sulfate to the inlet waters of two mesocosms to increase concentrations from approximately 100 to 250 mg L(-1) did not result in a clear effect on methyl mercury output, most likely due to sulfate concentrations being higher than optimal for methyl mercury production. Despite the lack of response to sulfate amendments, the change in sulfate concentration between the inlet and outlet of the mesocosms and temperature were the parameters best correlated with methyl mercury outputs.     

Channel change,sediment transport,and fish habitat in a coastal stream: Effects of an extreme event

A study on sediment transport and channel change was conducted on Zayante Creek and the lower San Lorenzo River in Santa Cruz County, California. A rainstorm with a recurrence interval locally in excess of 150 years occurred during the study year, 1982 WY. Stream surveys indicated that significant aggradation occurred during and after the peak flood. Upper study reaches were substantially recovered after high flows of early April, but the lower study reaches still had significant filling of pools and burial of riffles by sand. Increases in width-depth ratio were minor and localized in upper reaches, but were significant in lower reaches. Large inputs of sand, primarily from landsliding, altered the sediment transport regime. A higher proportion of the bedload is now transported by lower flows than before the January event. Roads and sand quarries contributed significantly to sediment input to the stream. A proposed dam may alter the sediment transport regime of Zayante Creek. Mitigating the effects of this dam on downstream fish habitat may require occasional bankfull discharges.     

Azadirachta indica leaf powder as an effective biosorbent for dyes: a case study with aqueous Congo Red solutions

In the present work, the leaves of Azadirachta indica (locally known as the Neem tree) in the form of a powder were investigated as a biosorbent of dyes taking aqueous Congo Red solution as a model system. The sorbent was made from mature Neem leaves and was investigated in a batch reactor under variable system parameters such as concentration of the aqueous dye solution, agitation time, adsorbent amount, pH, and temperature. An amount of 0.6 g of the Neem leaf powder (NLP) per litre could remove 52.0-99.0% of the dye from an aqueous solution of concentration 2.87 x 10(-2) mmol l(-1) with the agitation time increasing from 60 to 300 min. The interactions were tested with respect to both pseudo first-order and second-order reaction kinetics; the latter was found to be more suitable. Considerable intra-particle diffusion was found to occur simultaneously. The sorption process was in conformity with Langmuir and Freundlich isotherms yielding values of the adsorption coefficients in the following ranges: Freundlich n: 0.12-0.19, Kf: 0.1039-0.2648 L g(-1); Langmuir qm: 41.24-128.26 g kg(-1), b: 443.3-1898.0 l mmol(-1), which supported favourable adsorption. The Langmuir monolayer capacity (qm) was high and the values of the coefficient b indicated the equilibrium, dye + NLP = dye...NLP being shifted overwhelmingly towards adsorption. Thermodynamically, the sorption process was exothermic with an average heat of adsorption of -12.75 kJ mol(-1). The spontaneity of the sorption process was also confirmed by the favourable values of Gibbs energy (mean values: -1.09 to -1.81 kJ mol(-1)) and entropy of adsorption (range: -18.97 to -56.32 J mol(-1)K(-1)). The results point to the effectiveness of the Neem leaf powder as a biosorbent for removing dyes like Congo Red from water.     

“My garden is an expression of me”: Exploring householders' relationships with their gardens

Domestic gardens offer immense potential as sites for native biodiversity conservation. In urban areas they often comprise the largest land use, thus presenting an accessible and immediate way for urban dwellers to connect with nature and to support and enhance native biodiversity. This paper presents findings from a study of 55 domestic gardens undertaken in Dunedin, New Zealand, which explores householders' relationships with their gardens. The study data was derived from two interviews with householders, two photo exercises (approximately a year apart), together with a number of biological studies of the gardens. Gardens proved to be very important for our householders; for physical and mental health, as an expression of ownership and identity, as sites for social relationships, for connecting with nature and as site of domestic produce production. Householders' connections with nature were idiosyncratic, multifaceted and exhibited in ways that are more complex and varied than those usually considered by those working in the natural sciences and indeed biophilia supporters. We emphasize the importance of the people side of nature in seeking to build and support positive ecological change in the urban environment and the value of combining natural and social science approaches.     

Influence of organic loading on an anaerobic sequencing biofilm batch reactor (ASBBR) as a function of cycle period and wastewater concentration

The effect of organic loading on the performance of a mechanically stirred anaerobic sequencing biofilm batch reactor (ASBBR) has been investigated, by varying influent concentration and cycle period. For microbial immobilization 1-cm polyurethane foam cubes were used. An agitation rate of 500 rpm and temperature of 30+/-2 degrees C were employed. Organic loading rates (OLR) of 1.5-6.0gCODl(-1)d(-1) were applied to the 6.3-l reactor treating 2.0 l synthetic wastewater in 8 and 12-h batches and at concentrations of 500-2000mgCODl(-1), making it possible to analyze the effect of these two operation variables for the same organic loading range. Microbial immobilization on inert support maintained approximately 60 gTVS in the reactor. Filtered sample organic COD removal efficiencies ranged from 73 to 88% for organic loading up to 5.4gCODl(-1)d(-1). For higher organic loading (influent concentration of 2000mgCODl(-1) and 8-h cycle) the system presented total volatile acids accumulation, which reduced organics removal efficiency down to 55%. In this way, ASBBR with immobilized biomass was shown to be efficient for organic removal at organic loading rates of up to 5.4gCODl(-1)d(-1) and to be more stable to organic loading variations for 12-h cycles. This reactor might be an alternative to intermittent systems as it possesses greater operational flexibility. It might also be an alternative to batch systems suspended with microorganisms since it eliminates both the uncertainties regarding granulation and the time necessary for biomass sedimentation, hence reducing the total cycle period.