Scenario‐Based and Scenario‐Neutral Assessment of Climate Change Impacts on Operational Performance of a Multipurpose Reservoir

Scenario‐based and scenario‐neutral impacts assessment approaches provide complementary information about how climate change‐driven effects on streamflow may change the operational performance of multipurpose dams. Examining a case study of Cougar Dam in Oregon, United States, we simulated current reservoir operations under scenarios of plausible future hydrology. Streamflow projections from the CGCM3.1 general circulation model for the A1B emission scenario were used to generate stochastic reservoir inflows that were then further perturbed to simulate a potentially drier future. These were then used to drive a simple reservoir model. In the scenario‐based analysis, we found reservoir operations are vulnerable to climate change. Increases in fall and winter inflow could lead to more frequent flood storage, reducing flexibility to store incoming flood flows. Uncertainty in spring inflow volume complicates projection of future filling performance. The reservoir may fill more or less often, depending on whether springs are wetter or drier. In the summer, drawdown may occur earlier to meet conservation objectives. From the scenario‐neutral analysis, we identified thresholds of streamflow magnitude that can predict climate change impacts for a wide range of scenarios. Our results highlight projected operational challenges for Cougar Dam and provide an example of how scenario‐based and scenario‐neutral approaches may be applied concurrently to assess climate change impacts.     

Role of non-timber forest products in sustaining forest-based livelihoods and rural households' resilience capacity in and around protected area: a Bangladesh study†

People in the developing world derive a significant part of their livelihoods from various forest products, particularly non-timber forest products (NTFPs). This article attempts to explore the contribution of NTFPs in sustaining forest-based rural livelihood in and around a protected area (PA) of Bangladesh, and their potential role in enhancing households' resilience capacity. Based on empirical investigation, our study revealed that local communities gather a substantial amount of NTFPs from national park despite the official restrictions. Twenty seven percent households (HHs) of the area received at least some cash benefit from the collection, processing and selling of NTFPs, and NTFPs contribute to HHs' primary, supplementary and emergency sources of income. NTFPs also constituted an estimated 19% of HHs' net annual income, and were the primary occupation for about 18% of the HHs. HHs' dependency on nearby forests for various NTFPs varied vis-à-vis their socio-economic condition, as well as with their location from the park. Based on our case study, the article also offers some clues for improving the situation in PA.     

Characterizing Runoff and Water Yield for Headwater Catchments in the Southern Sierra Nevada

In a Mediterranean climate where much of the precipitation falls during winter, snowpacks serve as the primary source of dry season runoff. Increased warming has led to significant changes in hydrology of the western United States. An important question in this context is how to best manage forested catchments for water and other ecosystem services? Answering this basic question requires detailed understanding of hydrologic functioning of these catchments. Here, we depict the differences in hydrologic response of 10 catchments. Size of the study catchments ranges from 50 to 475 ha, and they span between 1,782 and 2,373 m elevation in the rain‐snow transitional zone. Mean annual streamflow ranged from 281 to 408 mm in the low elevation Providence and 436 to 656 mm in the high elevation Bull catchments, resulting in a 49 mm streamflow increase per 100 m (R² = 0.79) elevation gain, despite similar precipitation across the 10 catchments. Although high elevation Bull catchments received significantly more precipitation as snow and thus experienced a delayed melt, this increase in streamflow with elevation was mainly due to a reduction in evapotranspiration (ET) with elevation (45 mm/100 m, R² = 0.65). The reduction in ET was attributed to decline in vegetation density, growing season, and atmospheric demand with increasing elevation. These findings suggest changes in streamflow in response to climate warming may likely depend on how vegetation responds to those changes in climate.     

Laboratory study on solidification/stabilization of unwanted medications using asphalt as a binder

The rise in discarded or unwanted medications (UMs) is becoming an issue of great concern, as it has the potential to harm the components of the environment where it is discarded: particularly air, water and soil. To combat this problem, many researchers have investigated the best approach for the collection and proper disposal of UMs. This paper intends to elaborate upon a safe solution for treating this waste, specifically through a process of solidification/stabilization (S/S) that involves mixing UMs with asphalt cement and asphalt concrete mixtures. Volumes of 5, 10, 15 and 20 % of a mixture of UMs were mixed with asphalt cement and the analyzed properties of the mixture of UMs–asphalt included: softening point, ductility, penetration, flash and fire points, specific gravity and rotational viscosity. Marshal stability, flow, air voids, unit weight, voids in mineral aggregate (VMA) and voids filled with binder (VFB) of asphalt concrete mixture were also investigated. Results showed that this approach of S/S is a promising method for dual achievements to solve an environmental problem and to use the waste for road construction.     

Optimal production scale of open pit mining operations with uncertain metal supply and long-term stockpiles

An open pit mining operation consists of various stages, and the calculation of the production capacities of these stages depends upon the available supply of ore (mineralized material of economic value) and waste material. Cutoff grade is the criterion that specifies the amount of ore and waste. The material with grade equal to or higher than the cutoff grade is classified as ore. The material with grade less than the cutoff grade is considered waste. While this explains the link between cutoff grade theory and the calculation of production capacities, the majority of optimization models for finding production capacities not only disregards this relationship but also ignores expected variations and uncertainty in metal content or the available supply of ore and waste material.     

Hospital site selection using fuzzy AHP and its derivatives

Environmental managers are commonly faced with sophisticated decisions, such as choosing the location of a new facility subject to multiple conflicting criteria. This paper considers the specific problem of creating a well-distributed network of hospitals that delivers its services to the target population with minimal time, pollution and cost. We develop a Multi-Criteria Decision Analysis process that combines Geographical Information System (GIS) analysis with the Fuzzy Analytical Hierarchy Process (FAHP), and use this process to determine the optimum site for a new hospital in the Tehran urban area. The GIS was used to calculate and classify governing criteria, while FAHP was used to evaluate the decision factors and their impacts on alternative sites. Three methods were used to estimate the total weights and priorities of the candidate sites: fuzzy extent analysis, center-of-area defuzzification, and the α-cut method. The three methods yield identical priorities for the five alternatives considered. Fuzzy extent analysis provides less discriminating power, but is simpler to implement and compute than the other two methods. The α-cut method is more complicated, but integrates the uncertainty and overall attitude of the decision-maker. The usefulness of the new hospital site is evaluated by computing an accessibility index for each pixel in the GIS, defined as the ratio of population density to travel time. With the addition of a new hospital at the optimum site, this index improved over about 6.5 percent of the geographical area.     

Separation and determination of trace levels of aromatic amines by HPLC

Aromatic amines were analysed by normal phase and reverse phase high performance liquid chromatography employing silica gel and octadecyl silane (ODS) columns, respectively. A number of mobile phases were used. The results obtained on silica gel column were compared with those achieved on reverse phase column. Excellent results were obtained on ODS and shoulder peaks were eliminated when a mixture of methyl alcohol and sodium perchlorate was used as mobile phase.     

Evaluation of the in-situ aerobic cometabolism of chlorinated ethenes by toluene-utilizing microorganisms using push-pull tests

A series of transport, biostimulation, and activity push-pull tests were performed under induced and natural gradient conditions in a trichloroethene (TCE) and cis-dichloroethene (c-DCE) contaminated aquifer. Transport tests demonstrated the feasibility of injecting and recovering complex solute mixtures from the aquifer. During the biostimulation tests, decreases in toluene concentration and the production of o-cresol as an intermediate oxidation product indicated the presence of toluene-utilizing microorganisms. Activity tests demonstrated that the stimulated microbial community had the ability to transform injected c-DCE and trans-dichloroethene (t-DCE) at similar zero-order rates. Injected isobutene was oxidized to isobutene oxide, which indicated that a toluene ortho-monooxygenase enzyme system was likely responsible for the observed c-DCE and t-DCE transformations. c-DCE zero-order transformation rates in drift push-pull tests were similar to those obtained from traditional push-pull tests (about 0.1 microM/h). Analysis of drift test data using first-order kinetic analysis resulted in similar conclusions as those obtained using zero-order kinetic analyses. When 1-butyne, an inhibitor of toluene ortho-monooxygenase, was added to injected test solutions, the oxidation of toluene, and the transformation of isobutene, c-DCE, and t-DCE were inhibited. The results illustrate how a series of push-pull tests can be used in combination to detect, quantify and confirm in-situ cometabolic microbial transformations.