Rehabilitation and Flood Management Planning in a Steep,Boulder-Bedded Stream

This study demonstrates the integration of rehabilitation and flood management planning in a steep, boulder-bedded stream in a coastal urban catchment on the South Island of New Zealand. The Water of Leith, the primary stream flowing through the city of Dunedin, is used as a case study. The catchment is steep, with a short time of concentration and rapid hydrologic response, and the lower stream reaches are highly channelized with floodplain encroachment, a high potential for debris flows, significant flood risks, and severely degraded aquatic habitat. Because the objectives for rehabilitation and flood management in urban catchments are often conflicting, a number of types of analyses at both the catchment and the reach scales and careful planning with stakeholder consultation were needed for successful rehabilitation efforts. This included modeling and analysis of catchment hydrology, fluvial geomorphologic assessment, analysis of water quality and aquatic ecology, hydraulic modeling and flood risk evaluation, detailed feasibility studies, and preliminary design to optimize multiple rehabilitation and flood management objectives. The study showed that all of these analyses were needed for integrated rehabilitation and flood management and that some incremental improvements in stream ecological health, aesthetics, and public recreational opportunities could be achieved in this challenging environment. These methods should be considered in a range of types of stream rehabilitation projects.     

How integrated is river basin management?

Land and water management is increasingly focused upon the drainage basin. Thirty-six terms recently used for schemes of “integrated basin management” include reference to the subject or area and to the aims of integrated river basin management, often without allusion to the multiobjective nature. Diversity in usage of terms has occurred because of the involvement of different disciplines, of the increasing coherence of the drainage basin approach, and the problems posed in particular parts of the world. The components included in 21 different approaches are analyzed, and, in addition to showing that components related broadly to water supply, river channel, land, and leisure aspects, it is concluded that there are essentially five interrelated facets of integrated basin management that involved water, channel, land, ecology, and human activity. Two aspects not fully included in many previous schemes concern river channel changes and the dynamic integrity of the fluvial system. To clarify the terminology used, it is suggested that the termcomprehensive river basin management should be used where a wide range of components is involved, whereasintegrated basin management can signify the interactions of components and the dominance of certain components in the particular area.Holistic river basin management is advocated as a term representing an approach that is both fully comprehensive and integrated but also embraces the energetics of the river system and consideration of changes of river channels and of human impacts throughout the river system. The paradigm of working with the river can be extended to one of working with the river in the holistic basin context.     

Climatic, socio-economic, and health factors affecting human vulnerability to cholera in the Lake Victoria basin, East Africa

Cholera epidemics have a recorded history in the eastern Africa region dating to 1836. Cholera is now endemic in the Lake Victoria basin, a region with one of the poorest and fastest growing populations in the world. Analyses of precipitation, temperatures, and hydrological characteristics of selected stations in the Lake Victoria basin show that cholera epidemics are closely associated with El Ni?o years. Similarly, sustained temperatures high above normal (T(max)) in two consecutive seasons, followed by a slight cooling in the second season, trigger an outbreak of a cholera epidemic. The health and socioeconomic systems that the lake basin communities rely upon are not robust enough to cope with cholera outbreaks, thus rendering them vulnerable to the impact of climate variability and change. Collectively, this report argues that communities living around the Lake Victoria basin are vulnerable to climate-induced cholera that is aggravated by the low socioeconomic status and lack of an adequate health care system. In assessing the communities' adaptive capacity, the report concludes that persistent levels of poverty have made these communities vulnerable to cholera epidemics.     

Biochar-clay,biochar-microorganism and biochar-enzyme composites for environmental remediation: a review

Environmental Chemistry Letters - Worldwide pollution of waters and soils is a rising health issue calling for advanced decontamination methods such as adsorption of contaminants on biochar because...     

AMMONIA IN TEXAS STREAMS DURING LOW FLOW FROM MUNICIPAL WASTEWATER1

ABSTRACT: An investigation of treated municipal wastewaters discharged into Texas streams was conducted to determine the probable effect of concentrations of ammonia in receiving waters, based on existing data on ammonia levels which are lethal to various species of fish. Recorded data for most Texas cities were analyzed. Based on existing toxicity criteria for ammonia of 1/10 TL_m= 0.31 mg/1 NH₃-N, employing known discharge flow rates, and 7-day, 5-year or 7-day, 10-year low flows in Texas streams, appreciable numbers of sites were found to pose a threat to various species of fish. Using the bluegill (Lepomis macrochirus) as a median tolerance limit species, data from 65 cities which met the aforecited requirements, were analyzed. Those included a total of 92 wastewater effluents. Sixty-nine percent of those cities and 70% of their effluents exceeded the 0.31 mg/1 NH₃-N limit in the stream below the discharge point. Thirty-seven percent of the cities equaled or exceeded the 96-hour TL_m concentration limit of 3.1 mg/1 ammonia. Based on the 10 mg/1 NO₃-N standard for intake water for potable supplies, 32% of the effluents resulted in a stream concentration which exceeded 10 mg/1, assuming a straight conversion of NH₃-N to NO₃-N.     

Direct analysis of polycyclic aromatic hydrocarbons in cloud-water aerosol filtrates using laser desorption mass spectrometry

A novel technique for the rapid screening of polyaromatic hydrocarbons (PAHs) in atmospheric particulates is presented. Two-step laser desorption laser photoionisation time-of-flight mass spectrometry was used to assay for PAHs in cloud-water particulates collected near Peebles in southern Scotland. The particulates were examined in situ on their host filters removing the requirement for time-consuming sample extraction and separation. The mass spectra obtained from a single filter are shown. The principal components of these are assigned to PAH contaminants and phthalate contaminants. A distribution of PAHs was observed using 193 nm laser photoionisation. The mass spectrum obtained on using 248 nm laser photoionisation exhibits a different intensity distribution demonstrating an ionisation wavelength dependence. The utility of the technique for rapid screening of PAHs and other polyaromatic species is discussed.     

Controls on N Retention and Exports in a Forested Watershed

We conducted a 15N-tracer study in a fertilized, forested catchment at the Bear Brook Watersheds in Maine (BBWM), USA, in order to characterize N cycling processes, identify sinks for ammonium-N additions, and determine the contribution of the experimental ammonium additions to nitrate exports from the treated catchment. Distributions of 15N in plant tissues, soils, precipitation and streamwater collected before adding tracers showed that nitrate-N (the dominant form of inorganic N deposition at the site) inputs under ambient conditions were depleted in 15N relative to plants and that soil was enriched in 15N relative to plants. The 15N content of streamwater nitrate was within the range of 15N contents in natural plant tissues, suggesting that nitrate deposited from the atmosphere is reduced and assimilated into soil and plant N pools before being leached as nitrate from the catchment. Variations in 15N natural abundances also suggested that most N uptake by trees is from the forest floor and that nitrification occurs in soils at this catchment under ambient conditions. Changes in 15N contents of plant tissues, soils and streamwater after adding a 15N tracer to the ammonium sulfate fertilizer applied to the treated catchment showed that soils were the dominant sink for the labeled ammonium. Surface soils (Oca horizon plus any underlying mineral soil to 5cm depth) assimilated 19 to 31 percent of the 42 kg ha-1 of 15N-labelled ammonium-N during the tracer study. Aboveground biomass assimilated 8 to 17 percent of the labeled ammonium-N additions. Of the three forest types on the catchment, the soil:biomass assimilation ratio of labeled-N was highest in the spruce forest, intermediate in the beech-dominated hardwood forest and lowest in the mixed hardwood-spruce forest. Although ammonium sulfate additions led to increases in streamwater nitrate, only 2 of the 13 kg ha-1 of nitrate-N exported from the catchment during the 2 years of tracer additions was derived from the 42 kg ha-1 of labeled ammonium-N additions.     

Optimizing hurricane disaster relief goods distribution: model development and application with respect to planning strategies

Over the last few years, hurricane emergencies have been among the most pervasive major disruptions in the United States, particularly in the south‐east region of the country. A key aspect of managing hurricane disasters involves logistical planning to facilitate the distribution and transportation of relief goods to populations in need. This study shows how a variant of the capacitated warehouse location model can be used to manage the flow of goods shipments to people in need. In this application, the model is used with protocols set forth in Florida's Comprehensive Emergency Plan and tested in a smaller city in north Florida. Scenarios explore the effects of alternate goods distribution strategies on the provision of disaster relief. Results show that measures describing people's accessibility to relief goods are affected by the distribution infrastructure used to provide relief, as well as assumptions made regarding the population(s) assumed to be in need of aid.