FLOOD PROTECTION BENEFITS AS REFLECTED IN PROPERTY VALUE CHANGES1

ABSTRACT: Measuring flood control benefits from estimated property damage in prior floods omits losses in the form of depressed values of land put to less valuable uses because of annual flooding. Covariance analysis of real property values in three urban areas differently situated around Lake Cumberland, Kentucky shows a much larger rate of increase, over a 15-year period, for the area receiving flood protection. This suggests that the economic benefits from a flood protection facility include these additional property value increases as well as the prevented property damage.     

Stream macroinvertebrate baseline surveys: A comparative analysis from the oil-shale regions of Colorado,USA

General surveys of the benthic macroinvertebrates from Piceance Creek and the White River were conducted for nearly a decade prior to oil-shale exploitation in north central Colorado, USA. Comparison of the taxa collected in four studies on Piceance Creek and five studies on the White River shows little similarity among most studies. Studies were generally consistent in methods, site selection, and time of year for collection. Lack of agreement among the studies on what constitutes a baseline of common taxa is probably a result of taxonomic difficulties and differences in technique. More emphasis should be placed on testing possible impacts than on repeated, expensive, and inconclusive baseline inventories.     

How honeybees perceive communication dances,studied by means of a mechanical model

Summary A mechanical model of a dancing honeybee was used to investigate the role of various components of the wagging dance in the transfer of information to follower bees. The model simulates the dance, carries a scent, and has an acoustic near-field similar to that of live dancers. The movements of the model are controlled by a computer, and selected components of the dance can be manipulated independently of others. The number of bees approaching scented baits at various distances and directions from the hive was observed, both during simulated normal dances and dances in which different components provided potentially conflicting information about the location of the food. The results indicate that the wagging run is the master component of the dance. The figure-of-eight dance path does not seem to convey information. Both sound and wagging must be present in the dance, but no specific roles were found for these components. Both sound and wagging convey information about distance and direction, and they appear to be largely redundant. Offprint requests to: A. Michelsen     

Modeling Contaminant Transport at the Pore-Micropore Interface

Understanding and ultimately simulating the contaminant transport processes occurring in, or around, micropore zones is a topic that will help further the advancement of efficient design and implementation of future remediation techniques. This paper proposes a method to forecast effects of micropores on contaminant transport using a new conceptual method that is based on a model that comprises three zones, namely mobile, immobile, and micropore zones and has two different porosity zones. The model is successfully tested against other established methods (van Genuchten and Wierenga, 1976) and experimental data (Brusseau, 1993).     

Effects of discharge fluctuation and the addition of fine sediment on stream fish and macroinvertebrates below a water-filtration facility

A small, coastal stream in the San Francisco Bay area of California, USA, received the discharges from a drinking-water filtration plant. Two types of discharges were present. Discharges from filter backwashing were 3–4 times base stream flow, occurred 10–60 times per day, contained fine sediments, and each lasted about 10 min. The other discharge was a large, steady flow of relatively sediment-free water from occasional overflow of the delivery aqueduct which generally lasted several hours a day.Samples of invertebrates from natural substrates had significantly fewer taxa and lower density at the two stations below the backwash than at the two above. However, when stable artificial substrates were used, there were no significant differences among all four stations. The aqueduct apparently had no effect because the. invertebrate community at the station upstream of the backwash but downstream of the aqueduct was statistically similar to the station above the aqueduct. To test for acute toxicity, we exposed additional artificial substrates to short-term simulated backwash conditions. These exposures had no effect on invertebrate density or drift. Three-spine stickleback (Gasterosteus aculeatus) populations were also significantly reduced at the two downstream stations and were made up mostly of larger, adult fish. Prickly sculpins (Cottus asper), restricted to the most downstream station, were emaciated and had poor growth, probably as a result of scarce benthic food organisms. Artificial redds with eggs of rainbow trout (Salmo gairdneri) had significantly lower survival at two stations below the plant backwash (30.7% and 41.8%) than at the one above it (61.4%). Hatchery rainbow trout held in cages below the treatment plant from 7 to 37 days survived and continued to feed.Thus, the major effect of the water treatment plant on fish and invertebrates probably was not from acute toxicity in the discharges or the occasionally large discharge of clean water from the aqueduct, but was from the fluctuating backwash flows containing fine sediment that displaced small fish downstream and created unstable benthic substrates for invertebrates.The filter plant that we studied is a direct-feed type (that is, no sedimentation before filtration). These generally require greater frequencies of backwashing than do conventional plants and may therefore have greater biological impacts. Direct-feed plants are becoming increasingly popular throughout the world, for the most part because they are cheaper to build and operate. But if the associated biological problems are mitigated, then the cost savings of direct-feed compared to conventional plants may be lost.     

AN INTEGRATIVE APPROACH TOWARDS UNDERSTANDING ECOLOGICAL RESPONSES TO DAM REMOVAL: THE MANATAWNY CREEK STUDY1

ABSTRACT: Dam removal has been proposed as an effective method of river restoration, but few integrative studies have examined ecological responses to the removal of dams. In 1999, we initiated an interdisciplinary study to determine ecological responses to the removal of a 2 m high dam on lower Manatawny Creek in southeastern Pennsylvania. We used an integrative monitoring program to assess the physical, chemical, and biological responses to dam removal. Following removal in 2000, increased sediment transport has led to major changes in channel form in the former impoundment and downstream reaches. Water quality did not change markedly following removal, probably because of the impoundment's short hydraulic residence time (less than two hours at base flow) and infrequent temperature stratification. When the impoundment was converted to a free flowing reach, the composition of the benthic macroinvertebrate and fish assemblages in this portion of Manatawny Creek shifted dramatically from lentic to lotic taxa. Some fish species inhabiting the free flowing reach downstream from the dam were negatively affected by large scale sediment transport and habitat alteration following dam removal, but this appears to be a short term response. Based on our observations and experiences in this study, we provide a list of issues to evaluate when considering future dam removals.     

CDM host country institution building

Contrary to earlier forecasts, the global greenhouse gas market will initially be characterised by low prices and a strong competition between the different Kyoto Mechanisms. The CDM involves higher transaction costs than the other mechanisms and has lost a considerable share of its ‘early start’ advantage due to the continuous delays in defining the CDM rules on the international level. Host countries will have to compete intensively for CDM investments. Thus the development of effective institutions is crucial to reap benefits from this market, especially if a unilateral strategy is chosen. Countries should develop approval criteria and sectoral priorities in a broad stakeholder consultation. Moreover, capacity building of local actors, information exchange as well as marketing has to be organised. Experience from several countries shows that clear competencies are crucial to get investor confidence. Long-term professional staff is also an important asset. Fights between ministries will scare off investors. The optimum institution will be a CDM Office that is independent but has full approval powers. A second-best solution is a two-tiered system. A CDM Board with representatives of ministries would define criteria and priorities whereas a CDM Secretariat would evaluate (and possibly approve) project proposals and do outreach and marketing. Small countries would preferably use the existing focal point of the UNFCCC and flexibly involve consultants if project proposalscome in. Even under an optimal institutional structure, CDM projects will only be implemented if financing and contractual issues can be resolved. This revised version was published online in August 2006 with corrections to the Cover Date.     

The impact of storm Xynthia in 2010 on coastal flood prevention policy in France

Storm Xynthia occurred on 28 February 2010. It was one of the most destructive climatic events to hit metropolitan France for several decades, causing 47 victims in France, among whom more than half died in the department of Vendée. The occurence of various natural phenomena (atmospheric pressure, strength and orientation of the wind, tidal range) at the same time caused a major coastal flood in several urban areas from Vendée and Charente-Maritime (central Atlantic region of France). The evaluation of the disaster highlighted a number of problems, especially delays in approving the PPR-L (Plan de Prévention des Risques Littoraux) that allowed urbanization in the coastal flood plain that exposed population to major natural risks, such as sea level rise and floods. Since 28th February, 2010, the French government has focused on these issues and tried to define in a more accurate way the criteria used for the flood zonings of the PPR-L. A number of circulars and recommendations have been produced and they all specified rules of protection for properties against the risk of flood and the necessary measures for adapting or building current or future houses (e.g. height of the upper floor, presence of an upper floor refuge) in accordance with the level of risk. The objective of this paper is twofold: we wish to highlight the impact of the disaster Xynthia on the production of PPR-L in the short and medium terms while focusing on the example of the town of La-Faute-sur-Mer. We will also analyze the evolution of the regulations since 28 February 2010, with special attention paid to the proposed criteria to define the hazard.     

Setbacks to shoot growth are common in woody plants, so how are shoots of some species safer than others?

Tissue turnover is a critical facet of plant life history variation. This study quantifies losses from setbacks to growth of terminal woody shoots 1.2m long, across 83 species and seven sites in eastern Australia. Setbacks, where the leading meristem had been removed or died and a new leader had emerged, were common (median three per shoot). Shoots had lost an average of 0.25 m of lead-stem length for 1.2 m net shoot-length gain. Insects like girdlers and borers were prominent causes of large setbacks. The sites spanned tropical to temperate and humid to semiarid climates, but variation in stem loss was much greater across species than across sites. We measured 17 plant functional traits related to growth form, mechanics, hydraulics, and economics. Only four traits were correlated with variation across species in stem losses: stem diameter, stem nitrogen content, bark thickness, and maximum photosynthetic rate. The correlations were weak. Stem specific gravity (wood density) showed no correlation with risk. Our results suggest a pattern similar to the growth risk trade-off known for herbaceous plants, where traits associated with fast growth increase tissue turnover and herbivory, but the weak correlations leave ample scope for other influences that remain to be identified.     

Performance evaluation of an anaerobic/aerobic landfill-based digester using yard waste for energy and compost production

The objective of this study was to evaluate a new alternative for yard waste management by constructing, operating and monitoring a landfill-based two-stage batch digester (anaerobic/aerobic) with the recovery of energy and compost. The system was initially operated under anaerobic conditions for 366 days, after which the yard waste was aerated for an additional 191 days. Off gas generated from the aerobic stage was treated by biofilters. Net energy recovery was 84.3MWh, or 46kWh per million metric tons of wet waste (as received), and the biochemical methane potential of the treated waste decreased by 83% during the two-stage operation. The average removal efficiencies of volatile organic compounds and non-methane organic compounds in the biofilters were 96-99% and 68-99%, respectively.